When you start a session, if the user had no cookie, they get a new session id and they get a cookie. You can configure that cookie to last for n seconds via php.ini or session_cookie_set_params(). But, and this is a HUGE but for me, that cookie will expire in n seconds no matter what. Let me explain further. For my needs, the cookie should expire in n seconds from last activity. So, each page load where sessions are used should reset the cookie's expiration. This way, if a user leaves the site, they have n seconds to come back and still be logged in.
Consider an application that sets the cookie expiration to 5 minutes. The person clicks around on the site, gets a phone call that lasts 8 minutes and then gets back to using the site. Their session has expired!!!! How annoying is that? The only sites I know that do that are banks. They have good reason. I understand that.
My preference would be to either set an ini value that tells PHP sessions to keep the session active as long as the user is using the site. Or give me access to the internal function php_session_send_cookie(). That is the C function that sends the cookie to the user's browser. Hmm, perhaps a patch is in my future.
In the short term, this is what I do:
That will set the session cookie with a fresh ttl.
Ok, going to dig into some C code now and see if I can make a patch for this.