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()->userCanRead() ) {
 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                 $headers[] = 'Vary: Cookie';
 129         }
 130
 131         if ( !$img ) {
 132                 wfThumbError( 404, wfMsg( 'badtitletext' ) );
 133                 wfProfileOut( __METHOD__ );
 134                 return;
 135         }
 136         if ( !$img->exists() ) {
 137                 wfThumbError( 404, 'The source file for the specified thumbnail does not exist.' );
 138                 wfProfileOut( __METHOD__ );
 139                 return;
 140         }
 141         $sourcePath = $img->getPath();
 142         if ( $sourcePath === false ) {
 143                 wfThumbError( 500, 'The source file is not locally accessible.' );
 144                 wfProfileOut( __METHOD__ );
 145                 return;
 146         }
 147
 148         // Check IMS against the source file
 149         // This means that clients can keep a cached copy even after it has been deleted on the server
 150         if ( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
 151                 // Fix IE brokenness
 152                 $imsString = preg_replace( '/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"] );
 153                 // Calculate time
 154                 wfSuppressWarnings();
 155                 $imsUnix = strtotime( $imsString );
 156                 $stat = stat( $sourcePath );
 157                 wfRestoreWarnings();
 158                 if ( $stat['mtime'] <= $imsUnix ) {
 159                         header( 'HTTP/1.1 304 Not Modified' );
 160                         wfProfileOut( __METHOD__ );
 161                         return;
 162                 }
 163         }
 164
 165         // Stream the file if it exists already...
 166         try {
 167                 $thumbName = $img->thumbName( $params );
 168                 if ( $thumbName !== false ) { // valid params?
 169                         $thumbPath = $img->getThumbPath( $thumbName );
 170                         if ( is_file( $thumbPath ) ) {
 171                                 StreamFile::stream( $thumbPath, $headers );
 172                                 wfProfileOut( __METHOD__ );
 173                                 return;
 174                         }
 175                 }
 176         } catch ( MWException $e ) {
 177                 wfThumbError( 500, $e->getHTML() );
 178                 wfProfileOut( __METHOD__ );
 179                 return;
 180         }
 181
 182         // Thumbnail isn't already there, so create the new thumbnail...
 183         try {
 184                 $thumb = $img->transform( $params, File::RENDER_NOW );
 185         } catch( Exception $ex ) {
 186                 // Tried to select a page on a non-paged file?
 187                 $thumb = false;
 188         }
 189
 190         // Check for thumbnail generation errors...
 191         $errorMsg = false;
 192         if ( !$thumb ) {
 193                 $errorMsg = wfMsgHtml( 'thumbnail_error', 'File::transform() returned false' );
 194         } elseif ( $thumb->isError() ) {
 195                 $errorMsg = $thumb->getHtmlMsg();
 196         } elseif ( !$thumb->getPath() ) {
 197                 $errorMsg = wfMsgHtml( 'thumbnail_error', 'No path supplied in thumbnail object' );
 198         } elseif ( $thumb->getPath() == $img->getPath() ) {
 199                 $errorMsg = wfMsgHtml( 'thumbnail_error', 'Image was not scaled, ' .
 200                         'is the requested width bigger than the source?' );
 201         }
 202
 203         if ( $errorMsg !== false ) {
 204                 wfThumbError( 500, $errorMsg );
 205         } else {
 206                 // Stream the file if there were no errors
 207                 StreamFile::stream( $thumb->getPath(), $headers );
 208         }
 209
 210         wfProfileOut( __METHOD__ );
 211 }
 212
 213 /**
 214  * Extract the required params for thumb.php from the thumbnail request URI.
 215  * At least 'width' and 'f' should be set if the result is an array.
 216  *
 217  * @param $uri String Thumbnail request URI
 218  * @return Array|null associative params array or null
 219  */
 220 function wfExtractThumbParams( $uri ) {
 221         $repo = RepoGroup::singleton()->getLocalRepo();
 222
 223         $hashDirRegex = $subdirRegex = '';
 224         for ( $i = 0; $i < $repo->getHashLevels(); $i++ ) {
 225                 $subdirRegex .= '[0-9a-f]';
 226                 $hashDirRegex .= "$subdirRegex/";
 227         }
 228         $zoneUrlRegex = preg_quote( $repo->getZoneUrl( 'thumb' ) );
 229
 230         $thumbUrlRegex = "!^$zoneUrlRegex(/archive|/temp|)/$hashDirRegex([^/]*)/([^/]*)$!";
 231
 232         // Check if this is a valid looking thumbnail request...
 233         if ( preg_match( $thumbUrlRegex, $uri, $matches ) ) {
 234                 list( /* all */, $archOrTemp, $filename, $thumbname ) = $matches;
 235
 236                 $params = array( 'f' => $filename );
 237                 if ( $archOrTemp == '/archive' ) {
 238                         $params['archived'] = 1;
 239                 } elseif ( $archOrTemp == '/temp' ) {
 240                         $params['temp'] = 1;
 241                 }
 242
 243                 // Check if the parameters can be extracted from the thumbnail name...
 244                 // @TODO: remove 'page' stuff and make ProofreadPage handle it via hook.
 245                 if ( preg_match( '!^(page(\d*)-)*(\d*)px-[^/]*$!', $thumbname, $matches ) ) {
 246                         list( /* all */, $pagefull, $pagenum, $size ) = $matches;
 247                         $params['width'] = $size;
 248                         if ( $pagenum ) {
 249                                 $params['page'] = $pagenum;
 250                         }
 251                         return $params; // valid thumbnail URL
 252                 // Hooks return false if they manage to *resolve* the parameters
 253                 } elseif ( !wfRunHooks( 'ExtractThumbParameters', array( $thumbname, &$params ) ) ) {
 254                         return $params; // valid thumbnail URL (via extension or config)
 255                 }
 256         }
 257
 258         return null; // not a valid thumbnail URL
 259 }
 260
 261 /**
 262  * Output a thumbnail generation error message
 263  *
 264  * @param $status integer
 265  * @param $msg string
 266  * @return void
 267  */
 268 function wfThumbError( $status, $msg ) {
 269         global $wgShowHostnames;
 270
 271         header( 'Cache-Control: no-cache' );
 272         header( 'Content-Type: text/html; charset=utf-8' );
 273         if ( $status == 404 ) {
 274                 header( 'HTTP/1.1 404 Not found' );
 275         } elseif ( $status == 403 ) {
 276                 header( 'HTTP/1.1 403 Forbidden' );
 277                 header( 'Vary: Cookie' );
 278         } else {
 279                 header( 'HTTP/1.1 500 Internal server error' );
 280         }
 281         if ( $wgShowHostnames ) {
 282                 $url = htmlspecialchars( isset( $_SERVER['REQUEST_URI'] ) ? $_SERVER['REQUEST_URI'] : '' );
 283                 $hostname = htmlspecialchars( wfHostname() );
 284                 $debug = "<!-- $url -->\n<!-- $hostname -->\n";
 285         } else {
 286                 $debug = "";
 287         }
 288         echo <<<EOT
 289 <html><head><title>Error generating thumbnail</title></head>
 290 <body>
 291 <h1>Error generating thumbnail</h1>
 292 <p>
 293 $msg
 294 </p>
 295 $debug
 296 </body>
 297 </html>
 298
 299 EOT;
 300 }
 301