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