yii2-bootstrap/framework/widgets/FragmentCache.php

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

namespace yii\widgets;

use yii\base\Widget;

/**
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class FragmentCache extends Widget
{
	/**
	 * Prefix to the keys for storing cached data
	 */
	const CACHE_KEY_PREFIX = 'Yii.COutputCache.';

	/**
	 * @var string the ID of the cache application component. Defaults to 'cache' (the primary cache application component.)
	 */
	public $cacheID = 'cache';
	/**
	 * @var integer number of seconds that the data can remain in cache. Defaults to 60 seconds.
	 * If it is 0, existing cached content would be removed from the cache.
	 * If it is a negative value, the cache will be disabled (any existing cached content will
	 * remain in the cache.)
	 *
	 * Note, if cache dependency changes or cache space is limited,
	 * the data may be purged out of cache earlier.
	 */
	public $duration = 60;
	/**
	 * @var mixed the dependency that the cached content depends on.
	 * This can be either an object implementing {@link ICacheDependency} interface or an array
	 * specifying the configuration of the dependency object. For example,
	 * <pre>
	 * array(
	 *     'class'=>'CDbCacheDependency',
	 *     'sql'=>'SELECT MAX(lastModified) FROM Post',
	 * )
	 * </pre>
	 * would make the output cache depends on the last modified time of all posts.
	 * If any post has its modification time changed, the cached content would be invalidated.
	 */
	public $dependency;
	/**
	 * @var boolean whether the content being cached should be differentiated according to route.
	 * A route consists of the requested controller ID and action ID.
	 * Defaults to true.
	 */
	public $varyByRoute = true;
	/**
	 * @var boolean whether the content being cached should be differentiated according to user's language.
	 * A language is retrieved via Yii::app()->language.
	 * Defaults to false.
	 * @since 1.1.14
	 */
	public $varyByLanguage = false;
	/**
	 * @var array list of GET parameters that should participate in cache key calculation.
	 * By setting this property, the output cache will use different cached data
	 * for each different set of GET parameter values.
	 */
	public $varyByParam;
	/**
	 * @var string a PHP expression whose result is used in the cache key calculation.
	 * By setting this property, the output cache will use different cached data
	 * for each different expression result.
	 * The expression can also be a valid PHP callback,
	 * including class method name (array(ClassName/Object, MethodName)),
	 * or anonymous function (PHP 5.3.0+). The function/method signature should be as follows:
	 * <pre>
	 * function foo($cache) { ... }
	 * </pre>
	 * where $cache refers to the output cache component.
	 */
	public $varyByExpression;
	/**
	 * @var array list of request types (e.g. GET, POST) for which the cache should be enabled only.
	 * Defaults to null, meaning all request types.
	 */
	public $requestTypes;

	private $_key;
	private $_cache;
	private $_contentCached;
	private $_content;
	private $_actions;

	/**
	 * Marks the start of content to be cached.
	 * Content displayed after this method call and before {@link endCache()}
	 * will be captured and saved in cache.
	 * This method does nothing if valid content is already found in cache.
	 */
	public function init()
	{
		if ($this->getIsContentCached()) {
			$this->replayActions();
		} elseif ($this->_cache !== null) {
			$this->getController()->getCachingStack()->push($this);
			ob_start();
			ob_implicit_flush(false);
		}
	}

	/**
	 * Marks the end of content to be cached.
	 * Content displayed before this method call and after {@link init()}
	 * will be captured and saved in cache.
	 * This method does nothing if valid content is already found in cache.
	 */
	public function run()
	{
		if ($this->getIsContentCached()) {
			if ($this->getController()->isCachingStackEmpty()) {
				echo $this->getController()->processDynamicOutput($this->_content);
			} else {
				echo $this->_content;
			}
		} elseif ($this->_cache !== null) {
			$this->_content = ob_get_clean();
			$this->getController()->getCachingStack()->pop();
			$data = array($this->_content, $this->_actions);
			if (is_array($this->dependency)) {
				$this->dependency = Yii::createComponent($this->dependency);
			}
			$this->_cache->set($this->getCacheKey(), $data, $this->duration, $this->dependency);

			if ($this->getController()->isCachingStackEmpty()) {
				echo $this->getController()->processDynamicOutput($this->_content);
			} else {
				echo $this->_content;
			}
		}
	}

	/**
	 * @return boolean whether the content can be found from cache
	 */
	public function getIsContentCached()
	{
		if ($this->_contentCached !== null) {
			return $this->_contentCached;
		} else {
			return $this->_contentCached = $this->checkContentCache();
		}
	}

	/**
	 * Looks for content in cache.
	 * @return boolean whether the content is found in cache.
	 */
	protected function checkContentCache()
	{
		if ((empty($this->requestTypes) || in_array(Yii::app()->getRequest()->getRequestType(), $this->requestTypes))
			&& ($this->_cache = $this->getCache()) !== null
		) {
			if ($this->duration > 0 && ($data = $this->_cache->get($this->getCacheKey())) !== false) {
				$this->_content = $data[0];
				$this->_actions = $data[1];
				return true;
			}
			if ($this->duration == 0) {
				$this->_cache->delete($this->getCacheKey());
			}
			if ($this->duration <= 0) {
				$this->_cache = null;
			}
		}
		return false;
	}

	/**
	 * @return ICache the cache used for caching the content.
	 */
	protected function getCache()
	{
		return Yii::app()->getComponent($this->cacheID);
	}

	/**
	 * Caclulates the base cache key.
	 * The calculated key will be further variated in {@link getCacheKey}.
	 * Derived classes may override this method if more variations are needed.
	 * @return string basic cache key without variations
	 */
	protected function getBaseCacheKey()
	{
		return self::CACHE_KEY_PREFIX . $this->getId() . '.';
	}

	/**
	 * Calculates the cache key.
	 * The key is calculated based on {@link getBaseCacheKey} and other factors, including
	 * {@link varyByRoute}, {@link varyByParam}, {@link varyBySession} and {@link varyByLanguage}.
	 * @return string cache key
	 */
	protected function getCacheKey()
	{
		if ($this->_key !== null) {
			return $this->_key;
		} else {
			$key = $this->getBaseCacheKey() . '.';
			if ($this->varyByRoute) {
				$controller = $this->getController();
				$key .= $controller->getUniqueId() . '/';
				if (($action = $controller->getAction()) !== null) {
					$key .= $action->getId();
				}
			}
			$key .= '.';

			if ($this->varyBySession) {
				$key .= Yii::app()->getSession()->getSessionID();
			}
			$key .= '.';

			if (is_array($this->varyByParam) && isset($this->varyByParam[0])) {
				$params = array();
				foreach ($this->varyByParam as $name) {
					if (isset($_GET[$name])) {
						$params[$name] = $_GET[$name];
					} else {
						$params[$name] = '';
					}
				}
				$key .= serialize($params);
			}
			$key .= '.';

			if ($this->varyByExpression !== null) {
				$key .= $this->evaluateExpression($this->varyByExpression);
			}
			$key .= '.';

			if ($this->varyByLanguage) {
				$key .= Yii::app()->language;
			}
			$key .= '.';

			return $this->_key = $key;
		}
	}

	/**
	 * Records a method call when this output cache is in effect.
	 * When the content is served from the output cache, the recorded
	 * method will be re-invoked.
	 * @param string $context a property name of the controller. The property should refer to an object
	 * whose method is being recorded. If empty it means the controller itself.
	 * @param string $method the method name
	 * @param array $params parameters passed to the method
	 */
	public function recordAction($context, $method, $params)
	{
		$this->_actions[] = array($context, $method, $params);
	}

	/**
	 * Replays the recorded method calls.
	 */
	protected function replayActions()
	{
		if (empty($this->_actions)) {
			return;
		}
		$controller = $this->getController();
		$cs = Yii::app()->getClientScript();
		foreach ($this->_actions as $action) {
			if ($action[0] === 'clientScript') {
				$object = $cs;
			} elseif ($action[0] === '') {
				$object = $controller;
			} else {
				$object = $controller->{$action[0]};
			}
			if (method_exists($object, $action[1])) {
				call_user_func_array(array($object, $action[1]), $action[2]);
			} elseif ($action[0] === '' && function_exists($action[1])) {
				call_user_func_array($action[1], $action[2]);
			} else {
				throw new CException(Yii::t('yii', 'Unable to replay the action "{object}.{method}". The method does not exist.',
					array('object' => $action[0],
						'method' => $action[1])));
			}
		}
	}
}