Cache.php 18 KB
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
<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\caching;

use Yii;
use yii\base\Component;
use yii\base\InvalidConfigException;
use yii\helpers\StringHelper;

/**
 * Cache is the base class for cache classes supporting different cache storage implementation.
 *
 * A data item can be stored in cache by calling [[set()]] and be retrieved back
 * later (in the same or different request) by [[get()]]. In both operations,
 * a key identifying the data item is required. An expiration time and/or a [[Dependency|dependency]]
 * can also be specified when calling [[set()]]. If the data item expires or the dependency
 * changes at the time of calling [[get()]], the cache will return no data.
 *
 * A typical usage pattern of cache is like the following:
 *
 * ~~~
 * $key = 'demo';
 * $data = $cache->get($key);
 * if ($data === false) {
 *     // ...generate $data here...
 *     $cache->set($key, $data, $expire, $dependency);
 * }
 * ~~~
 *
 * Because Cache implements the ArrayAccess interface, it can be used like an array. For example,
 *
 * ~~~
 * $cache['foo'] = 'some data';
 * echo $cache['foo'];
 * ~~~
 *
 * Derived classes should implement the following methods:
 *
 * - [[getValue()]]: retrieve the value with a key (if any) from cache
 * - [[setValue()]]: store the value with a key into cache
 * - [[addValue()]]: store the value only if the cache does not have this key before
 * - [[deleteValue()]]: delete the value with the specified key from cache
 * - [[flushValues()]]: delete all values from cache
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
abstract class Cache extends Component implements \ArrayAccess
{
	/**
	 * @var string a string prefixed to every cache key so that it is unique. If not set,
	 * it will use a prefix generated from [[Application::id]]. You may set this property to be an empty string
	 * if you don't want to use key prefix. It is recommended that you explicitly set this property to some
	 * static value if the cached data needs to be shared among multiple applications.
	 *
	 * To ensure interoperability, only alphanumeric characters should be used.
	 */
	public $keyPrefix;
	/**
	 * @var array|boolean the functions used to serialize and unserialize cached data. Defaults to null, meaning
	 * using the default PHP `serialize()` and `unserialize()` functions. If you want to use some more efficient
	 * serializer (e.g. [igbinary](http://pecl.php.net/package/igbinary)), you may configure this property with
	 * a two-element array. The first element specifies the serialization function, and the second the deserialization
	 * function. If this property is set false, data will be directly sent to and retrieved from the underlying
	 * cache component without any serialization or deserialization. You should not turn off serialization if
	 * you are using [[Dependency|cache dependency]], because it relies on data serialization.
	 */
	public $serializer;


	/**
	 * Initializes the application component.
	 * This method overrides the parent implementation by setting default cache key prefix.
	 */
	public function init()
	{
		parent::init();
		if ($this->keyPrefix === null) {
			$this->keyPrefix = substr(md5(Yii::$app->id), 0, 5);
		}
	}

	/**
	 * Builds a normalized cache key from a given key.
	 *
	 * If the given key is a string containing alphanumeric characters only and no more than 32 characters,
	 * then the key will be returned back prefixed with [[keyPrefix]]. Otherwise, a normalized key
	 * is generated by serializing the given key, applying MD5 hashing, and prefixing with [[keyPrefix]].
	 *
	 * @param mixed $key the key to be normalized
	 * @return string the generated cache key
	 */
	protected function buildKey($key)
	{
		if (is_string($key)) {
			$key = ctype_alnum($key) && StringHelper::byteLength($key) <= 32 ? $key : md5($key);
		} else {
			$key = md5(json_encode($key));
		}
		return $this->keyPrefix . $key;
	}

	/**
	 * Retrieves a value from cache with a specified key.
	 * @param mixed $key a key identifying the cached value. This can be a simple string or
	 * a complex data structure consisting of factors representing the key.
	 * @return mixed the value stored in cache, false if the value is not in the cache, expired,
	 * or the dependency associated with the cached data has changed.
	 */
	public function get($key)
	{
		$key = $this->buildKey($key);
		$value = $this->getValue($key);
		if ($value === false || $this->serializer === false) {
			return $value;
		} elseif ($this->serializer === null) {
			$value = unserialize($value);
		} else {
			$value = call_user_func($this->serializer[1], $value);
		}
		if (is_array($value) && !($value[1] instanceof Dependency && $value[1]->getHasChanged($this))) {
			return $value[0];
		} else {
			return false;
		}
	}

	/**
	 * Checks whether a specified key exists in the cache.
	 * This can be faster than getting the value from the cache if the data is big.
	 * In case a cache does not support this feature natively, this method will try to simulate it
	 * but has no performance improvement over getting it.
	 * Note that this method does not check whether the dependency associated
	 * with the cached data, if there is any, has changed. So a call to [[get]]
	 * may return false while exists returns true.
	 * @param mixed $key a key identifying the cached value. This can be a simple string or
	 * a complex data structure consisting of factors representing the key.
	 * @return boolean true if a value exists in cache, false if the value is not in the cache or expired.
	 */
	public function exists($key)
	{
		$key = $this->buildKey($key);
		$value = $this->getValue($key);
		return $value !== false;
	}

	/**
	 * Retrieves multiple values from cache with the specified keys.
	 * Some caches (such as memcache, apc) allow retrieving multiple cached values at the same time,
	 * which may improve the performance. In case a cache does not support this feature natively,
	 * this method will try to simulate it.
	 * @param array $keys list of keys identifying the cached values
	 * @return array list of cached values corresponding to the specified keys. The array
	 * is returned in terms of (key, value) pairs.
	 * If a value is not cached or expired, the corresponding array value will be false.
	 */
	public function mget($keys)
	{
		$keyMap = [];
		foreach ($keys as $key) {
			$keyMap[$key] = $this->buildKey($key);
		}
		$values = $this->getValues(array_values($keyMap));
		$results = [];
		foreach ($keyMap as $key => $newKey) {
			$results[$key] = false;
			if (isset($values[$newKey])) {
				if ($this->serializer === false) {
					$results[$key] = $values[$newKey];
				} else {
					$value = $this->serializer === null ? unserialize($values[$newKey])
							: call_user_func($this->serializer[1], $values[$newKey]);

					if (is_array($value) && !($value[1] instanceof Dependency && $value[1]->getHasChanged($this))) {
						$results[$key] = $value[0];
					}
				}
			}
		}
		return $results;
	}

	/**
	 * Stores a value identified by a key into cache.
	 * If the cache already contains such a key, the existing value and
	 * expiration time will be replaced with the new ones, respectively.
	 *
	 * @param mixed $key a key identifying the value to be cached. This can be a simple string or
	 * a complex data structure consisting of factors representing the key.
	 * @param mixed $value the value to be cached
	 * @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
	 * @param Dependency $dependency dependency of the cached item. If the dependency changes,
	 * the corresponding value in the cache will be invalidated when it is fetched via [[get()]].
	 * This parameter is ignored if [[serializer]] is false.
	 * @return boolean whether the value is successfully stored into cache
	 */
	public function set($key, $value, $expire = 0, $dependency = null)
	{
		if ($dependency !== null && $this->serializer !== false) {
			$dependency->evaluateDependency($this);
		}
		if ($this->serializer === null) {
			$value = serialize([$value, $dependency]);
		} elseif ($this->serializer !== false) {
			$value = call_user_func($this->serializer[0], [$value, $dependency]);
		}
		$key = $this->buildKey($key);
		return $this->setValue($key, $value, $expire);
	}

	/**
	 * Stores multiple items in cache. Each item contains a value identified by a key.
	 * If the cache already contains such a key, the existing value and
	 * expiration time will be replaced with the new ones, respectively.
	 *
	 * @param array $items the items to be cached, as key-value pairs.
	 * @param integer $expire default number of seconds in which the cached values will expire. 0 means never expire.
	 * @param Dependency $dependency dependency of the cached items. If the dependency changes,
	 * the corresponding values in the cache will be invalidated when it is fetched via [[get()]].
	 * This parameter is ignored if [[serializer]] is false.
	 * @return boolean whether the items are successfully stored into cache
	 */
	public function mset($items, $expire = 0, $dependency = null)
	{
		if ($dependency !== null && $this->serializer !== false) {
			$dependency->evaluateDependency($this);
		}

		$data = [];
		foreach ($items as $key => $value) {
			$itemKey = $this->buildKey($key);
			if ($this->serializer === null) {
				$itemValue = serialize([$value, $dependency]);
			} elseif ($this->serializer !== false) {
				$itemValue = call_user_func($this->serializer[0], [$value, $dependency]);
			}

			$data[$itemKey] = $itemValue;
		}
		return $this->setValues($data, $expire);
	}

	/**
	 * Stores multiple items in cache. Each item contains a value identified by a key.
	 * If the cache already contains such a key, the existing value and expiration time will be preserved.
	 *
	 * @param array $items the items to be cached, as key-value pairs.
	 * @param integer $expire default number of seconds in which the cached values will expire. 0 means never expire.
	 * @param Dependency $dependency dependency of the cached items. If the dependency changes,
	 * the corresponding values in the cache will be invalidated when it is fetched via [[get()]].
	 * This parameter is ignored if [[serializer]] is false.
	 * @return boolean whether the items are successfully stored into cache
	 */
	public function madd($items, $expire = 0, $dependency = null)
	{
		if ($dependency !== null && $this->serializer !== false) {
			$dependency->evaluateDependency($this);
		}

		$data = [];
		foreach ($items as $key => $value) {
			$itemKey = $this->buildKey($key);
			if ($this->serializer === null) {
				$itemValue = serialize([$value, $dependency]);
			} elseif ($this->serializer !== false) {
				$itemValue = call_user_func($this->serializer[0], [$value, $dependency]);
			}

			$data[$itemKey] = $itemValue;
		}
		return $this->addValues($data, $expire);
	}

	/**
	 * Stores a value identified by a key into cache if the cache does not contain this key.
	 * Nothing will be done if the cache already contains the key.
	 * @param mixed $key a key identifying the value to be cached. This can be a simple string or
	 * a complex data structure consisting of factors representing the key.
	 * @param mixed $value the value to be cached
	 * @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
	 * @param Dependency $dependency dependency of the cached item. If the dependency changes,
	 * the corresponding value in the cache will be invalidated when it is fetched via [[get()]].
	 * This parameter is ignored if [[serializer]] is false.
	 * @return boolean whether the value is successfully stored into cache
	 */
	public function add($key, $value, $expire = 0, $dependency = null)
	{
		if ($dependency !== null && $this->serializer !== false) {
			$dependency->evaluateDependency($this);
		}
		if ($this->serializer === null) {
			$value = serialize([$value, $dependency]);
		} elseif ($this->serializer !== false) {
			$value = call_user_func($this->serializer[0], [$value, $dependency]);
		}
		$key = $this->buildKey($key);
		return $this->addValue($key, $value, $expire);
	}

	/**
	 * Deletes a value with the specified key from cache
	 * @param mixed $key a key identifying the value to be deleted from cache. This can be a simple string or
	 * a complex data structure consisting of factors representing the key.
	 * @return boolean if no error happens during deletion
	 */
	public function delete($key)
	{
		$key = $this->buildKey($key);
		return $this->deleteValue($key);
	}

	/**
	 * Deletes all values from cache.
	 * Be careful of performing this operation if the cache is shared among multiple applications.
	 * @return boolean whether the flush operation was successful.
	 */
	public function flush()
	{
		return $this->flushValues();
	}

	/**
	 * Retrieves a value from cache with a specified key.
	 * This method should be implemented by child classes to retrieve the data
	 * from specific cache storage.
	 * @param string $key a unique key identifying the cached value
	 * @return string|boolean the value stored in cache, false if the value is not in the cache or expired.
	 */
	abstract protected function getValue($key);

	/**
	 * Stores a value identified by a key in cache.
	 * This method should be implemented by child classes to store the data
	 * in specific cache storage.
	 * @param string $key the key identifying the value to be cached
	 * @param string $value the value to be cached
	 * @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
	 * @return boolean true if the value is successfully stored into cache, false otherwise
	 */
	abstract protected function setValue($key, $value, $expire);

	/**
	 * Stores a value identified by a key into cache if the cache does not contain this key.
	 * This method should be implemented by child classes to store the data
	 * in specific cache storage.
	 * @param string $key the key identifying the value to be cached
	 * @param string $value the value to be cached
	 * @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
	 * @return boolean true if the value is successfully stored into cache, false otherwise
	 */
	abstract protected function addValue($key, $value, $expire);

	/**
	 * Deletes a value with the specified key from cache
	 * This method should be implemented by child classes to delete the data from actual cache storage.
	 * @param string $key the key of the value to be deleted
	 * @return boolean if no error happens during deletion
	 */
	abstract protected function deleteValue($key);

	/**
	 * Deletes all values from cache.
	 * Child classes may implement this method to realize the flush operation.
	 * @return boolean whether the flush operation was successful.
	 */
	abstract protected function flushValues();

	/**
	 * Retrieves multiple values from cache with the specified keys.
	 * The default implementation calls [[getValue()]] multiple times to retrieve
	 * the cached values one by one. If the underlying cache storage supports multiget,
	 * this method should be overridden to exploit that feature.
	 * @param array $keys a list of keys identifying the cached values
	 * @return array a list of cached values indexed by the keys
	 */
	protected function getValues($keys)
	{
		$results = [];
		foreach ($keys as $key) {
			$results[$key] = $this->getValue($key);
		}
		return $results;
	}

	/**
	 * Stores multiple key-value pairs in cache.
	 * The default implementation calls [[setValue()]] multiple times store values one by one. If the underlying cache
	 * storage supports multiset, this method should be overridden to exploit that feature.
	 * @param array $data array where key corresponds to cache key while value is the value stored
	 * @param integer $expire the number of seconds in which the cached values will expire. 0 means never expire.
	 * @return array array of failed keys
	 */
	protected function setValues($data, $expire)
	{
		$failedKeys = [];
		foreach ($data as $key => $value)
		{
			if ($this->setValue($key, $value, $expire) === false) {
				$failedKeys[] = $key;
			}
		}
		return $failedKeys;
	}

	/**
	 * Adds multiple key-value pairs to cache.
	 * The default implementation calls [[addValue()]] multiple times add values one by one. If the underlying cache
	 * storage supports multiadd, this method should be overridden to exploit that feature.
	 * @param array $data array where key corresponds to cache key while value is the value stored
	 * @param integer $expire the number of seconds in which the cached values will expire. 0 means never expire.
	 * @return array array of failed keys
	 */
	protected function addValues($data, $expire)
	{
		$failedKeys = [];
		foreach ($data as $key => $value)
		{
			if ($this->addValue($key, $value, $expire) === false) {
				$failedKeys[] = $key;
			}
		}
		return $failedKeys;
	}

	/**
	 * Returns whether there is a cache entry with a specified key.
	 * This method is required by the interface ArrayAccess.
	 * @param string $key a key identifying the cached value
	 * @return boolean
	 */
	public function offsetExists($key)
	{
		return $this->get($key) !== false;
	}

	/**
	 * Retrieves the value from cache with a specified key.
	 * This method is required by the interface ArrayAccess.
	 * @param string $key a key identifying the cached value
	 * @return mixed the value stored in cache, false if the value is not in the cache or expired.
	 */
	public function offsetGet($key)
	{
		return $this->get($key);
	}

	/**
	 * Stores the value identified by a key into cache.
	 * If the cache already contains such a key, the existing value will be
	 * replaced with the new ones. To add expiration and dependencies, use the [[set()]] method.
	 * This method is required by the interface ArrayAccess.
	 * @param string $key the key identifying the value to be cached
	 * @param mixed $value the value to be cached
	 */
	public function offsetSet($key, $value)
	{
		$this->set($key, $value);
	}

	/**
	 * Deletes the value with the specified key from cache
	 * This method is required by the interface ArrayAccess.
	 * @param string $key the key of the value to be deleted
	 */
	public function offsetUnset($key)
	{
		$this->delete($key);
	}
}