feature/session (#3073): Add Memcached session driver
diff --git a/system/libraries/Session/drivers/Session_memcached_driver.php b/system/libraries/Session/drivers/Session_memcached_driver.php
new file mode 100644
index 0000000..c6ad565
--- /dev/null
+++ b/system/libraries/Session/drivers/Session_memcached_driver.php
@@ -0,0 +1,287 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst. It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package CodeIgniter
+ * @author Andrey Andreev
+ * @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
+ * @license http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link http://codeigniter.com
+ * @since Version 3.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * CodeIgniter Session Memcached Driver
+ *
+ * @package CodeIgniter
+ * @subpackage Libraries
+ * @category Sessions
+ * @author Andrey Andreev
+ * @link http://codeigniter.com/user_guide/libraries/sessions.html
+ */
+class CI_Session_memcached_driver extends CI_Session_driver implements SessionHandlerInterface {
+
+ /**
+ * Save path
+ *
+ * @var string
+ */
+ protected $_save_path;
+
+ /**
+ * Memcached instance
+ *
+ * @var Memcached
+ */
+ protected $_memcached;
+
+ /**
+ * Key prefix
+ *
+ * @var string
+ */
+ protected $_key_prefix = 'ci_session:';
+
+ /**
+ * Lock key
+ *
+ * @var string
+ */
+ protected $_lock_key;
+
+ // ------------------------------------------------------------------------
+
+ /**
+ * Class constructor
+ *
+ * @param array $params Configuration parameters
+ * @return void
+ */
+ public function __construct(&$params)
+ {
+ parent::__construct($params);
+
+ if (empty($this->_save_path))
+ {
+ log_message('error', 'Session: No Memcached save path configured.');
+ }
+
+ if ($this->_match_ip === TRUE)
+ {
+ $this->_key_prefix .= $_SERVER['REMOTE_ADDR'].':';
+ }
+ }
+
+ // ------------------------------------------------------------------------
+
+ public function open($save_path, $name)
+ {
+ $this->_memcached = new Memcached();
+ $server_list = array();
+ foreach ($this->_memcached->getServerList() as $server)
+ {
+ $server_list[] = $server['host'].':'.$server['port'];
+ }
+
+ if ( ! preg_match_all('#,?([^,:]+)\:(\d{1,5})(?:\:(\d+))?#', $this->_save_path, $matches, PREG_SET_ORDER))
+ {
+ $this->_memcached = NULL;
+ log_message('error', 'Session: Invalid Memcached save path format: '.$this->_save_path);
+ return FALSE;
+ }
+
+ foreach ($matches as $match)
+ {
+ // If Memcached already has this server (or if the port is invalid), skip it
+ if (in_array($match[1].':'.$match[2], $server_list, TRUE))
+ {
+ log_message('debug', 'Session: Memcached server pool already has '.$match[1].':'.$match[2]);
+ continue;
+ }
+
+ if ( ! $this->_memcached->addServer($match[1], $match[2], isset($match[3]) ? $match[3] : 0))
+ {
+ log_message('error', 'Could not add '.$match[1].':'.$match[2].' to Memcached server pool.');
+ }
+ else
+ {
+ $server_list[] = $server['host'].':'.$server['port'];
+ }
+ }
+
+ if (empty($server_list))
+ {
+ log_message('error', 'Session: Memcached server pool is empty.');
+ return FALSE;
+ }
+
+ return TRUE;
+ }
+
+ // ------------------------------------------------------------------------
+
+ public function read($session_id)
+ {
+ if (isset($this->_memcached) && $this->_get_lock($session_id))
+ {
+ $session_data = (string) $this->_memcached->get($this->_key_prefix.$session_id);
+ $this->_fingerprint = md5($session_data);
+ return $session_data;
+ }
+
+ return FALSE;
+ }
+
+ public function write($session_id, $session_data)
+ {
+ if (isset($this->_memcached, $this->_lock_key))
+ {
+ $this->_memcached->replace($this->_lock_key, time(), 5);
+ if ($this->_fingerprint !== ($fingerprint = md5($session_data)))
+ {
+ if ($this->_memcached->set($this->_key_prefix.$session_id, $session_data, $this->_expiration))
+ {
+ $this->_fingerprint = $fingerprint;
+ return TRUE;
+ }
+
+ return FALSE;
+ }
+
+ return $this->_memcached->touch($this->_key_prefix.$session_id, $this->_expiration);
+ }
+
+ return FALSE;
+ }
+
+ // ------------------------------------------------------------------------
+
+ public function close()
+ {
+ if (isset($this->_memcached))
+ {
+ isset($this->_lock_key) && $this->_memcached->delete($this->_lock_key);
+ if ( ! $this->_memcached->quit())
+ {
+ return FALSE;
+ }
+
+ $this->_memcached = NULL;
+ return TRUE;
+ }
+
+ return FALSE;
+ }
+
+ // ------------------------------------------------------------------------
+
+ public function destroy($session_id)
+ {
+ if (isset($this->_memcached, $this->_lock_key))
+ {
+ $this->_memcached->delete($this->_key_prefix.$session_id);
+ return ($this->_cookie_destroy() && $this->close());
+ }
+
+ return $this->close();
+ }
+
+ // ------------------------------------------------------------------------
+
+ public function gc($maxlifetime)
+ {
+ return TRUE;
+ }
+
+ // ------------------------------------------------------------------------
+
+ protected function _get_lock($session_id)
+ {
+ if (isset($this->_lock_key))
+ {
+ return $this->_memcached->replace($this->_lock_key, time(), 5);
+ }
+
+ $lock_key = $this->_key_prefix.$session_id.':lock';
+ if ( ! ($ts = $this->_memcached->get($lock_key)))
+ {
+ if ( ! $this->_memcached->set($lock_key, TRUE, 5))
+ {
+ log_message('error', 'Session: Error while trying to obtain lock for '.$this->_key_prefix.$session_id);
+ return FALSE;
+ }
+
+ $this->_lock_key = $lock_key;
+ $this->_lock = TRUE;
+ return TRUE;
+ }
+
+ // Another process has the lock, we'll try to wait for it to free itself ...
+ $attempt = 0;
+ while ($attempt++ < 5)
+ {
+ usleep(((time() - $ts) * 1000000) - 20000);
+ if (($ts = $this->_memcached->get($lock_key)) < time())
+ {
+ continue;
+ }
+
+ if ( ! $this->_memcached->set($lock_key, time(), 5))
+ {
+ log_message('error', 'Session: Error while trying to obtain lock for '.$this->_key_prefix.$session_id);
+ return FALSE;
+ }
+
+ $this->_lock_key = $lock_key;
+ break;
+ }
+
+ if ($attempt === 5)
+ {
+ log_message('error', 'Session: Unable to obtain lock for '.$this->_key_prefix.$session_id.' after 5 attempts, aborting.');
+ return FALSE;
+ }
+
+ $this->_lock = TRUE;
+ return TRUE;
+ }
+
+ // ------------------------------------------------------------------------
+
+ protected function _release_lock()
+ {
+ if (isset($this->_memcached, $this->_lock_key) && $this->_lock)
+ {
+ if ( ! $this->_memcached->delete($this->_lock_key) && $this->_memcached->getResultCode() !== Memcached::RES_NOTFOUND)
+ {
+ log_message('error', 'Session: Error while trying to free lock for '.$this->_key_prefix.$session_id);
+ return FALSE;
+ }
+
+ $this->_lock_key = NULL;
+ $this->_lock = FALSE;
+ }
+
+ return TRUE;
+ }
+
+}
+
+/* End of file Session_memcached_driver.php */
+/* Location: ./system/libraries/Session/drivers/Session_memcached_driver.php */
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