Exemple de class pour gérer les Session sans le mécanisme de session PHP.

session.class.php

<?php
/**
 * Author : Jean-Sébastien Tremblay <jean-seb@total-itech.com>
 * Description : Class for scalable, stateless and client-side sessions
 */


/* Usage :
generate IV :
   // do this only on time and save in config
   $td = mcrypt_module_open('tripledes', '', 'ecb', '');
   $iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
   $conf_iv = base64_encode($iv);

config :
   define('SESSION_NAME', 'myWebsiteCookie');
   define('CONFIG_KEY', 'text clef encryption');
   define('CONFIG_IV', ***generated iv***);

start session :
   $sess = new Session(CONFIG_KEY, CONFIG_IV);
   $sess->read(SESSION_NAME);

use :
   $sess->myVar = 'foo bar';
   echo $sess->myVar;

close session :
   // important before sending any data to client
   $sess->writeIfChange(SESSION_NAME);
*/

class Session
{
    private $mod = null;
    private $key;
    private $iv;

    private $data = array('expire'=>0, 'data'=>array());
    private $change = false;

    private $expire = 0;
    private $path = '/';

    public function  __construct($key, $iv)
    {
            $this->key = $key;
            $this->iv = base64_decode($iv);
    }

    public function config($expire, $path = '/')
    {
        $this->expire = $expire;
        $this->path = $path;
    }

    public function read($name)
    {
        if(!array_key_exists($name, $_COOKIE) || empty($_COOKIE[$name]))
            return false;

        $encSess = base64_decode($_COOKIE[$name], true);
        if($encSess === false)
            return false;

        if($this->mod === null)
            $this->open();

        mcrypt_generic_init($this->mod, $this->key, $this->iv);
        $data = mdecrypt_generic($this->mod, $encSess);
        mcrypt_generic_deinit($this->mod);
        $len = intval(substr($data, 0, 4));
        $this->data = json_decode(substr($data, 4, $len), true);
        if($this->data['expire'] == 0 || $this->data['expire'] > time())
        {
            return true;
        }
        $this->data['data'] = array();
        return false;
    }

    public function write($name)
    {
        if($this->mod === null)
            $this->open();

        $t = time();
        if($this->data['expire'] < time())
            $this->data['expire'] = ($this->expire == 0)?0:$t+$this->expire;

        $data = json_encode($this->data);
        mcrypt_generic_init($this->mod, $this->key, $this->iv);
        $encSess = mcrypt_generic($this->mod, str_pad(strlen($data), 4, '0', STR_PAD_LEFT).$data);
        mcrypt_generic_deinit($this->mod);
        $sess = base64_encode($encSess);

        setcookie($name, $sess, $t+(365*24*60*60), $this->path);
    }

    public function writeIfChange($name)
    {
        if($this->change)
            return $this->write ($name);
        return false;
    }

    private function open()
    {
        $this->mod = mcrypt_module_open('tripledes', '', 'ecb', '');
    }

    public function __destruct()
    {
        if($this->mod !== null)
            mcrypt_module_close($this->mod);
    }

	public function __get($name)
	{
		if(array_key_exists($name, $this->data['data']))
			return $this->data['data'][$name];
		return null;
	}

	public function  __set($name, $value)
	{
		$this->change = true;
		$this->data['data'][$name] = $value;
	}

	public function destroy()
	{
		$this->data = array(
			'data'=>  array(),
			'expire'=> 0
		);
		$this->data['expire'] = ($this->expire == 0)?0:time()+$this->expire;
		$this->change = true;
	}

}