CI_Session_memcached_driver - Code Metrics - Inspection of "Merge pull request #142 from dev-ggallon/f/Update_..." - ci-bonfire/Sprint - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — develop ( 7d455c...f6fa23 )

by Lonnie

created 2015-12-15 19:11 UTC

CI_Session_memcached_driver B

↳ Parent: Project

Complexity

Total Complexity

Size/Duplication

Total Lines	320
Duplicated Lines	28.44 %

Coupling/Cohesion

Components	1
Dependencies	1

Metric	Value
wmc	42
lcom	1
cbo	1
dl	91
loc	320
rs	8.2951

9 Methods

Rating	Name	Duplication	Size	Complexity
A	__construct()	4	14	3
C	open()	0	44	8
A	read()	14	14	3
D	write()	39	39	9
A	close()	0	16	4
A	destroy()	0	11	2
A	gc()	0	5	1
C	_get_lock()	18	40	7
B	_release_lock()	16	16	5

How to fix Duplicated Code Complexity

Duplicated Code

Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.

Common duplication problems, and corresponding solutions are:

If you have the same expression in different places: Extract expression to a method
If you have the same method in different sub-classes: Extract method, and pull up field to the parent class
If you have the same code in unrelated classes: Consider extracting the code to a new class, and injecting that class

Complex Class

Tip: Before tackling complexity, make sure that you eliminate any duplication first. This often can reduce the size of classes significantly.

Complex classes like CI_Session_memcached_driver often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.

Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.

While breaking up the class, it is a good idea to analyze how other classes use CI_Session_memcached_driver, and based on these observations, apply Extract Interface, too.

<?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'].':';
		}
	}

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

	/**
	 * Open
	 *
	 * Sanitizes save_path and initializes connections.
	 *
	 * @param	string	$save_path	Server path(s)
	 * @param	string	$name		Session cookie name, unused
	 * @return	bool
	 */
	public function open($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 $this->_failure;
		}

		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 $this->_failure;
		}

		return $this->_success;
	}

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

	/**
	 * 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->_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 $this->_failure;
	}

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

	/**
	 * 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->_memcached))
		{
			return $this->_failure;
		}
		// Was the ID regenerated?
		elseif ($session_id !== $this->_session_id)
		{
			if ( ! $this->_release_lock() OR ! $this->_get_lock($session_id))
			{
				return $this->_failure;
			}

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

		if (isset($this->_lock_key))
		{
			$this->_memcached->replace($this->_lock_key, time(), 300);
			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 $this->_success;
				}

				return $this->_failure;
			}

			return $this->_memcached->touch($this->_key_prefix.$session_id, $this->_config['expiration'])
				? $this->_success
				: $this->_failure;
		}

		return $this->_failure;
	}

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

	/**
	 * Close
	 *
	 * Releases locks and closes connection.
	 *
	 * @return	bool
	 */
	public function close()
	{
		if (isset($this->_memcached))
		{
			isset($this->_lock_key) && $this->_memcached->delete($this->_lock_key);
			if ( ! $this->_memcached->quit())
			{
				return $this->_failure;
			}

			$this->_memcached = NULL;
			return $this->_success;
		}

		return $this->_failure;
	}

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

	/**
	 * Destroy
	 *
	 * Destroys the current session.
	 *
	 * @param	string	$session_id	Session ID
	 * @return	bool
	 */
	public function destroy($session_id)
	{
		if (isset($this->_memcached, $this->_lock_key))
		{
			$this->_memcached->delete($this->_key_prefix.$session_id);
			$this->_cookie_destroy();
			return $this->_success;
		}

		return $this->_failure;
	}

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

	/**
	 * Garbage Collector
	 *
	 * Deletes expired sessions
	 *
	 * @param	int 	$maxlifetime	Maximum lifetime of sessions
	 * @return	bool
	 */
	public function gc($maxlifetime)
	{
		// Not necessary, Memcached 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)
	{
		if (isset($this->_lock_key))
		{
			return ($this->_memcached->replace($this->_lock_key, time(), 300))
				? $this->_success
				: $this->_failure;
		}

		// 30 attempts to obtain a lock, in case another request already has it
		$lock_key = $this->_key_prefix.$session_id.':lock';
		$attempt = 0;
		do
		{
			if ($this->_memcached->get($lock_key))
			{
				sleep(1);
				continue;
			}

			if ( ! $this->_memcached->set($lock_key, time(), 300))
			{
				log_message('error', 'Session: Error while trying to obtain lock for '.$this->_key_prefix.$session_id);
				return $this->_failure;
			}

			$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 $this->_failure;
		}

		$this->_lock = TRUE;
		return $this->_success;
	}

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

	/**
	 * Release lock
	 *
	 * Releases a previously acquired lock
	 *
	 * @return	bool
	 */
	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->_lock_key);
				return FALSE;
			}

			$this->_lock_key = NULL;
			$this->_lock = FALSE;
		}

		return TRUE;
	}

}


1		<?php
2		/**
3		* CodeIgniter
4		*
5		* An open source application development framework for PHP
6		*
7		* This content is released under the MIT License (MIT)
8		*
9		* Copyright (c) 2014 - 2015, British Columbia Institute of Technology
10		*
11		* Permission is hereby granted, free of charge, to any person obtaining a copy
12		* of this software and associated documentation files (the "Software"), to deal
13		* in the Software without restriction, including without limitation the rights
14		* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
15		* copies of the Software, and to permit persons to whom the Software is
16		* furnished to do so, subject to the following conditions:
17		*
18		* The above copyright notice and this permission notice shall be included in
19		* all copies or substantial portions of the Software.
20		*
21		* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
22		* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
23		* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
24		* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
25		* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
26		* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
27		* THE SOFTWARE.
28		*
29		* @package CodeIgniter
30		* @author EllisLab Dev Team
31		* @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
32		* @copyright Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
33		* @license http://opensource.org/licenses/MIT MIT License
34		* @link http://codeigniter.com
35		* @since Version 3.0.0
36		* @filesource
37		*/
38		defined('BASEPATH') OR exit('No direct script access allowed');
39
40		/**
41		* CodeIgniter Session Memcached Driver
42		*
43		* @package CodeIgniter
44		* @subpackage Libraries
45		* @category Sessions
46		* @author Andrey Andreev
47		* @link http://codeigniter.com/user_guide/libraries/sessions.html
48		*/
49		class CI_Session_memcached_driver extends CI_Session_driver implements SessionHandlerInterface {
50
51		/**
52		* Memcached instance
53		*
54		* @var Memcached
55		*/
56		protected $_memcached;
57
58		/**
59		* Key prefix
60		*
61		* @var string
62		*/
63		protected $_key_prefix = 'ci_session:';
64
65		/**
66		* Lock key
67		*
68		* @var string
69		*/
70		protected $_lock_key;
71
72		// ------------------------------------------------------------------------
73
74		/**
75		* Class constructor
76		*
77		* @param array $params Configuration parameters
78		* @return void
79		*/
80		public function __construct(&$params)
81		{
82		parent::__construct($params);
83
84		if (empty($this->_config['save_path']))
85		{
86		log_message('error', 'Session: No Memcached save path configured.');
87		}
88
89	View Code Duplication	if ($this->_config['match_ip'] === TRUE)
90		{
91		$this->_key_prefix .= $_SERVER['REMOTE_ADDR'].':';
92		}
93		}
94
95		// ------------------------------------------------------------------------
96
97		/**
98		* Open
99		*
100		* Sanitizes save_path and initializes connections.
101		*
102		* @param string $save_path Server path(s)
103		* @param string $name Session cookie name, unused
104		* @return bool
105		*/
106		public function open($save_path, $name)
107		{
108		$this->_memcached = new Memcached();
109		$this->_memcached->setOption(Memcached::OPT_BINARY_PROTOCOL, TRUE); // required for touch() usage
110		$server_list = array();
111		foreach ($this->_memcached->getServerList() as $server)
112		{
113		$server_list[] = $server['host'].':'.$server['port'];
114		}
115
116		if ( ! preg_match_all('#,?([^,:]+)\:(\d{1,5})(?:\:(\d+))?#', $this->_config['save_path'], $matches, PREG_SET_ORDER))
117		{
118		$this->_memcached = NULL;
119		log_message('error', 'Session: Invalid Memcached save path format: '.$this->_config['save_path']);
120		return $this->_failure;
121		}
122
123		foreach ($matches as $match)
124		{
125		// If Memcached already has this server (or if the port is invalid), skip it
126		if (in_array($match[1].':'.$match[2], $server_list, TRUE))
127		{
128		log_message('debug', 'Session: Memcached server pool already has '.$match[1].':'.$match[2]);
129		continue;
130		}
131
132		if ( ! $this->_memcached->addServer($match[1], $match[2], isset($match[3]) ? $match[3] : 0))
133		{
134		log_message('error', 'Could not add '.$match[1].':'.$match[2].' to Memcached server pool.');
135		}
136		else
137		{
138		$server_list[] = $match[1].':'.$match[2];
139		}
140		}
141
142		if (empty($server_list))
143		{
144		log_message('error', 'Session: Memcached server pool is empty.');
145		return $this->_failure;
146		}
147
148		return $this->_success;
149		}
150
151		// ------------------------------------------------------------------------
152
153		/**
154		* Read
155		*
156		* Reads session data and acquires a lock
157		*
158		* @param string $session_id Session ID
159		* @return string Serialized session data
160		*/
161	View Code Duplication	public function read($session_id)
162		{
163		if (isset($this->_memcached) && $this->_get_lock($session_id))
164		{
165		// Needed by write() to detect session_regenerate_id() calls
166		$this->_session_id = $session_id;
167
168		$session_data = (string) $this->_memcached->get($this->_key_prefix.$session_id);
169		$this->_fingerprint = md5($session_data);
170		return $session_data;
171		}
172
173		return $this->_failure;
174		}
175
176		// ------------------------------------------------------------------------
177
178		/**
179		* Write
180		*
181		* Writes (create / update) session data
182		*
183		* @param string $session_id Session ID
184		* @param string $session_data Serialized session data
185		* @return bool
186		*/
187	View Code Duplication	public function write($session_id, $session_data)
188		{
189		if ( ! isset($this->_memcached))
190		{
191		return $this->_failure;
192		}
193		// Was the ID regenerated?
194		elseif ($session_id !== $this->_session_id)
195		{
196		if ( ! $this->_release_lock() OR ! $this->_get_lock($session_id))
197		{
198		return $this->_failure;
199		}
200
201		$this->_fingerprint = md5('');
202		$this->_session_id = $session_id;
203		}
204
205		if (isset($this->_lock_key))
206		{
207		$this->_memcached->replace($this->_lock_key, time(), 300);
208		if ($this->_fingerprint !== ($fingerprint = md5($session_data)))
209		{
210		if ($this->_memcached->set($this->_key_prefix.$session_id, $session_data, $this->_config['expiration']))
211		{
212		$this->_fingerprint = $fingerprint;
213		return $this->_success;
214		}
215
216		return $this->_failure;
217		}
218
219		return $this->_memcached->touch($this->_key_prefix.$session_id, $this->_config['expiration'])
220		? $this->_success
221		: $this->_failure;
222		}
223
224		return $this->_failure;
225		}
226
227		// ------------------------------------------------------------------------
228
229		/**
230		* Close
231		*
232		* Releases locks and closes connection.
233		*
234		* @return bool
235		*/
236		public function close()
237		{
238		if (isset($this->_memcached))
239		{
240		isset($this->_lock_key) && $this->_memcached->delete($this->_lock_key);
241		if ( ! $this->_memcached->quit())
242		{
243		return $this->_failure;
244		}
245
246		$this->_memcached = NULL;
247		return $this->_success;
248		}
249
250		return $this->_failure;
251		}
252
253		// ------------------------------------------------------------------------
254
255		/**
256		* Destroy
257		*
258		* Destroys the current session.
259		*
260		* @param string $session_id Session ID
261		* @return bool
262		*/
263		public function destroy($session_id)
264		{
265		if (isset($this->_memcached, $this->_lock_key))
266		{
267		$this->_memcached->delete($this->_key_prefix.$session_id);
268		$this->_cookie_destroy();
269		return $this->_success;
270		}
271
272		return $this->_failure;
273		}
274
275		// ------------------------------------------------------------------------
276
277		/**
278		* Garbage Collector
279		*
280		* Deletes expired sessions
281		*
282		* @param int $maxlifetime Maximum lifetime of sessions
283		* @return bool
284		*/
285		public function gc($maxlifetime)
286		{
287		// Not necessary, Memcached takes care of that.
288		return $this->_success;
289		}
290
291		// ------------------------------------------------------------------------
292
293		/**
294		* Get lock
295		*
296		* Acquires an (emulated) lock.
297		*
298		* @param string $session_id Session ID
299		* @return bool
300		*/
301		protected function _get_lock($session_id)
302		{
303		if (isset($this->_lock_key))
304		{
305		return ($this->_memcached->replace($this->_lock_key, time(), 300))
306		? $this->_success
307		: $this->_failure;
308		}
309
310		// 30 attempts to obtain a lock, in case another request already has it
311		$lock_key = $this->_key_prefix.$session_id.':lock';
312		$attempt = 0;
313	View Code Duplication	do
314		{
315		if ($this->_memcached->get($lock_key))
316		{
317		sleep(1);
318		continue;
319		}
320
321		if ( ! $this->_memcached->set($lock_key, time(), 300))
322		{
323		log_message('error', 'Session: Error while trying to obtain lock for '.$this->_key_prefix.$session_id);
324		return $this->_failure;
325		}
326
327		$this->_lock_key = $lock_key;
328		break;
329		}
330		while (++$attempt < 30);
331
332		if ($attempt === 30)
333		{
334		log_message('error', 'Session: Unable to obtain lock for '.$this->_key_prefix.$session_id.' after 30 attempts, aborting.');
335		return $this->_failure;
336		}
337
338		$this->_lock = TRUE;
339		return $this->_success;
340		}
341
342		// ------------------------------------------------------------------------
343
344		/**
345		* Release lock
346		*
347		* Releases a previously acquired lock
348		*
349		* @return bool
350		*/
351	View Code Duplication	protected function _release_lock()
352		{
353		if (isset($this->_memcached, $this->_lock_key) && $this->_lock)
354		{
355		if ( ! $this->_memcached->delete($this->_lock_key) && $this->_memcached->getResultCode() !== Memcached::RES_NOTFOUND)
356		{
357		log_message('error', 'Session: Error while trying to free lock for '.$this->_lock_key);
358		return FALSE;
359		}
360
361		$this->_lock_key = NULL;
362		$this->_lock = FALSE;
363		}
364
365		return TRUE;
366		}
367
368		}
369

ci-bonfire / Sprint

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