How to Properly Destroy a PHP Session: A Comprehensive Guide

Destroying PHP Sessions: A Comprehensive Approach

When terminating a PHP session, it is essential to ensure that all relevant data is deleted and the session ID is invalidated. While various methods have been suggested, the most effective approach involves a multi-step process:

1. Deleting Session Data:

   <code class="php">session_start();
   $_SESSION = array();</code>

   This wipes out any session data that may still be present.

2. Invalidating Session ID:

   <code class="php">session_destroy();</code>

   This destroys the current session ID and generates a new one.

3. Preventing Session Continuity:

   <code class="php">unset($_COOKIE[session_name()]);</code>

   This forces the browser to discard the session cookie, preventing it from attaching to a new session.

To ensure that only authorized sessions are established, it is recommended to create a unique session flag upon session initialization and check for its presence:

<code class="php">session_start();
if (!isset($_SESSION['CREATED'])) {
   session_regenerate_id(true);
   $_SESSION['CREATED'] = time();
}</code>

Finally, to limit the lifetime of the session ID, the following code can be used to periodically swap it:

<code class="php">if (time() - $_SESSION['CREATED'] > ini_get('session.gc_maxlifetime')) {
   session_regenerate_id(true);
   $_SESSION['CREATED'] = time();
}</code>

By following these steps, you can effectively destroy a PHP session and ensure that it cannot be resumed without authorization.

The above is the detailed content of How to Properly Destroy a PHP Session: A Comprehensive Guide. For more information, please follow other related articles on the PHP Chinese website!