Handle ViewExireException/ajax and display a Primefaces dialog - jsf-2

Question

I don't redirect or forward my user to another page. So when the my SessionExpiredExceptionHandler (extends ExceptionHandlerWrapper) handles the ViewExireException. I want the user to stay on the same page and display a PrimeFaces Dialog. For notifying that the session has expired and that the user needs to login again (dialog based). I am use Servlet 3.1 functions to login/logout user and Basic/file for auth-method to map the users to different system roles.
What is happening now is that the View/page get refreshed after 2 min, but the session doesn't get invalidated. That only happens the second time when the page refreshes, after 4 min.
<session-config>
<session-timeout>2</session-timeout>
</session-config>
Edit:
Which is refreshed by the meta tag:
<meta http-equiv="refresh" content="#{session.maxInactiveInterval}" />
How can I make SessionExpiredExceptionHandlerinvalidate the session object (Servlet logout) when the Exceptions occur the first time, and how can I invoke a JavaScript (expireDlg.show()) on the client to display a PrimeFaces dialog ?
I have looked at some other threads but not found a viable solution.
Session time-out
SessionExpiredExceptionHandler
#Override
public void handle() throws FacesException {
for (Iterator<ExceptionQueuedEvent> i = getUnhandledExceptionQueuedEvents().iterator(); i.hasNext();) {
ExceptionQueuedEvent event = i.next();
ExceptionQueuedEventContext context = (ExceptionQueuedEventContext) event.getSource();
Throwable t = context.getException();
if (t instanceof ViewExpiredException) {
ViewExpiredException vee = (ViewExpiredException) t;
FacesContext fc = FacesContext.getCurrentInstance();
Map<String, Object> requestMap = fc.getExternalContext().getRequestMap();
NavigationHandler nav = fc.getApplication().getNavigationHandler();
try {
requestMap.put("currentViewId", vee.getViewId());
nav.handleNavigation(fc, null, "Home");
fc.renderResponse();
} finally {
i.remove();
}
}
}
// At this point, the queue will not contain any ViewExpiredEvents.
// Therefore, let the parent handle them.
getWrapped().handle();
}
web.xml
<exception-type>javax.faces.application.ViewExpiredException</exception-type>
<location>/home.xhtml</location>
</error-page>

Answer 1

How can I make SessionExpiredExceptionHandler invalidate the session object (Servlet logout) when the Exceptions occur the first time
The session is supposedly to be already invalidated/expired (otherwise a ViewExpiredException wouldn't be thrown at all), so I don't see how it's useful to manually invalidate/expire it yourself. But for the case that, you can invalidate it as follows:
externalContext.invalidateSession();
and how can I invoke a JavaScript (expireDlg.show()) on the client to display a PrimeFaces dialog ?
You can use the PrimeFaces RequestContext API to programmatically instruct PrimeFaces to execute some JS code on complete of ajax response.
RequestContext.getCurrentInstance().execute("expireDlg.show()");
Don't forget to remove the navigation handler block from the exception handler if you actually don't want to navigate.

Answer 2

This solution worked for my case. It seams that Primefaces (3.3) is swallowing the ExceptionQueuedEvent. There are no Exception to handle when my ViewExceptionHandler gets called. So instead I used the p:idleMonitor component with event listner. I also removed the meta refresh tag.
<p:idleMonitor timeout="#{(session.maxInactiveInterval-60)*1000}">
<p:ajax event="idle" process="#this" update="sessionMsg" listener="#{userController.userIdleSession()}" />
<p:ajax event="active" process="#this" update="sessionMsg" listener="#{userController.userActiveSession()}"/>
</p:idleMonitor>
One weird thing is if the timeoutis excatly the same as the web.xmlsession time-out parameter, the listener won't be invoked.
Bean functions
public void userIdleSession() {
if (!userIdleMsgVisable) {
userIdleMsgVisable = true;
JsfUtil.addWarningMessage(JsfUtil.getResourceMessage("session_expire_title"), JsfUtil.getResourceMessage("session_expire_content"));
}
}
public void userActiveSession() {
if (!userSessionDlgVisable) {
userSessionDlgVisable = true;
RequestContext.getCurrentInstance().execute("sessionExipreDlg.show()");
}
}
The dialog (sessionExipreDlg) called the redirect instead of using navigation handler to get new scope and refresh the page.
public void userInactiveRedirect() {
FacesContext fc = FacesContext.getCurrentInstance();
userIdleMsgVisable = false;
userSessionDlgVisable = false;
sessionUser = null;
HttpServletRequest request = (HttpServletRequest) fc.getExternalContext().getRequest();
JsfUtil.findBean("homeController", HomeController.class).clearCurrentValues();
try {
fc.getExternalContext().redirect(JsfUtil.getApplicationPath(request, false, null));
} catch (IOException ex) {
BeanUtil.severe(ex.getLocalizedMessage());
}
}