source: trunk/w/thumb.php @ 1484

<?php

/**
 * PHP script to stream out an image thumbnail.
 *
 * @file
 * @ingroup Media
 */
define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
require_once( './includes/WebStart.php' );

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

require_once( "$IP/includes/StreamFile.php" );

wfThumbMain();
wfLogProfilingData();

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

function wfThumbMain() {
        wfProfileIn( __METHOD__ );

        $headers = array();

        // Get input parameters
        if ( get_magic_quotes_gpc() ) {
                $params = array_map( 'stripslashes', $_REQUEST );
        } else {
                $params = $_REQUEST;
        }

        $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'] );

        // 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( '!', $fileName, 2 );
                if( !isset($bits[1]) ) {
                        wfThumbError( 404, wfMsg( 'badtitletext' ) );
                        return;
                }
                $title = Title::makeTitleSafe( NS_FILE, $bits[1] );
                if( is_null($title) ) {
                        wfThumbError( 404, wfMsg( 'badtitletext' ) );
                        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()->userCanRead() ) {
                        wfThumbError( 403, 'Access denied. You do not have permission to access ' . 
                                'the source file.' );
                        return;
                }
                $headers[] = 'Cache-Control: private';
                $headers[] = 'Vary: Cookie';
        }

        if ( !$img ) {
                wfThumbError( 404, wfMsg( 'badtitletext' ) );
                return;
        }
        if ( !$img->exists() ) {
                wfThumbError( 404, 'The source file for the specified thumbnail does not exist.' );
                return;
        }
        $sourcePath = $img->getPath();
        if ( $sourcePath === false ) {
                wfThumbError( 500, 'The source file is not locally accessible.' );
                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();
                $stat = @stat( $sourcePath );
                if ( $stat['mtime'] <= $imsUnix ) {
                        header( 'HTTP/1.1 304 Not Modified' );
                        return;
                }
        }

        // Stream the file if it exists already
        try {
                if ( false != ( $thumbName = $img->thumbName( $params ) ) ) {
                        $thumbPath = $img->getThumbPath( $thumbName );

                        if ( is_file( $thumbPath ) ) {
                                wfStreamFile( $thumbPath, $headers );
                                return;
                        }
                }
        } catch ( MWException $e ) {
                wfThumbError( 500, $e->getHTML() );
                return;
        }

        try {
                $thumb = $img->transform( $params, File::RENDER_NOW );
        } catch( Exception $ex ) {
                // Tried to select a page on a non-paged file?
                $thumb = false;
        }

        $errorMsg = false;
        if ( !$thumb ) {
                $errorMsg = wfMsgHtml( 'thumbnail_error', 'File::transform() returned false' );
        } elseif ( $thumb->isError() ) {
                $errorMsg = $thumb->getHtmlMsg();
        } elseif ( !$thumb->getPath() ) {
                $errorMsg = wfMsgHtml( 'thumbnail_error', 'No path supplied in thumbnail object' );
        } elseif ( $thumb->getPath() == $img->getPath() ) {
                $errorMsg = wfMsgHtml( 'thumbnail_error', 'Image was not scaled, ' .
                        'is the requested width bigger than the source?' );
        } else {
                wfStreamFile( $thumb->getPath(), $headers );
        }
        if ( $errorMsg !== false ) {
                wfThumbError( 500, $errorMsg );
        }

        wfProfileOut( __METHOD__ );
}

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 ) {
                $url = htmlspecialchars( @$_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;
}