Why Is My PHP Session Data Disappearing?

Troubleshooting Lost PHP Session Data

Experiencing unexplained session data loss across pages or refreshes can be frustrating. If you're confident you haven't modified the scripts, it's worth investigating potential server-side issues.

PHP Configuration Checks:

To start, you can use PHP's phpinfo() function to inspect your host's server configuration. Look for the following settings:

• session.save_path: This path indicates where session data is being stored. If it's set to a non-existent directory, session data will not be saved properly.
• session.gc_maxlifetime: This value specifies the amount of time before a session expires. Ensure it's not set to a low value.

Session Startup Issues:

Verify that you're explicitly starting a session at the beginning of every script using session_start(). This function should always be the first line of any script that deals with session data.

Server-Side Bottlenecks:

If the session data is not being saved even after correcting the configuration settings, it may indicate an underlying server-side issue. Check with your host to confirm:

• Disk space availability: Ensure the session save path directory has sufficient free space.
• File system permissions: Check if the session save path directory is writable by the web server user.
• Conflicting settings: In rare cases, specific Linux security or web server settings can interfere with session saving.

Solution:

In the case described in the original question, the host had changed servers and modified the session save path. By working with the host to explicitly set a valid session path, the issue was resolved.

Remember to double-check your code and verify whether your host has made any recent changes to their server configuration that could affect session functionality.

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