How to detect if a user has logged out, in php?

Question

After the user successfully logs in, I store login = true in database. But how do I check if the user logged out by closing the browser without clicking the logout button? A

Answer 1

IMHO the best way is to store last activity timestamp in DB on each update of user record. After logoff or timeout (maintain timeouts with cronjob) just set it to zero-value and use as flag.

$user = new User($user_id);
$user->logged_in = (bool)($last_activity > 0);

Sometimes you will need to say smth. like "last seen on ...", then leave last activity and just add a boolean flag (tinyint) logged_in to your users table.