Automatically perform action in client side when the session expires

Question

I want to display in a that the session has expired. I found many methods to handle session expiration like Session timeout and ViewExpiredExcep

Answer 1

The code posted by @uı6ʎɹnɯ lǝıuɐp i's very useful, but i will add some observations:

• @Jonathan L sugests replace processTimer = setTimeout("timedCount()", 1000) to setInterval("timedCount()", 1000). I think makes sense, but need some modifications:

  function doTimer() {
      if (!timer_is_on) {
          timer_is_on = 1;
          processTimer = setInterval("timedCount()", 1000);
      }
  }
  
  function stopCount() {
      clearInterval(processTimer);
      timer_is_on = 0;
      keepAlive();
  }
  

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• The method timedCount() can be changed to:

  function timedCount() {
      txtCountDown.innerHTML = countTimer;
      if (countTimer > 0) {
          countTimer = countTimer - 1;
      } else {
          clearInterval(processTimer);
          doLogout();
      }
  }
  

  And you need add under the keepAlive remoteCommand something like this:

  Inside Managed Bean:

  public void logout() {
      FacesContext.getCurrentInstance().getExternalContext().invalidateSession();
      validUser = false;
      loggedUser = false;
      redirectToPage("/login.xhtml");
  }
  
  private void redirectToPage(String page) {
      ExternalContext context = FacesContext.getCurrentInstance().getExternalContext();
      context.redirect(context.getRequestContextPath() + page);
  }
  

  Remember the atribute name="doLogout" of p:remoteCommand is converted in a javascript function that you can call anywhere. It's perfect to iterate the view with managed bean.

  This approach will prevent your system stacks the ViewExpiredException.

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• Some people doesn't understand the keepAlive concept, but it's very easy, just add a simple function inside your managed bean. Example keepSessionAlive action:

  public void keepSessionAlive () {
      System.out.println(">>> Session is alive... ");
  }
  

  Remember the p:remoteCommand named keepAlive is a javascript function called keepAlive() and that call an action keepSessionAlive inside your managed bean.

  This action signs you are not idle.

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• The session.maxInactiveInterval of idleMonitor references of web.xml

  I recommend put session monitor to execute 5 seconds before finish the session to prevent run doLogout() after session end and get the ViewExpiredException.

  The first line of javascript code is var TIME = 120; // in seconds, this represents the time to finalize the session. The original code # {session.maxInactiveInterval * 1000 - 125000} will use session-timeout mutiplicated by 1.000 (because it's miliseconds) and subtract 125.000 that represents 125 seconds, 5 seconds less than counter, therefore doesn't need changes.

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I hope this helps... Good Luck!