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<?php
/**
* CodeIgniter
*
* An open source application development framework for PHP
*
* This content is released under the MIT License (MIT)
*
* Copyright (c) 2014 - 2017, British Columbia Institute of Technology
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
* @package CodeIgniter
* @author EllisLab Dev Team
* @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
* @copyright Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
* @license http://opensource.org/licenses/MIT MIT License
* @link https://codeigniter.com
* @since Version 3.0.0
* @filesource
*/
defined('BASEPATH') OR exit('No direct script access allowed');
/**
* CodeIgniter Session Redis Driver
*
* @package CodeIgniter
* @subpackage Libraries
* @category Sessions
* @author Andrey Andreev
* @link https://codeigniter.com/user_guide/libraries/sessions.html
*/
class CI_Session_redis_driver extends CI_Session_driver implements SessionHandlerInterface {
/**
* phpRedis instance
*
* @var Redis
*/
protected $_redis;
/**
* Key prefix
*
* @var string
*/
protected $_key_prefix = 'ci_session:';
/**
* Lock key
*
* @var string
*/
protected $_lock_key;
/**
* Key exists flag
*
* @var bool
*/
protected $_key_exists = FALSE;
// ------------------------------------------------------------------------
/**
* Class constructor
*
* @param array $params Configuration parameters
* @return void
*/
public function __construct(&$params)
{
parent::__construct($params);
if (empty($this->_config['save_path']))
{
log_message('error', 'Session: No Redis save path configured.');
}
elseif (preg_match('#(?:tcp://)?([^:?]+)(?:\:(\d+))?(\?.+)?#', $this->_config['save_path'], $matches))
{
isset($matches[3]) OR $matches[3] = ''; // Just to avoid undefined index notices below
$this->_config['save_path'] = array(
'host' => $matches[1],
'port' => empty($matches[2]) ? NULL : $matches[2],
'password' => preg_match('#auth=([^\s&]+)#', $matches[3], $match) ? $match[1] : NULL,
'database' => preg_match('#database=(\d+)#', $matches[3], $match) ? (int) $match[1] : NULL,
'timeout' => preg_match('#timeout=(\d+\.\d+)#', $matches[3], $match) ? (float) $match[1] : NULL
);
preg_match('#prefix=([^\s&]+)#', $matches[3], $match) && $this->_key_prefix = $match[1];
}
else
{
log_message('error', 'Session: Invalid Redis save path format: '.$this->_config['save_path']);
}
if ($this->_config['match_ip'] === TRUE)
{
$this->_key_prefix .= $_SERVER['REMOTE_ADDR'].':';
}
}
// ------------------------------------------------------------------------
/**
* Open
*
* Sanitizes save_path and initializes connection.
*
* @param string $save_path Server path
* @param string $name Session cookie name, unused
* @return bool
*/
public function open($save_path, $name)
{
if (empty($this->_config['save_path']))
{
return $this->_fail();
}
$redis = new Redis();
if ( ! $redis->connect($this->_config['save_path']['host'], $this->_config['save_path']['port'], $this->_config['save_path']['timeout']))
{
log_message('error', 'Session: Unable to connect to Redis with the configured settings.');
}
elseif (isset($this->_config['save_path']['password']) && ! $redis->auth($this->_config['save_path']['password']))
{
log_message('error', 'Session: Unable to authenticate to Redis instance.');
}
elseif (isset($this->_config['save_path']['database']) && ! $redis->select($this->_config['save_path']['database']))
{
log_message('error', 'Session: Unable to select Redis database with index '.$this->_config['save_path']['database']);
}
else
{
$this->_redis = $redis;
return $this->_success;
}
return $this->_fail();
}
// ------------------------------------------------------------------------
/**
* Read
*
* Reads session data and acquires a lock
*
* @param string $session_id Session ID
* @return string Serialized session data
*/
public function read($session_id)
{
if (isset($this->_redis) && $this->_get_lock($session_id))
{
// Needed by write() to detect session_regenerate_id() calls
$this->_session_id = $session_id;
$session_data = $this->_redis->get($this->_key_prefix.$session_id);
is_string($session_data)
? $this->_key_exists = TRUE
: $session_data = '';
$this->_fingerprint = md5($session_data);
return $session_data;
}
return $this->_fail();
}
// ------------------------------------------------------------------------
/**
* Write
*
* Writes (create / update) session data
*
* @param string $session_id Session ID
* @param string $session_data Serialized session data
* @return bool
*/
public function write($session_id, $session_data)
{
if ( ! isset($this->_redis, $this->_lock_key))
{
return $this->_fail();
}
// Was the ID regenerated?
elseif ($session_id !== $this->_session_id)
{
if ( ! $this->_release_lock() OR ! $this->_get_lock($session_id))
{
return $this->_fail();
}
$this->_key_exists = FALSE;
$this->_session_id = $session_id;
}
$this->_redis->setTimeout($this->_lock_key, 300);
if ($this->_fingerprint !== ($fingerprint = md5($session_data)) OR $this->_key_exists === FALSE)
{
if ($this->_redis->set($this->_key_prefix.$session_id, $session_data, $this->_config['expiration']))
{
$this->_fingerprint = $fingerprint;
$this->_key_exists = TRUE;
return $this->_success;
}
return $this->_fail();
}
return ($this->_redis->setTimeout($this->_key_prefix.$session_id, $this->_config['expiration']))
? $this->_success
: $this->_fail();
}
// ------------------------------------------------------------------------
/**
* Close
*
* Releases locks and closes connection.
*
* @return bool
*/
public function close()
{
if (isset($this->_redis))
{
try {
if ($this->_redis->ping() === '+PONG')
{
$this->_release_lock();
if ($this->_redis->close() === FALSE)
{
return $this->_fail();
}
}
}
catch (RedisException $e)
{
log_message('error', 'Session: Got RedisException on close(): '.$e->getMessage());
}
$this->_redis = NULL;
return $this->_success;
}
return $this->_success;
}
// ------------------------------------------------------------------------
/**
* Destroy
*
* Destroys the current session.
*
* @param string $session_id Session ID
* @return bool
*/
public function destroy($session_id)
{
if (isset($this->_redis, $this->_lock_key))
{
if (($result = $this->_redis->delete($this->_key_prefix.$session_id)) !== 1)
{
log_message('debug', 'Session: Redis::delete() expected to return 1, got '.var_export($result, TRUE).' instead.');
}
$this->_cookie_destroy();
return $this->_success;
}
return $this->_fail();
}
// ------------------------------------------------------------------------
/**
* Garbage Collector
*
* Deletes expired sessions
*
* @param int $maxlifetime Maximum lifetime of sessions
* @return bool
*/
public function gc($maxlifetime)
{
// Not necessary, Redis takes care of that.
return $this->_success;
}
// ------------------------------------------------------------------------
/**
* Get lock
*
* Acquires an (emulated) lock.
*
* @param string $session_id Session ID
* @return bool
*/
protected function _get_lock($session_id)
{
// PHP 7 reuses the SessionHandler object on regeneration,
// so we need to check here if the lock key is for the
// correct session ID.
if ($this->_lock_key === $this->_key_prefix.$session_id.':lock')
{
return $this->_redis->setTimeout($this->_lock_key, 300);
}
// 30 attempts to obtain a lock, in case another request already has it
$lock_key = $this->_key_prefix.$session_id.':lock';
$attempt = 0;
do
{
if (($ttl = $this->_redis->ttl($lock_key)) > 0)
{
sleep(1);
continue;
}
$result = ($ttl === -2)
? $this->_redis->set($lock_key, time(), array('nx', 'ex' => 300))
: $this->_redis->setex($lock_key, 300, time());
if ( ! $result)
{
log_message('error', 'Session: Error while trying to obtain lock for '.$this->_key_prefix.$session_id);
return FALSE;
}
$this->_lock_key = $lock_key;
break;
}
while (++$attempt < 30);
if ($attempt === 30)
{
log_message('error', 'Session: Unable to obtain lock for '.$this->_key_prefix.$session_id.' after 30 attempts, aborting.');
return FALSE;
}
elseif ($ttl === -1)
{
log_message('debug', 'Session: Lock for '.$this->_key_prefix.$session_id.' had no TTL, overriding.');
}
$this->_lock = TRUE;
return TRUE;
}
// ------------------------------------------------------------------------
/**
* Release lock
*
* Releases a previously acquired lock
*
* @return bool
*/
protected function _release_lock()
{
if (isset($this->_redis, $this->_lock_key) && $this->_lock)
{
if ( ! $this->_redis->delete($this->_lock_key))
{
log_message('error', 'Session: Error while trying to free lock for '.$this->_lock_key);
return FALSE;
}
$this->_lock_key = NULL;
$this->_lock = FALSE;
}
return TRUE;
}
}
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