thumb.php

Go to the documentation of this file.

<?php

define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
if ( isset( $_SERVER['MW_COMPILED'] ) ) {
        require( 'phase3/includes/WebStart.php' );
} else {
        require( dirname( __FILE__ ) . '/includes/WebStart.php' );
}

// Don't use fancy mime detection, just check the file extension for jpg/gif/png
$wgTrivialMimeDetection = true;

if ( defined( 'THUMB_HANDLER' ) ) {
        // Called from thumb_handler.php via 404; extract params from the URI...
        wfThumbHandle404();
} else {
        // Called directly, use $_REQUEST params
        wfThumbHandleRequest();
}
wfLogProfilingData();

//--------------------------------------------------------------------------

function wfThumbHandleRequest() {
        $params = get_magic_quotes_gpc()
                ? array_map( 'stripslashes', $_REQUEST )
                : $_REQUEST;

        wfStreamThumb( $params ); // stream the thumbnail
}

function wfThumbHandle404() {
        # lighttpd puts the original request in REQUEST_URI, while sjs sets
        # that to the 404 handler, and puts the original request in REDIRECT_URL.
        if ( isset( $_SERVER['REDIRECT_URL'] ) ) {
                # The URL is un-encoded, so put it back how it was
                $uri = str_replace( "%2F", "/", urlencode( $_SERVER['REDIRECT_URL'] ) );
                # Just get the URI path (REDIRECT_URL is either a full URL or a path)
                if ( $uri[0] !== '/' ) {
                        $bits = wfParseUrl( $uri );
                        if ( $bits && isset( $bits['path'] ) ) {
                                $uri = $bits['path'];
                        }
                }
        } else {
                $uri = $_SERVER['REQUEST_URI'];
        }

        $params = wfExtractThumbParams( $uri ); // basic wiki URL param extracting
        if ( $params == null ) {
                wfThumbError( 404, 'The source file for the specified thumbnail does not exist.' );
                return;
        }

        wfStreamThumb( $params ); // stream the thumbnail
}

function wfStreamThumb( array $params ) {
        wfProfileIn( __METHOD__ );

        $headers = array(); // HTTP headers to send

        $fileName = isset( $params['f'] ) ? $params['f'] : '';
        unset( $params['f'] );

        // Backwards compatibility parameters
        if ( isset( $params['w'] ) ) {
                $params['width'] = $params['w'];
                unset( $params['w'] );
        }
        if ( isset( $params['p'] ) ) {
                $params['page'] = $params['p'];
        }
        unset( $params['r'] ); // ignore 'r' because we unconditionally pass File::RENDER

        // Is this a thumb of an archived file?
        $isOld = ( isset( $params['archived'] ) && $params['archived'] );
        unset( $params['archived'] );

        // Some basic input validation
        $fileName = strtr( $fileName, '\\/', '__' );

        // Actually fetch the image. Method depends on whether it is archived or not.
        if ( $isOld ) {
                // Format is <timestamp>!<name>
                $bits = explode( '!', $fileName, 2 );
                if ( count( $bits ) != 2 ) {
                        wfThumbError( 404, wfMsg( 'badtitletext' ) );
                        wfProfileOut( __METHOD__ );
                        return;
                }
                $title = Title::makeTitleSafe( NS_FILE, $bits[1] );
                if ( !$title ) {
                        wfThumbError( 404, wfMsg( 'badtitletext' ) );
                        wfProfileOut( __METHOD__ );
                        return;
                }
                $img = RepoGroup::singleton()->getLocalRepo()->newFromArchiveName( $title, $fileName );
        } else {
                $img = wfLocalFile( $fileName );
        }

        // Check permissions if there are read restrictions
        if ( !in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) ) {
                if ( !$img->getTitle()->userCan( 'read' ) ) {
                        wfThumbError( 403, 'Access denied. You do not have permission to access ' .
                                'the source file.' );
                        wfProfileOut( __METHOD__ );
                        return;
                }
                $headers[] = 'Cache-Control: private';
                $headers[] = 'Vary: Cookie';
        }

        // Check the source file storage path
        if ( !$img ) {
                wfThumbError( 404, wfMsg( 'badtitletext' ) );
                wfProfileOut( __METHOD__ );
                return;
        }
        if ( !$img->exists() ) {
                wfThumbError( 404, 'The source file for the specified thumbnail does not exist.' );
                wfProfileOut( __METHOD__ );
                return;
        }
        $sourcePath = $img->getPath();
        if ( $sourcePath === false ) {
                wfThumbError( 500, 'The source file is not locally accessible.' );
                wfProfileOut( __METHOD__ );
                return;
        }

        // Check IMS against the source file
        // This means that clients can keep a cached copy even after it has been deleted on the server
        if ( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
                // Fix IE brokenness
                $imsString = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );
                // Calculate time
                wfSuppressWarnings();
                $imsUnix = strtotime( $imsString );
                wfRestoreWarnings();
                $sourceTsUnix = wfTimestamp( TS_UNIX, $img->getTimestamp() );
                if ( $sourceTsUnix <= $imsUnix ) {
                        header( 'HTTP/1.1 304 Not Modified' );
                        wfProfileOut( __METHOD__ );
                        return;
                }
        }

        // Stream the file if it exists already...
        try {
                $thumbName = $img->thumbName( $params );
                if ( strlen( $thumbName ) ) { // valid params?
                        // For 404 handled thumbnails, we only use the the base name of the URI
                        // for the thumb params and the parent directory for the source file name.
                        // Check that the zone relative path matches up so squid caches won't pick
                        // up thumbs that would not be purged on source file deletion (bug 34231).
                        if ( isset( $params['rel404'] ) // thumbnail was handled via 404
                                && urldecode( $params['rel404'] ) !== $img->getThumbRel( $thumbName ) ) 
                        {
                                wfThumbError( 404, 'The source file for the specified thumbnail does not exist.' );
                                wfProfileOut( __METHOD__ );
                                return;
                        }
                        $thumbPath = $img->getThumbPath( $thumbName );
                        if ( $img->getRepo()->fileExists( $thumbPath ) ) {
                                $img->getRepo()->streamFile( $thumbPath, $headers );
                                wfProfileOut( __METHOD__ );
                                return;
                        }
                }
        } catch ( MWException $e ) {
                wfThumbError( 500, $e->getHTML() );
                wfProfileOut( __METHOD__ );
                return;
        }

        // Thumbnail isn't already there, so create the new thumbnail...
        try {
                $thumb = $img->transform( $params, File::RENDER_NOW );
        } catch ( Exception $ex ) {
                // Tried to select a page on a non-paged file?
                $thumb = false;
        }

        // Check for thumbnail generation errors...
        $errorMsg = false;
        if ( !$thumb ) {
                $errorMsg = wfMsgHtml( 'thumbnail_error', 'File::transform() returned false' );
        } elseif ( $thumb->isError() ) {
                $errorMsg = $thumb->getHtmlMsg();
        } elseif ( !$thumb->hasFile() ) {
                $errorMsg = wfMsgHtml( 'thumbnail_error', 'No path supplied in thumbnail object' );
        } elseif ( $thumb->fileIsSource() ) {
                $errorMsg = wfMsgHtml( 'thumbnail_error',
                        'Image was not scaled, is the requested width bigger than the source?' );
        }

        if ( $errorMsg !== false ) {
                wfThumbError( 500, $errorMsg );
        } else {
                // Stream the file if there were no errors
                $thumb->streamFile( $headers );
        }

        wfProfileOut( __METHOD__ );
}

function wfExtractThumbParams( $uri ) {
        $repo = RepoGroup::singleton()->getLocalRepo();

        $zoneURI = $repo->getZoneUrl( 'thumb' );
        if ( substr( $zoneURI, 0, 1 ) !== '/' ) {
                $bits = wfParseUrl( $zoneURI );
                if ( $bits && isset( $bits['path'] ) ) {
                        $zoneURI = $bits['path'];
                } else {
                        return null;
                }
        }
        $zoneUrlRegex = preg_quote( $zoneURI );

        $hashDirRegex = $subdirRegex = '';
        for ( $i = 0; $i < $repo->getHashLevels(); $i++ ) {
                $subdirRegex .= '[0-9a-f]';
                $hashDirRegex .= "$subdirRegex/";
        }

        $thumbUrlRegex = "!^$zoneUrlRegex/((archive/|temp/)?$hashDirRegex([^/]*)/([^/]*))$!";

        // Check if this is a valid looking thumbnail request...
        if ( preg_match( $thumbUrlRegex, $uri, $matches ) ) {
                list( /* all */, $rel, $archOrTemp, $filename, $thumbname ) = $matches;
                $filename = urldecode( $filename );
                $thumbname = urldecode( $thumbname );

                $params = array( 'f' => $filename, 'rel404' => $rel );
                if ( $archOrTemp == 'archive/' ) {
                        $params['archived'] = 1;
                } elseif ( $archOrTemp == 'temp/' ) {
                        $params['temp'] = 1;
                }

                // Check if the parameters can be extracted from the thumbnail name...
                if ( preg_match( '!^(page(\d*)-)*(\d*)px-[^/]*$!', $thumbname, $matches ) ) {
                        list( /* all */, $pagefull, $pagenum, $size ) = $matches;
                        $params['width'] = $size;
                        if ( $pagenum ) {
                                $params['page'] = $pagenum;
                        }
                        return $params; // valid thumbnail URL
                // Hooks return false if they manage to *resolve* the parameters
                } elseif ( !wfRunHooks( 'ExtractThumbParameters', array( $thumbname, &$params ) ) ) {
                        return $params; // valid thumbnail URL (via extension or config)
                }
        }

        return null; // not a valid thumbnail URL
}

function wfThumbError( $status, $msg ) {
        global $wgShowHostnames;

        header( 'Cache-Control: no-cache' );
        header( 'Content-Type: text/html; charset=utf-8' );
        if ( $status == 404 ) {
                header( 'HTTP/1.1 404 Not found' );
        } elseif ( $status == 403 ) {
                header( 'HTTP/1.1 403 Forbidden' );
                header( 'Vary: Cookie' );
        } else {
                header( 'HTTP/1.1 500 Internal server error' );
        }
        if ( $wgShowHostnames ) {
                $url = htmlspecialchars( isset( $_SERVER['REQUEST_URI'] ) ? $_SERVER['REQUEST_URI'] : '' );
                $hostname = htmlspecialchars( wfHostname() );
                $debug = "<!-- $url -->\n<!-- $hostname -->\n";
        } else {
                $debug = "";
        }
        echo <<<EOT
<html><head><title>Error generating thumbnail</title></head>
<body>
<h1>Error generating thumbnail</h1>
<p>
$msg
</p>
$debug
</body>
</html>

EOT;
}