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! * * 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 SpecialPage * @author Jeroen De Dauw < jeroendedauw@gmail.com > * @since 1.20 */ abstract class SpecialCachedPage extends SpecialPage 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; /** * Gets called after @see SpecialPage::execute. * * @since 1.20 * * @param string|null $subPage */ protected function afterExecute( $subPage ) { $this->saveCache(); parent::afterExecute( $subPage ); } /** * 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 ) { if ( !isset( $this->cacheHelper ) ) { $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 ) { $this->getOutput()->addHTML( $this->cacheHelper->getCachedValue( $computeFunction, $args, $key ) ); } /** * 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() { if ( isset( $this->cacheHelper ) ) { $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 [ $this->mName, $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() ) ); } } }