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  Classes of Lars Moelleken   PHP Session MySQL Handler   Download  
Role: Documentation
Content type: text/markdown
Description: Documentation
Class: PHP Session MySQL Handler
Handler for storing session data in MySQL
Author: By
Last change: Update
Date: 4 years ago
Size: 6,580 bytes


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:crown: Session2DB

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

Session2DB 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").

Session2DB is was inspired by John Herren's code from the Trick out your session handler article and Chris Shiflett's articles about PHP sessions and based on Zebra_Session.

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


PHP 7.x with the mysqli extension activated, MySQL 5.x+ (recommanded: mysqlnd extension)

How to install

composer require voku/session2db

How to use

After installing, you will need to initialise the database table from the install directory from this repo, it will 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!

// simple (dirty) example

    use voku\db\DB;
    use voku\helper\Session2DB;
    DB::getInstance('hostname', 'username', 'password', 'database');
    new Session2DB();
    // from now on, use sessions as you would normally
    // this is why it is called a "drop-in replacement" :)
    $_SESSION['foo'] = 'bar';

// extended example

    use voku\db\DB;
    use voku\helper\DbWrapper4Session;
    use voku\helper\Session2DB;

    // include autoloader
    require_once 'composer/autoload.php';

    // initialize the database connection e.g. via "voku\db\DB"-class
    $db = DB::getInstance(
        'hostname', // e.g. localhost
        'username', // e.g. user_1
        'password', // e.g. 
        'database', // e.g. db_1
        'port',     // e.g. 3306
        'charset',  // e.g. utf8mb4
        true,       // e.g. true|false (exit_on_error)
        true,       // e.g. true|false (echo_on_error)
        '',         // e.g. 'framework\Logger' (logger_class_name)
        ''          // e.g. 'DEBUG' (logger_level)
    // you can also use you own database implementation via the "Db4Session"-interface,
    // take a look at the "DbWrapper4Session"-class for a example
    $db_wrapper = new DbWrapper4Session($db);
    // initialize "Session to DB"
    new Session2DB(
      'add_your_own_security_code_here', // security_code
      0,                                 // session_lifetime
      false,                             // lock_to_user_agent 
      false,                             // lock_to_ip
      1,                                 // gc_probability 
      1000,                              // gc_divisor 
      'session_data',                    // table_name
      60,                                // lock_timeout 
      $db_wrapper,                       // db (must implement the "Db4Session"-interface)
      true                               // start_session (start the session-handling automatically, otherwise you need to use session2db->start() afterwards)

    // 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!


For support and donations please visit Github | Issues | PayPal | Patreon.

For status updates and release announcements please visit Releases | Twitter | Patreon.

For professional support please contact me.


  • Thanks to GitHub (Microsoft) for hosting the code and a good infrastructure including Issues-Managment, etc.
  • Thanks to IntelliJ as they make the best IDEs for PHP and they gave me an open source license for PhpStorm!
  • Thanks to Travis CI for being the most awesome, easiest continous integration tool out there!
  • Thanks to StyleCI for the simple but powerfull code style check.
  • Thanks to PHPStan && Psalm for relly great Static analysis tools and for discover bugs in the code!