if (isset($_SESSION['LAST_ACTIVITY']) && (time() - $_SESSION['LAST_ACTIVITY'] > 1800)) {
// last request was more than 30 minutes ago
session_unset(); // unset $_SESSION variable for the run-time
session_destroy(); // destroy session data in storage
}
$_SESSION['LAST_ACTIVITY'] = time(); // update last activity time stamp
/*
You can also use an additional time stamp to regenerate the session ID periodically to avoid attacks on sessions like session fixation:
*/
if (!isset($_SESSION['CREATED'])) {
$_SESSION['CREATED'] = time();
} else if (time() - $_SESSION['CREATED'] > 1800) {
// session started more than 30 minutes ago
session_regenerate_id(true); // change session ID for the current session an invalidate old session ID
$_SESSION['CREATED'] = time(); // update creation time
}
//note that session.gc_maxlifetime should be at least equal to the life time of this custom expiration handler (1800 in this example).