summaryrefslogtreecommitdiffstats
path: root/system/libraries/Session/drivers/Session_redis_driver.php
blob: 0562301b2b3e2d8b81e80d03e2359b71b82c1079 (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
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2018, 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 - 2018, British Columbia Institute of Technology (https://bcit.ca/)
 * @license	https://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($this->_config['save_path']))
		{
			log_message('error', 'Session: No Redis save path configured.');
		}
		elseif (preg_match('#^unix://([^\?]+)(?<options>\?.+)?$#', $this->_config['save_path'], $matches))
		{
			$save_path = array('path' => $matches[1]);
		}
		elseif (preg_match('#(?:tcp://)?([^:?]+)(?:\:(\d+))?(?<options>\?.+)?#', $this->_config['save_path'], $matches))
		{
			$save_path = array(
				'host'    => $matches[1],
				'port'    => empty($matches[2]) ? NULL : $matches[2],
				'timeout' => NULL // We always pass this to Redis::connect(), so it needs to exist
			);
		}
		else
		{
			log_message('error', 'Session: Invalid Redis save path format: '.$this->_config['save_path']);
		}

		if (isset($save_path))
		{
			if (isset($matches['options']))
			{
				$save_path['password'] = preg_match('#auth=([^\s&]+)#', $matches['options'], $match) ? $match[1] : NULL;
				$save_path['database'] = preg_match('#database=(\d+)#', $matches['options'], $match) ? (int) $match[1] : NULL;
				$save_path['timeout']  = preg_match('#timeout=(\d+\.\d+)#', $matches['options'], $match) ? (float) $match[1] : NULL;

				preg_match('#prefix=([^\s&]+)#', $matches['options'], $match) && $this->_key_prefix = $match[1];
			}

			$this->_config['save_path'] = $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();
		$connected = isset($this->_config['save_path']['path'])
			? $redis->connect($this->_config['save_path']['path'])
			: $redis->connect(
				$this->_config['save_path']['host'],
				$this->_config['save_path']['port'],
				$this->_config['save_path']['timeout']
			);

		if ($connected)
		{
			if (isset($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;
			}
		}
		else
		{
			log_message('error', 'Session: Unable to connect to Redis with the configured settings.');
		}

		$this->php5_validate_id();

		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;
	}

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

	/**
	 * Validate ID
	 *
	 * Checks whether a session ID record exists server-side,
	 * to enforce session.use_strict_mode.
	 *
	 * @param	string	$id
	 * @return	bool
	 */
	public function validateId($id)
	{
		return (bool) $this->_redis->exists($this->_key_prefix.$id);
	}

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

	/**
	 * 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;
	}

}