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https://issues.apache.org/jira/browse/EXTCDI-316?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14140797#comment-14140797
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Nuno G. de M edited comment on EXTCDI-316 at 9/19/14 4:25 PM:
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Hi Gerhard, thanks a lot for the feedback.
Concerning the viewScoped, I made a mistake, because I was thinking of the CODI
scope "@WindowScoped" instead.
@windoIdToToDrop
That is actually what we do, but it is more tricky than that actually.
Before switching the iframe from the client Side, we ajax the server telling it
to know about the windowId about to be swapped out.
Finally, only on the onloadEvent of the new iframe can you actually really kill
the "windowIdToDrop".
The reason for this is that while you are loading a new window onto this
iframe, if you use "comet-like" mechanism, the page can still be polling
iformation from the server - and were youto wipeout the state until the view is
replaced, you would a view expired exception.
Your feedback was very helpful, I think i know how to proceed to make the UI
more stable Thanks.
was (Author: ngdem):
Hi Gerhard, thanks a lot for the feedback.
Concerning the viewScoped, I made a mistake, because I was thinking of the CODI
scope "@WindowScoped" instead.
@windoIdToToDrop
That is actually what we do, but it is more tricky than that actually.
Before switching the iframe from the client Side, we ajax the server telling it
to know about the windowId about to be swapped out.
Finally, only on the onloadEvent of the new iframe can you actually really kill
the "windowIdToDrop".
The reason for this is that while you are loading a new window onto this
iframe, if you use "comet-like" mechanism, the page can still be polling
iformation from the server - and were youto wipeout the state until the view is
replaced, you would a view expired exception.
So far the safest approach, would be, if it were possible, to keep the
windowId/context of a given iframe constant throughout time as well as the
corresponding JSF server side state key.
That means using standard JSF navigation to swap the view of a given iframe.
But this also implies that in order to do this, all the beans created within
the scope of this windo iframe would have to be thrown away and replaced by the
new beans for the view.
This would be the ideal thing.
> Close window context view leakge - JSF 2.1 Multiple Iframes per page
> --------------------------------------------------------------------
>
> Key: EXTCDI-316
> URL: https://issues.apache.org/jira/browse/EXTCDI-316
> Project: MyFaces CODI
> Issue Type: Bug
> Components: Core
> Affects Versions: 1.0.3
> Environment: Oracle GlassFish Server 3.1.2.5 (build 2), jdk1.6.0_45
> Reporter: Nuno G. de M
> Original Estimate: 72h
> Remaining Estimate: 72h
>
> Hi, and thank you for your support.
> First, I would just like to stat that I am unsure if the "issue" detected in
> our application is a real issue within CODI, or if it is we that are misusing
> the framework. Therefore, I would be happy to get your input on the issue I
> am about to detail.
> ISSUE SUMMARY:
> - we have a ui architecture comprised by several Iframes within a main page,
> where each iframe has its own CODI window context. After several clicks
> replacing the content that of a targetIfram by new content, we were having
> CODI view context leakage as well as JSF view state leakage.
> ISSUE DETAILS:
> For historical as well performance reasons reasons, we have a UI that is
> composed into several IFrames within a parent portal iframe. This decomposing
> of the view into sub-views means the JSF context to serialize-deserialize per
> iframe/.xhtml present in the UI is smaller. As opposed to a single big-ui
> view state.
> An overview of the core iframes invovled would be:
> (1) window.top - Contains the Header and a left-side navigation menu
> (2) window.top.contentIfram - Iframe Contains your typical page conent
> (.xhtml)
> (3) window.top.footer - iframe containing a dynamic footer (its own .xhtml)
> (4) wintow.top.applet - Iframe that includes an applet
> (5) window.top.special - an auxiliary .xhtml that complements the applet data
> (6) window.top.clean - iframe that contains an .xhtml to do CODI window
> context and JSF sever state cleanup (created to deal with the issue being
> explained here)
> The BUG in view navigation is the following:
> Each time the user interacts with the UI, e.g by clicing on an menu command
> button, or on a applet view element, prompting for a new .xhtml view to be
> loaded and replace the old .xhtml loaded on a target iframe we leak both a
> JSF and CODI window context.
> Our steps are the following:
> (1) we change the src of the iframe to point to the new view to be loaded
> e.g iframe.src = 'urlTonewPageToBeLoaded.xhtml?requestViewParameters'
> In this request we do not inclode the old windowId of the iframe being
> replaced. Meaning codi will have to create a new view ID for this new page
> load.
> (2) We also trigger an ajax request to server to have the old codi window
> context being closed.
> Intially here did:
> (2.1)WindowContext wContext =
> windowContextManager.getWindowContext('windowIdToClose);
> wContext.close()
> It turns out that as we did these two steps we had two leakages.
> After about 64 clicks on the applet, if we interatcted with views that the
> applet had been loading we would have no issues. If we clicked on some of
> the older views that had been loaded after the login and not interacted with
> since then (e.g. the footer) we would have a view timeout exception.
> This happened because with each new iframe.src='newView', CODI was not
> cleaning up its window context map, namely the following line:
> this.windowContextMap.remove(editableWindowContext.getId());
> is not executed during a WindowContext.close().
> So despite our class to close the window context, the map would continue to
> hold the view just closed. After 64 clicks the view uffer of CODI would be
> totally populated, and each new click was destroying the one of the least
> recently used views. This could be the main menu, this could be the page
> content or this could be the footer.
> To address this issue, we had to start injecting the
> EditableWindowContextManager, and use its close API.
> So the procedure for closing a CODI window context avoiding CODI view leakge
> turned into a :
> Map<String, EditableWindowContext> existingContextIds =
> getExistingContextIds();
> windowContextManager.closeWindowContext(windowIdOfContextToClose);
> Finally, there was still one last view leakge to address.
> Even when we use the
> windowContextManager.closeWindowContext(windowIdOfContextToClose), the JSF
> view state associate to this view still exists in the JSF view map.
> JSF-core (e.g majorra) seems to have a limit of 15 views within this LRU
> logical map.
> So once we stopped leaking views in CODI, we still had to tackle the leakage
> in JSF. Meaning, when we close a CODI window context, we need to the
> javax.views.state string to access the JSF map of logical views and remove
> them.
> Object sessionObj = externalContext.getSession(false);
> synchronized (sessionObj) {
> Map logicalMap = (Map) externalContext.getSessionMap().get(LOGICAL_VIEW_MAP);
> Map actualMap = (Map) logicalMap.get(idInLogicalMap);
> actualMap.clear();
> // remove the leaked view from the LRU map of logical
> views
> logicalMap.remove(idInLogicalMap);
> }
> ------
> Naturally, an application should normally not have to dig deep into framework
> code. One of the two is for sure true:
> - either we are misusing CODI to manage our views
> - or CODI has an issue
> Thanks in advance for any input on this issue.
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