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          * True if the handled types can be transformed
 248          * @return bool
 249          */
 250         function canRender( $file ) { return true; }
 251         /**
 252          * True if handled types cannot be displayed directly in a browser
 253          * but can be rendered
 254          * @return bool
 255          */
 256         function mustRender( $file ) { return false; }
 257         /**
 258          * True if the type has multi-page capabilities
 259          * @return bool
 260          */
 261         function isMultiPage( $file ) { return false; }
 262         /**
 263          * Page count for a multi-page document, false if unsupported or unknown
 264          * @return bool
 265          */
 266         function pageCount( $file ) { return false; }
 267         /**
 268          * The material is vectorized and thus scaling is lossless
 269          * @return bool
 270          */
 271         function isVectorized( $file ) { return false; }
 272         /**
 273          * False if the handler is disabled for all files
 274          * @return bool
 275          */
 276         function isEnabled() { return true; }
 277
 278         /**
 279          * Get an associative array of page dimensions
 280          * Currently "width" and "height" are understood, but this might be
 281          * expanded in the future.
 282          * Returns false if unknown or if the document is not multi-page.
 283          *
 284          * @param $image File
 285          * @param $page Unused, left for backcompatibility?
 286          * @return array
 287          */
 288         function getPageDimensions( $image, $page ) {
 289                 $gis = $this->getImageSize( $image, $image->getLocalRefPath() );
 290                 return array(
 291                         'width' => $gis[0],
 292                         'height' => $gis[1]
 293                 );
 294         }
 295
 296         /**
 297          * Generic getter for text layer.
 298          * Currently overloaded by PDF and DjVu handlers
 299          * @return bool
 300          */
 301         function getPageText( $image, $page ) {
 302                 return false;
 303         }
 304
 305         /**
 306          * Get an array structure that looks like this:
 307          *
 308          * array(
 309          *    'visible' => array(
 310          *       'Human-readable name' => 'Human readable value',
 311          *       ...
 312          *    ),
 313          *    'collapsed' => array(
 314          *       'Human-readable name' => 'Human readable value',
 315          *       ...
 316          *    )
 317          * )
 318          * The UI will format this into a table where the visible fields are always
 319          * visible, and the collapsed fields are optionally visible.
 320          *
 321          * The function should return false if there is no metadata to display.
 322          */
 323
 324         /**
 325          * @todo FIXME: I don't really like this interface, it's not very flexible
 326          * I think the media handler should generate HTML instead. It can do
 327          * all the formatting according to some standard. That makes it possible
 328          * to do things like visual indication of grouped and chained streams
 329          * in ogg container files.
 330          * @return bool
 331          */
 332         function formatMetadata( $image ) {
 333                 return false;
 334         }
 335
 336         /** sorts the visible/invisible field.
 337          * Split off from ImageHandler::formatMetadata, as used by more than
 338          * one type of handler.
 339          *
 340          * This is used by the media handlers that use the FormatMetadata class
 341          *
 342          * @param $metadataArray Array metadata array
 343          * @return array for use displaying metadata.
 344          */
 345         function formatMetadataHelper( $metadataArray ) {
 346                  $result = array(
 347                         'visible' => array(),
 348                         'collapsed' => array()
 349                 );
 350
 351                 $formatted = FormatMetadata::getFormattedData( $metadataArray );
 352                 // Sort fields into visible and collapsed
 353                 $visibleFields = $this->visibleMetadataFields();
 354                 foreach ( $formatted as $name => $value ) {
 355                         $tag = strtolower( $name );
 356                         self::addMeta( $result,
 357                                 in_array( $tag, $visibleFields ) ? 'visible' : 'collapsed',
 358                                 'exif',
 359                                 $tag,
 360                                 $value
 361                         );
 362                 }
 363                 return $result;
 364         }
 365
 366         /**
 367          * Get a list of metadata items which should be displayed when
 368          * the metadata table is collapsed.
 369          *
 370          * @return array of strings
 371          * @access protected
 372          */
 373         function visibleMetadataFields() {
 374                 $fields = array();
 375                 $lines = explode( "\n", wfMsgForContent( 'metadata-fields' ) );
 376                 foreach( $lines as $line ) {
 377                         $matches = array();
 378                         if( preg_match( '/^\\*\s*(.*?)\s*$/', $line, $matches ) ) {
 379                                 $fields[] = $matches[1];
 380                         }
 381                 }
 382                 $fields = array_map( 'strtolower', $fields );
 383                 return $fields;
 384         }
 385
 386
 387         /**
 388          * This is used to generate an array element for each metadata value
 389          * That array is then used to generate the table of metadata values
 390          * on the image page
 391          *
 392          * @param &$array Array An array containing elements for each type of visibility
 393          * and each of those elements being an array of metadata items. This function adds
 394          * a value to that array.
 395          * @param $visibility string ('visible' or 'collapsed') if this value is hidden
 396          * by default.
 397          * @param $type String type of metadata tag (currently always 'exif')
 398          * @param $id String the name of the metadata tag (like 'artist' for example).
 399          * its name in the table displayed is the message "$type-$id" (Ex exif-artist ).
 400          * @param $value String thingy goes into a wikitext table; it used to be escaped but
 401          * that was incompatible with previous practise of customized display
 402          * with wikitext formatting via messages such as 'exif-model-value'.
 403          * So the escaping is taken back out, but generally this seems a confusing
 404          * interface.
 405          * @param $param String value to pass to the message for the name of the field
 406          * as $1. Currently this parameter doesn't seem to ever be used.
 407          *
 408          * Note, everything here is passed through the parser later on (!)
 409          */
 410         protected static function addMeta( &$array, $visibility, $type, $id, $value, $param = false ) {
 411                 $msg = wfMessage( "$type-$id", $param );
 412                 if ( $msg->exists() ) {
 413                         $name = $msg->text();
 414                 } else {
 415                         // This is for future compatibility when using instant commons.
 416                         // So as to not display as ugly a name if a new metadata
 417                         // property is defined that we don't know about
 418                         // (not a major issue since such a property would be collapsed
 419                         // by default).
 420                         wfDebug( __METHOD__ . ' Unknown metadata name: ' . $id . "\n" );
 421                         $name = wfEscapeWikiText( $id );
 422                 }
 423                 $array[$visibility][] = array(
 424                         'id' => "$type-$id",
 425                         'name' => $name,
 426                         'value' => $value
 427                 );
 428         }
 429
 430         /**
 431          * @param $file File
 432          * @return string
 433          */
 434         function getShortDesc( $file ) {
 435                 global $wgLang;
 436                 return htmlspecialchars( $wgLang->formatSize( $file->getSize() ) );
 437         }
 438
 439         /**
 440          * @param $file File
 441          * @return string
 442          */
 443         function getLongDesc( $file ) {
 444                 global $wgLang;
 445                 return wfMessage( 'file-info', htmlspecialchars( $wgLang->formatSize( $file->getSize() ) ),
 446                         $file->getMimeType() )->parse();
 447         }
 448
 449         /**
 450          * @param $file File
 451          * @return string
 452          */
 453         static function getGeneralShortDesc( $file ) {
 454                 global $wgLang;
 455                 return $wgLang->formatSize( $file->getSize() );
 456         }
 457
 458         /**
 459          * @param $file File
 460          * @return string
 461          */
 462         static function getGeneralLongDesc( $file ) {
 463                 global $wgLang;
 464                 return wfMessage( 'file-info', $wgLang->formatSize( $file->getSize() ),
 465                         $file->getMimeType() )->parse();
 466         }
 467
 468         /**
 469          * Calculate the largest thumbnail width for a given original file size
 470          * such that the thumbnail's height is at most $maxHeight.
 471          * @param $boxWidth Integer Width of the thumbnail box.
 472          * @param $boxHeight Integer Height of the thumbnail box.
 473          * @param $maxHeight Integer Maximum height expected for the thumbnail.
 474          * @return Integer.
 475          */
 476         public static function fitBoxWidth( $boxWidth, $boxHeight, $maxHeight ) {
 477                 $idealWidth = $boxWidth * $maxHeight / $boxHeight;
 478                 $roundedUp = ceil( $idealWidth );
 479                 if( round( $roundedUp * $boxHeight / $boxWidth ) > $maxHeight ) {
 480                         return floor( $idealWidth );
 481                 } else {
 482                         return $roundedUp;
 483                 }
 484         }
 485
 486         function getDimensionsString( $file ) {
 487                 return '';
 488         }
 489
 490         /**
 491          * Modify the parser object post-transform
 492          */
 493         function parserTransformHook( $parser, $file ) {}
 494
 495         /**
 496          * File validation hook called on upload.
 497          *
 498          * If the file at the given local path is not valid, or its MIME type does not
 499          * match the handler class, a Status object should be returned containing
 500          * relevant errors.
 501          *
 502          * @param $fileName string The local path to the file.
 503          * @return Status object
 504          */
 505         function verifyUpload( $fileName ) {
 506                 return Status::newGood();
 507         }
 508
 509         /**
 510          * Check for zero-sized thumbnails. These can be generated when
 511          * no disk space is available or some other error occurs
 512          *
 513          * @param $dstPath string The location of the suspect file
 514          * @param $retval int Return value of some shell process, file will be deleted if this is non-zero
 515          * @return bool True if removed, false otherwise
 516          */
 517         function removeBadFile( $dstPath, $retval = 0 ) {
 518                 if( file_exists( $dstPath ) ) {
 519                         $thumbstat = stat( $dstPath );
 520                         if( $thumbstat['size'] == 0 || $retval != 0 ) {
 521                                 $result = unlink( $dstPath );
 522
 523                                 if ( $result ) {
 524                                         wfDebugLog( 'thumbnail',
 525                                                 sprintf( 'Removing bad %d-byte thumbnail "%s". unlink() succeeded',
 526                                                         $thumbstat['size'], $dstPath ) );
 527                                 } else {
 528                                         wfDebugLog( 'thumbnail',
 529                                                 sprintf( 'Removing bad %d-byte thumbnail "%s". unlink() failed',
 530                                                         $thumbstat['size'], $dstPath ) );
 531                                 }
 532                                 return true;
 533                         }
 534                 }
 535                 return false;
 536         }
 537
 538         /**
 539          * Remove files from the purge list
 540          *
 541          * @param array $files
 542          * @param array $options
 543          */
 544         public function filterThumbnailPurgeList( &$files, $options ) {
 545                 // Do nothing
 546         }
 547 }