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( $request = null ) {
  40                 global $wgRequest;
  41
  42                 parent::__construct( 'UploadStash', 'upload' );
  43                 try {
  44                         $this->stash = new UploadStash( );
  45                 } catch ( UploadStashNotAvailableException $e ) {
  46                         return null;
  47                 }
  48
  49                 $this->loadRequest( is_null( $request ) ? $wgRequest : $request );
  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 $wgOut, $wgUser;
  60
  61                 if ( !$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                 $wgOut->disable();
  85
  86                 try {
  87                         if ( preg_match( '/^(\d+)px-(.*)$/', $key, $matches ) ) {
  88                                 list( /* full match */, $width, $key ) = $matches;
  89                                 return $this->outputThumbFromStash( $key, $width );
  90                         } else {
  91                                 return $this->outputFileFromStash( $key );
  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          * Get a file from stash and stream it out. Rely on parent to catch exceptions and transform them into HTTP
 116          * @param String: $key - key of this file in the stash, which probably looks like a filename with extension.
 117          * @return boolean
 118          */
 119         private function outputFileFromStash( $key ) {
 120                 $file = $this->stash->getFile( $key );
 121                 return $this->outputLocalFile( $file );
 122         }
 123
 124
 125         /**
 126          * Get a thumbnail for file, either generated locally or remotely, and stream it out
 127          * @param String $key: key for the file in the stash
 128          * @param int $width: width of desired thumbnail
 129          * @return boolean success
 130          */
 131         private function outputThumbFromStash( $key, $width ) {
 132
 133                 // this global, if it exists, points to a "scaler", as you might find in the Wikimedia Foundation cluster. See outputRemoteScaledThumb()
 134                 // 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
 135                 // happens to share it over NFS
 136                 global $wgUploadStashScalerBaseUrl;
 137
 138                 // let exceptions propagate to caller.
 139                 $file = $this->stash->getFile( $key );
 140
 141                 // OK, we're here and no exception was thrown,
 142                 // so the original file must exist.
 143
 144                 // let's get ready to transform the original -- these are standard
 145                 $params = array( 'width' => $width );
 146                 $flags = 0;
 147
 148                 return $wgUploadStashScalerBaseUrl ? $this->outputRemoteScaledThumb( $file, $params, $flags )
 149                                                    : $this->outputLocallyScaledThumb( $file, $params, $flags );
 150
 151         }
 152
 153
 154         /**
 155          * Scale a file (probably with a locally installed imagemagick, or similar) and output it to STDOUT.
 156          * @param $file: File object
 157          * @param $params: scaling parameters ( e.g. array( width => '50' ) );
 158          * @param $flags: scaling flags ( see File:: constants )
 159          * @throws MWException
 160          * @return boolean success
 161          */
 162         private function outputLocallyScaledThumb( $file, $params, $flags ) {
 163
 164                 // n.b. this is stupid, we insist on re-transforming the file every time we are invoked. We rely
 165                 // on HTTP caching to ensure this doesn't happen.
 166
 167                 $flags |= File::RENDER_NOW;
 168
 169                 $thumbnailImage = $file->transform( $params, $flags );
 170                 if ( !$thumbnailImage ) {
 171                         throw new MWException( 'Could not obtain thumbnail' );
 172                 }
 173
 174                 // we should have just generated it locally
 175                 if ( ! $thumbnailImage->getPath() ) {
 176                         throw new UploadStashFileNotFoundException( "no local path for scaled item" );
 177                 }
 178
 179                 // now we should construct a File, so we can get mime and other such info in a standard way
 180                 // n.b. mimetype may be different from original (ogx original -> jpeg thumb)
 181                 $thumbFile = new UnregisteredLocalFile( false, $this->stash->repo, $thumbnailImage->getPath(), false );
 182                 if ( ! $thumbFile ) {
 183                         throw new UploadStashFileNotFoundException( "couldn't create local file object for thumbnail" );
 184                 }
 185
 186                 return $this->outputLocalFile( $thumbFile );
 187
 188         }
 189
 190         /**
 191          * Scale a file with a remote "scaler", as exists on the Wikimedia Foundation cluster, and output it to STDOUT.
 192          * Note: unlike the usual thumbnail process, the web client never sees the cluster URL; we do the whole HTTP transaction to the scaler ourselves
 193          *  and cat the results out.
 194          * 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
 195          *   propagated back to our filesystem. Instead we take the results of the HTTP request instead.
 196          * Note: no caching is being done here, although we are instructing the client to cache it forever.
 197          * @param $file: File object
 198          * @param $params: scaling parameters ( e.g. array( width => '50' ) );
 199          * @param $flags: scaling flags ( see File:: constants )
 200          * @throws MWException
 201          * @return boolean success
 202          */
 203         private function outputRemoteScaledThumb( $file, $params, $flags ) {
 204
 205                 // this global probably looks something like 'http://upload.wikimedia.org/wikipedia/test/thumb/temp'
 206                 // do not use trailing slash
 207                 global $wgUploadStashScalerBaseUrl;
 208
 209                 $scalerThumbName = $file->getParamThumbName( $file->name, $params );
 210                 $scalerThumbUrl = $wgUploadStashScalerBaseUrl . '/' . $file->getRel() . '/' . $scalerThumbName;
 211
 212                 // make a curl call to the scaler to create a thumbnail
 213                 $httpOptions = array(
 214                         'method' => 'GET',
 215                         'timeout' => 'default'
 216                 );
 217                 $req = MWHttpRequest::factory( $scalerThumbUrl, $httpOptions );
 218                 $status = $req->execute();
 219                 if ( ! $status->isOK() ) {
 220                         $errors = $status->getErrorsArray();
 221                         throw new MWException( "Fetching thumbnail failed: " . join( ", ", $errors ) );
 222                 }
 223                 $contentType = $req->getResponseHeader( "content-type" );
 224                 if ( ! $contentType ) {
 225                         throw new MWException( "Missing content-type header" );
 226                 }
 227                 return $this->outputContents( $req->getContent(), $contentType );
 228         }
 229
 230         /**
 231          * Output HTTP response for file
 232          * Side effect: writes HTTP response to STDOUT.
 233          * XXX could use wfStreamfile (in includes/Streamfile.php), but for consistency with outputContents() doing it this way.
 234          * XXX is mimeType really enough, or do we need encoding for full Content-Type header?
 235          *
 236          * @param $file File object with a local path (e.g. UnregisteredLocalFile, LocalFile. Oddly these don't share an ancestor!)
 237          */
 238         private function outputLocalFile( $file ) {
 239                 if ( $file->getSize() > self::MAX_SERVE_BYTES ) {
 240                         throw new SpecialUploadStashTooLargeException();
 241                 }
 242                 self::outputFileHeaders( $file->getMimeType(), $file->getSize() );
 243                 readfile( $file->getPath() );
 244                 return true;
 245         }
 246
 247         /**
 248          * Output HTTP response of raw content
 249          * Side effect: writes HTTP response to STDOUT.
 250          * @param String $content: content
 251          * @param String $mimeType: mime type
 252          */
 253         private function outputContents( $content, $contentType ) {
 254                 $size = strlen( $content );
 255                 if ( $size > self::MAX_SERVE_BYTES ) {
 256                         throw new SpecialUploadStashTooLargeException();
 257                 }
 258                 self::outputFileHeaders( $contentType, $size );
 259                 print $content;
 260                 return true;
 261         }
 262
 263         /**
 264          * Output headers for streaming
 265          * 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.
 266          * Side effect: preps PHP to write headers to STDOUT.
 267          * @param String $contentType : string suitable for content-type header
 268          * @param String $size: length in bytes
 269          */
 270         private static function outputFileHeaders( $contentType, $size ) {
 271                 header( "Content-Type: $contentType", true );
 272                 header( 'Content-Transfer-Encoding: binary', true );
 273                 header( 'Expires: Sun, 17-Jan-2038 19:14:07 GMT', true );
 274                 header( "Content-Length: $size", true );
 275         }
 276
 277
 278         /**
 279          * Initialize authorization & actions to take, from the request
 280          * @param $request: WebRequest
 281          */
 282         private function loadRequest( $request ) {
 283                 global $wgUser;
 284                 if ( $request->wasPosted() ) {
 285
 286                         $token = $request->getVal( 'wpEditToken' );
 287                         $this->isEditAuthorized = $wgUser->matchEditToken( $token );
 288
 289                         $this->requestedClear = $request->getBool( 'clear' );
 290
 291                 }
 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                 wfDebug( __METHOD__ . " form data : " . print_r( $formData, 1 ) );
 303                 if ( isset( $formData['clear'] ) and $formData['clear'] ) {
 304                         $stash = new UploadStash();
 305                         wfDebug( "stash has: " . print_r( $stash->listFiles(), 1 ) );
 306                         if ( ! $stash->clear() ) {
 307                                 return Status::newFatal( 'uploadstash-errclear' );
 308                         }
 309                 }
 310                 return Status::newGood();
 311         }
 312
 313         /**
 314          * Default action when we don't have a subpage -- just show links to the uploads we have,
 315          * Also show a button to clear stashed files
 316          * @param Status : $status - the result of processRequest
 317          */
 318         private function showUploads( $status = null ) {
 319                 global $wgOut;
 320                 if ( $status === null ) {
 321                         $status = Status::newGood();
 322                 }
 323
 324                 // sets the title, etc.
 325                 $this->setHeaders();
 326                 $this->outputHeader();
 327
 328
 329                 // create the form, which will also be used to execute a callback to process incoming form data
 330                 // this design is extremely dubious, but supposedly HTMLForm is our standard now?
 331
 332                 $form = new HTMLForm( array(
 333                         'Clear' => array(
 334                                 'type' => 'hidden',
 335                                 'default' => true,
 336                                 'name' => 'clear',
 337                         )
 338                 ), 'clearStashedUploads' );
 339                 $form->setSubmitCallback( array( __CLASS__, 'tryClearStashedUploads' ) );
 340                 $form->setTitle( $this->getTitle() );
 341                 $form->addHiddenField( 'clear', true, array( 'type' => 'boolean' ) );
 342                 $form->setSubmitText( wfMsg( 'uploadstash-clear' ) );
 343
 344                 $form->prepareForm();
 345                 $formResult = $form->tryAuthorizedSubmit();
 346
 347
 348                 // show the files + form, if there are any, or just say there are none
 349                 $refreshHtml = Html::element( 'a', array( 'href' => $this->getTitle()->getLocalURL() ), wfMsg( 'uploadstash-refresh' ) );
 350                 $files = $this->stash->listFiles();
 351                 if ( count( $files ) ) {
 352                         sort( $files );
 353                         $fileListItemsHtml = '';
 354                         foreach ( $files as $file ) {
 355                                 $fileListItemsHtml .= Html::rawElement( 'li', array(),
 356                                         Html::element( 'a', array( 'href' => $this->getTitle( $file )->getLocalURL() ), $file )
 357                                 );
 358                         }
 359                         $wgOut->addHtml( Html::rawElement( 'ul', array(), $fileListItemsHtml ) );
 360                         $form->displayForm( $formResult );
 361                         $wgOut->addHtml( Html::rawElement( 'p', array(), $refreshHtml ) );
 362                 } else {
 363                         $wgOut->addHtml( Html::rawElement( 'p', array(),
 364                                 Html::element( 'span', array(), wfMsg( 'uploadstash-nofiles' ) )
 365                                 . ' '
 366                                 . $refreshHtml
 367                         ) );
 368                 }
 369
 370                 return true;
 371         }
 372 }
 373
 374 class SpecialUploadStashTooLargeException extends MWException {};