summaryrefslogtreecommitdiff
path: root/framework/Caching/TDbCache.php
blob: d41edd09a8c1a8942e987289e061ede76e25036a (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
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
<?php
/**
 * TDbCache class file
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2014 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @version $Id: TDbCache.php 3245 2013-01-07 20:23:32Z ctrlaltca $
 * @package System.Caching
 */

Prado::using('System.Data.TDbConnection');

/**
 * TDbCache class
 *
 * TDbCache implements a cache application module by storing cached data in a database.
 *
 * TDbCache relies on {@link http://www.php.net/manual/en/ref.pdo.php PDO} to retrieve
 * data from databases. In order to use TDbCache, you need to enable the PDO extension
 * as well as the corresponding PDO DB driver. For example, to use SQLite database
 * to store cached data, you need both php_pdo and php_pdo_sqlite extensions.
 *
 * By default, TDbCache creates and uses an SQLite database under the application
 * runtime directory. You may change this default setting by specifying the following
 * properties:
 * - {@link setConnectionID ConnectionID} or
 * - {@link setConnectionString ConnectionString}, {@link setUsername Username} and {@link setPassword Pasword}.
 *
 * The cached data is stored in a table in the specified database.
 * By default, the name of the table is called 'pradocache'. If the table does not
 * exist in the database, it will be automatically created with the following structure:
 * <code>
 * CREATE TABLE pradocache (itemkey CHAR(128), value BLOB, expire INT)
 * CREATE INDEX IX_itemkey ON pradocache (itemkey)
 * CREATE INDEX IX_expire ON pradocache (expire)
 * </code>
 *
 * Note, some DBMS might not support BLOB type. In this case, replace 'BLOB' with a suitable
 * binary data type (e.g. LONGBLOB in MySQL, BYTEA in PostgreSQL.)
 *
 * Important: Make sure that the indices are non-unique!
 *
 * If you want to change the cache table name, or if you want to create the table by yourself,
 * you may set {@link setCacheTableName CacheTableName} and {@link setAutoCreateCacheTable AutoCreateCacheTableName} properties.
 *
 * {@link setFlushInterval FlushInterval} control how often expired items will be removed from cache.
 * If you prefer to remove expired items manualy e.g. via cronjob you can disable automatic deletion by setting FlushInterval to '0'.
 *
 * The following basic cache operations are implemented:
 * - {@link get} : retrieve the value with a key (if any) from cache
 * - {@link set} : store the value with a key into cache
 * - {@link add} : store the value only if cache does not have this key
 * - {@link delete} : delete the value with the specified key from cache
 * - {@link flush} : delete all values from cache
 *
 * Each value is associated with an expiration time. The {@link get} operation
 * ensures that any expired value will not be returned. The expiration time by
 * the number of seconds. A expiration time 0 represents never expire.
 *
 * By definition, cache does not ensure the existence of a value
 * even if it never expires. Cache is not meant to be an persistent storage.
 *
 * Do not use the same database file for multiple applications using TDbCache.
 * Also note, cache is shared by all user sessions of an application.
 *
 * Some usage examples of TDbCache are as follows,
 * <code>
 * $cache=new TDbCache;  // TDbCache may also be loaded as a Prado application module
 * $cache->init(null);
 * $cache->add('object',$object);
 * $object2=$cache->get('object');
 * </code>
 *
 * If loaded, TDbCache will register itself with {@link TApplication} as the
 * cache module. It can be accessed via {@link TApplication::getCache()}.
 *
 * TDbCache may be configured in application configuration file as follows
 * <code>
 * <module id="cache" class="System.Caching.TDbCache" />
 * </code>
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TDbCache.php 3245 2013-01-07 20:23:32Z ctrlaltca $
 * @package System.Caching
 * @since 3.1.0
 */
class TDbCache extends TCache
{
	/**
	 * @var string the ID of TDataSourceConfig module
	 */
	private $_connID='';
	/**
	 * @var TDbConnection the DB connection instance
	 */
	private $_db;
	/**
	 * @var string name of the DB cache table
	 */
	private $_cacheTable='pradocache';
	/**
	 * @var integer Interval expired items will be removed from cache
	 */
	private $_flushInterval=60;
	/**
	 * @var boolean
	 */
	private $_cacheInitialized = false;
	/**
	 * @var boolean
	 */
	private $_createCheck= false;
	/**
	 * @var boolean whether the cache DB table should be created automatically
	 */
	private $_autoCreate=true;
	private $_username='';
	private $_password='';
	private $_connectionString='';

	/**
	 * Destructor.
	 * Disconnect the db connection.
	 */
	public function __destruct()
	{
		if($this->_db!==null)
			$this->_db->setActive(false);
	}

	/**
	 * Initializes this module.
	 * This method is required by the IModule interface.
	 * attach {@link doInitializeCache} to TApplication.OnLoadStateComplete event
	 * attach {@link doFlushCacheExpired} to TApplication.OnSaveState event
	 *
	 * @param TXmlElement configuration for this module, can be null
	 */
	public function init($config)
	{
		$this -> getApplication() -> attachEventHandler('OnLoadStateComplete', array($this, 'doInitializeCache'));
		$this -> getApplication() -> attachEventHandler('OnSaveState', array($this, 'doFlushCacheExpired'));
		parent::init($config);
	}

	/**
	 * Event listener for TApplication.OnSaveState
	 * @return void
	 * @since 3.1.5
	 * @see flushCacheExpired
	 */
	public function doFlushCacheExpired()
	{
		$this->flushCacheExpired(false);
	}

	/**
	 * Event listener for TApplication.OnLoadStateComplete
	 *
	 * @return void
	 * @since 3.1.5
	 * @see initializeCache
	 */
	public function doInitializeCache()
	{
		$this->initializeCache();
	}

	/**
	 * Initialize TDbCache
	 *
	 * If {@link setAutoCreateCacheTable AutoCreateCacheTableName} is 'true' check existence of cache table
	 * and create table if does not exist.
	 *
	 * @param boolean Force override global state check
	 * @return void
	 * @throws TConfigurationException if any error happens during creating database or cache table.
	 * @since 3.1.5
	 */
	protected function initializeCache($force=false)
	{
		if($this->_cacheInitialized && !$force) return;
		$db=$this->getDbConnection();
		try
		{
			$key = 'TDbCache:' . $this->_cacheTable . ':created';
			if($force)
				$this -> _createCheck = false;
			else
				$this -> _createCheck = $this -> getApplication() -> getGlobalState($key, 0);

			if($this->_autoCreate && !$this -> _createCheck) {

				Prado::trace(($force ? 'Force initializing: ' : 'Initializing: ') . $this -> id . ', ' . $this->_cacheTable, 'System.Caching.TDbCache');

				$sql='SELECT 1 FROM '.$this->_cacheTable.' WHERE 0=1';
				$db->createCommand($sql)->queryScalar();

				$this -> _createCheck = true;
				$this -> getApplication() -> setGlobalState($key, time());
			}
		}
		catch(Exception $e)
		{
			// DB table not exists
			if($this->_autoCreate)
			{
				Prado::trace('Autocreate: ' . $this->_cacheTable, 'System.Caching.TDbCache');

				$driver=$db->getDriverName();
				if($driver==='mysql')
					$blob='LONGBLOB';
				else if($driver==='pgsql')
					$blob='BYTEA';
				else
					$blob='BLOB';

				$sql='CREATE TABLE '.$this->_cacheTable." (itemkey CHAR(128) PRIMARY KEY, value $blob, expire INTEGER)";
				$db->createCommand($sql)->execute();

				$sql='CREATE INDEX IX_expire ON ' . $this->_cacheTable . ' (expire)';
				$db->createCommand($sql)->execute();

				$this -> _createCheck = true;
				$this -> getApplication() -> setGlobalState($key, time());
			}
			else
				throw new TConfigurationException('db_cachetable_inexistent',$this->_cacheTable);
		}
		$this->_cacheInitialized = true;
	}

	/**
	 * Flush expired values from cache depending on {@link setFlushInterval FlushInterval}
	 * @param boolean override {@link setFlushInterval FlushInterval} and force deletion of expired items
	 * @return void
	 * @since 3.1.5
	 */
	public function flushCacheExpired($force=false)
	{
		$interval = $this -> getFlushInterval();
		if(!$force && $interval === 0) return;

		$key	= 'TDbCache:' . $this->_cacheTable . ':flushed';
		$now	= time();
		$next	= $interval + (integer)$this -> getApplication() -> getGlobalState($key, 0);

		if($force || $next <= $now)
		{
			if(!$this->_cacheInitialized) $this->initializeCache();
			Prado::trace(($force ? 'Force flush of expired items: ' : 'Flush expired items: ') . $this -> id . ', ' . $this->_cacheTable, 'System.Caching.TDbCache');
			$sql='DELETE FROM '.$this->_cacheTable.' WHERE expire<>0 AND expire<'.$now;
			$this->getDbConnection()->createCommand($sql)->execute();
			$this -> getApplication() -> setGlobalState($key, $now);
		}
	}

	/**
	 * @return integer Interval in sec expired items will be removed from cache. Default to 60
	 * @since 3.1.5
	 */
	public function getFlushInterval()
	{
		return $this->_flushInterval;
	}

	/**
	 * Sets interval expired items will be removed from cache
	 *
	 * To disable automatic deletion of expired items,
	 * e.g. for external flushing via cron you can set value to '0'
	 *
	 * @param integer Interval in sec
	 * @since 3.1.5
	 */
	public function setFlushInterval($value)
	{
		$this->_flushInterval = (integer) $value;
	}

	/**
	 * Creates the DB connection.
	 * @param string the module ID for TDataSourceConfig
	 * @return TDbConnection the created DB connection
	 * @throws TConfigurationException if module ID is invalid or empty
	 */
	protected function createDbConnection()
	{
		if($this->_connID!=='')
		{
			$config=$this->getApplication()->getModule($this->_connID);
			if($config instanceof TDataSourceConfig)
				return $config->getDbConnection();
			else
				throw new TConfigurationException('dbcache_connectionid_invalid',$this->_connID);
		}
		else
		{
			$db=new TDbConnection;
			if($this->_connectionString!=='')
			{
				$db->setConnectionString($this->_connectionString);
				if($this->_username!=='')
					$db->setUsername($this->_username);
				if($this->_password!=='')
					$db->setPassword($this->_password);
			}
			else
			{
				// default to SQLite3 database
				$dbFile=$this->getApplication()->getRuntimePath().'/sqlite3.cache';
				$db->setConnectionString('sqlite:'.$dbFile);
			}
			return $db;
		}
	}

	/**
	 * @return TDbConnection the DB connection instance
	 */
	public function getDbConnection()
	{
		if($this->_db===null)
			$this->_db=$this->createDbConnection();

		$this->_db->setActive(true);
		return $this->_db;
	}

	/**
	 * @return string the ID of a {@link TDataSourceConfig} module. Defaults to empty string, meaning not set.
	 * @since 3.1.1
	 */
	public function getConnectionID()
	{
		return $this->_connID;
	}

	/**
	 * Sets the ID of a TDataSourceConfig module.
	 * The datasource module will be used to establish the DB connection for this cache module.
	 * The database connection can also be specified via {@link setConnectionString ConnectionString}.
	 * When both ConnectionID and ConnectionString are specified, the former takes precedence.
	 * @param string ID of the {@link TDataSourceConfig} module
	 * @since 3.1.1
	 */
	public function setConnectionID($value)
	{
		$this->_connID=$value;
	}

	/**
	 * @return string The Data Source Name, or DSN, contains the information required to connect to the database.
	 */
	public function getConnectionString()
	{
		return $this->_connectionString;
	}

	/**
	 * @param string The Data Source Name, or DSN, contains the information required to connect to the database.
	 * @see http://www.php.net/manual/en/function.pdo-construct.php
	 */
	public function setConnectionString($value)
	{
		$this->_connectionString=$value;
	}

	/**
	 * @return string the username for establishing DB connection. Defaults to empty string.
	 */
	public function getUsername()
	{
		return $this->_username;
	}

	/**
	 * @param string the username for establishing DB connection
	 */
	public function setUsername($value)
	{
		$this->_username=$value;
	}

	/**
	 * @return string the password for establishing DB connection. Defaults to empty string.
	 */
	public function getPassword()
	{
		return $this->_password;
	}

	/**
	 * @param string the password for establishing DB connection
	 */
	public function setPassword($value)
	{
		$this->_password=$value;
	}

	/**
	 * @return string the name of the DB table to store cache content. Defaults to 'pradocache'.
	 * @see setAutoCreateCacheTable
	 */
	public function getCacheTableName()
	{
		return $this->_cacheTable;
	}

	/**
	 * Sets the name of the DB table to store cache content.
	 * Note, if {@link setAutoCreateCacheTable AutoCreateCacheTable} is false
	 * and you want to create the DB table manually by yourself,
	 * you need to make sure the DB table is of the following structure:
	 * <code>
	 * CREATE TABLE pradocache (itemkey CHAR(128), value BLOB, expire INT)
	 * CREATE INDEX IX_itemkey ON pradocache (itemkey)
	 * CREATE INDEX IX_expire ON pradocache (expire)
	 * </code>
	 *
	 * Note, some DBMS might not support BLOB type. In this case, replace 'BLOB' with a suitable
	 * binary data type (e.g. LONGBLOB in MySQL, BYTEA in PostgreSQL.)
	 *
	 * Important: Make sure that the indices are non-unique!
	 *
	 * @param string the name of the DB table to store cache content
	 * @see setAutoCreateCacheTable
	 */
	public function setCacheTableName($value)
	{
		$this->_cacheTable=$value;
	}

	/**
	 * @return boolean whether the cache DB table should be automatically created if not exists. Defaults to true.
	 * @see setAutoCreateCacheTable
	 */
	public function getAutoCreateCacheTable()
	{
		return $this->_autoCreate;
	}

	/**
	 * @param boolean whether the cache DB table should be automatically created if not exists.
	 * @see setCacheTableName
	 */
	public function setAutoCreateCacheTable($value)
	{
		$this->_autoCreate=TPropertyValue::ensureBoolean($value);
	}

	/**
	 * Retrieves a value from cache with a specified key.
	 * This is the implementation of the method declared in the parent class.
	 * @param string a unique key identifying the cached value
	 * @return string the value stored in cache, false if the value is not in the cache or expired.
	 */
	protected function getValue($key)
	{
		if(!$this->_cacheInitialized) $this->initializeCache();
		try {
			$sql='SELECT value FROM '.$this->_cacheTable.' WHERE itemkey=\''.$key.'\' AND (expire=0 OR expire>'.time().') ORDER BY expire DESC';
			$command=$this->getDbConnection()->createCommand($sql);
			return unserialize($command->queryScalar());
		}
		catch(Exception $e)
		{
			$this->initializeCache(true);
			return unserialize($command->queryScalar());
		}
	}

	/**
	 * Stores a value identified by a key in cache.
	 * This is the implementation of the method declared in the parent class.
	 *
	 * @param string the key identifying the value to be cached
	 * @param string the value to be cached
	 * @param integer the number of seconds in which the cached value will expire. 0 means never expire.
	 * @return boolean true if the value is successfully stored into cache, false otherwise
	 */
	protected function setValue($key,$value,$expire)
	{
		$this->deleteValue($key);
		return $this->addValue($key,$value,$expire);
	}

	/**
	 * Stores a value identified by a key into cache if the cache does not contain this key.
	 * This is the implementation of the method declared in the parent class.
	 *
	 * @param string the key identifying the value to be cached
	 * @param string the value to be cached
	 * @param integer the number of seconds in which the cached value will expire. 0 means never expire.
	 * @return boolean true if the value is successfully stored into cache, false otherwise
	 */
	protected function addValue($key,$value,$expire)
	{
		if(!$this->_cacheInitialized) $this->initializeCache();
		$expire=($expire<=0)?0:time()+$expire;
		$sql="INSERT INTO {$this->_cacheTable} (itemkey,value,expire) VALUES(:key,:value,$expire)";
		try
		{
			$command=$this->getDbConnection()->createCommand($sql);
			$command->bindValue(':key',$key,PDO::PARAM_STR);
			$command->bindValue(':value',serialize($value),PDO::PARAM_LOB);
			$command->execute();
			return true;
		}
		catch(Exception $e)
		{
			try
			{
				$this->initializeCache(true);
				$command->execute();
				return true;
			}
			catch(Exception $e)
			{
				return false;
			}
		}
	}

	/**
	 * Deletes a value with the specified key from cache
	 * This is the implementation of the method declared in the parent class.
	 * @param string the key of the value to be deleted
	 * @return boolean if no error happens during deletion
	 */
	protected function deleteValue($key)
	{
		if(!$this->_cacheInitialized) $this->initializeCache();
		try
		{
			$command=$this->getDbConnection()->createCommand("DELETE FROM {$this->_cacheTable} WHERE itemkey=:key");
			$command->bindValue(':key',$key,PDO::PARAM_STR);
			$command->execute();
			return true;
		}
		catch(Exception $e)
		{
			$this->initializeCache(true);
			$command->execute();
			return true;
		}
	}

	/**
	 * Deletes all values from cache.
	 * Be careful of performing this operation if the cache is shared by multiple applications.
	 */
	public function flush()
	{
		if(!$this->_cacheInitialized) $this->initializeCache();
		try
		{
			$command = $this->getDbConnection()->createCommand("DELETE FROM {$this->_cacheTable}");
			$command->execute();
		}
		catch(Exception $e)
		{
			try
			{
				$this->initializeCache(true);
				$command->execute();
				return true;
			}
			catch(Exception $e)
			{
				return false;
			}
		}
		return true;
	}
}