HTMLFileCache.php

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<?php
class HTMLFileCache extends FileCacheBase {
    public static function newFromTitle( $title, $action ) {
        return new self( $title, $action );
    }

    public function __construct( $title, $action ) {
        parent::__construct();
        $allowedTypes = self::cacheablePageActions();
        if ( !in_array( $action, $allowedTypes ) ) {
            throw new MWException( 'Invalid file cache type given.' );
        }
        $this->mKey = ( $title instanceof Title )
            ? $title->getPrefixedDBkey()
            : (string)$title;
        $this->mType = (string)$action;
        $this->mExt = 'html';
    }

    protected static function cacheablePageActions() {
        return [ 'view', 'history' ];
    }

    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 ) {
        global $wgUseFileCache, $wgDebugToolbar, $wgContLang;
        if ( !$wgUseFileCache ) {
            return false;
        }
        if ( $wgDebugToolbar ) {
            wfDebug( "HTML file cache skipped. \$wgDebugToolbar on\n" );

            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::cacheablePageActions() ) ) {
                continue;
            // Below are header setting params
            } elseif ( $query === 'maxage' || $query === 'smaxage' ) {
                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()->getCode();
        $clang = $wgContLang->getCode();

        // Check that there are no other sources of variation
        if ( $user->getId() || $user->getNewtalk() || $ulang != $clang ) {
            return false;
        }
        // Allow extensions to disable caching
        return Hooks::run( 'HTMLFileCache::useFileCache', [ $context ] );
    }

    public function loadFromFileCache( IContextSource $context ) {
        global $wgMimeType, $wgLanguageCode;

        wfDebug( __METHOD__ . "()\n" );
        $filename = $this->cachePath();

        $context->getOutput()->sendCacheControl();
        header( "Content-Type: $wgMimeType; charset=UTF-8" );
        header( "Content-Language: $wgLanguageCode" );
        if ( $this->useGzip() ) {
            if ( wfClientAcceptsGzip() ) {
                header( 'Content-Encoding: gzip' );
                readfile( $filename );
            } else {
                /* Send uncompressed */
                wfDebug( __METHOD__ . " uncompressing cache file and sending it\n" );
                readgzfile( $filename );
            }
        } else {
            readfile( $filename );
        }
        $context->getOutput()->disable(); // tell $wgOut that output is taken care of
    }

    public function saveToFileCache( $text ) {
        global $wgUseFileCache;

        if ( !$wgUseFileCache || 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...
        if ( $this->useGzip() ) {
            // @todo Ugly wfClientAcceptsGzip() function - use context!
            if ( wfClientAcceptsGzip() ) {
                header( 'Content-Encoding: gzip' );

                return $compressed;
            } else {
                return $text;
            }
        } else {
            return $text;
        }
    }

    public static function clearFileCache( Title $title ) {
        global $wgUseFileCache;

        if ( !$wgUseFileCache ) {
            return false;
        }

        foreach ( self::cacheablePageActions() as $type ) {
            $fc = new self( $title, $type );
            $fc->clearCache();
        }

        return true;
    }
}