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<?php |
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/** |
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* @link http://www.yiiframework.com/ |
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* @copyright Copyright (c) 2008 Yii Software LLC |
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* @license http://www.yiiframework.com/license/ |
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*/ |
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namespace yii\widgets; |
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use Yii; |
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use yii\base\Widget; |
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use yii\caching\Cache; |
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use yii\caching\Dependency; |
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use yii\di\Instance; |
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/** |
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* FragmentCache is used by [[\yii\base\View]] to provide caching of page fragments. |
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* |
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* @property string|false $cachedContent The cached content. False is returned if valid content is not found |
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* in the cache. This property is read-only. |
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* |
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* @author Qiang Xue <[email protected]> |
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* @since 2.0 |
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*/ |
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class FragmentCache extends Widget |
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{ |
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/** |
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* @var Cache|array|string the cache object or the application component ID of the cache object. |
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* After the FragmentCache object is created, if you want to change this property, |
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* you should only assign it with a cache object. |
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* Starting from version 2.0.2, this can also be a configuration array for creating the object. |
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*/ |
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public $cache = 'cache'; |
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/** |
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* @var int number of seconds that the data can remain valid in cache. |
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* Use 0 to indicate that the cached data will never expire. |
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*/ |
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public $duration = 60; |
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/** |
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* @var array|Dependency the dependency that the cached content depends on. |
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* This can be either a [[Dependency]] object or a configuration array for creating the dependency object. |
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* For example, |
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* |
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* ```php |
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* [ |
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* 'class' => 'yii\caching\DbDependency', |
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* 'sql' => 'SELECT MAX(updated_at) FROM post', |
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* ] |
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* ``` |
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* |
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* would make the output cache depends on the last modified time of all posts. |
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* If any post has its modification time changed, the cached content would be invalidated. |
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*/ |
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public $dependency; |
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/** |
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* @var array list of factors that would cause the variation of the content being cached. |
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* Each factor is a string representing a variation (e.g. the language, a GET parameter). |
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* The following variation setting will cause the content to be cached in different versions |
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* according to the current application language: |
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* |
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* ```php |
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* [ |
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* Yii::$app->language, |
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* ] |
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* ``` |
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*/ |
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public $variations; |
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/** |
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* @var bool whether to enable the fragment cache. You may use this property to turn on and off |
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* the fragment cache according to specific setting (e.g. enable fragment cache only for GET requests). |
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*/ |
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public $enabled = true; |
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/** |
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* @var array a list of placeholders for embedding dynamic contents. This property |
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* is used internally to implement the content caching feature. Do not modify it. |
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*/ |
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public $dynamicPlaceholders; |
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/** |
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* Initializes the FragmentCache object. |
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*/ |
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public function init() |
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{ |
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parent::init(); |
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$this->cache = $this->enabled ? Instance::ensure($this->cache, Cache::className()) : null; |
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if ($this->cache instanceof Cache && $this->getCachedContent() === false) { |
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$this->getView()->cacheStack[] = $this; |
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ob_start(); |
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ob_implicit_flush(false); |
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} |
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} |
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/** |
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* Marks the end of content to be cached. |
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* Content displayed before this method call and after [[init()]] |
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* will be captured and saved in cache. |
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* This method does nothing if valid content is already found in cache. |
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*/ |
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public function run() |
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{ |
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if (($content = $this->getCachedContent()) !== false) { |
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echo $content; |
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} elseif ($this->cache instanceof Cache) { |
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array_pop($this->getView()->cacheStack); |
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$content = ob_get_clean(); |
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if ($content === false || $content === '') { |
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return; |
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} |
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if (is_array($this->dependency)) { |
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$this->dependency = Yii::createObject($this->dependency); |
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} |
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$data = [$content, $this->dynamicPlaceholders]; |
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$this->cache->set($this->calculateKey(), $data, $this->duration, $this->dependency); |
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if (empty($this->getView()->cacheStack) && !empty($this->dynamicPlaceholders)) { |
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$content = $this->updateDynamicContent($content, $this->dynamicPlaceholders); |
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} |
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echo $content; |
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} |
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} |
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/** |
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* @var string|bool the cached content. False if the content is not cached. |
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*/ |
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private $_content; |
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/** |
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* Returns the cached content if available. |
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* @return string|false the cached content. False is returned if valid content is not found in the cache. |
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*/ |
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public function getCachedContent() |
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{ |
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if ($this->_content === null) { |
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$this->_content = false; |
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if ($this->cache instanceof Cache) { |
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$key = $this->calculateKey(); |
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$data = $this->cache->get($key); |
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if (is_array($data) && count($data) === 2) { |
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list ($content, $placeholders) = $data; |
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if (is_array($placeholders) && count($placeholders) > 0) { |
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if (empty($this->getView()->cacheStack)) { |
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// outermost cache: replace placeholder with dynamic content |
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$content = $this->updateDynamicContent($content, $placeholders); |
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} |
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foreach ($placeholders as $name => $statements) { |
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$this->getView()->addDynamicPlaceholder($name, $statements); |
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} |
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} |
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$this->_content = $content; |
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} |
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} |
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} |
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return $this->_content; |
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} |
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/** |
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* Replaces placeholders in content by results of evaluated dynamic statements. |
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* |
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* @param string $content |
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* @param array $placeholders |
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* @return string final content |
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*/ |
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protected function updateDynamicContent($content, $placeholders) |
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{ |
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foreach ($placeholders as $name => $statements) { |
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$placeholders[$name] = $this->getView()->evaluateDynamicContent($statements); |
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} |
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return strtr($content, $placeholders); |
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} |
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/** |
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* Generates a unique key used for storing the content in cache. |
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* The key generated depends on both [[id]] and [[variations]]. |
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* @return mixed a valid cache key |
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*/ |
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protected function calculateKey() |
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{ |
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$factors = [__CLASS__, $this->getId()]; |
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if (is_array($this->variations)) { |
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foreach ($this->variations as $factor) { |
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$factors[] = $factor; |
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} |
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} |
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return $factors; |
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} |
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} |
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