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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) 2014-2019 British Columbia Institute of Technology
* Copyright (c) 2019 CodeIgniter Foundation
*
* 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 CodeIgniter Dev Team
* @copyright 2019 CodeIgniter Foundation
* @license https://opensource.org/licenses/MIT MIT License
* @link https://codeigniter.com
* @since Version 4.0.0
* @filesource
*/
namespace CodeIgniter\Session\Handlers;
use CodeIgniter\Config\BaseConfig;
use CodeIgniter\Session\Exceptions\SessionException;
/**
* Session handler using Redis for persistence
*/
class RedisHandler extends BaseHandler implements \SessionHandlerInterface
{
/**
* phpRedis instance
*
* @var resource
*/
protected $redis;
/**
* Key prefix
*
* @var string
*/
protected $keyPrefix = 'ci_session:';
/**
* Lock key
*
* @var string
*/
protected $lockKey;
/**
* Key exists flag
*
* @var boolean
*/
protected $keyExists = false;
/**
* Number of seconds until the session ends.
*
* @var integer
*/
protected $sessionExpiration = 7200;
//--------------------------------------------------------------------
/**
* Constructor
*
* @param BaseConfig $config
* @param string $ipAddress
*
* @throws \Exception
*/
public function __construct(BaseConfig $config, string $ipAddress)
{
parent::__construct($config, $ipAddress);
if (empty($this->savePath))
{
throw SessionException::forEmptySavepath();
}
elseif (preg_match('#(?:tcp://)?([^:?]+)(?:\:(\d+))?(\?.+)?#', $this->savePath, $matches))
{
isset($matches[3]) || $matches[3] = ''; // Just to avoid undefined index notices below
$this->savePath = [
'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->keyPrefix = $match[1];
}
else
{
throw SessionException::forInvalidSavePathFormat($this->savePath);
}
if ($this->matchIP === true)
{
$this->keyPrefix .= $this->ipAddress . ':';
}
$this->sessionExpiration = $config->sessionExpiration;
}
//--------------------------------------------------------------------
/**
* Open
*
* Sanitizes save_path and initializes connection.
*
* @param string $save_path Server path
* @param string $name Session cookie name, unused
* @return boolean
*/
public function open($save_path, $name): bool
{
if (empty($this->savePath))
{
return false;
}
$redis = new \Redis();
if (! $redis->connect($this->savePath['host'], $this->savePath['port'], $this->savePath['timeout']))
{
$this->logger->error('Session: Unable to connect to Redis with the configured settings.');
}
elseif (isset($this->savePath['password']) && ! $redis->auth($this->savePath['password']))
{
$this->logger->error('Session: Unable to authenticate to Redis instance.');
}
elseif (isset($this->savePath['database']) && ! $redis->select($this->savePath['database']))
{
$this->logger->error('Session: Unable to select Redis database with index ' . $this->savePath['database']);
}
else
{
$this->redis = $redis;
return true;
}
return false;
}
//--------------------------------------------------------------------
/**
* Read
*
* Reads session data and acquires a lock
*
* @param string $sessionID Session ID
*
* @return string|false Serialized session data
*/
public function read($sessionID): string
{
if (isset($this->redis) && $this->lockSession($sessionID))
{
// Needed by write() to detect session_regenerate_id() calls
if (is_null($this->sessionID))
{
$this->sessionID = $sessionID;
}
$session_data = $this->redis->get($this->keyPrefix . $sessionID);
is_string($session_data) ? $this->keyExists = true : $session_data = '';
$this->fingerprint = md5($session_data);
return $session_data;
}
return '';
}
//--------------------------------------------------------------------
/**
* Write
*
* Writes (create / update) session data
*
* @param string $sessionID Session ID
* @param string $sessionData Serialized session data
*
* @return boolean
*/
public function write($sessionID, $sessionData): bool
{
if (! isset($this->redis))
{
return false;
}
// Was the ID regenerated?
elseif ($sessionID !== $this->sessionID)
{
if (! $this->releaseLock() || ! $this->lockSession($sessionID))
{
return false;
}
$this->keyExists = false;
$this->sessionID = $sessionID;
}
if (isset($this->lockKey))
{
$this->redis->expire($this->lockKey, 300);
if ($this->fingerprint !== ($fingerprint = md5($sessionData)) || $this->keyExists === false)
{
if ($this->redis->set($this->keyPrefix . $sessionID, $sessionData, $this->sessionExpiration))
{
$this->fingerprint = $fingerprint;
$this->keyExists = true;
return true;
}
return false;
}
return $this->redis->expire($this->keyPrefix . $sessionID, $this->sessionExpiration);
}
return false;
}
//--------------------------------------------------------------------
/**
* Close
*
* Releases locks and closes connection.
*
* @return boolean
*/
public function close(): bool
{
if (isset($this->redis))
{
try
{
$ping_reply = $this->redis->ping();
if (($ping_reply === true) || ($ping_reply === '+PONG'))
{
isset($this->lockKey) && $this->redis->del($this->lockKey);
if (! $this->redis->close())
{
return false;
}
}
}
catch (\RedisException $e)
{
$this->logger->error('Session: Got RedisException on close(): ' . $e->getMessage());
}
$this->redis = null;
return true;
}
return true;
}
//--------------------------------------------------------------------
/**
* Destroy
*
* Destroys the current session.
*
* @param string $sessionID
*
* @return boolean
*/
public function destroy($sessionID): bool
{
if (isset($this->redis, $this->lockKey))
{
if (($result = $this->redis->del($this->keyPrefix . $sessionID)) !== 1)
{
$this->logger->debug('Session: Redis::del() expected to return 1, got ' . var_export($result, true) . ' instead.');
}
return $this->destroyCookie();
}
return false;
}
//--------------------------------------------------------------------
/**
* Garbage Collector
*
* Deletes expired sessions
*
* @param integer $maxlifetime Maximum lifetime of sessions
* @return boolean
*/
public function gc($maxlifetime): bool
{
// Not necessary, Redis takes care of that.
return true;
}
//--------------------------------------------------------------------
/**
* Get lock
*
* Acquires an (emulated) lock.
*
* @param string $sessionID Session ID
*
* @return boolean
*/
protected function lockSession(string $sessionID): bool
{
// PHP 7 reuses the SessionHandler object on regeneration,
// so we need to check here if the lock key is for the
// correct session ID.
if ($this->lockKey === $this->keyPrefix . $sessionID . ':lock')
{
return $this->redis->expire($this->lockKey, 300);
}
// 30 attempts to obtain a lock, in case another request already has it
$lock_key = $this->keyPrefix . $sessionID . ':lock';
$attempt = 0;
do
{
if (($ttl = $this->redis->ttl($lock_key)) > 0)
{
sleep(1);
continue;
}
if (! $this->redis->setex($lock_key, 300, time()))
{
$this->logger->error('Session: Error while trying to obtain lock for ' . $this->keyPrefix . $sessionID);
return false;
}
$this->lockKey = $lock_key;
break;
}
while (++ $attempt < 30);
if ($attempt === 30)
{
log_message('error', 'Session: Unable to obtain lock for ' . $this->keyPrefix . $sessionID . ' after 30 attempts, aborting.');
return false;
}
elseif ($ttl === -1)
{
log_message('debug', 'Session: Lock for ' . $this->keyPrefix . $sessionID . ' had no TTL, overriding.');
}
$this->lock = true;
return true;
}
//--------------------------------------------------------------------
/**
* Release lock
*
* Releases a previously acquired lock
*
* @return boolean
*/
protected function releaseLock(): bool
{
if (isset($this->redis, $this->lockKey) && $this->lock)
{
if (! $this->redis->del($this->lockKey))
{
$this->logger->error('Session: Error while trying to free lock for ' . $this->lockKey);
return false;
}
$this->lockKey = null;
$this->lock = false;
}
return true;
}
//--------------------------------------------------------------------
}