X-Git-Url: https://scripts.mit.edu/gitweb/autoinstallsdev/mediawiki.git/blobdiff_plain/19e297c21b10b1b8a3acad5e73fc71dcb35db44a..6932310fd58ebef145fa01eb76edf7150284d8ea:/includes/actions/CachedAction.php

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+<?php
+/**
+ * Abstract action class with scaffolding for caching HTML and other values
+ * in a single blob.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @ingroup Actions
+ * @author Jeroen De Dauw < jeroendedauw@gmail.com >
+ * @since 1.20
+ */
+
+/**
+ * Abstract action class with scaffolding for caching HTML and other values
+ * in a single blob.
+ *
+ * Before using any of the caching functionality, call startCache.
+ * After the last call to either getCachedValue or addCachedHTML, call saveCache.
+ *
+ * To get a cached value or compute it, use getCachedValue like this:
+ * $this->getCachedValue( $callback );
+ *
+ * To add HTML that should be cached, use addCachedHTML like this:
+ * $this->addCachedHTML( $callback );
+ *
+ * The callback function is only called when needed, so do all your expensive
+ * computations here. This function should returns the HTML to be cached.
+ * It should not add anything to the PageOutput object!
+ *
+ * @ingroup Actions
+ */
+abstract class CachedAction extends FormlessAction implements ICacheHelper {
+
+	/**
+	 * CacheHelper object to which we forward the non-SpecialPage specific caching work.
+	 * Initialized in startCache.
+	 *
+	 * @since 1.20
+	 * @var CacheHelper
+	 */
+	protected $cacheHelper;
+
+	/**
+	 * If the cache is enabled or not.
+	 *
+	 * @since 1.20
+	 * @var bool
+	 */
+	protected $cacheEnabled = true;
+
+	/**
+	 * Sets if the cache should be enabled or not.
+	 *
+	 * @since 1.20
+	 * @param bool $cacheEnabled
+	 */
+	public function setCacheEnabled( $cacheEnabled ) {
+		$this->cacheHelper->setCacheEnabled( $cacheEnabled );
+	}
+
+	/**
+	 * Initializes the caching.
+	 * Should be called before the first time anything is added via addCachedHTML.
+	 *
+	 * @since 1.20
+	 *
+	 * @param int|null $cacheExpiry Sets the cache expiry, either ttl in seconds or unix timestamp.
+	 * @param bool|null $cacheEnabled Sets if the cache should be enabled or not.
+	 */
+	public function startCache( $cacheExpiry = null, $cacheEnabled = null ) {
+		$this->cacheHelper = new CacheHelper();
+
+		$this->cacheHelper->setCacheEnabled( $this->cacheEnabled );
+		$this->cacheHelper->setOnInitializedHandler( [ $this, 'onCacheInitialized' ] );
+
+		$keyArgs = $this->getCacheKey();
+
+		if ( array_key_exists( 'action', $keyArgs ) && $keyArgs['action'] === 'purge' ) {
+			unset( $keyArgs['action'] );
+		}
+
+		$this->cacheHelper->setCacheKey( $keyArgs );
+
+		if ( $this->getRequest()->getText( 'action' ) === 'purge' ) {
+			$this->cacheHelper->rebuildOnDemand();
+		}
+
+		$this->cacheHelper->startCache( $cacheExpiry, $cacheEnabled );
+	}
+
+	/**
+	 * Get a cached value if available or compute it if not and then cache it if possible.
+	 * The provided $computeFunction is only called when the computation needs to happen
+	 * and should return a result value. $args are arguments that will be passed to the
+	 * compute function when called.
+	 *
+	 * @since 1.20
+	 *
+	 * @param callable $computeFunction
+	 * @param array|mixed $args
+	 * @param string|null $key
+	 *
+	 * @return mixed
+	 */
+	public function getCachedValue( $computeFunction, $args = [], $key = null ) {
+		return $this->cacheHelper->getCachedValue( $computeFunction, $args, $key );
+	}
+
+	/**
+	 * Add some HTML to be cached.
+	 * This is done by providing a callback function that should
+	 * return the HTML to be added. It will only be called if the
+	 * item is not in the cache yet or when the cache has been invalidated.
+	 *
+	 * @since 1.20
+	 *
+	 * @param callable $computeFunction
+	 * @param array $args
+	 * @param string|null $key
+	 */
+	public function addCachedHTML( $computeFunction, $args = [], $key = null ) {
+		$html = $this->cacheHelper->getCachedValue( $computeFunction, $args, $key );
+		$this->getOutput()->addHTML( $html );
+	}
+
+	/**
+	 * Saves the HTML to the cache in case it got recomputed.
+	 * Should be called after the last time anything is added via addCachedHTML.
+	 *
+	 * @since 1.20
+	 */
+	public function saveCache() {
+		$this->cacheHelper->saveCache();
+	}
+
+	/**
+	 * Sets the time to live for the cache, in seconds or a unix timestamp
+	 * indicating the point of expiry.
+	 *
+	 * @since 1.20
+	 *
+	 * @param int $cacheExpiry
+	 */
+	public function setExpiry( $cacheExpiry ) {
+		$this->cacheHelper->setExpiry( $cacheExpiry );
+	}
+
+	/**
+	 * Returns the variables used to constructed the cache key in an array.
+	 *
+	 * @since 1.20
+	 *
+	 * @return array
+	 */
+	protected function getCacheKey() {
+		return [
+			get_class( $this->page ),
+			$this->getName(),
+			$this->getLanguage()->getCode()
+		];
+	}
+
+	/**
+	 * Gets called after the cache got initialized.
+	 *
+	 * @since 1.20
+	 *
+	 * @param bool $hasCached
+	 */
+	public function onCacheInitialized( $hasCached ) {
+		if ( $hasCached ) {
+			$this->getOutput()->setSubtitle( $this->cacheHelper->getCachedNotice( $this->getContext() ) );
+		}
+	}
+}