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 = 1048576; // 1MB
  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, HttpStatus::getMessage( $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          * Get a thumbnail for file, either generated locally or remotely, and stream it out
 138          *
 139          * @param $file
 140          * @param $params array
 141          *
 142          * @return boolean success
 143          */
 144         private function outputThumbFromStash( $file, $params ) {
 145
 146                 // this global, if it exists, points to a "scaler", as you might find in the Wikimedia Foundation cluster. See outputRemoteScaledThumb()
 147                 // 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
 148                 // happens to share it over NFS
 149                 global $wgUploadStashScalerBaseUrl;
 150
 151                 $flags = 0;
 152                 if ( $wgUploadStashScalerBaseUrl ) {
 153                         $this->outputRemoteScaledThumb( $file, $params, $flags );
 154                 } else {
 155                         $this->outputLocallyScaledThumb( $file, $params, $flags );
 156                 }
 157         }
 158
 159         /**
 160          * Scale a file (probably with a locally installed imagemagick, or similar) and output it to STDOUT.
 161          * @param $file: File object
 162          * @param $params: scaling parameters ( e.g. array( width => '50' ) );
 163          * @param $flags: scaling flags ( see File:: constants )
 164          * @throws MWException
 165          * @return boolean success
 166          */
 167         private function outputLocallyScaledThumb( $file, $params, $flags ) {
 168
 169                 // n.b. this is stupid, we insist on re-transforming the file every time we are invoked. We rely
 170                 // on HTTP caching to ensure this doesn't happen.
 171
 172                 $flags |= File::RENDER_NOW;
 173
 174                 $thumbnailImage = $file->transform( $params, $flags );
 175                 if ( !$thumbnailImage ) {
 176                         throw new MWException( 'Could not obtain thumbnail' );
 177                 }
 178
 179                 // we should have just generated it locally
 180                 if ( ! $thumbnailImage->getPath() ) {
 181                         throw new UploadStashFileNotFoundException( "no local path for scaled item" );
 182                 }
 183
 184                 // now we should construct a File, so we can get mime and other such info in a standard way
 185                 // n.b. mimetype may be different from original (ogx original -> jpeg thumb)
 186                 $thumbFile = new UnregisteredLocalFile( false, $this->stash->repo, $thumbnailImage->getPath(), false );
 187                 if ( ! $thumbFile ) {
 188                         throw new UploadStashFileNotFoundException( "couldn't create local file object for thumbnail" );
 189                 }
 190
 191                 return $this->outputLocalFile( $thumbFile );
 192
 193         }
 194
 195         /**
 196          * Scale a file with a remote "scaler", as exists on the Wikimedia Foundation cluster, and output it to STDOUT.
 197          * Note: unlike the usual thumbnail process, the web client never sees the cluster URL; we do the whole HTTP transaction to the scaler ourselves
 198          *  and cat the results out.
 199          * 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
 200          *   propagated back to our filesystem. Instead we take the results of the HTTP request instead.
 201          * Note: no caching is being done here, although we are instructing the client to cache it forever.
 202          * @param $file: File object
 203          * @param $params: scaling parameters ( e.g. array( width => '50' ) );
 204          * @param $flags: scaling flags ( see File:: constants )
 205          * @throws MWException
 206          * @return boolean success
 207          */
 208         private function outputRemoteScaledThumb( $file, $params, $flags ) {
 209
 210                 // this global probably looks something like 'http://upload.wikimedia.org/wikipedia/test/thumb/temp'
 211                 // do not use trailing slash
 212                 global $wgUploadStashScalerBaseUrl;
 213
 214                 // We need to use generateThumbName() instead of thumbName(), because
 215                 // the suffix needs to match the file name for the remote thumbnailer
 216                 // to work
 217                 $scalerThumbName = $file->generateThumbName( $file->getName(), $params );
 218                 $scalerThumbUrl = $wgUploadStashScalerBaseUrl . '/' . $file->getUrlRel() .
 219                         '/' . rawurlencode( $scalerThumbName );
 220
 221                 // make a curl call to the scaler to create a thumbnail
 222                 $httpOptions = array(
 223                         'method' => 'GET',
 224                         'timeout' => 'default'
 225                 );
 226                 $req = MWHttpRequest::factory( $scalerThumbUrl, $httpOptions );
 227                 $status = $req->execute();
 228                 if ( ! $status->isOK() ) {
 229                         $errors = $status->getWikiTextArray( $status->getErrorsArray() );
 230                         throw new MWException( "Fetching thumbnail failed: " . print_r( $errors, 1 ) );
 231                 }
 232                 $contentType = $req->getResponseHeader( "content-type" );
 233                 if ( ! $contentType ) {
 234                         throw new MWException( "Missing content-type header" );
 235                 }
 236                 return $this->outputContents( $req->getContent(), $contentType );
 237         }
 238
 239         /**
 240          * Output HTTP response for file
 241          * Side effect: writes HTTP response to STDOUT.
 242          * XXX could use wfStreamfile (in includes/Streamfile.php), but for consistency with outputContents() doing it this way.
 243          * XXX is mimeType really enough, or do we need encoding for full Content-Type header?
 244          *
 245          * @param $file File object with a local path (e.g. UnregisteredLocalFile, LocalFile. Oddly these don't share an ancestor!)
 246          */
 247         private function outputLocalFile( $file ) {
 248                 if ( $file->getSize() > self::MAX_SERVE_BYTES ) {
 249                         throw new SpecialUploadStashTooLargeException();
 250                 }
 251                 self::outputFileHeaders( $file->getMimeType(), $file->getSize() );
 252                 readfile( $file->getPath() );
 253                 return true;
 254         }
 255
 256         /**
 257          * Output HTTP response of raw content
 258          * Side effect: writes HTTP response to STDOUT.
 259          * @param String $content: content
 260          * @param String $mimeType: mime type
 261          */
 262         private function outputContents( $content, $contentType ) {
 263                 $size = strlen( $content );
 264                 if ( $size > self::MAX_SERVE_BYTES ) {
 265                         throw new SpecialUploadStashTooLargeException();
 266                 }
 267                 self::outputFileHeaders( $contentType, $size );
 268                 print $content;
 269                 return true;
 270         }
 271
 272         /**
 273          * Output headers for streaming
 274          * 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.
 275          * Side effect: preps PHP to write headers to STDOUT.
 276          * @param String $contentType : string suitable for content-type header
 277          * @param String $size: length in bytes
 278          */
 279         private static function outputFileHeaders( $contentType, $size ) {
 280                 header( "Content-Type: $contentType", true );
 281                 header( 'Content-Transfer-Encoding: binary', true );
 282                 header( 'Expires: Sun, 17-Jan-2038 19:14:07 GMT', true );
 283                 header( "Content-Length: $size", true );
 284         }
 285
 286         /**
 287          * Static callback for the HTMLForm in showUploads, to process
 288          * Note the stash has to be recreated since this is being called in a static context.
 289          * This works, because there really is only one stash per logged-in user, despite appearances.
 290          *
 291          * @return Status
 292          */
 293         public static function tryClearStashedUploads( $formData ) {
 294                 if ( isset( $formData['Clear'] ) ) {
 295                         $stash = RepoGroup::singleton()->getLocalRepo()->getUploadStash();
 296                         wfDebug( "stash has: " . print_r( $stash->listFiles(), true ) );
 297                         if ( ! $stash->clear() ) {
 298                                 return Status::newFatal( 'uploadstash-errclear' );
 299                         }
 300                 }
 301                 return Status::newGood();
 302         }
 303
 304         /**
 305          * Default action when we don't have a subpage -- just show links to the uploads we have,
 306          * Also show a button to clear stashed files
 307          * @param Status : $status - the result of processRequest
 308          */
 309         private function showUploads( $status = null ) {
 310                 global $wgOut;
 311                 if ( $status === null ) {
 312                         $status = Status::newGood();
 313                 }
 314
 315                 // sets the title, etc.
 316                 $this->setHeaders();
 317                 $this->outputHeader();
 318
 319                 // create the form, which will also be used to execute a callback to process incoming form data
 320                 // this design is extremely dubious, but supposedly HTMLForm is our standard now?
 321
 322                 $form = new HTMLForm( array(
 323                         'Clear' => array(
 324                                 'type' => 'hidden',
 325                                 'default' => true,
 326                                 'name' => 'clear',
 327                         )
 328                 ), 'clearStashedUploads' );
 329                 $form->setSubmitCallback( array( __CLASS__ , 'tryClearStashedUploads' ) );
 330                 $form->setTitle( $this->getTitle() );
 331                 $form->setSubmitText( wfMsg( 'uploadstash-clear' ) );
 332
 333                 $form->prepareForm();
 334                 $formResult = $form->tryAuthorizedSubmit();
 335
 336                 // show the files + form, if there are any, or just say there are none
 337                 $refreshHtml = Html::element( 'a',
 338                         array( 'href' => $this->getTitle()->getLocalURL() ),
 339                         wfMsg( 'uploadstash-refresh' ) );
 340                 $files = $this->stash->listFiles();
 341                 if ( count( $files ) ) {
 342                         sort( $files );
 343                         $fileListItemsHtml = '';
 344                         foreach ( $files as $file ) {
 345                                 // TODO: Use Linker::link or even construct the list in plain wikitext
 346                                 $fileListItemsHtml .= Html::rawElement( 'li', array(),
 347                                         Html::element( 'a', array( 'href' =>
 348                                                 $this->getTitle( "file/$file" )->getLocalURL() ), $file )
 349                                 );
 350                         }
 351                         $wgOut->addHtml( Html::rawElement( 'ul', array(), $fileListItemsHtml ) );
 352                         $form->displayForm( $formResult );
 353                         $wgOut->addHtml( Html::rawElement( 'p', array(), $refreshHtml ) );
 354                 } else {
 355                         $wgOut->addHtml( Html::rawElement( 'p', array(),
 356                                 Html::element( 'span', array(), wfMsg( 'uploadstash-nofiles' ) )
 357                                 . ' '
 358                                 . $refreshHtml
 359                         ) );
 360                 }
 361
 362                 return true;
 363         }
 364 }
 365
 366 class SpecialUploadStashTooLargeException extends MWException {};