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         // is the edit request authorized? boolean
  24         private $isEditAuthorized;
  25
  26         // did the user request us to clear the stash? boolean
  27         private $requestedClear;
  28
  29         // Since we are directly writing the file to STDOUT,
  30         // we should not be reading in really big files and serving them out.
  31         //
  32         // We also don't want people using this as a file drop, even if they
  33         // share credentials.
  34         //
  35         // This service is really for thumbnails and other such previews while
  36         // uploading.
  37         const MAX_SERVE_BYTES = 262144; // 256K
  38
  39         public function __construct() {
  40                 global $wgRequest;
  41
  42                 parent::__construct( 'UploadStash', 'upload' );
  43                 try {
  44                         $this->stash = RepoGroup::singleton()->getLocalRepo()->getUploadStash();
  45                 } catch ( UploadStashNotAvailableException $e ) {
  46                         return null;
  47                 }
  48
  49                 $this->loadRequest( $wgRequest );
  50         }
  51
  52         /**
  53          * Execute page -- can output a file directly or show a listing of them.
  54          *
  55          * @param $subPage String: subpage, e.g. in http://example.com/wiki/Special:UploadStash/foo.jpg, the "foo.jpg" part
  56          * @return Boolean: success
  57          */
  58         public function execute( $subPage ) {
  59                 global $wgUser;
  60
  61                 if ( !$this->userCanExecute( $wgUser ) ) {
  62                         $this->displayRestrictionError();
  63                         return;
  64                 }
  65
  66                 if ( !isset( $subPage ) || $subPage === '' ) {
  67                         return $this->showUploads();
  68                 }
  69
  70                 return $this->showUpload( $subPage );
  71         }
  72
  73
  74         /**
  75          * If file available in stash, cats it out to the client as a simple HTTP response.
  76          * n.b. Most sanity checking done in UploadStashLocalFile, so this is straightforward.
  77          *
  78          * @param $key String: the key of a particular requested file
  79          */
  80         public function showUpload( $key ) {
  81                 global $wgOut;
  82
  83                 // prevent callers from doing standard HTML output -- we'll take it from here
  84                 $wgOut->disable();
  85
  86                 try {
  87                         $params = $this->parseKey( $key );
  88                         if ( $params['type'] === 'thumb' ) {
  89                                 return $this->outputThumbFromStash( $params['file'], $params['params'] );
  90                         } else {
  91                                 return $this->outputLocalFile( $params['file'] );
  92                         }
  93                 } catch( UploadStashFileNotFoundException $e ) {
  94                         $code = 404;
  95                         $message = $e->getMessage();
  96                 } catch( UploadStashZeroLengthFileException $e ) {
  97                         $code = 500;
  98                         $message = $e->getMessage();
  99                 } catch( UploadStashBadPathException $e ) {
 100                         $code = 500;
 101                         $message = $e->getMessage();
 102                 } catch( SpecialUploadStashTooLargeException $e ) {
 103                         $code = 500;
 104                         $message = 'Cannot serve a file larger than ' . self::MAX_SERVE_BYTES . ' bytes. ' . $e->getMessage();
 105                 } catch( Exception $e ) {
 106                         $code = 500;
 107                         $message = $e->getMessage();
 108                 }
 109
 110                 wfHttpError( $code, OutputPage::getStatusMessage( $code ), $message );
 111                 return false;
 112         }
 113
 114         /**
 115          * Parse the key passed to the SpecialPage. Returns an array containing
 116          * the associated file object, the type ('file' or 'thumb') and if
 117          * application the transform parameters
 118          *
 119          * @param string $key
 120          * @return array
 121          */
 122         private function parseKey( $key ) {
 123                 $type = strtok( $key, '/' );
 124
 125                 if ( $type !== 'file' && $type !== 'thumb' ) {
 126                         throw new UploadStashBadPathException( "Unknown type '$type'" );
 127                 }
 128                 $fileName = strtok( '/' );
 129                 $thumbPart = strtok( '/' );
 130                 $file = $this->stash->getFile( $fileName );
 131                 if ( $type === 'thumb' ) {
 132                         $srcNamePos = strrpos( $thumbPart, $fileName );
 133                         if ( $srcNamePos === false || $srcNamePos < 1 ) {
 134                                 throw new UploadStashBadPathException( 'Unrecognized thumb name' );
 135                         }
 136                         $paramString = substr( $thumbPart, 0, $srcNamePos - 1 );
 137
 138                         $handler = $file->getHandler();
 139                         $params = $handler->parseParamString( $paramString );
 140                         return array( 'file' => $file, 'type' => $type, 'params' => $params );
 141                 }
 142
 143                 return array( 'file' => $file, 'type' => $type );
 144         }
 145
 146
 147
 148
 149         /**
 150          * Get a thumbnail for file, either generated locally or remotely, and stream it out
 151          * @param String $key: key for the file in the stash
 152          * @param int $width: width of desired thumbnail
 153          * @return boolean success
 154          */
 155         private function outputThumbFromStash( $file, $params ) {
 156
 157                 // this global, if it exists, points to a "scaler", as you might find in the Wikimedia Foundation cluster. See outputRemoteScaledThumb()
 158                 // 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
 159                 // happens to share it over NFS
 160                 global $wgUploadStashScalerBaseUrl;
 161
 162                 $flags = 0;
 163                 if ( $wgUploadStashScalerBaseUrl ) {
 164                         $this->outputRemoteScaledThumb( $file, $params, $flags );
 165                 } else {
 166                         $this->outputLocallyScaledThumb( $file, $params, $flags );
 167                 }
 168
 169
 170         }
 171
 172
 173         /**
 174          * Scale a file (probably with a locally installed imagemagick, or similar) and output it to STDOUT.
 175          * @param $file: File object
 176          * @param $params: scaling parameters ( e.g. array( width => '50' ) );
 177          * @param $flags: scaling flags ( see File:: constants )
 178          * @throws MWException
 179          * @return boolean success
 180          */
 181         private function outputLocallyScaledThumb( $file, $params, $flags ) {
 182
 183                 // n.b. this is stupid, we insist on re-transforming the file every time we are invoked. We rely
 184                 // on HTTP caching to ensure this doesn't happen.
 185
 186                 $flags |= File::RENDER_NOW;
 187
 188                 $thumbnailImage = $file->transform( $params, $flags );
 189                 if ( !$thumbnailImage ) {
 190                         throw new MWException( 'Could not obtain thumbnail' );
 191                 }
 192
 193                 // we should have just generated it locally
 194                 if ( ! $thumbnailImage->getPath() ) {
 195                         throw new UploadStashFileNotFoundException( "no local path for scaled item" );
 196                 }
 197
 198                 // now we should construct a File, so we can get mime and other such info in a standard way
 199                 // n.b. mimetype may be different from original (ogx original -> jpeg thumb)
 200                 $thumbFile = new UnregisteredLocalFile( false, $this->stash->repo, $thumbnailImage->getPath(), false );
 201                 if ( ! $thumbFile ) {
 202                         throw new UploadStashFileNotFoundException( "couldn't create local file object for thumbnail" );
 203                 }
 204
 205                 return $this->outputLocalFile( $thumbFile );
 206
 207         }
 208
 209         /**
 210          * Scale a file with a remote "scaler", as exists on the Wikimedia Foundation cluster, and output it to STDOUT.
 211          * Note: unlike the usual thumbnail process, the web client never sees the cluster URL; we do the whole HTTP transaction to the scaler ourselves
 212          *  and cat the results out.
 213          * 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
 214          *   propagated back to our filesystem. Instead we take the results of the HTTP request instead.
 215          * Note: no caching is being done here, although we are instructing the client to cache it forever.
 216          * @param $file: File object
 217          * @param $params: scaling parameters ( e.g. array( width => '50' ) );
 218          * @param $flags: scaling flags ( see File:: constants )
 219          * @throws MWException
 220          * @return boolean success
 221          */
 222         private function outputRemoteScaledThumb( $file, $params, $flags ) {
 223
 224                 // this global probably looks something like 'http://upload.wikimedia.org/wikipedia/test/thumb/temp'
 225                 // do not use trailing slash
 226                 global $wgUploadStashScalerBaseUrl;
 227
 228                 $scalerThumbName = $file->getParamThumbName( $file->name, $params );
 229                 $scalerThumbUrl = $wgUploadStashScalerBaseUrl . '/' . $file->getRel() . '/' . $scalerThumbName;
 230
 231                 // make a curl call to the scaler to create a thumbnail
 232                 $httpOptions = array(
 233                         'method' => 'GET',
 234                         'timeout' => 'default'
 235                 );
 236                 $req = MWHttpRequest::factory( $scalerThumbUrl, $httpOptions );
 237                 $status = $req->execute();
 238                 if ( ! $status->isOK() ) {
 239                         $errors = $status->getErrorsArray();
 240                         throw new MWException( "Fetching thumbnail failed: " . join( ", ", $errors ) );
 241                 }
 242                 $contentType = $req->getResponseHeader( "content-type" );
 243                 if ( ! $contentType ) {
 244                         throw new MWException( "Missing content-type header" );
 245                 }
 246                 return $this->outputContents( $req->getContent(), $contentType );
 247         }
 248
 249         /**
 250          * Output HTTP response for file
 251          * Side effect: writes HTTP response to STDOUT.
 252          * XXX could use wfStreamfile (in includes/Streamfile.php), but for consistency with outputContents() doing it this way.
 253          * XXX is mimeType really enough, or do we need encoding for full Content-Type header?
 254          *
 255          * @param $file File object with a local path (e.g. UnregisteredLocalFile, LocalFile. Oddly these don't share an ancestor!)
 256          */
 257         private function outputLocalFile( $file ) {
 258                 if ( $file->getSize() > self::MAX_SERVE_BYTES ) {
 259                         throw new SpecialUploadStashTooLargeException();
 260                 }
 261                 self::outputFileHeaders( $file->getMimeType(), $file->getSize() );
 262                 readfile( $file->getPath() );
 263                 return true;
 264         }
 265
 266         /**
 267          * Output HTTP response of raw content
 268          * Side effect: writes HTTP response to STDOUT.
 269          * @param String $content: content
 270          * @param String $mimeType: mime type
 271          */
 272         private function outputContents( $content, $contentType ) {
 273                 $size = strlen( $content );
 274                 if ( $size > self::MAX_SERVE_BYTES ) {
 275                         throw new SpecialUploadStashTooLargeException();
 276                 }
 277                 self::outputFileHeaders( $contentType, $size );
 278                 print $content;
 279                 return true;
 280         }
 281
 282         /**
 283          * Output headers for streaming
 284          * 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.
 285          * Side effect: preps PHP to write headers to STDOUT.
 286          * @param String $contentType : string suitable for content-type header
 287          * @param String $size: length in bytes
 288          */
 289         private static function outputFileHeaders( $contentType, $size ) {
 290                 header( "Content-Type: $contentType", true );
 291                 header( 'Content-Transfer-Encoding: binary', true );
 292                 header( 'Expires: Sun, 17-Jan-2038 19:14:07 GMT', true );
 293                 header( "Content-Length: $size", true );
 294         }
 295
 296
 297         /**
 298          * Initialize authorization & actions to take, from the request
 299          * @param $request: WebRequest
 300          */
 301         private function loadRequest( $request ) {
 302                 global $wgUser;
 303                 if ( $request->wasPosted() ) {
 304
 305                         $token = $request->getVal( 'wpEditToken' );
 306                         $this->isEditAuthorized = $wgUser->matchEditToken( $token );
 307
 308                         $this->requestedClear = $request->getBool( 'clear' );
 309
 310                 }
 311         }
 312
 313         /**
 314          * Static callback for the HTMLForm in showUploads, to process
 315          * Note the stash has to be recreated since this is being called in a static context.
 316          * This works, because there really is only one stash per logged-in user, despite appearances.
 317          *
 318          * @return Status
 319          */
 320         public static function tryClearStashedUploads( $formData ) {
 321                 wfDebug( __METHOD__ . " form data : " . print_r( $formData, 1 ) );
 322                 if ( isset( $formData['clear'] ) and $formData['clear'] ) {
 323                         $stash = new UploadStash();
 324                         wfDebug( "stash has: " . print_r( $stash->listFiles(), 1 ) );
 325                         if ( ! $stash->clear() ) {
 326                                 return Status::newFatal( 'uploadstash-errclear' );
 327                         }
 328                 }
 329                 return Status::newGood();
 330         }
 331
 332         /**
 333          * Default action when we don't have a subpage -- just show links to the uploads we have,
 334          * Also show a button to clear stashed files
 335          * @param Status : $status - the result of processRequest
 336          */
 337         private function showUploads( $status = null ) {
 338                 global $wgOut;
 339                 if ( $status === null ) {
 340                         $status = Status::newGood();
 341                 }
 342
 343                 // sets the title, etc.
 344                 $this->setHeaders();
 345                 $this->outputHeader();
 346
 347
 348                 // create the form, which will also be used to execute a callback to process incoming form data
 349                 // this design is extremely dubious, but supposedly HTMLForm is our standard now?
 350
 351                 $form = new HTMLForm( array(
 352                         'Clear' => array(
 353                                 'type' => 'hidden',
 354                                 'default' => true,
 355                                 'name' => 'clear',
 356                         )
 357                 ), 'clearStashedUploads' );
 358                 $form->setSubmitCallback( array( __CLASS__, 'tryClearStashedUploads' ) );
 359                 $form->setTitle( $this->getTitle() );
 360                 $form->addHiddenField( 'clear', true, array( 'type' => 'boolean' ) );
 361                 $form->setSubmitText( wfMsg( 'uploadstash-clear' ) );
 362
 363                 $form->prepareForm();
 364                 $formResult = $form->tryAuthorizedSubmit();
 365
 366
 367                 // show the files + form, if there are any, or just say there are none
 368                 $refreshHtml = Html::element( 'a', array( 'href' => $this->getTitle()->getLocalURL() ), wfMsg( 'uploadstash-refresh' ) );
 369                 $files = $this->stash->listFiles();
 370                 if ( count( $files ) ) {
 371                         sort( $files );
 372                         $fileListItemsHtml = '';
 373                         foreach ( $files as $file ) {
 374                                 $fileListItemsHtml .= Html::rawElement( 'li', array(),
 375                                         Html::element( 'a', array( 'href' =>
 376                                                 $this->getTitle( "file/$file" )->getLocalURL() ), $file )
 377                                 );
 378                         }
 379                         $wgOut->addHtml( Html::rawElement( 'ul', array(), $fileListItemsHtml ) );
 380                         $form->displayForm( $formResult );
 381                         $wgOut->addHtml( Html::rawElement( 'p', array(), $refreshHtml ) );
 382                 } else {
 383                         $wgOut->addHtml( Html::rawElement( 'p', array(),
 384                                 Html::element( 'span', array(), wfMsg( 'uploadstash-nofiles' ) )
 385                                 . ' '
 386                                 . $refreshHtml
 387                         ) );
 388                 }
 389
 390                 return true;
 391         }
 392 }
 393
 394 class SpecialUploadStashTooLargeException extends MWException {};