thumb.php

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<?php
define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
if ( isset( $_SERVER['MW_COMPILED'] ) ) {
        require( 'core/includes/WebStart.php' );
} else {
        require( __DIR__ . '/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 $_GET params
        wfThumbHandleRequest();
}

wfLogProfilingData();

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

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

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

function wfThumbHandle404() {
        global $wgArticlePath;

        # Set action base paths so that WebRequest::getPathInfo()
        # recognizes the "X" as the 'title' in ../thumb_handler.php/X urls.
        $wgArticlePath = false; # Don't let a "/*" article path clober our action path

        $matches = WebRequest::getPathInfo();
        if ( !isset( $matches['title'] ) ) {
                wfThumbError( 404, 'Could not determine the name of the requested thumbnail.' );
                return;
        }

        $params = wfExtractThumbParams( $matches['title'] ); // basic wiki URL param extracting
        if ( $params == null ) {
                wfThumbError( 400, 'The specified thumbnail parameters are not recognized.' );
                return;
        }

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

function wfStreamThumb( array $params ) {
        global $wgVaryOnXFP;

        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'] ); // handlers don't care

        // Is this a thumb of a temp file?
        $isTemp = ( isset( $params['temp'] ) && $params['temp'] );
        unset( $params['temp'] ); // handlers don't care

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

        // Actually fetch the image. Method depends on whether it is archived or not.
        if ( $isTemp ) {
                $repo = RepoGroup::singleton()->getLocalRepo()->getTempRepo();
                $img = new UnregisteredLocalFile( null, $repo,
                        # Temp files are hashed based on the name without the timestamp.
                        # The thumbnails will be hashed based on the entire name however.
                        # @TODO: fix this convention to actually be reasonable.
                        $repo->getZonePath( 'public' ) . '/' . $repo->getTempHashPath( $fileName ) . $fileName
                );
        } elseif ( $isOld ) {
                // Format is <timestamp>!<name>
                $bits = explode( '!', $fileName, 2 );
                if ( count( $bits ) != 2 ) {
                        wfThumbError( 404, wfMessage( 'badtitletext' )->text() );
                        wfProfileOut( __METHOD__ );
                        return;
                }
                $title = Title::makeTitleSafe( NS_FILE, $bits[1] );
                if ( !$title ) {
                        wfThumbError( 404, wfMessage( 'badtitletext' )->text() );
                        wfProfileOut( __METHOD__ );
                        return;
                }
                $img = RepoGroup::singleton()->getLocalRepo()->newFromArchiveName( $title, $fileName );
        } else {
                $img = wfLocalFile( $fileName );
        }

        // Check the source file title
        if ( !$img ) {
                wfThumbError( 404, wfMessage( 'badtitletext' )->text() );
                wfProfileOut( __METHOD__ );
                return;
        }

        // Check permissions if there are read restrictions
        $varyHeader = array();
        if ( !in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) ) {
                if ( !$img->getTitle() || !$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';
                $varyHeader[] = 'Cookie';
        }

        // Check the source file storage path
        if ( !$img->exists() ) {
                wfThumbError( 404, "The source file '$fileName' does not exist." );
                wfProfileOut( __METHOD__ );
                return;
        } elseif ( $img->getPath() === false ) {
                wfThumbError( 500, "The source file '$fileName' 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();
                if ( wfTimestamp( TS_UNIX, $img->getTimestamp() ) <= $imsUnix ) {
                        header( 'HTTP/1.1 304 Not Modified' );
                        wfProfileOut( __METHOD__ );
                        return;
                }
        }

        // Get the normalized thumbnail name from the parameters...
        try {
                $thumbName = $img->thumbName( $params );
                if ( !strlen( $thumbName ) ) { // invalid params?
                        wfThumbError( 400, 'The specified thumbnail parameters are not valid.' );
                        wfProfileOut( __METHOD__ );
                        return;
                }
                $thumbName2 = $img->thumbName( $params, File::THUMB_FULL_NAME ); // b/c; "long" style
        } catch ( MWException $e ) {
                wfThumbError( 500, $e->getHTML() );
                wfProfileOut( __METHOD__ );
                return;
        }

        // 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
                if ( rawurldecode( $params['rel404'] ) === $img->getThumbRel( $thumbName ) ) {
                        // Request for the canonical thumbnail name
                } elseif ( rawurldecode( $params['rel404'] ) === $img->getThumbRel( $thumbName2 ) ) {
                        // Request for the "long" thumbnail name; redirect to canonical name
                        $response = RequestContext::getMain()->getRequest()->response();
                        $response->header( "HTTP/1.1 301 " . HttpStatus::getMessage( 301 ) );
                        $response->header( 'Location: ' .
                                wfExpandUrl( $img->getThumbUrl( $thumbName ), PROTO_CURRENT ) );
                        $response->header( 'Expires: ' .
                                gmdate( 'D, d M Y H:i:s', time() + 7 * 86400 ) . ' GMT' );
                        if ( $wgVaryOnXFP ) {
                                $varyHeader[] = 'X-Forwarded-Proto';
                        }
                        if ( count( $varyHeader ) ) {
                                $response->header( 'Vary: ' . implode( ', ', $varyHeader ) );
                        }
                        wfProfileOut( __METHOD__ );
                        return;
                } else {
                        wfThumbError( 404, "The given path of the specified thumbnail is incorrect;
                                expected '" . $img->getThumbRel( $thumbName ) . "' but got '" .
                                rawurldecode( $params['rel404'] ) . "'." );
                        wfProfileOut( __METHOD__ );
                        return;
                }
        }

        // Suggest a good name for users downloading this thumbnail
        $headers[] = "Content-Disposition: {$img->getThumbDisposition( $thumbName )}";

        if ( count( $varyHeader ) ) {
                $headers[] = 'Vary: ' . implode( ', ', $varyHeader );
        }

        // Stream the file if it exists already...
        $thumbPath = $img->getThumbPath( $thumbName );
        if ( $img->getRepo()->fileExists( $thumbPath ) ) {
                $img->getRepo()->streamFile( $thumbPath, $headers );
                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;
        $msg = wfMessage( 'thumbnail_error' );
        if ( !$thumb ) {
                $errorMsg = $msg->rawParams( 'File::transform() returned false' )->escaped();
        } elseif ( $thumb->isError() ) {
                $errorMsg = $thumb->getHtmlMsg();
        } elseif ( !$thumb->hasFile() ) {
                $errorMsg = $msg->rawParams( 'No path supplied in thumbnail object' )->escaped();
        } elseif ( $thumb->fileIsSource() ) {
                $errorMsg = $msg->
                        rawParams( 'Image was not scaled, is the requested width bigger than the source?' )->escaped();
        }

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

        wfProfileOut( __METHOD__ );
}

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

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

        // Check if this is a thumbnail of an original in the local file repo
        if ( preg_match( "!^((archive/)?$hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
                list( /*all*/, $rel, $archOrTemp, $filename, $thumbname ) = $m;
        // Check if this is a thumbnail of an temp file in the local file repo
        } elseif ( preg_match( "!^(temp/)($hashDirReg([^/]*)/([^/]*))$!", $thumbRel, $m ) ) {
                list( /*all*/, $archOrTemp, $rel, $filename, $thumbname ) = $m;
        } else {
                return null; // not a valid looking thumbnail request
        }

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

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

        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;
}