How Long Does a PHP Session Last?

Understanding Session Lifetime in PHP

When you initiate a PHP session using session_start(), the server generates a unique session ID and stores it on the client's computer. This enables the server to identify the user and maintain their session data across multiple page requests. However, there's a finite lifespan associated with each session.

Default Session Lifetime

The default lifetime of a session, or the duration for which a session ID remains valid, varies depending on the PHP configuration. By default, the session.gc_maxlifetime directive in your php.ini file governs this behavior.

session.gc_maxlifetime = 1440

This setting specifies that a session will expire after 1440 seconds, which is approximately 24 minutes.

Refreshing a Page and Session Expiration

When you refresh a page, the browser sends a new HTTP request to the server. If you have enabled session handling by calling session_start(), the server checks the session ID sent in the request. If the session ID is still valid (has not expired), the server retrieves the associated session data and the session continues.

However, if the session ID has expired since the last page request, the server will initiate a new session and assign a new session ID. In this case, you will lose access to the data stored in the previous session.

Customizing Session Lifetime

You can modify the session lifetime by adjusting the session.gc_maxlifetime setting in your php.ini file. If you want to extend the lifetime of a session, increase the value in seconds. Conversely, if you want to shorten the lifetime, decrease the value.

Note: It's important to note that the session lifetime is primarily controlled by the session.gc_maxlifetime setting. However, there are other factors that can affect the actual expiration time, such as browser settings, server configurations, and garbage collection algorithms.

The above is the detailed content of How Long Does a PHP Session Last?. For more information, please follow other related articles on the PHP Chinese website!