PHP Session Lifetime: A work around session.gc_maxlifetime

I needed to limit my session life time in a specific site running in my remote server. But could not set session.gc_maxlifetime. Also I know that session.gc_maxlifetime is not good! It is not reliable and it's tricky to get a different session max life time for each site running in your server.

So I made my own script that would clean session and cookies after a predefined number of minutes. Then all I had to do is to include this script in the start of my index.php:

// checks if session is idle for too much time
// if it is it will erase all session vars!
// if not it will update last activity time
// returns true if session was wiped
function session_check() {
 // time out in seconds
 $max_idle_time = 10 * 60;
 // name of session variable used to store last activity
 $sname = '_session_last_activity';
 $cleaned = false;

 // start session if it wasn't yet
 if (session_id() == '') session_start();

 // check if session variable is set
 if (isset($_SESSION[$sname])) {
  $t_old = $_SESSION[$sname];
  $t_now = mktime();
  // check if session expired
  if ($t_now - $t_old > $max_idle_time) {
   // wipe sessions
   session_unset();
   session_destroy();
   $_SESSION = array();
   // wipe cookies
   foreach ($_COOKIE as $key => $value) setcookie($key, '',
   time()-1);
   $cleaned = true;
  }
 }
 // create or refresh session
 $_SESSION[$sname] = mktime();

 return $cleaned;
}

// call funtion
if (session_check()) {
 // echo 'Session was just cleaned...';
}

One thing the world must learn

"Hackers like to work for people with high standards. But it's not enough just to be exacting. You have to insist on the right things. Which usually means that you have to be a hacker yourself. I've seen occasional articles about how to manage programmers. Really there should be two articles: one about what to do if you are yourself a programmer, and one about what to do if you're not. And the second could probably be condensed into two words: give up."
- Article from http://www.paulgraham.com/gh.html