how to expire php session if user is inactive for 15 mins

Question

i have created one project in PHP, into which i am managing sessions.

I am creating session in my config.php file by writing following line of code.

Answer 1

Store time() in the $time variable. create variable called $setTime and set the time you want user to timeout.

After that check the condition that if $_SESSION['setTime'] is empty OR not set then store the timeout value into the session, otherwise when the page will refresh the new value will be assigned to the $_SESSION['setTime'].

$time = time ();
    $setTime = time () + 60;
    if (empty ( $_SESSION ['setTime'] ) || !isset ( $_SESSION ['setTime'] )) {
        $_SESSION ['setTime'] = $setTime;
    }

After that check that current time is more than equal to the stored time. and if it is unset the session. destroy the session as well.

if (time () >= ( int ) $_SESSION ['setTime']) {
   session_unset ();
   session_destroy ();
}