<p>I've used the PHP MVC framework Symfony to build an on-demand web app.</p>

<p>It has an annoying bug - the session expires after about 15-30 minutes of inactivity. There is a config directive to prevent session expiration but it does not work. Even workarounds such as <a href="http://robrosenbaum.com/php/howto-disable-session-timeout-in-symfony/" rel="nofollow noreferrer">this one</a> did not help me.</p>

<p>I intend not to migrate to Symfony 1.1 (which fixes this bug) in the foreseeable future.</p>

<p>Has anyone been there and solved it? I would be most grateful for a hint or two!</p>

The company I work for has been using Symfony and the workaround that we've used is to trigger a warning with javascript before the user gets logged out. I suspect that there is a a way to make 'heartbeat' ajax calls to the server to trigger the timer to reset, but that may be a lot of trouble. I think that there may not be a full fix that's suitable for you though, except maybe re-writing the session handler.
Sorry I couldn't be more specific, if I get the chance, I'll ask our Symfony devs if they know of a better solution.