MetadataStorageHelper.php

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<?php
use MediaWiki\Logger\LoggerFactory;
use MediaWiki\Storage\BlobStore;
 
class MetadataStorageHelper {
    private $repo;
 
    public function __construct( LocalRepo $repo ) {
        $this->repo = $repo;
    }
 
    public function getJsonMetadata( $file, $envelope ) {
        // Try encoding
        $s = $this->jsonEncode( $envelope );
 
        // Decide whether to try splitting the metadata.
        // Return early if it's not going to happen.
        if ( !$this->repo->isSplitMetadataEnabled()
            || !$file->getHandler()
            || !$file->getHandler()->useSplitMetadata()
        ) {
            return [ $s, [] ];
        }
        $threshold = $this->repo->getSplitMetadataThreshold();
        if ( !$threshold || strlen( $s ) <= $threshold ) {
            return [ $s, [] ];
        }
        $blobStore = $this->repo->getBlobStore();
        if ( !$blobStore ) {
            return [ $s, [] ];
        }
 
        // The data as a whole is above the item threshold. Look for
        // large items that can be split out.
        $blobAddresses = [];
        foreach ( $envelope['data'] as $name => $value ) {
            $encoded = $this->jsonEncode( $value );
            if ( strlen( $encoded ) > $threshold ) {
                $blobAddresses[$name] = $blobStore->storeBlob(
                    $encoded,
                    [ BlobStore::IMAGE_HINT => $file->getName() ]
                );
            }
        }
        // Remove any items that were split out
        $envelope['data'] = array_diff_key( $envelope['data'], $blobAddresses );
        $envelope['blobs'] = $blobAddresses;
        $s = $this->jsonEncode( $envelope );
 
        return [ $s, $blobAddresses ];
    }
 
    public function jsonEncode( $data ): string {
        $s = json_encode( $data,
            JSON_INVALID_UTF8_IGNORE |
            JSON_UNESCAPED_SLASHES |
            JSON_UNESCAPED_UNICODE );
        if ( $s === false ) {
            throw new MWException( __METHOD__ . ': metadata is not JSON-serializable ' );
        }
        return $s;
    }
 
    public function getMetadataFromBlobStore( array $addresses ): array {
        $result = [];
        if ( $addresses ) {
            $blobStore = $this->repo->getBlobStore();
            if ( !$blobStore ) {
                LoggerFactory::getInstance( 'LocalFile' )->warning(
                    "Unable to load metadata: repo has no blob store" );
                return $result;
            }
            $status = $blobStore->getBlobBatch( $addresses );
            if ( !$status->isGood() ) {
                $msg = Status::wrap( $status )->getWikiText(
                    false, false, 'en' );
                LoggerFactory::getInstance( 'LocalFile' )->warning(
                    "Error loading metadata from BlobStore: $msg" );
            }
            foreach ( $addresses as $itemName => $address ) {
                $json = $status->getValue()[$address] ?? null;
                if ( $json !== null ) {
                    $value = $this->jsonDecode( $json );
                    $result[$itemName] = $value;
                }
            }
        }
        return $result;
    }
 
    public function jsonDecode( string $s ) {
        // phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged
        return @json_decode( $s, true, 512, JSON_INVALID_UTF8_IGNORE );
    }
 
}