seam conversations - conceptual design issues
wschwendt Jul 4, 2007 8:25 PMHello,
(first of all excuse my bad English).
when a conversationId is restored from the PageContext (this happens when a Faces request is received), the validateLongRunningConversation property of org.jboss.seam.core.ConversationPropagation is set to page.isConversationLongRunning().
Consequently, in the case of a long-running conversation, org.jboss.seam.core.Manager.restoreConversation() returns true or false, depending on whether or not the conversation was successfully restored.
In contrast, when a non-faces request is received, the conversationId is retrieved from the request parameters and the validateLongRunningConversation of org.jboss.seam.core.ConversationPropagation remains false.
Consequently, in the case of a long-running conversation, org.jboss.seam.core.Manager.restoreConversation() always returns true, even when it was not possible anymore to restore the long-running conversation and a fresh temporary conversation was therefore created instead. (see the last line of org.jboss.seam.core.Manager.restoreConversation() ).
// last line of org.jboss.seam.core.Manager.restoreConversation() public boolean restoreConversation() { ConversationPropagation cp = ConversationPropagation.instance(); ... return restoreAndLockConversation(ce) || !cp.isValidateLongRunningConversation(); }
It follows that for non-faces requests we don't have a validation of long-running conversations.
class org.jboss.seam.jsf.SeamPhaseListener { ... /** * Restore the page and conversation contexts during a JSF request */ protected void afterRestoreView(FacesContext facesContext) { FacesLifecycle.resumePage(); Map parameters = facesContext.getExternalContext().getRequestParameterMap(); ConversationPropagation.instance().restoreConversationId(parameters); boolean conversationFound = Manager.instance().restoreConversation(); FacesLifecycle.resumeConversation( facesContext.getExternalContext() ); // see my notes above: For non-faces requests conversationFound is // always true, even if the conversation was actually not found and a // temporary conversation was created if (!conversationFound) { Pages.instance().redirectToNoConversationView(); }
I thought about what could be Gavin's intention that there is no validation of long-running conversations when a non-faces request is received.
Perhaps the reason is that URLs are bookmarkable and the user could bookmark a URL that contains a conversationID of a long-running conversation. If the user then makes a request with this bookmarked URL, he would not be able to access the corresponding page if the conversationID contained in the URL was validated.
But we pay a big price if we simply give up the validation of long-running conversations. I think it would be much better if the last line of
org.jboss.seam.core.Manager.restoreConversation() was simply as follows:
// last line of org.jboss.seam.core.Manager.restoreConversation() public boolean restoreConversation() { ConversationPropagation cp = ConversationPropagation.instance(); ... return restoreAndLockConversation(ce); }
In order to support bookmarkable URLs where a contained conversation ID should not be validated, we could simply add another request parameter to indicate that restoreConversation should return true even if the long-running conversation couldn't be successfully restored.
Please give us the same validation behavior for non-faces requests as we have for faces requests!