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  * @return void
  34  */
  35 function wfThumbHandleRequest() {
  36         $params = get_magic_quotes_gpc()
  37                 ? array_map( 'stripslashes', $_REQUEST )
  38                 : $_REQUEST;
  39
  40         wfStreamThumb( $params ); // stream the thumbnail
  41 }
  42
  43 /**
  44  * Handle a thumbnail request via thumbnail file URL
  45  *
  46  * @return void
  47  */
  48 function wfThumbHandle404() {
  49         # lighttpd puts the original request in REQUEST_URI, while
  50         # sjs sets that to the 404 handler, and puts the original
  51         # request in REDIRECT_URL.
  52         if ( isset( $_SERVER['REDIRECT_URL'] ) ) {
  53                 # The URL is un-encoded, so put it back how it was.
  54                 $uri = str_replace( "%2F", "/", urlencode( $_SERVER['REDIRECT_URL'] ) );
  55         } else {
  56                 $uri = $_SERVER['REQUEST_URI'];
  57         }
  58
  59         $params = wfExtractThumbParams( $uri ); // basic wiki URL param extracting
  60         if ( $params == null ) {
  61                 wfThumbError( 404, 'The source file for the specified thumbnail does not exist.' );
  62                 return;
  63         }
  64
  65         wfStreamThumb( $params ); // stream the thumbnail
  66 }
  67
  68 /**
  69  * Stream a thumbnail specified by parameters
  70  *
  71  * @param $params Array
  72  * @return void
  73  */
  74 function wfStreamThumb( array $params ) {
  75         wfProfileIn( __METHOD__ );
  76
  77         $headers = array(); // HTTP headers to send
  78
  79         $fileName = isset( $params['f'] ) ? $params['f'] : '';
  80         unset( $params['f'] );
  81
  82         // Backwards compatibility parameters
  83         if ( isset( $params['w'] ) ) {
  84                 $params['width'] = $params['w'];
  85                 unset( $params['w'] );
  86         }
  87         if ( isset( $params['p'] ) ) {
  88                 $params['page'] = $params['p'];
  89         }
  90         unset( $params['r'] ); // ignore 'r' because we unconditionally pass File::RENDER
  91
  92         // Is this a thumb of an archived file?
  93         $isOld = ( isset( $params['archived'] ) && $params['archived'] );
  94         unset( $params['archived'] );
  95
  96         // Some basic input validation
  97         $fileName = strtr( $fileName, '\\/', '__' );
  98
  99         // Actually fetch the image. Method depends on whether it is archived or not.
 100         if ( $isOld ) {
 101                 // Format is <timestamp>!<name>
 102                 $bits = explode( '!', $fileName, 2 );
 103                 if ( count( $bits ) != 2 ) {
 104                         wfThumbError( 404, wfMsg( 'badtitletext' ) );
 105                         wfProfileOut( __METHOD__ );
 106                         return;
 107                 }
 108                 $title = Title::makeTitleSafe( NS_FILE, $bits[1] );
 109                 if ( !$title ) {
 110                         wfThumbError( 404, wfMsg( 'badtitletext' ) );
 111                         wfProfileOut( __METHOD__ );
 112                         return;
 113                 }
 114                 $img = RepoGroup::singleton()->getLocalRepo()->newFromArchiveName( $title, $fileName );
 115         } else {
 116                 $img = wfLocalFile( $fileName );
 117         }
 118
 119         // Check permissions if there are read restrictions
 120         if ( !in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) ) {
 121                 if ( !$img->getTitle()->userCan( 'read' ) ) {
 122                         wfThumbError( 403, 'Access denied. You do not have permission to access ' .
 123                                 'the source file.' );
 124                         wfProfileOut( __METHOD__ );
 125                         return;
 126                 }
 127                 $headers[] = 'Cache-Control: private';
 128                 $headers[] = 'Vary: Cookie';
 129         }
 130
 131         // Check the source file storage path
 132         if ( !$img ) {
 133                 wfThumbError( 404, wfMsg( 'badtitletext' ) );
 134                 wfProfileOut( __METHOD__ );
 135                 return;
 136         }
 137         if ( !$img->exists() ) {
 138                 wfThumbError( 404, 'The source file for the specified thumbnail does not exist.' );
 139                 wfProfileOut( __METHOD__ );
 140                 return;
 141         }
 142         $sourcePath = $img->getPath();
 143         if ( $sourcePath === false ) {
 144                 wfThumbError( 500, 'The source file is not locally accessible.' );
 145                 wfProfileOut( __METHOD__ );
 146                 return;
 147         }
 148
 149         // Check IMS against the source file
 150         // This means that clients can keep a cached copy even after it has been deleted on the server
 151         if ( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
 152                 // Fix IE brokenness
 153                 $imsString = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );
 154                 // Calculate time
 155                 wfSuppressWarnings();
 156                 $imsUnix = strtotime( $imsString );
 157                 wfRestoreWarnings();
 158                 $sourceTsUnix = wfTimestamp( TS_UNIX, $img->getTimestamp() );
 159                 if ( $sourceTsUnix <= $imsUnix ) {
 160                         header( 'HTTP/1.1 304 Not Modified' );
 161                         wfProfileOut( __METHOD__ );
 162                         return;
 163                 }
 164         }
 165
 166         // Stream the file if it exists already...
 167         try {
 168                 $thumbName = $img->thumbName( $params );
 169                 if ( strlen( $thumbName ) ) { // valid params?
 170                         $thumbPath = $img->getThumbPath( $thumbName );
 171                         if ( $img->getRepo()->fileExists( $thumbPath ) ) {
 172                                 $img->getRepo()->streamFile( $thumbPath, $headers );
 173                                 wfProfileOut( __METHOD__ );
 174                                 return;
 175                         }
 176                 }
 177         } catch ( MWException $e ) {
 178                 wfThumbError( 500, $e->getHTML() );
 179                 wfProfileOut( __METHOD__ );
 180                 return;
 181         }
 182
 183         // Thumbnail isn't already there, so create the new thumbnail...
 184         try {
 185                 $thumb = $img->transform( $params, File::RENDER_NOW );
 186         } catch ( Exception $ex ) {
 187                 // Tried to select a page on a non-paged file?
 188                 $thumb = false;
 189         }
 190
 191         // Check for thumbnail generation errors...
 192         $errorMsg = false;
 193         if ( !$thumb ) {
 194                 $errorMsg = wfMsgHtml( 'thumbnail_error', 'File::transform() returned false' );
 195         } elseif ( $thumb->isError() ) {
 196                 $errorMsg = $thumb->getHtmlMsg();
 197         } elseif ( !$thumb->hasFile() ) {
 198                 $errorMsg = wfMsgHtml( 'thumbnail_error', 'No path supplied in thumbnail object' );
 199         } elseif ( $thumb->fileIsSource() ) {
 200                 $errorMsg = wfMsgHtml( 'thumbnail_error',
 201                         'Image was not scaled, is the requested width bigger than the source?' );
 202         }
 203
 204         if ( $errorMsg !== false ) {
 205                 wfThumbError( 500, $errorMsg );
 206         } else {
 207                 // Stream the file if there were no errors
 208                 $thumb->streamFile( $headers );
 209         }
 210
 211         wfProfileOut( __METHOD__ );
 212 }
 213
 214 /**
 215  * Extract the required params for thumb.php from the thumbnail request URI.
 216  * At least 'width' and 'f' should be set if the result is an array.
 217  *
 218  * @param $uri String Thumbnail request URI
 219  * @return Array|null associative params array or null
 220  */
 221 function wfExtractThumbParams( $uri ) {
 222         $repo = RepoGroup::singleton()->getLocalRepo();
 223
 224         $hashDirRegex = $subdirRegex = '';
 225         for ( $i = 0; $i < $repo->getHashLevels(); $i++ ) {
 226                 $subdirRegex .= '[0-9a-f]';
 227                 $hashDirRegex .= "$subdirRegex/";
 228         }
 229         $zoneUrlRegex = preg_quote( $repo->getZoneUrl( 'thumb' ) );
 230
 231         $thumbUrlRegex = "!^$zoneUrlRegex(/archive|/temp|)/$hashDirRegex([^/]*)/([^/]*)$!";
 232
 233         // Check if this is a valid looking thumbnail request...
 234         if ( preg_match( $thumbUrlRegex, $uri, $matches ) ) {
 235                 list( /* all */, $archOrTemp, $filename, $thumbname ) = $matches;
 236                 $filename = urldecode( $filename );
 237                 $thumbname = urldecode( $thumbname );
 238
 239                 $params = array( 'f' => $filename );
 240                 if ( $archOrTemp == '/archive' ) {
 241                         $params['archived'] = 1;
 242                 } elseif ( $archOrTemp == '/temp' ) {
 243                         $params['temp'] = 1;
 244                 }
 245
 246                 // Check if the parameters can be extracted from the thumbnail name...
 247                 // @TODO: remove 'page' stuff and make ProofreadPage handle it via hook.
 248                 if ( preg_match( '!^(page(\d*)-)*(\d*)px-[^/]*$!', $thumbname, $matches ) ) {
 249                         list( /* all */, $pagefull, $pagenum, $size ) = $matches;
 250                         $params['width'] = $size;
 251                         if ( $pagenum ) {
 252                                 $params['page'] = $pagenum;
 253                         }
 254                         return $params; // valid thumbnail URL
 255                 // Hooks return false if they manage to *resolve* the parameters
 256                 } elseif ( !wfRunHooks( 'ExtractThumbParameters', array( $thumbname, &$params ) ) ) {
 257                         return $params; // valid thumbnail URL (via extension or config)
 258                 }
 259         }
 260
 261         return null; // not a valid thumbnail URL
 262 }
 263
 264 /**
 265  * Output a thumbnail generation error message
 266  *
 267  * @param $status integer
 268  * @param $msg string
 269  * @return void
 270  */
 271 function wfThumbError( $status, $msg ) {
 272         global $wgShowHostnames;
 273
 274         header( 'Cache-Control: no-cache' );
 275         header( 'Content-Type: text/html; charset=utf-8' );
 276         if ( $status == 404 ) {
 277                 header( 'HTTP/1.1 404 Not found' );
 278         } elseif ( $status == 403 ) {
 279                 header( 'HTTP/1.1 403 Forbidden' );
 280                 header( 'Vary: Cookie' );
 281         } else {
 282                 header( 'HTTP/1.1 500 Internal server error' );
 283         }
 284         if ( $wgShowHostnames ) {
 285                 $url = htmlspecialchars( isset( $_SERVER['REQUEST_URI'] ) ? $_SERVER['REQUEST_URI'] : '' );
 286                 $hostname = htmlspecialchars( wfHostname() );
 287                 $debug = "<!-- $url -->\n<!-- $hostname -->\n";
 288         } else {
 289                 $debug = "";
 290         }
 291         echo <<<EOT
 292 <html><head><title>Error generating thumbnail</title></head>
 293 <body>
 294 <h1>Error generating thumbnail</h1>
 295 <p>
 296 $msg
 297 </p>
 298 $debug
 299 </body>
 300 </html>
 301
 302 EOT;
 303 }