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