Using PHP sessions

PHP sessions allow you to store and manage information about visitors as they navigate your website. Since HTTP is a stateless protocol, sessions provide a way to maintain data across multiple page requests. On ruachost.com, sessions are supported by default and can be used to build shopping carts, login systems, and other dynamic applications.

What Are PHP Sessions?

• HTTP does not remember users between page loads.
• Sessions solve this by assigning each visitor a unique session identifier.
• Data is stored on the server and linked to the visitor’s session ID.
• Common use cases: shopping carts, authentication, hit counters, and user preferences.

Starting a Session

To begin a session, use the session_start() function at the top of your PHP script:

<?php
session_start();
?>

• Must be called before any HTML output.
• Generates a session ID and creates a file in the server’s session storage directory (default: /tmp).

Working with Session Variables

Session data is stored in the $_SESSION superglobal array:

<?php
session_start();
$_SESSION['username'] = "timothy";
echo "Welcome, " . $_SESSION['username'];
?>

• Values persist across multiple pages until the session ends.
• You can store strings, numbers, arrays, or objects.

Ending a Session

To destroy a session and clear its data:

<?php
session_start();
session_destroy();
?>

• Useful for logout functionality.
• Removes all session variables and deletes the session file.

Configuring Sessions in php.ini

You can adjust session behavior in the php.ini configuration file:

• session.cookie_lifetime → controls how long a session cookie remains valid.
• session.auto_start → automatically starts sessions without calling session_start().
• session.save_path → specifies where session files are stored.

Security Considerations

• Protect against session hijacking and fixation attacks.
• Use HTTPS to encrypt session cookies.
• Regenerate session IDs after login for added security.