bryan-d-lee / zebra_session

A drop-in replacement for PHP's default session handler which stores session data in a MySQL database, providing both better performance and better security and protection against session fixation and session hijacking.

##Zebra_Session

####A drop-in replacement for PHP's default session handler which stores session data in a MySQL database, providing both better performance and better security and protection against session fixation and session hijacking.

Zebra_Session implements session locking - a way to ensure that data is correctly handled in a scenario with multiple concurrent AJAX requests.

It is also a solution for applications that are scaled across multiple web servers (using a load balancer or a round-robin DNS) and where the user's session data needs to be available. Storing sessions in a database makes them available to all of the servers!

The library supports "flashdata" - session variable which will only be available for the next server request, and which will be automatically deleted afterwards. Typically used for informational or status messages (for example: "data has been successfully updated").

Zebra_Session is was inspired by John Herren's code from the Trick out your session handler article and Chris Shiflett's articles about PHP sessions.

The code is heavily commented and generates no warnings/errors/notices when PHP's error reporting level is set to E_ALL.

##Features

• acts as a wrapper for PHP’s default session handling functions, but instead of storing session data in flat files it stores them in a MySQL database, providing better security and better performance

• it is a drop-in and seamingless replacement for PHP’s default session handler: PHP sessions will be used in the same way as prior to using the library; you don’t need to change any existing code!

• implements row locks, ensuring that data is correctly handled in scenarios with multiple concurrent AJAX requests

• because session data is stored in a database, the library represents a solution for applications that are scaled across multiple web servers (using a load balancer or a round-robin DNS)

• has comprehensive documentation

• the code is heavily commented and generates no warnings/errors/notices when PHP’s error reporting level is set to E_ALL

Requirements

PHP 5.1.0+ with the mysqli extension activated, MySQL 4.1.22+

How to use

Download the latest version, unpack it, and put it in a place accessible to your scripts. After unpacking, you will notice a directory called install containing a file named session_data.sql. This file contains the SQL code that will create a table that is used by the class to store session data. Import or execute the SQL code using your preferred MySQL manager (like phpMyAdmin or the fantastic Adminer) into a database of your choice.

Note that this class assumes that there is an active connection to a MySQL database and it does not attempt to create one! If you really need the class to make a database connection, put the code in the "open" method of the class.

<?php

    // first, connect to a database containing the sessions table
    // like $link = mysqli_connect(host, username, password, database);

    // include the Zebra_Session class
    include 'path/to/Zebra_Session.php';

    // instantiate the class
    // this also calls session_start()
    $session = new Zebra_Session($link, 'sEcUr1tY_c0dE');

    // from now on, use sessions as you would normally
    // this is why it is called a "drop-in replacement" :)
    $_SESSION['foo'] = 'bar';

    // data is in the database!

?>

Visit the project's homepage for more information.