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