L'interface SessionHandlerInterface

(PHP 5 >= 5.4.0, PHP 7, PHP 8)

Introduction

SessionHandlerInterface est une interface qui définit un prototype minimal pour la création d'un gestionnaire de session personnalisé. Afin de passer un gestionnaire de session personnalisé à la fonction session_set_save_handler() en utilisant son invocation OOP, la classe peut implémenter cette interface.

Notez que ces méthodes sont destinées à être appelées de manière interne par PHP, et non depuis l'espace utilisateur.

Sommaire de l'Interface

interface SessionHandlerInterface {

/* Méthodes */

public close(): bool

public destroy(string $id): bool

public gc(int $max_lifetime): int|false

public open(string $path, string $name): bool

public read(string $id): string|false

public write(string $id, string $data): bool

}

Exemples

Exemple #1 Exemple avec SessionHandlerInterface

L'exemple qui suit propose un gestionnaire de stockage de sessions basé sur des fichiers, basiquement comme les sessions PHP fonctionnent en interne de manière native, avec le gestionnaire embarqué files. Cet exemple pourrait être transformé facilement pour utiliser une base de données.

Nous utilisons le style orienté objet avec session_set_save_handler() et nous enregistrons la fonction de fermeture grâce au paramètre de la fonction. C'est en général conseillé lorsque le gestionnaire de session est basé sur des objets.

Attention

Pour plus de brièveté, cet exemple omet la validation d'entrée. Toutefois, les paramètres $id sont en fait des valeurs fournies par l'utilisateur qui nécessitent une validation/assainissement appropriée pour éviter les vulnérabilités, telles que les problèmes de parcours de chemin. N'utilisez donc pas cet exemple sans modification dans les environnements de production.

<?php
class MySessionHandler implements SessionHandlerInterface
{
    private $savePath;

    public function open($savePath, $sessionName): bool
    {
        $this->savePath = $savePath;
        if (!is_dir($this->savePath)) {
            mkdir($this->savePath, 0777);
        }

        return true;
    }

    public function close(): bool
    {
        return true;
    }

    #[\ReturnTypeWillChange]
    public function read($id)
    {
        return (string) @file_get_contents("$this->savePath/sess_$id");
    }

    public function write($id, $data): bool
    {
        return file_put_contents("$this->savePath/sess_$id", $data) === false ? false : true;
    }

    public function destroy($id): bool
    {
        $file = "$this->savePath/sess_$id";
        if (file_exists($file)) {
            unlink($file);
        }

        return true;
    }

    #[\ReturnTypeWillChange]
    public function gc($maxlifetime)
    {
        foreach (glob("$this->savePath/sess_*") as $file) {
            if (filemtime($file) + $maxlifetime < time() && file_exists($file)) {
                unlink($file);
            }
        }

        return true;
    }
}

$handler = new MySessionHandler();
session_set_save_handler($handler, true);
session_start();

// enregistre/récupère des données avec $_SESSION

Sommaire

SessionHandlerInterface::close — Ferme la session
SessionHandlerInterface::destroy — Détruit une session
SessionHandlerInterface::gc — Nettoie les vieilles sessions
SessionHandlerInterface::open — Initialise la session
SessionHandlerInterface::read — Lit les données de session
SessionHandlerInterface::write — Ecrit les données de session

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User Contributed Notes 8 notes

down

ohcc at 163 dot com ¶

6 years ago

As of PHP 7.0, you can implement SessionUpdateTimestampHandlerInterface to 
define your own session id validating method like validate_sid and the timestamp updating method like update_timestamp in the non-OOP prototype of session_set_save_handler().

SessionUpdateTimestampHandlerInterface is a new interface introduced in PHP 7.0, which has not been documented yet. It has two abstract methods: SessionUpdateTimestampHandlerInterface :: validateId($sessionId) and SessionUpdateTimestampHandlerInterface :: updateTimestamp($sessionId, $sessionData).

<?php
    /*
       @author Wu Xiancheng
       Code structure for PHP 7.0+ only because SessionUpdateTimestampHandlerInterface is introduced in PHP 7.0
       With this class you can validate php session id and update the timestamp of php session data
       with the OOP prototype of session_set_save_handler() in PHP 7.0+
    */
    class PHPSessionXHandler implements SessionHandlerInterface, SessionUpdateTimestampHandlerInterface {
        public function close(){
            // return value should be true for success or false for failure
            // ...
        }
        public function destroy($sessionId){
            // return value should be true for success or false for failure
            // ... 
        }
        public function gc($maximumLifetime){
            // return value should be true for success or false for failure
            // ...
        }
        public function open($sessionSavePath, $sessionName){
            // return value should be true for success or false for failure
            // ...
        }
        public function read($sessionId){
            // return value should be the session data or an empty string
            // ...
        }
        public function write($sessionId, $sessionData){
            // return value should be true for success or false for failure
            // ...
        }
        public function create_sid(){
            // available since PHP 5.5.1
            // invoked internally when a new session id is needed
            // no parameter is needed and return value should be the new session id created
            // ...
        }
        public function validateId($sessionId){
            // implements SessionUpdateTimestampHandlerInterface::validateId()
            // available since PHP 7.0
            // return value should be true if the session id is valid otherwise false
            // if false is returned a new session id will be generated by php internally
            // ...
        }
        public function updateTimestamp($sessionId, $sessionData){
            // implements SessionUpdateTimestampHandlerInterface::validateId()
            // available since PHP 7.0
            // return value should be true for success or false for failure
            // ...
        }
    }
?>

down

ohcc at 163 dot com ¶

6 years ago

The non-OOP prototype of session_set_save_handler() supports validate_sid and update_timestamp as of PHP 7.0 while the OOP prototype doesn't even in PHP 7.2. However the OOP prototype does support create_sid since PHP 5.5.1.

validate_sid($sessionId)
  This callback is to validate $sessionId. Its return value should be true for valid session id $sessionId or false for invalid session id $sessionId. If false is returned, a new session id is generated to replace the invalid session id $sessionId.

update_timestamp($sessionId)
  This call back is to update timestamp, and its return value should be true for success or false for failure.

down

ohcc at 163 dot com ¶

6 years ago

As of PHP 5.5.1, another method create_sid() is supported. It will be called when session_regenerate_id() is invoked.

SessionHandlerInterface {
    /* Methods */
    abstract public bool close ( void )
    abstract public bool create_sid ( void )    
    abstract public bool destroy ( string $session_id )
    abstract public bool gc ( int $maxlifetime )
    abstract public bool open ( string $save_path , string $session_name )
    abstract public string read ( string $session_id )
    abstract public bool write ( string $session_id , string $session_data )
}

down

avenidagez at foro5 dot com ¶

9 years ago

Note that session_start( ) calls open then read and the class returns true for open and the value of session or empty for read.
Well, then there is no catch for errors, this is, session_start() must return false on failure, but that is not the case for the class implementation on method open, no matter if you return true or false or whatever from open, it is ignored by session_start() function and proceeds to read method
A bug?, if open returns false, session_start() should stop the next step (read) and return itself false

if(session_start()) ...code
else exit( );

So forget about session_start() return value, you need to implement an error catch routine and exit() in case of failure on open method

down

warxcell at gmail dot com ¶

12 years ago

You should prepend <b>\</b> before class name, to tell php its from root namespace.

down

tony at marston-home dot demon dot co dot uk ¶

6 years ago

Your custom session handler should not contain calls to any of the session functions, such as session_name() or session_id(), as the relevant values are passed as arguments on various handler methods. Attempting to obtain values from alternative sources may not work as expected.

down

ohcc at 163 dot com ¶

4 years ago

If you want to use type declarations in your own session handling class, don't "implements" the SessionHandlerInterface, SessionIdInterface, or SessinUpdateTimestampInterface, otherwise you will get a fatal error saying that declaration of the class method must be compatible with the interface method.

a bad example
<?php
    class SessionWuXianchengHandler implements SessionHandlerInterface {        
        public function open(string $sessionPath, string $sessionName) : bool {
        }
        ......
    }
?>

a good example
<?php
    class SessionWuXianchengHandler {
        public function open(string $sessionPath, string $sessionName) : bool {
        }
        ......
    }
?>

down

-5

StanE ¶

9 years ago

I think there is a small "error" in the example of the class MySessionHandler in method gc(). It uses the function filemtime() whose return value is cached by PHP. Add the following line inside the foreach block in the gc() method:

clearstatcache(true, $file);

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