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<?php
/**
* Copyright © Magento, Inc. All rights reserved.
* See COPYING.txt for license details.
*/
declare(strict_types=1);
namespace Magento\MediaGalleryMetadata\Model\Png\Segment;
use Magento\Framework\Exception\LocalizedException;
use Magento\MediaGalleryMetadataApi\Api\Data\MetadataInterface;
use Magento\MediaGalleryMetadataApi\Api\Data\MetadataInterfaceFactory;
use Magento\MediaGalleryMetadataApi\Model\FileInterface;
use Magento\MediaGalleryMetadataApi\Model\ReadMetadataInterface;
use Magento\MediaGalleryMetadataApi\Model\SegmentInterface;
/**
* IPTC Reader to read IPTC data for png image
*/
class ReadIptc implements ReadMetadataInterface
{
private const IPTC_SEGMENT_NAME = 'zTXt';
private const IPTC_SEGMENT_START = 'iptc';
private const IPTC_DATA_START_POSITION = 17;
private const IPTC_CHUNK_MARKER_LENGTH = 4;
/**
* @var MetadataInterfaceFactory
*/
private $metadataFactory;
/**
* @param MetadataInterfaceFactory $metadataFactory
*/
public function __construct(
MetadataInterfaceFactory $metadataFactory
) {
$this->metadataFactory = $metadataFactory;
}
/**
* @inheritdoc
*/
public function execute(FileInterface $file): MetadataInterface
{
foreach ($file->getSegments() as $segment) {
if ($this->isIptcSegment($segment)) {
if (!is_callable('gzcompress') && !is_callable('gzuncompress')) {
throw new LocalizedException(
__('zlib gzcompress() && zlib gzuncompress() must be enabled in php configuration')
);
}
return $this->getIptcData($segment);
}
}
return $this->metadataFactory->create([
'title' => null,
'description' => null,
'keywords' => null
]);
}
/**
* Read iptc data from zTXt segment
*
* @param SegmentInterface $segment
*/
private function getIptcData(SegmentInterface $segment): MetadataInterface
{
$description = null;
$title = null;
$keywords = null;
$iptSegmentStartPosition = strpos($segment->getData(), pack("C", 0) . pack("C", 0) . 'x');
//phpcs:ignore Magento2.Functions.DiscouragedFunction
$uncompressedData = gzuncompress(substr($segment->getData(), $iptSegmentStartPosition + 2));
$data = explode(PHP_EOL, trim($uncompressedData));
//remove header and size from hex string
$iptcData = implode(array_slice($data, 2));
$binData = hex2bin($iptcData);
$descriptionMarker = pack("C", 2) . 'x' . pack("C", 0);
$descriptionStartPosition = strpos($binData, $descriptionMarker);
if ($descriptionStartPosition) {
$description = substr(
$binData,
$descriptionStartPosition + self::IPTC_CHUNK_MARKER_LENGTH,
ord(substr($binData, $descriptionStartPosition + 3, 1))
);
}
$titleMarker = pack("C", 2) . 'i' . pack("C", 0);
$titleStartPosition = strpos($binData, $titleMarker);
if ($titleStartPosition) {
$title = substr(
$binData,
$titleStartPosition + self::IPTC_CHUNK_MARKER_LENGTH,
ord(substr($binData, $titleStartPosition + 3, 1))
);
}
$keywordsMarker = pack("C", 2) . pack("C", 25) . pack("C", 0);
$keywordsStartPosition = strpos($binData, $keywordsMarker);
if ($keywordsStartPosition) {
$keywords = substr(
$binData,
$keywordsStartPosition + self::IPTC_CHUNK_MARKER_LENGTH,
ord(substr($binData, $keywordsStartPosition + 3, 1))
);
}
return $this->metadataFactory->create([
'title' => $title,
'description' => $description,
'keywords' => !empty($keywords) ? explode(',', $keywords) : null
]);
}
/**
* Does segment contain IPTC data
*
* @param SegmentInterface $segment
* @return bool
*/
private function isIptcSegment(SegmentInterface $segment): bool
{
return $segment->getName() === self::IPTC_SEGMENT_NAME
&& strncmp(
substr($segment->getData(), self::IPTC_DATA_START_POSITION, 4),
self::IPTC_SEGMENT_START,
self::IPTC_DATA_START_POSITION
) == 0;
}
}