includes/media/MediaHandler.php

   1 <?php
   2 /**
   3  * Media-handling base classes and generic functionality.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Media
  22  */
  23
  24 /**
  25  * Base media handler class
  26  *
  27  * @ingroup Media
  28  */
  29 abstract class MediaHandler {
  30         const TRANSFORM_LATER = 1;
  31         const METADATA_GOOD = true;
  32         const METADATA_BAD = false;
  33         const METADATA_COMPATIBLE = 2; // for old but backwards compatible.
  34         /**
  35          * Instance cache
  36          */
  37         static $handlers = array();
  38
  39         /**
  40          * Get a MediaHandler for a given MIME type from the instance cache
  41          *
  42          * @param $type string
  43          *
  44          * @return MediaHandler
  45          */
  46         static function getHandler( $type ) {
  47                 global $wgMediaHandlers;
  48                 if ( !isset( $wgMediaHandlers[$type] ) ) {
  49                         wfDebug( __METHOD__ . ": no handler found for $type.\n");
  50                         return false;
  51                 }
  52                 $class = $wgMediaHandlers[$type];
  53                 if ( !isset( self::$handlers[$class] ) ) {
  54                         self::$handlers[$class] = new $class;
  55                         if ( !self::$handlers[$class]->isEnabled() ) {
  56                                 self::$handlers[$class] = false;
  57                         }
  58                 }
  59                 return self::$handlers[$class];
  60         }
  61
  62         /**
  63          * Get an associative array mapping magic word IDs to parameter names.
  64          * Will be used by the parser to identify parameters.
  65          */
  66         abstract function getParamMap();
  67
  68         /**
  69          * Validate a thumbnail parameter at parse time.
  70          * Return true to accept the parameter, and false to reject it.
  71          * If you return false, the parser will do something quiet and forgiving.
  72          *
  73          * @param $name
  74          * @param $value
  75          */
  76         abstract function validateParam( $name, $value );
  77
  78         /**
  79          * Merge a parameter array into a string appropriate for inclusion in filenames
  80          *
  81          * @param $params array
  82          */
  83         abstract function makeParamString( $params );
  84
  85         /**
  86          * Parse a param string made with makeParamString back into an array
  87          *
  88          * @param $str string
  89          */
  90         abstract function parseParamString( $str );
  91
  92         /**
  93          * Changes the parameter array as necessary, ready for transformation.
  94          * Should be idempotent.
  95          * Returns false if the parameters are unacceptable and the transform should fail
  96          * @param $image
  97          * @param $params
  98          */
  99         abstract function normaliseParams( $image, &$params );
 100
 101         /**
 102          * Get an image size array like that returned by getimagesize(), or false if it
 103          * can't be determined.
 104          *
 105          * @param $image File: the image object, or false if there isn't one
 106          * @param $path String: the filename
 107          * @return Array Follow the format of PHP getimagesize() internal function. See http://www.php.net/getimagesize
 108          */
 109         abstract function getImageSize( $image, $path );
 110
 111         /**
 112          * Get handler-specific metadata which will be saved in the img_metadata field.
 113          *
 114          * @param $image File: the image object, or false if there isn't one.
 115          *   Warning, FSFile::getPropsFromPath might pass an (object)array() instead (!)
 116          * @param $path String: the filename
 117          * @return String
 118          */
 119         function getMetadata( $image, $path ) { return ''; }
 120
 121         /**
 122         * Get metadata version.
 123         *
 124         * This is not used for validating metadata, this is used for the api when returning
 125         * metadata, since api content formats should stay the same over time, and so things
 126         * using ForiegnApiRepo can keep backwards compatibility
 127         *
 128         * All core media handlers share a common version number, and extensions can
 129         * use the GetMetadataVersion hook to append to the array (they should append a unique
 130         * string so not to get confusing). If there was a media handler named 'foo' with metadata
 131         * version 3 it might add to the end of the array the element 'foo=3'. if the core metadata
 132         * version is 2, the end version string would look like '2;foo=3'.
 133         *
 134         * @return string version string
 135         */
 136         static function getMetadataVersion () {
 137                 $version = Array( '2' ); // core metadata version
 138                 wfRunHooks('GetMetadataVersion', Array(&$version));
 139                 return implode( ';', $version);
 140          }
 141
 142         /**
 143         * Convert metadata version.
 144         *
 145         * By default just returns $metadata, but can be used to allow
 146         * media handlers to convert between metadata versions.
 147         *
 148         * @param $metadata Mixed String or Array metadata array (serialized if string)
 149         * @param $version Integer target version
 150         * @return Array serialized metadata in specified version, or $metadata on fail.
 151         */
 152         function convertMetadataVersion( $metadata, $version = 1 ) {
 153                 if ( !is_array( $metadata ) ) {
 154
 155                         //unserialize to keep return parameter consistent.
 156                         wfSuppressWarnings();
 157                         $ret = unserialize( $metadata );
 158                         wfRestoreWarnings();
 159                         return $ret;
 160                 }
 161                 return $metadata;
 162         }
 163
 164         /**
 165          * Get a string describing the type of metadata, for display purposes.
 166          *
 167          * @return string
 168          */
 169         function getMetadataType( $image ) { return false; }
 170
 171         /**
 172          * Check if the metadata string is valid for this handler.
 173          * If it returns MediaHandler::METADATA_BAD (or false), Image
 174          * will reload the metadata from the file and update the database.
 175          * MediaHandler::METADATA_GOOD for if the metadata is a-ok,
 176          * MediaHanlder::METADATA_COMPATIBLE if metadata is old but backwards
 177          * compatible (which may or may not trigger a metadata reload).
 178          * @return bool
 179          */
 180         function isMetadataValid( $image, $metadata ) {
 181                 return self::METADATA_GOOD;
 182         }
 183
 184
 185         /**
 186          * Get a MediaTransformOutput object representing an alternate of the transformed
 187          * output which will call an intermediary thumbnail assist script.
 188          *
 189          * Used when the repository has a thumbnailScriptUrl option configured.
 190          *
 191          * Return false to fall back to the regular getTransform().
 192          * @return bool
 193          */
 194         function getScriptedTransform( $image, $script, $params ) {
 195                 return false;
 196         }
 197
 198         /**
 199          * Get a MediaTransformOutput object representing the transformed output. Does not
 200          * actually do the transform.
 201          *
 202          * @param $image File: the image object
 203          * @param $dstPath String: filesystem destination path
 204          * @param $dstUrl String: Destination URL to use in output HTML
 205          * @param $params Array: Arbitrary set of parameters validated by $this->validateParam()
 206          * @return MediaTransformOutput
 207          */
 208         final function getTransform( $image, $dstPath, $dstUrl, $params ) {
 209                 return $this->doTransform( $image, $dstPath, $dstUrl, $params, self::TRANSFORM_LATER );
 210         }
 211
 212         /**
 213          * Get a MediaTransformOutput object representing the transformed output. Does the
 214          * transform unless $flags contains self::TRANSFORM_LATER.
 215          *
 216          * @param $image File: the image object
 217          * @param $dstPath String: filesystem destination path
 218          * @param $dstUrl String: destination URL to use in output HTML
 219          * @param $params Array: arbitrary set of parameters validated by $this->validateParam()
 220          * @param $flags Integer: a bitfield, may contain self::TRANSFORM_LATER
 221          *
 222          * @return MediaTransformOutput
 223          */
 224         abstract function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 );
 225
 226         /**
 227          * Get the thumbnail extension and MIME type for a given source MIME type
 228          * @return array thumbnail extension and MIME type
 229          */
 230         function getThumbType( $ext, $mime, $params = null ) {
 231                 $magic = MimeMagic::singleton();
 232                 if ( !$ext || $magic->isMatchingExtension( $ext, $mime ) === false ) {
 233                         // The extension is not valid for this mime type and we do
 234                         // recognize the mime type
 235                         $extensions = $magic->getExtensionsForType( $mime );
 236                         if ( $extensions ) {
 237                                 return array( strtok( $extensions, ' ' ), $mime );
 238                         }
 239                 }
 240
 241                 // The extension is correct (true) or the mime type is unknown to
 242                 // MediaWiki (null)
 243                 return array( $ext, $mime );
 244         }
 245
 246         /**
 247          * Get useful response headers for GET/HEAD requests for a file with the given metadata
 248          * @param $metadata mixed Result of the getMetadata() function of this handler for a file
 249          * @return Array
 250          */
 251         public function getStreamHeaders( $metadata ) {
 252                 return array();
 253         }
 254
 255         /**
 256          * True if the handled types can be transformed
 257          * @return bool
 258          */
 259         function canRender( $file ) { return true; }
 260         /**
 261          * True if handled types cannot be displayed directly in a browser
 262          * but can be rendered
 263          * @return bool
 264          */
 265         function mustRender( $file ) { return false; }
 266         /**
 267          * True if the type has multi-page capabilities
 268          * @return bool
 269          */
 270         function isMultiPage( $file ) { return false; }
 271         /**
 272          * Page count for a multi-page document, false if unsupported or unknown
 273          * @return bool
 274          */
 275         function pageCount( $file ) { return false; }
 276         /**
 277          * The material is vectorized and thus scaling is lossless
 278          * @return bool
 279          */
 280         function isVectorized( $file ) { return false; }
 281         /**
 282          * The material is an image, and is animated.
 283          * In particular, video material need not return true.
 284          * @note Before 1.20, this was a method of ImageHandler only
 285          * @return bool
 286          */
 287         function isAnimatedImage( $file ) { return false; }
 288         /**
 289          * If the material is animated, we can animate the thumbnail
 290          * @since 1.20
 291          * @return bool If material is not animated, handler may return any value.
 292          */
 293         function canAnimateThumbnail( $file ) { return true; }
 294         /**
 295          * False if the handler is disabled for all files
 296          * @return bool
 297          */
 298         function isEnabled() { return true; }
 299
 300         /**
 301          * Get an associative array of page dimensions
 302          * Currently "width" and "height" are understood, but this might be
 303          * expanded in the future.
 304          * Returns false if unknown or if the document is not multi-page.
 305          *
 306          * @param $image File
 307          * @param $page Unused, left for backcompatibility?
 308          * @return array
 309          */
 310         function getPageDimensions( $image, $page ) {
 311                 $gis = $this->getImageSize( $image, $image->getLocalRefPath() );
 312                 return array(
 313                         'width' => $gis[0],
 314                         'height' => $gis[1]
 315                 );
 316         }
 317
 318         /**
 319          * Generic getter for text layer.
 320          * Currently overloaded by PDF and DjVu handlers
 321          * @return bool
 322          */
 323         function getPageText( $image, $page ) {
 324                 return false;
 325         }
 326
 327         /**
 328          * Get an array structure that looks like this:
 329          *
 330          * array(
 331          *    'visible' => array(
 332          *       'Human-readable name' => 'Human readable value',
 333          *       ...
 334          *    ),
 335          *    'collapsed' => array(
 336          *       'Human-readable name' => 'Human readable value',
 337          *       ...
 338          *    )
 339          * )
 340          * The UI will format this into a table where the visible fields are always
 341          * visible, and the collapsed fields are optionally visible.
 342          *
 343          * The function should return false if there is no metadata to display.
 344          */
 345
 346         /**
 347          * @todo FIXME: I don't really like this interface, it's not very flexible
 348          * I think the media handler should generate HTML instead. It can do
 349          * all the formatting according to some standard. That makes it possible
 350          * to do things like visual indication of grouped and chained streams
 351          * in ogg container files.
 352          * @return bool
 353          */
 354         function formatMetadata( $image ) {
 355                 return false;
 356         }
 357
 358         /** sorts the visible/invisible field.
 359          * Split off from ImageHandler::formatMetadata, as used by more than
 360          * one type of handler.
 361          *
 362          * This is used by the media handlers that use the FormatMetadata class
 363          *
 364          * @param $metadataArray Array metadata array
 365          * @return array for use displaying metadata.
 366          */
 367         function formatMetadataHelper( $metadataArray ) {
 368                  $result = array(
 369                         'visible' => array(),
 370                         'collapsed' => array()
 371                 );
 372
 373                 $formatted = FormatMetadata::getFormattedData( $metadataArray );
 374                 // Sort fields into visible and collapsed
 375                 $visibleFields = $this->visibleMetadataFields();
 376                 foreach ( $formatted as $name => $value ) {
 377                         $tag = strtolower( $name );
 378                         self::addMeta( $result,
 379                                 in_array( $tag, $visibleFields ) ? 'visible' : 'collapsed',
 380                                 'exif',
 381                                 $tag,
 382                                 $value
 383                         );
 384                 }
 385                 return $result;
 386         }
 387
 388         /**
 389          * Get a list of metadata items which should be displayed when
 390          * the metadata table is collapsed.
 391          *
 392          * @return array of strings
 393          * @access protected
 394          */
 395         function visibleMetadataFields() {
 396                 $fields = array();
 397                 $lines = explode( "\n", wfMessage( 'metadata-fields' )->inContentLanguage()->text() );
 398                 foreach( $lines as $line ) {
 399                         $matches = array();
 400                         if( preg_match( '/^\\*\s*(.*?)\s*$/', $line, $matches ) ) {
 401                                 $fields[] = $matches[1];
 402                         }
 403                 }
 404                 $fields = array_map( 'strtolower', $fields );
 405                 return $fields;
 406         }
 407
 408
 409         /**
 410          * This is used to generate an array element for each metadata value
 411          * That array is then used to generate the table of metadata values
 412          * on the image page
 413          *
 414          * @param &$array Array An array containing elements for each type of visibility
 415          * and each of those elements being an array of metadata items. This function adds
 416          * a value to that array.
 417          * @param $visibility string ('visible' or 'collapsed') if this value is hidden
 418          * by default.
 419          * @param $type String type of metadata tag (currently always 'exif')
 420          * @param $id String the name of the metadata tag (like 'artist' for example).
 421          * its name in the table displayed is the message "$type-$id" (Ex exif-artist ).
 422          * @param $value String thingy goes into a wikitext table; it used to be escaped but
 423          * that was incompatible with previous practise of customized display
 424          * with wikitext formatting via messages such as 'exif-model-value'.
 425          * So the escaping is taken back out, but generally this seems a confusing
 426          * interface.
 427          * @param $param String value to pass to the message for the name of the field
 428          * as $1. Currently this parameter doesn't seem to ever be used.
 429          *
 430          * Note, everything here is passed through the parser later on (!)
 431          */
 432         protected static function addMeta( &$array, $visibility, $type, $id, $value, $param = false ) {
 433                 $msg = wfMessage( "$type-$id", $param );
 434                 if ( $msg->exists() ) {
 435                         $name = $msg->text();
 436                 } else {
 437                         // This is for future compatibility when using instant commons.
 438                         // So as to not display as ugly a name if a new metadata
 439                         // property is defined that we don't know about
 440                         // (not a major issue since such a property would be collapsed
 441                         // by default).
 442                         wfDebug( __METHOD__ . ' Unknown metadata name: ' . $id . "\n" );
 443                         $name = wfEscapeWikiText( $id );
 444                 }
 445                 $array[$visibility][] = array(
 446                         'id' => "$type-$id",
 447                         'name' => $name,
 448                         'value' => $value
 449                 );
 450         }
 451
 452         /**
 453          * @param $file File
 454          * @return string
 455          */
 456         function getShortDesc( $file ) {
 457                 global $wgLang;
 458                 return htmlspecialchars( $wgLang->formatSize( $file->getSize() ) );
 459         }
 460
 461         /**
 462          * @param $file File
 463          * @return string
 464          */
 465         function getLongDesc( $file ) {
 466                 global $wgLang;
 467                 return wfMessage( 'file-info', htmlspecialchars( $wgLang->formatSize( $file->getSize() ) ),
 468                         $file->getMimeType() )->parse();
 469         }
 470
 471         /**
 472          * @param $file File
 473          * @return string
 474          */
 475         static function getGeneralShortDesc( $file ) {
 476                 global $wgLang;
 477                 return $wgLang->formatSize( $file->getSize() );
 478         }
 479
 480         /**
 481          * @param $file File
 482          * @return string
 483          */
 484         static function getGeneralLongDesc( $file ) {
 485                 global $wgLang;
 486                 return wfMessage( 'file-info', $wgLang->formatSize( $file->getSize() ),
 487                         $file->getMimeType() )->parse();
 488         }
 489
 490         /**
 491          * Calculate the largest thumbnail width for a given original file size
 492          * such that the thumbnail's height is at most $maxHeight.
 493          * @param $boxWidth Integer Width of the thumbnail box.
 494          * @param $boxHeight Integer Height of the thumbnail box.
 495          * @param $maxHeight Integer Maximum height expected for the thumbnail.
 496          * @return Integer.
 497          */
 498         public static function fitBoxWidth( $boxWidth, $boxHeight, $maxHeight ) {
 499                 $idealWidth = $boxWidth * $maxHeight / $boxHeight;
 500                 $roundedUp = ceil( $idealWidth );
 501                 if( round( $roundedUp * $boxHeight / $boxWidth ) > $maxHeight ) {
 502                         return floor( $idealWidth );
 503                 } else {
 504                         return $roundedUp;
 505                 }
 506         }
 507
 508         function getDimensionsString( $file ) {
 509                 return '';
 510         }
 511
 512         /**
 513          * Modify the parser object post-transform
 514          */
 515         function parserTransformHook( $parser, $file ) {}
 516
 517         /**
 518          * File validation hook called on upload.
 519          *
 520          * If the file at the given local path is not valid, or its MIME type does not
 521          * match the handler class, a Status object should be returned containing
 522          * relevant errors.
 523          *
 524          * @param $fileName string The local path to the file.
 525          * @return Status object
 526          */
 527         function verifyUpload( $fileName ) {
 528                 return Status::newGood();
 529         }
 530
 531         /**
 532          * Check for zero-sized thumbnails. These can be generated when
 533          * no disk space is available or some other error occurs
 534          *
 535          * @param $dstPath string The location of the suspect file
 536          * @param $retval int Return value of some shell process, file will be deleted if this is non-zero
 537          * @return bool True if removed, false otherwise
 538          */
 539         function removeBadFile( $dstPath, $retval = 0 ) {
 540                 if( file_exists( $dstPath ) ) {
 541                         $thumbstat = stat( $dstPath );
 542                         if( $thumbstat['size'] == 0 || $retval != 0 ) {
 543                                 $result = unlink( $dstPath );
 544
 545                                 if ( $result ) {
 546                                         wfDebugLog( 'thumbnail',
 547                                                 sprintf( 'Removing bad %d-byte thumbnail "%s". unlink() succeeded',
 548                                                         $thumbstat['size'], $dstPath ) );
 549                                 } else {
 550                                         wfDebugLog( 'thumbnail',
 551                                                 sprintf( 'Removing bad %d-byte thumbnail "%s". unlink() failed',
 552                                                         $thumbstat['size'], $dstPath ) );
 553                                 }
 554                                 return true;
 555                         }
 556                 }
 557                 return false;
 558         }
 559
 560         /**
 561          * Remove files from the purge list
 562          *
 563          * @param array $files
 564          * @param array $options
 565          */
 566         public function filterThumbnailPurgeList( &$files, $options ) {
 567                 // Do nothing
 568         }
 569 }