Zend Session on Redis

gistfile1.php

<?php

/**
 * @see Zend_Session
 */
require_once 'Zend/Session.php';

/**
 * @see Zend_Config
 */
require_once 'Zend/Config.php';

/**
 * Zend_Session_SaveHandler_DbTable
 *
 * @category   Zend
 * @package    Zend_Session
 * @subpackage SaveHandler
 * @copyright  Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Common_Session_SaveHandler_Redis implements Zend_Session_SaveHandler_Interface {

	/**
	 * @var Redis
	 */
	protected $_redis;

	/**
	 * Session Key Prefix
	 *
	 * @var string
	 */
	protected $_keyPrefix = 'php:session';

	/**
	 * Session lifetime
	 * By default this time is 1440 seconds (24 minutes)
	 * @var int
	 */
	protected $_lifetime = 1440;

	/**
	 * Session name
	 *
	 * @var string
	 */
	protected $_sessionName = '';

	/**
	 * Session save path
	 *
	 * @var string
	 */
	protected $_savePath = '';

	/**
	 * Construct save handler
	 *
	 * @param Zend_Config|array $options
	 */
	public function __construct($options = array()) {

		if ($options instanceof Zend_Config) {
			$options = $options->toArray();
		}

		/**
		 * Setting default lifetime
		 */
		if (isset($options['lifetime'])) {
        	$lifetime = (int) $options['lifetime'];
        	unset($options['lifetime']);
		} else {
			$lifetime = (int) ini_get('session.gc_maxlifetime');
		}

		/**
		 * Checking if lifetime is valid
		 */
		if( $lifetime != 0 ) {
			$this->_lifetime = $lifetime;
		} else {
			trigger_error( "Please set session.gc_maxlifetime to enable garbage collection.", E_USER_WARNING );
		}

		/**
		 * Checking extension avaliable
		 */
		if (!extension_loaded('redis')) {
			Zend_Session_SaveHandler_Exception::throwException('The redis extension must be loaded for using this backend !');
		}
	}

	/**
	 * Close session
	 *
	 * @return boolean
	 */
	public function close() {
		return TRUE;
	}

	/**
	 * Destroy session
	 *
	 * @param string $id
	 * @return boolean
	 */
	public function destroy($id) {
		$key = $this->_getKeyName($id);
		if(!$this->_redis->exists($key)) {
			return FALSE;
		}
		$this->_redis->del($key);
		return TRUE;
	}

	/**
	 * Garbage Collection
	 *
	 * @param int $maxlifetime
	 * @return true
	 */
	public function gc($maxlifetime) {
		return TRUE;
	}

	/**
	 * Open Session
	 *
	 * @param string $save_path
	 * @param string $name
	 * @return boolean
	 */
	public function open($save_path, $name) {

		/**
		 * Setting session name
		 */
		$this->_sessionName = $name;

		/**
		 * Setting save path
		 */
		$this->_savePath = $save_path;

		try {
			$this->_redis = new Redis();
			$this->_redis->connect( empty($save_path) ? '127.0.0.1' : $save_path );
		} catch(Exception $e) {
			return FALSE;
		}
		return TRUE;
	}

	/**
	 * Read session data
	 *
	 * @param string $id
	 * @return mixed
	 */
	public function read($id) {
		$key = $this->_getKeyName($id);
		if($this->_redis->exists($key)) {
			return $this->_redis->get($key);
		}
		return '';
	}

	/**
	 * Write session data
	 *
	 * @param string $id
	 * @param string $data
	 * @return boolean
	 */
	public function write($id, $data) {

		$key = $this->_getKeyName($id);

		$this->_redis->setex($key, $this->_lifetime, $data);

		return TRUE;
	}

	/**
	 * Destructor
	 *
	 * @return void
	 */
	public function __destruct() {
		Zend_Session::writeClose();
		if(isset($this->_redis) && $this->_redis instanceof Redis ){
			$this->_redis->close();
		}
	}

	/**
	 * Add prefix to session name
	 * @param string $id
	 * @return string
	 */
	protected function _getKeyName($id) {
		return "{$this->_keyPrefix}:{$this->_sessionName}:{$id}";
	}

}