MongoSessionStorage.php

<?php
/**
* MongoSessionStrage manages session storage via MongoDB
*
* This class stores the session data in via MongoDB and with an id issued in a
* signed cookie. Useful when you don't want to store the session.
*
* @package    PHP
* @subpackage session
* @author     Masao Maeda <brt.river@gmail.com>
*/
class MongoSessionStorage
{
    static protected
        $sessionIdRegenerated = false,
        $sessionStarted       = false,
        $db = null,
        $col = null,
        $options = array(
            'db_name'     => 'php_session',
            'collection_name' => 'session',
            'db_id_col'   => 'sess_id',
            'db_data_col' => 'sess_data',
            'db_time_col' => 'sess_time',
            'host' => 'localhost',
            'port' => '27017',
        );

    /**
    * Available options:
    *
    *   * collection_name: The database table in which session data will be stored
    *   * db_name:         The sfDatabase object to use
    *   * db_id_col:       The database column in which the session id will be stored (sess_id by default)
    *   * db_data_col:     The database column in which the session data will be stored (sess_data by default)
    *   * db_time_col:     The database column in which the session timestamp will be stored (sess_time by default)
    *
    * @param  array $options  An associative array of options
    *
    */
    static public function init($options = array())
    {
        self::$options = array_merge(self::$options, $options);

        if (!isset(self::$options['db_name']))
        {
            throw new Exception('You must provide a "db_name" option to sfMongoSessionStorage.');
        }

        if (!isset(self::$options['collection_name']))
        {
            throw new Exception('You must provide a "collection_name" option to sfMongoSessionStorage.');
        }

        // use this object as the session handler
        session_set_save_handler(array(__CLASS__, 'sessionOpen'),
            array(__CLASS__, 'sessionClose'),
            array(__CLASS__, 'sessionRead'),
            array(__CLASS__, 'sessionWrite'),
            array(__CLASS__, 'sessionDestroy'),
            array(__CLASS__, 'sessionGC'));

        // start our session
        //session_start();
    }

    /**
    * Closes a session.
    *
    * @return boolean true, if the session was closed, otherwise false
    */
    static public function sessionClose()
    {
        // do nothing
        return true;
    }

    /**
    * Opens a session.
    *
    * @param  string $path  (ignored)
    * @param  string $name  (ignored)
    *
    * @return boolean true, if the session was opened, otherwise an exception is thrown
    *
    * @throws <b>Exception</b> If a connection with the database does not exist or cannot be created
    */
    static public function sessionOpen($path = null, $name = null)
    {
        // what host and port are we using?
        $host = self::$options['host'];
        $port = self::$options['port'];

        // what database are we using?
        $db_name = self::$options['db_name'];

        if (!class_exists('Mongo'))
        {
            throw new Exception('Mongo class does not exist!');
        }
        $mongo = new Mongo(sprintf("%s:%s", $host, $port));
        self::$db = $mongo->selectDB($db_name);
        self::$col = self::$db->selectCollection(self::$options['collection_name']);
        if (null === self::$db && null === self::$col)
        {
            throw new Exception('MongoDB connection does not exist. Unable to open session.');
        }
        return true;
    }

    /**
    * Destroys a session.
    *
    * @param  string $id  A session ID
    *
    * @return bool true, if the session was destroyed, otherwise an exception is thrown
    *
    * @throws <b>Exception</b> If the session cannot be destroyed
    */
    static public function sessionDestroy($id) {
        if (self::$col->remove(array(self::$options['db_id_col'] => $id)))
        {
            return true;
        }
        $last_error = self::$db->lastError();
        throw new Exception(sprintf('%s cannot destroy session id "%s" (%s).', __CLASS__, $id, $last_error['err']));
    }

    /**
    * Cleans up old sessions.
    *
    * @param  int $lifetime  The lifetime of a session
    *
    * @return bool true, if old sessions have been cleaned, otherwise an exception is thrown
    *
    * @throws <b>Exception</b> If any old sessions cannot be cleaned
    */
    static public function sessionGC($lifetime)
    {
        // get column
        $db_time_col = self::$options['db_time_col'];

        // delete the record older than the authorised session life time 
        if (self::$col->remove(array('$where' => sprintf('this.%s + %d < %d', $db_time_col, $lifetime, time()))))
        {
            return true;
        }
        $last_error = self::$db->lastError();
        throw new Exception(sprintf('%s cannot delete old sessions (%s).', __CLASS__, $last_error['err']));
    }


    /**
    * Reads a session.
    *
    * @param  string $id  A session ID
    *
    * @return bool true, if the session was read, otherwise an exception is thrown
    *
    * @throws <b>Exception</b> If the session cannot be read
    */
    static public function sessionRead($id)
    {
        // get column
        $db_data_col = self::$options['db_data_col'];
        $db_id_col   = self::$options['db_id_col'];
        $db_time_col = self::$options['db_time_col'];

        $obj = self::$col->findOne(array(self::$options['db_id_col'] => $id));
        if (count($obj))
        {
            // found the session
            return $obj[$db_data_col];
        }
        else
        {
            $obj = array(
                $db_id_col => $id,
                $db_data_col => '',
                $db_time_col => time(),
                );
            // session does not exist, create it
            if (self::$col->insert($obj))
            {
                //self::$col->ensureIndex(array($db_id_col => 1));
                return '';
            }

            // can't create record
            $last_error = self::$db->lastError();
            throw new Exception(sprintf('%s cannot create new record for id "%s" (%s).', __CLASS__, $id, $last_error['err']));
        }
    }
    /**
    * Writes session data.
    *
    * @param  string $id    A session ID
    * @param  string $data  A serialized chunk of session data
    *
    * @return bool true, if the session was written, otherwise an exception is thrown
    *
    * @throws <b>Exception</b> If the session data cannot be written
    */
    static public function sessionWrite($id, $data)
    {
        // get column
        $db_data_col = self::$options['db_data_col'];
        $db_id_col   = self::$options['db_id_col'];
        $db_time_col = self::$options['db_time_col'];

        // update the record associated with this id
        $obj = array(
            $db_id_col => $id,
            $db_data_col => $data,
            $db_time_col => time(),
            );
        if (self::$col->update(array($db_id_col => $id), $obj))
        {
            return true;
        }
        // failed to write session data
        $last_error = self::$db->lastError();
        throw new Exception(sprintf('%s cannot write session data for id "%s" (%s).', __CLASS__, $id, $last_error['err']));
    }

    /**
    * Regenerates id that represents this storage.
    *
    * @param  boolean $destroy Destroy session when regenerating?
    *
    * @return boolean True if session regenerated, false if error
    *
    */
    static public function regenerate($destroy = false)
    {
        if (self::$sessionIdRegenerated)
        {
            return;
        }
        $currentId = session_id();
        // regenerate a new session id once per object
        session_regenerate_id($destroy);

        self::$sessionIdRegenerated = true;

        $newId = session_id();
        self::sessionRead($newId);

        return self::sessionWrite($newId, self::sessionRead($currentId));
    }

    /**
    * Executes the shutdown procedure.
    *
    */
    static public function shutdown()
    {
        session_write_close();
    }
}

test.php

<?php
// simple tests
error_reporting(E_ALL);
ini_set('display_errors', 'On');

echo "<h3>start test</h3>";
try{
    // (1) include library
    require_once dirname(__FILE__) . '/MongoSessionStorage.php';
    $options = array(
        'db_name'     => 'php_session',
        'collection_name' => 'session',
        'db_id_col'   => 'sess_id',
        'db_data_col' => 'sess_data',
        'db_time_col' => 'sess_time',
        'host' => 'localhost',
        'port' => '27017',
    );
    MongoSessionStorage::init($options);

    // (2) session start
    if (!session_start()) throw new Exception('cannot start session');

    // (3) write to session
    $hoge = 'red bull!';
    $_SESSION['test'] = $hoge;
    if ($_SESSION['test'] !== $hoge) throw new Exception("cannot write/read session");

    // (4) regenerate session id
    // TODO: If I set the first parameter to 'true', I cannot destory the session data from MongoDB...
    $id = session_id();
    MongoSessionStorage::regenerate();
    if ($id === session_id()) throw new Exception("cannot re-generate session id");

    // (5) gc, in this teset, MongoDB data are cleaned up.
    MongoSessionStorage::sessionGC(-10);
    if (MongoSessionStorage::sessionRead(session_id()) !== "") throw new Exception("cannot run gc");

} catch (Exception $e) {
    echo "<div style='color:red;'><h4>Failure.</h4>";
    echo $e->getMessage();
    echo "</div>";
}
echo "<h3>done.</h3>";