includes/specials/SpecialUploadStash.php

   1 <?php
   2 /**
   3  * Implements Special:UploadStash
   4  *
   5  * Web access for files temporarily stored by UploadStash.
   6  *
   7  * For example -- files that were uploaded with the UploadWizard extension are stored temporarily
   8  * before committing them to the db. But we want to see their thumbnails and get other information
   9  * about them.
  10  *
  11  * Since this is based on the user's session, in effect this creates a private temporary file area.
  12  * However, the URLs for the files cannot be shared.
  13  *
  14  * @file
  15  * @ingroup SpecialPage
  16  * @ingroup Upload
  17  */
  18
  19 class SpecialUploadStash extends UnlistedSpecialPage {
  20         // UploadStash
  21         private $stash;
  22
  23         // Since we are directly writing the file to STDOUT,
  24         // we should not be reading in really big files and serving them out.
  25         //
  26         // We also don't want people using this as a file drop, even if they
  27         // share credentials.
  28         //
  29         // This service is really for thumbnails and other such previews while
  30         // uploading.
  31         const MAX_SERVE_BYTES = 262144; // 256K
  32
  33         public function __construct() {
  34                 parent::__construct( 'UploadStash', 'upload' );
  35                 try {
  36                         $this->stash = RepoGroup::singleton()->getLocalRepo()->getUploadStash();
  37                 } catch ( UploadStashNotAvailableException $e ) {
  38                         return null;
  39                 }
  40         }
  41
  42         /**
  43          * Execute page -- can output a file directly or show a listing of them.
  44          *
  45          * @param $subPage String: subpage, e.g. in http://example.com/wiki/Special:UploadStash/foo.jpg, the "foo.jpg" part
  46          * @return Boolean: success
  47          */
  48         public function execute( $subPage ) {
  49                 global $wgUser;
  50
  51                 if ( !$this->userCanExecute( $wgUser ) ) {
  52                         $this->displayRestrictionError();
  53                         return;
  54                 }
  55
  56                 if ( !isset( $subPage ) || $subPage === '' ) {
  57                         return $this->showUploads();
  58                 }
  59
  60                 return $this->showUpload( $subPage );
  61         }
  62
  63
  64         /**
  65          * If file available in stash, cats it out to the client as a simple HTTP response.
  66          * n.b. Most sanity checking done in UploadStashLocalFile, so this is straightforward.
  67          *
  68          * @param $key String: the key of a particular requested file
  69          */
  70         public function showUpload( $key ) {
  71                 global $wgOut;
  72
  73                 // prevent callers from doing standard HTML output -- we'll take it from here
  74                 $wgOut->disable();
  75
  76                 try {
  77                         $params = $this->parseKey( $key );
  78                         if ( $params['type'] === 'thumb' ) {
  79                                 return $this->outputThumbFromStash( $params['file'], $params['params'] );
  80                         } else {
  81                                 return $this->outputLocalFile( $params['file'] );
  82                         }
  83                 } catch( UploadStashFileNotFoundException $e ) {
  84                         $code = 404;
  85                         $message = $e->getMessage();
  86                 } catch( UploadStashZeroLengthFileException $e ) {
  87                         $code = 500;
  88                         $message = $e->getMessage();
  89                 } catch( UploadStashBadPathException $e ) {
  90                         $code = 500;
  91                         $message = $e->getMessage();
  92                 } catch( SpecialUploadStashTooLargeException $e ) {
  93                         $code = 500;
  94                         $message = 'Cannot serve a file larger than ' . self::MAX_SERVE_BYTES . ' bytes. ' . $e->getMessage();
  95                 } catch( Exception $e ) {
  96                         $code = 500;
  97                         $message = $e->getMessage();
  98                 }
  99
 100                 wfHttpError( $code, OutputPage::getStatusMessage( $code ), $message );
 101                 return false;
 102         }
 103
 104         /**
 105          * Parse the key passed to the SpecialPage. Returns an array containing
 106          * the associated file object, the type ('file' or 'thumb') and if
 107          * application the transform parameters
 108          *
 109          * @param string $key
 110          * @return array
 111          */
 112         private function parseKey( $key ) {
 113                 $type = strtok( $key, '/' );
 114
 115                 if ( $type !== 'file' && $type !== 'thumb' ) {
 116                         throw new UploadStashBadPathException( "Unknown type '$type'" );
 117                 }
 118                 $fileName = strtok( '/' );
 119                 $thumbPart = strtok( '/' );
 120                 $file = $this->stash->getFile( $fileName );
 121                 if ( $type === 'thumb' ) {
 122                         $srcNamePos = strrpos( $thumbPart, $fileName );
 123                         if ( $srcNamePos === false || $srcNamePos < 1 ) {
 124                                 throw new UploadStashBadPathException( 'Unrecognized thumb name' );
 125                         }
 126                         $paramString = substr( $thumbPart, 0, $srcNamePos - 1 );
 127
 128                         $handler = $file->getHandler();
 129                         $params = $handler->parseParamString( $paramString );
 130                         return array( 'file' => $file, 'type' => $type, 'params' => $params );
 131                 }
 132
 133                 return array( 'file' => $file, 'type' => $type );
 134         }
 135
 136
 137
 138
 139         /**
 140          * Get a thumbnail for file, either generated locally or remotely, and stream it out
 141          * @param String $key: key for the file in the stash
 142          * @param int $width: width of desired thumbnail
 143          * @return boolean success
 144          */
 145         private function outputThumbFromStash( $file, $params ) {
 146
 147                 // this global, if it exists, points to a "scaler", as you might find in the Wikimedia Foundation cluster. See outputRemoteScaledThumb()
 148                 // this is part of our horrible NFS-based system, we create a file on a mount point here, but fetch the scaled file from somewhere else that
 149                 // happens to share it over NFS
 150                 global $wgUploadStashScalerBaseUrl;
 151
 152                 $flags = 0;
 153                 if ( $wgUploadStashScalerBaseUrl ) {
 154                         $this->outputRemoteScaledThumb( $file, $params, $flags );
 155                 } else {
 156                         $this->outputLocallyScaledThumb( $file, $params, $flags );
 157                 }
 158
 159
 160         }
 161
 162
 163         /**
 164          * Scale a file (probably with a locally installed imagemagick, or similar) and output it to STDOUT.
 165          * @param $file: File object
 166          * @param $params: scaling parameters ( e.g. array( width => '50' ) );
 167          * @param $flags: scaling flags ( see File:: constants )
 168          * @throws MWException
 169          * @return boolean success
 170          */
 171         private function outputLocallyScaledThumb( $file, $params, $flags ) {
 172
 173                 // n.b. this is stupid, we insist on re-transforming the file every time we are invoked. We rely
 174                 // on HTTP caching to ensure this doesn't happen.
 175
 176                 $flags |= File::RENDER_NOW;
 177
 178                 $thumbnailImage = $file->transform( $params, $flags );
 179                 if ( !$thumbnailImage ) {
 180                         throw new MWException( 'Could not obtain thumbnail' );
 181                 }
 182
 183                 // we should have just generated it locally
 184                 if ( ! $thumbnailImage->getPath() ) {
 185                         throw new UploadStashFileNotFoundException( "no local path for scaled item" );
 186                 }
 187
 188                 // now we should construct a File, so we can get mime and other such info in a standard way
 189                 // n.b. mimetype may be different from original (ogx original -> jpeg thumb)
 190                 $thumbFile = new UnregisteredLocalFile( false, $this->stash->repo, $thumbnailImage->getPath(), false );
 191                 if ( ! $thumbFile ) {
 192                         throw new UploadStashFileNotFoundException( "couldn't create local file object for thumbnail" );
 193                 }
 194
 195                 return $this->outputLocalFile( $thumbFile );
 196
 197         }
 198
 199         /**
 200          * Scale a file with a remote "scaler", as exists on the Wikimedia Foundation cluster, and output it to STDOUT.
 201          * Note: unlike the usual thumbnail process, the web client never sees the cluster URL; we do the whole HTTP transaction to the scaler ourselves
 202          *  and cat the results out.
 203          * Note: We rely on NFS to have propagated the file contents to the scaler. However, we do not rely on the thumbnail being created in NFS and then
 204          *   propagated back to our filesystem. Instead we take the results of the HTTP request instead.
 205          * Note: no caching is being done here, although we are instructing the client to cache it forever.
 206          * @param $file: File object
 207          * @param $params: scaling parameters ( e.g. array( width => '50' ) );
 208          * @param $flags: scaling flags ( see File:: constants )
 209          * @throws MWException
 210          * @return boolean success
 211          */
 212         private function outputRemoteScaledThumb( $file, $params, $flags ) {
 213
 214                 // this global probably looks something like 'http://upload.wikimedia.org/wikipedia/test/thumb/temp'
 215                 // do not use trailing slash
 216                 global $wgUploadStashScalerBaseUrl;
 217
 218                 // We need to use generateThumbName() instead of thumbName(), because
 219                 // the suffix needs to match the file name for the remote thumbnailer
 220                 // to work
 221                 $scalerThumbName = $file->generateThumbName( $file->getName(), $params );
 222                 $scalerThumbUrl = $wgUploadStashScalerBaseUrl . '/' . $file->getUrlRel() .
 223                         '/' . rawurlencode( $scalerThumbName );
 224
 225                 // make a curl call to the scaler to create a thumbnail
 226                 $httpOptions = array(
 227                         'method' => 'GET',
 228                         'timeout' => 'default'
 229                 );
 230                 $req = MWHttpRequest::factory( $scalerThumbUrl, $httpOptions );
 231                 $status = $req->execute();
 232                 if ( ! $status->isOK() ) {
 233                         $errors = $status->getWikiTextArray( $status->getErrorsArray() );
 234                         throw new MWException( "Fetching thumbnail failed: " . join( ", ", $errors ) );
 235                 }
 236                 $contentType = $req->getResponseHeader( "content-type" );
 237                 if ( ! $contentType ) {
 238                         throw new MWException( "Missing content-type header" );
 239                 }
 240                 return $this->outputContents( $req->getContent(), $contentType );
 241         }
 242
 243         /**
 244          * Output HTTP response for file
 245          * Side effect: writes HTTP response to STDOUT.
 246          * XXX could use wfStreamfile (in includes/Streamfile.php), but for consistency with outputContents() doing it this way.
 247          * XXX is mimeType really enough, or do we need encoding for full Content-Type header?
 248          *
 249          * @param $file File object with a local path (e.g. UnregisteredLocalFile, LocalFile. Oddly these don't share an ancestor!)
 250          */
 251         private function outputLocalFile( $file ) {
 252                 if ( $file->getSize() > self::MAX_SERVE_BYTES ) {
 253                         throw new SpecialUploadStashTooLargeException();
 254                 }
 255                 self::outputFileHeaders( $file->getMimeType(), $file->getSize() );
 256                 readfile( $file->getPath() );
 257                 return true;
 258         }
 259
 260         /**
 261          * Output HTTP response of raw content
 262          * Side effect: writes HTTP response to STDOUT.
 263          * @param String $content: content
 264          * @param String $mimeType: mime type
 265          */
 266         private function outputContents( $content, $contentType ) {
 267                 $size = strlen( $content );
 268                 if ( $size > self::MAX_SERVE_BYTES ) {
 269                         throw new SpecialUploadStashTooLargeException();
 270                 }
 271                 self::outputFileHeaders( $contentType, $size );
 272                 print $content;
 273                 return true;
 274         }
 275
 276         /**
 277          * Output headers for streaming
 278          * XXX unsure about encoding as binary; if we received from HTTP perhaps we should use that encoding, concatted with semicolon to mimeType as it usually is.
 279          * Side effect: preps PHP to write headers to STDOUT.
 280          * @param String $contentType : string suitable for content-type header
 281          * @param String $size: length in bytes
 282          */
 283         private static function outputFileHeaders( $contentType, $size ) {
 284                 header( "Content-Type: $contentType", true );
 285                 header( 'Content-Transfer-Encoding: binary', true );
 286                 header( 'Expires: Sun, 17-Jan-2038 19:14:07 GMT', true );
 287                 header( "Content-Length: $size", true );
 288         }
 289
 290         /**
 291          * Static callback for the HTMLForm in showUploads, to process
 292          * Note the stash has to be recreated since this is being called in a static context.
 293          * This works, because there really is only one stash per logged-in user, despite appearances.
 294          *
 295          * @return Status
 296          */
 297         public static function tryClearStashedUploads( $formData ) {
 298                 if ( isset( $formData['Clear'] ) ) {
 299                         $stash = RepoGroup::singleton()->getLocalRepo()->getUploadStash();
 300                         wfDebug( "stash has: " . print_r( $stash->listFiles(), true ) );
 301                         if ( ! $stash->clear() ) {
 302                                 return Status::newFatal( 'uploadstash-errclear' );
 303                         }
 304                 }
 305                 return Status::newGood();
 306         }
 307
 308         /**
 309          * Default action when we don't have a subpage -- just show links to the uploads we have,
 310          * Also show a button to clear stashed files
 311          * @param Status : $status - the result of processRequest
 312          */
 313         private function showUploads( $status = null ) {
 314                 global $wgOut;
 315                 if ( $status === null ) {
 316                         $status = Status::newGood();
 317                 }
 318
 319                 // sets the title, etc.
 320                 $this->setHeaders();
 321                 $this->outputHeader();
 322
 323
 324                 // create the form, which will also be used to execute a callback to process incoming form data
 325                 // this design is extremely dubious, but supposedly HTMLForm is our standard now?
 326
 327                 $form = new HTMLForm( array(
 328                         'Clear' => array(
 329                                 'type' => 'hidden',
 330                                 'default' => true,
 331                                 'name' => 'clear',
 332                         )
 333                 ), 'clearStashedUploads' );
 334                 $form->setSubmitCallback( array( __CLASS__ , 'tryClearStashedUploads' ) );
 335                 $form->setTitle( $this->getTitle() );
 336                 $form->setSubmitText( wfMsg( 'uploadstash-clear' ) );
 337
 338                 $form->prepareForm();
 339                 $formResult = $form->tryAuthorizedSubmit();
 340
 341
 342                 // show the files + form, if there are any, or just say there are none
 343                 $refreshHtml = Html::element( 'a',
 344                         array( 'href' => $this->getTitle()->getLocalURL() ),
 345                         wfMsg( 'uploadstash-refresh' ) );
 346                 $files = $this->stash->listFiles();
 347                 if ( count( $files ) ) {
 348                         sort( $files );
 349                         $fileListItemsHtml = '';
 350                         foreach ( $files as $file ) {
 351                                 // TODO: Use Linker::link or even construct the list in plain wikitext
 352                                 $fileListItemsHtml .= Html::rawElement( 'li', array(),
 353                                         Html::element( 'a', array( 'href' =>
 354                                                 $this->getTitle( "file/$file" )->getLocalURL() ), $file )
 355                                 );
 356                         }
 357                         $wgOut->addHtml( Html::rawElement( 'ul', array(), $fileListItemsHtml ) );
 358                         $form->displayForm( $formResult );
 359                         $wgOut->addHtml( Html::rawElement( 'p', array(), $refreshHtml ) );
 360                 } else {
 361                         $wgOut->addHtml( Html::rawElement( 'p', array(),
 362                                 Html::element( 'span', array(), wfMsg( 'uploadstash-nofiles' ) )
 363                                 . ' '
 364                                 . $refreshHtml
 365                         ) );
 366                 }
 367
 368                 return true;
 369         }
 370 }
 371
 372 class SpecialUploadStashTooLargeException extends MWException {};