thumb.php

   1 <?php
   2
   3 /**
   4  * PHP script to stream out an image thumbnail.
   5  *
   6  * @file
   7  * @ingroup Media
   8  */
   9 define( 'MW_NO_OUTPUT_COMPRESSION', 1 );
  10 if ( isset( $_SERVER['MW_COMPILED'] ) ) {
  11         require( 'phase3/includes/WebStart.php' );
  12 } else {
  13         require( dirname( __FILE__ ) . '/includes/WebStart.php' );
  14 }
  15
  16 // Don't use fancy mime detection, just check the file extension for jpg/gif/png
  17 $wgTrivialMimeDetection = true;
  18
  19 if ( defined( 'THUMB_HANDLER' ) ) {
  20         // Called from thumb_handler.php via 404; extract params from the URI...
  21         wfThumbHandle404();
  22 } else {
  23         // Called directly, use $_REQUEST params
  24         wfThumbHandleRequest();
  25 }
  26 wfLogProfilingData();
  27
  28 //--------------------------------------------------------------------------
  29
  30 /**
  31  * Handle a thumbnail request via query parameters
  32  */
  33 function wfThumbHandleRequest() {
  34         $params = get_magic_quotes_gpc()
  35                 ? array_map( 'stripslashes', $_REQUEST )
  36                 : $_REQUEST;
  37
  38         wfStreamThumb( $params ); // stream the thumbnail
  39 }
  40
  41 /**
  42  * Handle a thumbnail request via thumbnail file URL
  43  */
  44 function wfThumbHandle404() {
  45         # lighttpd puts the original request in REQUEST_URI, while
  46         # sjs sets that to the 404 handler, and puts the original
  47         # request in REDIRECT_URL.
  48         if ( isset( $_SERVER['REDIRECT_URL'] ) ) {
  49                 # The URL is un-encoded, so put it back how it was.
  50                 $uri = str_replace( "%2F", "/", urlencode( $_SERVER['REDIRECT_URL'] ) );
  51         } else {
  52                 $uri = $_SERVER['REQUEST_URI'];
  53         }
  54
  55         $params = wfExtractThumbParams( $uri ); // basic wiki URL param extracting
  56         if ( $params == null ) {
  57                 wfThumbError( 404, 'The source file for the specified thumbnail does not exist.' );
  58                 return;
  59         }
  60
  61         wfStreamThumb( $params ); // stream the thumbnail
  62 }
  63
  64 /**
  65  * Stream a thumbnail specified by parameters
  66  *
  67  * @param $params Array
  68  */
  69 function wfStreamThumb( array $params ) {
  70         wfProfileIn( __METHOD__ );
  71
  72         $headers = array(); // HTTP headers to send
  73
  74         $fileName = isset( $params['f'] ) ? $params['f'] : '';
  75         unset( $params['f'] );
  76
  77         // Backwards compatibility parameters
  78         if ( isset( $params['w'] ) ) {
  79                 $params['width'] = $params['w'];
  80                 unset( $params['w'] );
  81         }
  82         if ( isset( $params['p'] ) ) {
  83                 $params['page'] = $params['p'];
  84         }
  85         unset( $params['r'] ); // ignore 'r' because we unconditionally pass File::RENDER
  86
  87         // Is this a thumb of an archived file?
  88         $isOld = ( isset( $params['archived'] ) && $params['archived'] );
  89         unset( $params['archived'] );
  90
  91         // Some basic input validation
  92         $fileName = strtr( $fileName, '\\/', '__' );
  93
  94         // Actually fetch the image. Method depends on whether it is archived or not.
  95         if ( $isOld ) {
  96                 // Format is <timestamp>!<name>
  97                 $bits = explode( '!', $fileName, 2 );
  98                 if ( count( $bits ) != 2 ) {
  99                         wfThumbError( 404, wfMsg( 'badtitletext' ) );
 100                         wfProfileOut( __METHOD__ );
 101                         return;
 102                 }
 103                 $title = Title::makeTitleSafe( NS_FILE, $bits[1] );
 104                 if ( !$title ) {
 105                         wfThumbError( 404, wfMsg( 'badtitletext' ) );
 106                         wfProfileOut( __METHOD__ );
 107                         return;
 108                 }
 109                 $img = RepoGroup::singleton()->getLocalRepo()->newFromArchiveName( $title, $fileName );
 110         } else {
 111                 $img = wfLocalFile( $fileName );
 112         }
 113
 114         // Check permissions if there are read restrictions
 115         if ( !in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) ) {
 116                 if ( !$img->getTitle()->userCan( 'read' ) ) {
 117                         wfThumbError( 403, 'Access denied. You do not have permission to access ' .
 118                                 'the source file.' );
 119                         wfProfileOut( __METHOD__ );
 120                         return;
 121                 }
 122                 $headers[] = 'Cache-Control: private';
 123                 $headers[] = 'Vary: Cookie';
 124         }
 125
 126         // Check the source file storage path
 127         if ( !$img ) {
 128                 wfThumbError( 404, wfMsg( 'badtitletext' ) );
 129                 wfProfileOut( __METHOD__ );
 130                 return;
 131         }
 132         if ( !$img->exists() ) {
 133                 wfThumbError( 404, 'The source file for the specified thumbnail does not exist.' );
 134                 wfProfileOut( __METHOD__ );
 135                 return;
 136         }
 137         $sourcePath = $img->getPath();
 138         if ( $sourcePath === false ) {
 139                 wfThumbError( 500, 'The source file is not locally accessible.' );
 140                 wfProfileOut( __METHOD__ );
 141                 return;
 142         }
 143
 144         // Check IMS against the source file
 145         // This means that clients can keep a cached copy even after it has been deleted on the server
 146         if ( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
 147                 // Fix IE brokenness
 148                 $imsString = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );
 149                 // Calculate time
 150                 wfSuppressWarnings();
 151                 $imsUnix = strtotime( $imsString );
 152                 wfRestoreWarnings();
 153                 $sourceTsUnix = wfTimestamp( TS_UNIX, $img->getTimestamp() );
 154                 if ( $sourceTsUnix <= $imsUnix ) {
 155                         header( 'HTTP/1.1 304 Not Modified' );
 156                         wfProfileOut( __METHOD__ );
 157                         return;
 158                 }
 159         }
 160
 161         // Stream the file if it exists already...
 162         try {
 163                 $thumbName = $img->thumbName( $params );
 164                 if ( strlen( $thumbName ) ) { // valid params?
 165                         $thumbPath = $img->getThumbPath( $thumbName );
 166                         if ( $img->getRepo()->fileExists( $thumbPath ) ) {
 167                                 $img->getRepo()->streamFile( $thumbPath, $headers );
 168                                 wfProfileOut( __METHOD__ );
 169                                 return;
 170                         }
 171                 }
 172         } catch ( MWException $e ) {
 173                 wfThumbError( 500, $e->getHTML() );
 174                 wfProfileOut( __METHOD__ );
 175                 return;
 176         }
 177
 178         // Thumbnail isn't already there, so create the new thumbnail...
 179         try {
 180                 $thumb = $img->transform( $params, File::RENDER_NOW );
 181         } catch ( Exception $ex ) {
 182                 // Tried to select a page on a non-paged file?
 183                 $thumb = false;
 184         }
 185
 186         // Check for thumbnail generation errors...
 187         $errorMsg = false;
 188         if ( !$thumb ) {
 189                 $errorMsg = wfMsgHtml( 'thumbnail_error', 'File::transform() returned false' );
 190         } elseif ( $thumb->isError() ) {
 191                 $errorMsg = $thumb->getHtmlMsg();
 192         } elseif ( !$thumb->hasFile() ) {
 193                 $errorMsg = wfMsgHtml( 'thumbnail_error', 'No path supplied in thumbnail object' );
 194         } elseif ( $thumb->fileIsSource() ) {
 195                 $errorMsg = wfMsgHtml( 'thumbnail_error',
 196                         'Image was not scaled, is the requested width bigger than the source?' );
 197         }
 198
 199         if ( $errorMsg !== false ) {
 200                 wfThumbError( 500, $errorMsg );
 201         } else {
 202                 // Stream the file if there were no errors
 203                 $thumb->streamFile( $headers );
 204         }
 205
 206         wfProfileOut( __METHOD__ );
 207 }
 208
 209 /**
 210  * Extract the required params for thumb.php from the thumbnail request URI.
 211  * At least 'width' and 'f' should be set if the result is an array.
 212  *
 213  * @param $uri String Thumbnail request URI
 214  * @return Array|null associative params array or null
 215  */
 216 function wfExtractThumbParams( $uri ) {
 217         $repo = RepoGroup::singleton()->getLocalRepo();
 218
 219         $hashDirRegex = $subdirRegex = '';
 220         for ( $i = 0; $i < $repo->getHashLevels(); $i++ ) {
 221                 $subdirRegex .= '[0-9a-f]';
 222                 $hashDirRegex .= "$subdirRegex/";
 223         }
 224         $zoneUrlRegex = preg_quote( $repo->getZoneUrl( 'thumb' ) );
 225
 226         $thumbUrlRegex = "!^$zoneUrlRegex(/archive|/temp|)/$hashDirRegex([^/]*)/([^/]*)$!";
 227
 228         // Check if this is a valid looking thumbnail request...
 229         if ( preg_match( $thumbUrlRegex, $uri, $matches ) ) {
 230                 list( /* all */, $archOrTemp, $filename, $thumbname ) = $matches;
 231                 $filename = urldecode( $filename );
 232                 $thumbname = urldecode( $thumbname );
 233
 234                 $params = array( 'f' => $filename );
 235                 if ( $archOrTemp == '/archive' ) {
 236                         $params['archived'] = 1;
 237                 } elseif ( $archOrTemp == '/temp' ) {
 238                         $params['temp'] = 1;
 239                 }
 240
 241                 // Check if the parameters can be extracted from the thumbnail name...
 242                 // @TODO: remove 'page' stuff and make ProofreadPage handle it via hook.
 243                 if ( preg_match( '!^(page(\d*)-)*(\d*)px-[^/]*$!', $thumbname, $matches ) ) {
 244                         list( /* all */, $pagefull, $pagenum, $size ) = $matches;
 245                         $params['width'] = $size;
 246                         if ( $pagenum ) {
 247                                 $params['page'] = $pagenum;
 248                         }
 249                         return $params; // valid thumbnail URL
 250                 // Hooks return false if they manage to *resolve* the parameters
 251                 } elseif ( !wfRunHooks( 'ExtractThumbParameters', array( $thumbname, &$params ) ) ) {
 252                         return $params; // valid thumbnail URL (via extension or config)
 253                 }
 254         }
 255
 256         return null; // not a valid thumbnail URL
 257 }
 258
 259 /**
 260  * Output a thumbnail generation error message
 261  *
 262  * @param $status integer
 263  * @param $msg string
 264  */
 265 function wfThumbError( $status, $msg ) {
 266         global $wgShowHostnames;
 267
 268         header( 'Cache-Control: no-cache' );
 269         header( 'Content-Type: text/html; charset=utf-8' );
 270         if ( $status == 404 ) {
 271                 header( 'HTTP/1.1 404 Not found' );
 272         } elseif ( $status == 403 ) {
 273                 header( 'HTTP/1.1 403 Forbidden' );
 274                 header( 'Vary: Cookie' );
 275         } else {
 276                 header( 'HTTP/1.1 500 Internal server error' );
 277         }
 278         if ( $wgShowHostnames ) {
 279                 $url = htmlspecialchars( isset( $_SERVER['REQUEST_URI'] ) ? $_SERVER['REQUEST_URI'] : '' );
 280                 $hostname = htmlspecialchars( wfHostname() );
 281                 $debug = "<!-- $url -->\n<!-- $hostname -->\n";
 282         } else {
 283                 $debug = "";
 284         }
 285         echo <<<EOT
 286 <html><head><title>Error generating thumbnail</title></head>
 287 <body>
 288 <h1>Error generating thumbnail</h1>
 289 <p>
 290 $msg
 291 </p>
 292 $debug
 293 </body>
 294 </html>
 295
 296 EOT;
 297 }