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https://issues.apache.org/jira/browse/EXTCDI-316?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14138666#comment-14138666
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Gerhard Petracek commented on EXTCDI-316:
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no - that's the reason i didn't mention it (mojarra vs. myfaces-core).
codi is compatible with both and we know users with huge codi/jsf (with
mojarra) based projects.
leo just mentioned that myfaces-core is smarter when it comes to state-saving
and the chance is higher that you won't see (some of) the issues you saw with
mojarra caused by the usage of iframes.
e.g. once the fallback to WindowContextIdHolderComponent is used to resolve the
window-id, the proper handling depends on the quality of the state-saving
algorithm (provided by the jsf implementation).
once you call #close for the correct window manually, you don't see a leak >in
codi<.
however, since there is no jsf-api for it, codi can't trigger a cleanup of the
view-state.
jsf 2.2 introduced the window-concept (based on apis introduced by codi and
similar frameworks).
however, even with jsf 2.2, the jsf implementation is responsible for doing a
cleanup of the state internally (there is no explicit api for it).
the benefit for users is that the jsf implementation is aware of windows (as a
concept) and >can< do improvements (more easily) for handling the state in a
better way (but there is no specified rule for it).
@iframes:
it >sounds< like the major issue in your case is that you replace the content
of the iframe on the client-side.
a lot really depends on details of your implementation and maybe even on other
details like the used browser (you wouldn't belief how hard it is to support
something simple like the proper handling after "open in new tab" across the
major browsers).
> 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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