--- /dev/null
+<?php
+
+/**
+ * Abstract special page class with scaffolding for caching the HTML output.
+ *
+ * To enable the caching functionality, the cacheExpiry field should be set
+ * in the constructor.
+ *
+ * To add HTML that should be cached, use addCachedHTML like this:
+ * $this->addCachedHTML( array( $this, 'displayCachedContent' ) );
+ *
+ * After adding the last HTML that should be cached, call $this->saveCache();
+ *
+ * @since 1.20
+ *
+ * @file SpecialCachedPage.php
+ * @ingroup SpecialPage
+ *
+ * @licence GNU GPL v2 or later
+ * @author Jeroen De Dauw < jeroendedauw@gmail.com >
+ */
+abstract class SpecialCachedPage extends SpecialPage {
+
+ /**
+ * The time to live for the cache, in seconds or a unix timestamp indicating the point of expiry.
+ *
+ * @since 1.20
+ * @var integer|null
+ */
+ protected $cacheExpiry = null;
+
+ /**
+ * List of HTML chunks to be cached (if !hasCached) or that where cashed (of hasCached).
+ * If no cached already, then the newly computed chunks are added here,
+ * if it as cached already, chunks are removed from this list as they are needed.
+ *
+ * @since 1.20
+ * @var array
+ */
+ protected $cachedChunks;
+
+ /**
+ * Indicates if the to be cached content was already cached.
+ * Null if this information is not available yet.
+ *
+ * @since 1.20
+ * @var boolean|null
+ */
+ protected $hasCached = null;
+
+ /**
+ * Main method.
+ *
+ * @since 1.20
+ *
+ * @param string|null $subPage
+ */
+ public function execute( $subPage ) {
+ if ( $this->getRequest()->getText( 'action' ) === 'purge' ) {
+ $this->hasCached = false;
+ }
+
+ if ( !is_null( $this->cacheExpiry ) ) {
+ $this->initCaching();
+
+ if ( $this->hasCached === true ) {
+ $this->getOutput()->setSubtitle( $this->getCachedNotice( $subPage ) );
+ }
+ }
+ }
+
+ /**
+ * Returns a message that notifies the user he/she is looking at
+ * a cached version of the page, including a refresh link.
+ *
+ * @since 1.20
+ *
+ * @param string|null $subPage
+ *
+ * @return string
+ */
+ protected function getCachedNotice( $subPage ) {
+ $refreshArgs = $_GET;
+ unset( $refreshArgs['title'] );
+ $refreshArgs['action'] = 'purge';
+
+ $refreshLink = Linker::link(
+ $this->getTitle( $subPage ),
+ $this->msg( 'cachedspecial-refresh-now' )->escaped(),
+ array(),
+ $refreshArgs
+ );
+
+ if ( $this->cacheExpiry < 1000000000 ) {
+ $message = $this->msg(
+ 'cachedspecial-viewing-cached-ttl',
+ $this->getLanguage()->duration( $this->cacheExpiry )
+ )->escaped();
+ }
+ else {
+ $message = $this->msg(
+ 'cachedspecial-viewing-cached-ts'
+ )->escaped();
+ }
+
+ return $message . ' ' . $refreshLink;
+ }
+
+ /**
+ * Initializes the caching if not already done so.
+ * Should be called before any of the caching functionality is used.
+ *
+ * @since 1.20
+ */
+ protected function initCaching() {
+ if ( is_null( $this->hasCached ) ) {
+ $cachedChunks = wfGetCache( CACHE_ANYTHING )->get( $this->getCacheKey() );
+
+ $this->hasCached = is_array( $cachedChunks );
+ $this->cachedChunks = $this->hasCached ? $cachedChunks : array();
+ }
+ }
+
+ /**
+ * 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 {function} $callback
+ * @param array $args
+ * @param string|null $key
+ */
+ public function addCachedHTML( $callback, $args = array(), $key = null ) {
+ $this->initCaching();
+
+ if ( $this->hasCached ) {
+ $html = '';
+
+ if ( is_null( $key ) ) {
+ $itemKey = array_keys( array_slice( $this->cachedChunks, 0, 1 ) );
+ $itemKey = array_shift( $itemKey );
+
+ if ( !is_integer( $itemKey ) ) {
+ wfWarn( "Attempted to get item with non-numeric key while the next item in the queue has a key ($itemKey) in " . __METHOD__ );
+ }
+ elseif ( is_null( $itemKey ) ) {
+ wfWarn( "Attempted to get an item while the queue is empty in " . __METHOD__ );
+ }
+ else {
+ $html = array_shift( $this->cachedChunks );
+ }
+ }
+ else {
+ if ( array_key_exists( $key, $this->cachedChunks ) ) {
+ $html = $this->cachedChunks[$key];
+ unset( $this->cachedChunks[$key] );
+ }
+ else {
+ wfWarn( "There is no item with key '$key' in this->cachedChunks in " . __METHOD__ );
+ }
+ }
+ }
+ else {
+ $html = call_user_func_array( $callback, $args );
+
+ if ( is_null( $key ) ) {
+ $this->cachedChunks[] = $html;
+ }
+ else {
+ $this->cachedChunks[$key] = $html;
+ }
+ }
+
+ $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() {
+ if ( $this->hasCached === false && !empty( $this->cachedChunks ) ) {
+ wfGetCache( CACHE_ANYTHING )->set( $this->getCacheKey(), $this->cachedChunks, $this->cacheExpiry );
+ }
+ }
+
+ /**
+ * Sets the time to live for the cache, in seconds or a unix timestamp indicating the point of expiry..
+ *
+ * @since 1.20
+ *
+ * @param integer $cacheExpiry
+ */
+ protected function setExpirey( $cacheExpiry ) {
+ $this->cacheExpiry = $cacheExpiry;
+ }
+
+ /**
+ * Returns the cache key to use to cache this page's HTML output.
+ * Is constructed from the special page name and language code.
+ *
+ * @since 1.20
+ *
+ * @return string
+ */
+ protected function getCacheKey() {
+ return wfMemcKey( $this->mName, $this->getLanguage()->getCode() );
+ }
+
+}
dépôts / lhc / web / wiklou.git / commitdiff