PHP 5.4.36 Released

The SessionHandlerInterface class

(PHP 5 >= 5.4.0)

Introduction

SessionHandlerInterface is an interface which defines a prototype for creating a custom session handler. In order to pass a custom session handler to session_set_save_handler() using its OOP invocation, the class must implement this interface.

Please note the callback methods of this class are designed to be called internally by PHP and are not meant to be called from user-space code.

Class synopsis

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

Example #1 Example using SessionHandlerInterface

The following example provides file based session storage similar to the PHP sessions default save handler files. This example could easily be extended to cover database storage using your favorite PHP supported database engine.

Note we use the OOP prototype with session_set_save_handler() and register the shutdown function using the function's parameter flag. This is generally advised when registering objects as session save handlers.

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

    public function 
open($savePath$sessionName)
    {
        
$this->savePath $savePath;
        if (!
is_dir($this->savePath)) {
            
mkdir($this->savePath0777);
        }

        return 
true;
    }

    public function 
close()
    {
        return 
true;
    }

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

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

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

        return 
true;
    }

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

        return 
true;
    }
}

$handler = new MySessionHandler();
session_set_save_handler($handlertrue);
session_start();

// proceed to set and retrieve values by key from $_SESSION

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User Contributed Notes 3 notes

up
11
warxcell at gmail dot com
2 years ago
You should prepend <b>\</b> before class name, to tell php its from root namespace.
up
0
avenidagez at foro5 dot com
14 days 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
up
-26
PHPaficionado
2 years ago
This interface like classes doesn't show up if you have a namespace defined.

If you're getting an error like:
Fatal error: Interface 'MyNamespace\SessionHandlerInterface' not found
under your namespace you can just write the line:
use SessionHandlerInterface;
and all will be fine.

You can now implement this interface as usual.
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