User Authentication With Apache And PHP - Time To Live (
Page 9 of 11 )
Finally, once the user has
logged in, it is good practice to offer a log out button on every page. This
provides the user with the ability to manually destroy the session and session
variables created during the initial log-in phase, and eliminates the
possibility of malicious users "spoofing" sessions.
Here's what
"logout.php" looks like:
<?
// logout.php - destroys session and returns to login form
// destroy all session variables
session_start();
session_destroy();
// redirect browser back to login page
header("Location: /index.php");
?>
The session_destroy() function provides a convenient way to
destroy all information in the current session.
You should also make it a
point to specify a session lifetime in your PHP configuration, so that sessions
are automatically destroyed if inactive for a specific period of time (thirty
minutes is generally considered reasonable).
Obviously, you can also
destroy a session just by closing your browser, just as with HTTP
authentication.