PHP Session Mechanism: Complete Guide

PHP’s session mechanism is a technology that stores user information on the server side, creating a session when a user visits a website and maintaining the user’s state information throughout the session. These information are stored on the server rather than on the user’s computer, making it relatively secure and inaccessible for direct modification by users. The session mechanism is typically used to save user login status, shopping cart information, user preference settings, etc. In PHP, session data can be accessed and manipulated through the global variable $_SESSION. To use sessions, one must call the session_start() function at the beginning of the script to initiate the session. When the user closes the browser, the session will be automatically destroyed. The storage time of the session can be extended by setting the session expiration time.