HTMLFileCache.php

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<?php
use MediaWiki\Cache\CacheKeyHelper;
use MediaWiki\Cache\FileCacheBase;
use MediaWiki\Context\IContextSource;
use MediaWiki\HookContainer\HookRunner;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\Page\PageIdentity;
 
class HTMLFileCache extends FileCacheBase {
    public const MODE_NORMAL = 0; // normal cache mode
    public const MODE_OUTAGE = 1; // fallback cache for DB outages
    public const MODE_REBUILD = 2; // background cache rebuild mode
 
    private const CACHEABLE_ACTIONS = [
        'view',
        'history',
    ];
 
    public function __construct( $page, $action ) {
        parent::__construct();
 
        if ( !in_array( $action, self::CACHEABLE_ACTIONS ) ) {
            throw new InvalidArgumentException( 'Invalid file cache type given.' );
        }
 
        $this->mKey = CacheKeyHelper::getKeyForPage( $page );
        $this->mType = (string)$action;
        $this->mExt = 'html';
    }
 
    protected function cacheDirectory() {
        return $this->baseCacheDirectory(); // no subdir for b/c with old cache files
    }
 
    protected function typeSubdirectory() {
        if ( $this->mType === 'view' ) {
            return ''; // b/c to not skip existing cache
        } else {
            return $this->mType . '/';
        }
    }
 
    public static function useFileCache( IContextSource $context, $mode = self::MODE_NORMAL ) {
        $services = MediaWikiServices::getInstance();
        $config = $services->getMainConfig();
 
        if ( !$config->get( MainConfigNames::UseFileCache ) && $mode !== self::MODE_REBUILD ) {
            return false;
        }
 
        // Get all query values
        $queryVals = $context->getRequest()->getValues();
        foreach ( $queryVals as $query => $val ) {
            if ( $query === 'title' || $query === 'curid' ) {
                continue; // note: curid sets title
            // Normal page view in query form can have action=view.
            } elseif ( $query === 'action' && in_array( $val, self::CACHEABLE_ACTIONS ) ) {
                continue;
            // Below are header setting params
            } elseif ( $query === 'maxage' || $query === 'smaxage' ) {
                continue;
            // Uselang value is checked below
            } elseif ( $query === 'uselang' ) {
                continue;
            }
 
            return false;
        }
 
        $user = $context->getUser();
        // Check for non-standard user language; this covers uselang,
        // and extensions for auto-detecting user language.
        $ulang = $context->getLanguage();
 
        // Check that there are no other sources of variation
        if ( $user->isRegistered() ||
            !$ulang->equals( $services->getContentLanguage() ) ) {
            return false;
        }
 
        $userHasNewMessages = $services->getTalkPageNotificationManager()->userHasNewMessages( $user );
        if ( ( $mode === self::MODE_NORMAL ) && $userHasNewMessages ) {
            return false;
        }
 
        // Allow extensions to disable caching
        return ( new HookRunner( $services->getHookContainer() ) )->onHTMLFileCache__useFileCache( $context );
    }
 
    public function loadFromFileCache( IContextSource $context, $mode = self::MODE_NORMAL ) {
        wfDebug( __METHOD__ . "()" );
        $filename = $this->cachePath();
 
        if ( $mode === self::MODE_OUTAGE ) {
            // Avoid DB errors for queries in sendCacheControl()
            $context->getTitle()->resetArticleID( 0 );
        }
 
        $context->getOutput()->sendCacheControl();
        header( "Content-Type: {$this->options->get( MainConfigNames::MimeType )}; charset=UTF-8" );
        header( 'Content-Language: ' .
            MediaWikiServices::getInstance()->getContentLanguage()->getHtmlCode() );
        if ( $this->useGzip() ) {
            if ( wfClientAcceptsGzip() ) {
                header( 'Content-Encoding: gzip' );
                readfile( $filename );
            } else {
                /* Send uncompressed */
                wfDebug( __METHOD__ . " uncompressing cache file and sending it" );
                readgzfile( $filename );
            }
        } else {
            readfile( $filename );
        }
 
        $context->getOutput()->disable(); // tell $wgOut that output is taken care of
    }
 
    public function saveToFileCache( $text ) {
        if ( strlen( $text ) < 512 ) {
            // Disabled or empty/broken output (OOM and PHP errors)
            return $text;
        }
 
        wfDebug( __METHOD__ . "()\n", 'private' );
 
        $now = wfTimestampNow();
        if ( $this->useGzip() ) {
            $text = str_replace(
                '</html>', '<!-- Cached/compressed ' . $now . " -->\n</html>", $text );
        } else {
            $text = str_replace(
                '</html>', '<!-- Cached ' . $now . " -->\n</html>", $text );
        }
 
        // Store text to FS...
        $compressed = $this->saveText( $text );
        if ( $compressed === false ) {
            return $text; // error
        }
 
        // gzip output to buffer as needed and set headers...
        // @todo Ugly wfClientAcceptsGzip() function - use context!
        if ( $this->useGzip() && wfClientAcceptsGzip() ) {
            header( 'Content-Encoding: gzip' );
 
            return $compressed;
        }
 
        return $text;
    }
 
    public static function clearFileCache( $page ) {
        $config = MediaWikiServices::getInstance()->getMainConfig();
        if ( !$config->get( MainConfigNames::UseFileCache ) ) {
            return false;
        }
 
        foreach ( self::CACHEABLE_ACTIONS as $type ) {
            $fc = new self( $page, $type );
            $fc->clearCache();
        }
 
        return true;
    }
}