summaryrefslogtreecommitdiffstats
path: root/system/libraries/Session/drivers/Session_memcached_driver.php
blob: e2b568f5212e615b276775471a319ab2b4770060 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2015, 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. (http://ellislab.com/)
 * @copyright	Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
 * @license	http://opensource.org/licenses/MIT	MIT License
 * @link	http://codeigniter.com
 * @since	Version 3.0.0
 * @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 {

	/**
	 * 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->_config['save_path']))
		{
			log_message('error', 'Session: No Memcached save path configured.');
		}

		if ($this->_config['match_ip'] === TRUE)
		{
			$this->_key_prefix .= $_SERVER['REMOTE_ADDR'].':';
		}
	}

	// ------------------------------------------------------------------------

	public function open($save_path, $name)
	{
		$this->_memcached = new Memcached();
		$this->_memcached->setOption(Memcached::OPT_BINARY_PROTOCOL, TRUE); // required for touch() usage
		$server_list = array();
		foreach ($this->_memcached->getServerList() as $server)
		{
			$server_list[] = $server['host'].':'.$server['port'];
		}

		if ( ! preg_match_all('#,?([^,:]+)\:(\d{1,5})(?:\:(\d+))?#', $this->_config['save_path'], $matches, PREG_SET_ORDER))
		{
			$this->_memcached = NULL;
			log_message('error', 'Session: Invalid Memcached save path format: '.$this->_config['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[] = $match[1].':'.$match[2];
			}
		}

		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))
		{
			// Needed by write() to detect session_regenerate_id() calls
			$this->_session_id = $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))
		{
			return FALSE;
		}
		// Was the ID regenerated?
		elseif ($session_id !== $this->_session_id)
		{
			if ( ! $this->_release_lock() OR ! $this->_get_lock($session_id))
			{
				return FALSE;
			}

			$this->_fingerprint = md5('');
			$this->_session_id = $session_id;
		}

		if (isset($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->_config['expiration']))
				{
					$this->_fingerprint = $fingerprint;
					return TRUE;
				}

				return FALSE;
			}

			return $this->_memcached->touch($this->_key_prefix.$session_id, $this->_config['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();
		}

		return FALSE;
	}

	// ------------------------------------------------------------------------

	public function gc($maxlifetime)
	{
		// Not necessary, Memcached takes care of that.
		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 */