MySQL Cookbook

Using MySQL-Based Storage with the PHP Session Manager

Problem

You want to use session storage for PHP scripts.

Solution

PHP 4 includes session managment. By default, it uses temporary files for backing store, but you can configure it to use MySQL instead.

Discussion

PHP 4 includes a native session manager. This section shows how to use it and how to extend it by implementing a storage module that saves session data in MySQL.^[68] If your PHP configuration has both the track_vars and register_globals configuration directives enabled, session variables will exist as global variables of the same names in your script. (track_vars is enabled automatically for PHP 4.0.3 or later; for earlier versions, you should enable it explicitly.) If register_globals is not enabled, you’ll need to access session variables as elements of the $HTTP_SESSION_VARS global array or the $_SESSION superglobal array. This is less convenient than relying on register_globals, but is also more secure. (Recipe 18.6 discusses PHP’s global and superglobal arrays and the security implications of register_globals.)

The PHP 4 Session Management Interface

PHP’s session management capabilities are based on a small set of functions, all of which are documented in the PHP manual. The following list describes those likely to be most useful for day-to-day session programming:

session_start ( )

Opens a session and extracts any variables previously stored in it, making them available in the script’s global namespace. For example, ...