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BitmapMetadataHandler.php
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BitmapMetadataHandler.php
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<?php
/**
* Extraction of metadata from different bitmap image types.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
* @ingroup Media
*/
use MediaWiki\Logger\LoggerFactory;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use Wikimedia\XMPReader\Reader as XMPReader;
/**
* Class to deal with reconciling and extracting metadata from bitmap images.
* This is meant to comply with http://www.metadataworkinggroup.org/pdf/mwg_guidance.pdf
*
* This sort of acts as an intermediary between MediaHandler::getMetadata
* and the various metadata extractors.
*
* @todo Other image formats.
* @newable
* @note marked as newable in 1.35 for lack of a better alternative,
* but should become a stateless service, or a handler managed
* registry for metadata handlers for different file types.
* @ingroup Media
*/
class BitmapMetadataHandler {
/** @var array */
private $metadata = [];
/** @var array Metadata priority */
private $metaPriority = [
20 => [ 'other' ],
40 => [ 'native' ],
60 => [ 'iptc-good-hash', 'iptc-no-hash' ],
70 => [ 'xmp-deprecated' ],
80 => [ 'xmp-general' ],
90 => [ 'xmp-exif' ],
100 => [ 'iptc-bad-hash' ],
120 => [ 'exif' ],
];
/** @var string */
private $iptcType = 'iptc-no-hash';
/**
* This does the photoshop image resource app13 block
* of interest, IPTC-IIM metadata is stored here.
*
* Mostly just calls doPSIR and doIPTC
*
* @param string $app13 String containing app13 block from jpeg file
*/
private function doApp13( $app13 ) {
try {
$this->iptcType = JpegMetadataExtractor::doPSIR( $app13 );
} catch ( InvalidPSIRException $e ) {
// Error reading the iptc hash information.
// This probably means the App13 segment is something other than what we expect.
// However, still try to read it, and treat it as if the hash didn't exist.
wfDebug( "Error parsing iptc data of file: " . $e->getMessage() );
$this->iptcType = 'iptc-no-hash';
}
$iptc = IPTC::parse( $app13 );
$this->addMetadata( $iptc, $this->iptcType );
}
/**
* Get exif info using exif class.
* Basically what used to be in BitmapHandler::getMetadata().
* Just calls stuff in the Exif class.
*
* Parameters are passed to the Exif class.
*
* @param string $filename
* @param string $byteOrder
*/
public function getExif( $filename, $byteOrder ) {
$showEXIF = MediaWikiServices::getInstance()->getMainConfig()->get( MainConfigNames::ShowEXIF );
if ( file_exists( $filename ) && $showEXIF ) {
$exif = new Exif( $filename, $byteOrder );
$data = $exif->getFilteredData();
if ( $data ) {
$this->addMetadata( $data, 'exif' );
}
}
}
/** Add misc metadata. Warning: atm if the metadata category
* doesn't have a priority, it will be silently discarded.
*
* @param array $metaArray Array of metadata values
* @param string $type Type. defaults to other. if two things have the same type they're merged
*/
public function addMetadata( $metaArray, $type = 'other' ) {
if ( isset( $this->metadata[$type] ) ) {
/* merge with old data */
$metaArray += $this->metadata[$type];
}
$this->metadata[$type] = $metaArray;
}
/**
* Merge together the various types of metadata
* the different types have different priorities,
* and are merged in order.
*
* This function is generally called by the media handlers' getMetadata()
*
* @return array
*/
public function getMetadataArray() {
// this seems a bit ugly... This is all so its merged in right order
// based on the MWG recommendation.
$temp = [];
krsort( $this->metaPriority );
foreach ( $this->metaPriority as $pri ) {
foreach ( $pri as $type ) {
if ( isset( $this->metadata[$type] ) ) {
// Do some special casing for multilingual values.
// Don't discard translations if also as a simple value.
foreach ( $this->metadata[$type] as $itemName => $item ) {
if ( is_array( $item ) && isset( $item['_type'] ) && $item['_type'] === 'lang' &&
isset( $temp[$itemName] ) && !is_array( $temp[$itemName] )
) {
$default = $temp[$itemName];
$temp[$itemName] = $item;
$temp[$itemName]['x-default'] = $default;
unset( $this->metadata[$type][$itemName] );
}
}
$temp += $this->metadata[$type];
}
}
}
return $temp;
}
/** Main entry point for jpeg's.
*
* @param string $filename Filename (with full path)
* @return array Metadata result array.
* @throws InvalidJpegException
*/
public static function Jpeg( $filename ) {
$showXMP = XMPReader::isSupported();
$meta = new self();
$seg = JpegMetadataExtractor::segmentSplitter( $filename );
if ( isset( $seg['SOF'] ) ) {
$meta->addMetadata( [ 'SOF' => $seg['SOF'] ] );
}
if ( isset( $seg['COM'] ) && isset( $seg['COM'][0] ) ) {
$meta->addMetadata( [ 'JPEGFileComment' => $seg['COM'] ], 'native' );
}
if ( isset( $seg['PSIR'] ) && count( $seg['PSIR'] ) > 0 ) {
foreach ( $seg['PSIR'] as $curPSIRValue ) {
$meta->doApp13( $curPSIRValue );
}
}
if ( isset( $seg['XMP'] ) && $showXMP ) {
$xmp = new XMPReader( LoggerFactory::getInstance( 'XMP' ), $filename );
$xmp->parse( $seg['XMP'] );
foreach ( $seg['XMP_ext'] as $xmpExt ) {
/* Support for extended xmp in jpeg files
* is not well tested and a bit fragile.
*/
$xmp->parseExtended( $xmpExt );
}
$res = $xmp->getResults();
foreach ( $res as $type => $array ) {
$meta->addMetadata( $array, $type );
}
}
$meta->getExif( $filename, $seg['byteOrder'] ?? 'BE' );
return $meta->getMetadataArray();
}
/** Entry point for png
* At some point in the future this might
* merge the png various tEXt chunks to that
* are interesting, but for now it only does XMP
*
* @param string $filename Full path to file
* @return array Array for storage in img_metadata.
*/
public static function PNG( $filename ) {
$showXMP = XMPReader::isSupported();
$meta = new self();
$array = PNGMetadataExtractor::getMetadata( $filename );
if ( isset( $array['text']['xmp']['x-default'] )
&& $array['text']['xmp']['x-default'] !== '' && $showXMP
) {
$xmp = new XMPReader( LoggerFactory::getInstance( 'XMP' ), $filename );
$xmp->parse( $array['text']['xmp']['x-default'] );
$xmpRes = $xmp->getResults();
foreach ( $xmpRes as $type => $xmpSection ) {
$meta->addMetadata( $xmpSection, $type );
}
}
unset( $array['text']['xmp'] );
// @phan-suppress-next-line PhanTypePossiblyInvalidDimOffset xmp is not alone in text, makes text always set
$meta->addMetadata( $array['text'], 'native' );
unset( $array['text'] );
$array['metadata'] = $meta->getMetadataArray();
$array['metadata']['_MW_PNG_VERSION'] = PNGMetadataExtractor::VERSION;
return $array;
}
/** function for gif images.
*
* They don't really have native metadata, so just merges together
* XMP and image comment.
*
* @param string $filename Full path to file
* @return array Metadata array
*/
public static function GIF( $filename ) {
$meta = new self();
$baseArray = GIFMetadataExtractor::getMetadata( $filename );
if ( count( $baseArray['comment'] ) > 0 ) {
$meta->addMetadata( [ 'GIFFileComment' => $baseArray['comment'] ], 'native' );
}
if ( $baseArray['xmp'] !== '' && XMPReader::isSupported() ) {
$xmp = new XMPReader( LoggerFactory::getInstance( 'XMP' ), $filename );
$xmp->parse( $baseArray['xmp'] );
$xmpRes = $xmp->getResults();
foreach ( $xmpRes as $type => $xmpSection ) {
$meta->addMetadata( $xmpSection, $type );
}
}
unset( $baseArray['comment'] );
unset( $baseArray['xmp'] );
$baseArray['metadata'] = $meta->getMetadataArray();
$baseArray['metadata']['_MW_GIF_VERSION'] = GIFMetadataExtractor::VERSION;
return $baseArray;
}
/**
* This doesn't do much yet, but eventually I plan to add
* XMP support for Tiff. (PHP's exif support already extracts
* but needs some further processing because PHP's exif support
* is stupid...)
*
* @todo Add XMP support, so this function actually makes sense to put here.
*
* The various exceptions this throws are caught later.
* @param string $filename
* @throws InvalidTiffException
* @return array The metadata.
*/
public static function Tiff( $filename ) {
if ( file_exists( $filename ) ) {
$byteOrder = self::getTiffByteOrder( $filename );
if ( !$byteOrder ) {
throw new InvalidTiffException( "Error determining byte order of $filename" );
}
$exif = new Exif( $filename, $byteOrder );
$data = $exif->getFilteredData();
if ( $data ) {
$data['MEDIAWIKI_EXIF_VERSION'] = Exif::version();
return $data;
} else {
throw new InvalidTiffException( "Could not extract data from tiff file $filename" );
}
} else {
throw new InvalidTiffException( "File doesn't exist - $filename" );
}
}
/**
* Read the first 2 bytes of a tiff file to figure out
* Little Endian or Big Endian. Needed for exif stuff.
*
* @param string $filename
* @return string|false 'BE' or 'LE' or false
*/
public static function getTiffByteOrder( $filename ) {
$fh = fopen( $filename, 'rb' );
if ( !$fh ) {
return false;
}
$head = fread( $fh, 2 );
fclose( $fh );
switch ( $head ) {
case 'II':
return 'LE'; // II for intel.
case 'MM':
return 'BE'; // MM for motorla.
default:
return false; // Something went wrong.
}
}
}

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BitmapMetadataHandler.php (9 KB)

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