[richfaces-issues] [JBoss JIRA] (RF-13674) a4j:push broken on WebLogic 12c

[Val Blant (JIRA)]

     [ https://issues.jboss.org/browse/RF-13674?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Val Blant updated RF-13674:
---------------------------

    Attachment: atmosphere-weblogic12c-bug-0.8.4.war
                atmosphere-weblogic12c-bug-0.8.4-sources.jar


Attaching a demo app that clearly demonstrates the problem.

> a4j:push broken on WebLogic 12c
> -------------------------------
>
>                 Key: RF-13674
>                 URL: https://issues.jboss.org/browse/RF-13674
>             Project: RichFaces
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>          Components: component-push/poll
>    Affects Versions: 4.2.0.Final
>         Environment: WebLogic 12c
>            Reporter: Val Blant
>         Attachments: atmosphere-weblogic12c-bug-0.8.4-sources.jar, atmosphere-weblogic12c-bug-0.8.4.war
>
>
> <a4j:push />  works properly on Tomcat 7, but fails on WebLogic 12c. 
> {code:title=Page.xhtml|borderStyle=solid}
> <a4j:push address="systemLinks" >  
>   <a4j:ajax event="dataavailable" render="systemLinksPanel" />  
> </a4j:push>  
>   
> <a4j:outputPanel id="systemLinksPanel">  
>      stuff here  
> </a4j:outputPanel>  
> {code}
> {code:title=Java Code}
> TopicKey topicKey = new TopicKey("systemLinks");  
> TopicsContext topicsContext = TopicsContext.lookup();  
> topicsContext.publish(topicKey, "fly, you fools!");  
> {code}
> On Tomcat 7 this work perfectly, and always refreshes '_systemLinksPanel_' when data is published. 
> On Weblogic 12c the data is not flushed correctly. If you use Wireshark, you'd see the following response coming back from the server:
> {panel:title=Tomcat 7}
> 3b
> <"topic":"systemLinks","data":"fly, you fools!","number":0>
> 0
> {panel}
> {panel:title=Weblogic 12c}
> 003b
> <"topic":"systemLinks","data":"fly, you fools!","number":0>
> {panel}
> *Note the missing zero terminator line in the WebLogic response!*
> I narrowed down the problem to the following:
> {code:title=org.richfaces.application.push.impl.RequestImpl}
>     public synchronized void onBroadcast(AtmosphereResourceEvent<HttpServletRequest, HttpServletResponse> event) {
>         MessageDataScriptString serializedMessages = (MessageDataScriptString) event.getMessage();
>         getSession().clearBroadcastedMessages(serializedMessages.getLastSequenceNumber());
>         hasActiveBroadcaster = false;
>         if (isPolling()) {
>             event.getResource().resume(); // <= THIS LINE
>         } else {
>             postMessages();
>         }
>     }
> {code}
> There is nothing wrong with this in principle, but it does not work due to a bug in Atmosphere 0.8.4. Calling _AtmosphereResource.resume()_ at this point seems reasonable, since it is supposed to properly finish/commit the _HttpServletResponse_.  However, this does not work on WebLogic 12c and leads to incorrectly flushed data demonstrated above. 
> The underlying problem seems to be the fact that _AtmosphereResource.resume()_ method interrupts the thread which flushed the socket Writer before a call to _asyncContext.complete()_ is made:
> {code}
> public AtmosphereResource resume() {
> ....
>  if (!b.isDestroyed()) {
>      b.removeAtmosphereResource(event.getResource());
>  }
> ....
>  asyncSupport.action(this); // <= This is where asyncContext.complete() is called
> }
> {code}
> I have verified that calling _asyncContext.complete()_ before we clean up Atmosphere resources fixes the problem.
> Here's the fix, which needs to go into _RequestImpl.onBroadcast_:
> {code:title=org.richfaces.application.push.impl.RequestImpl}
>     public synchronized void onBroadcast(AtmosphereResourceEvent<HttpServletRequest, HttpServletResponse> event) {
>   ..............
>         if (isPolling()) {
> // This is the workaround. Completing AsyncContext before cleaning up Atmosphere resources
> // seems to make this work everywhere.
> //
> AsyncContext asyncContext = (AsyncContext) 
> 	event
> 		.getResource()
> 		.getRequest()
> 		.getAttribute("org.atmosphere.container.asyncContext");
>    if ( asyncContext != null ) {
> 	asyncContext.complete();
>    }
>             event.getResource().resume();
>         } else {
>             postMessages();
>         }
>     }
>   ..............
> {code}
> I am attaching a very simple WAR file that demonstrates the problem clearly. The demo app does not use Richfaces, b/c I wanted to remove all unnecessary complexity. Instead I created a couple of simple classes that mimic the behavior of _org.richfaces.webapp.PushHandlerFilter_ and _org.richfaces.application.push.impl.RequestImpl_. In the demo app, _MeteorRequest = RequestImpl_, which is where the fix needs to go.



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