wikimedia/mediawiki-extensions-Wikibase

<?php

declare( strict_types = 1 );
namespace Wikibase\Repo\FederatedProperties;

use Wikibase\Lib\FederatedProperties\FederatedPropertyId;
use Wikimedia\Assert\Assert;

/**
 * A class that handles fetching and in-memory caching of entities.
 *
 * @license GPL-2.0-or-later
 */
class ApiEntityLookup {

    /**
     * @var GenericActionApiClient
     */
    private $api;

    /**
     * Local cache used to store the results during one request.
     * @var array
     */
    private $lookupCache = [];

    public function __construct( GenericActionApiClient $api ) {
        $this->api = $api;
    }

    /**
     * Fetches entities from the source and stores the result in cache.
     * @param FederatedPropertyId[] $ids
     */
    public function fetchEntities( array $ids ): void {
        Assert::parameterElementType( FederatedPropertyId::class, $ids, '$entityIds' );

        // Fetch up to 50 entities each time
        $entityIdBatches = array_chunk( $ids, 50 );
        foreach ( $entityIdBatches as $entityIdBatch ) {
            $this->lookupCache = array_merge(
                $this->lookupCache,
                $this->getEntities( $this->getEntitiesToFetch( $entityIdBatch ) )
            );
        }
    }

    /**
     * @param FederatedPropertyId[] $entityIds
     * @return FederatedPropertyId[]
     */
    private function getEntitiesToFetch( array $entityIds ): array {
        return array_filter( $entityIds, function ( $id ) {
            return !array_key_exists( $id->getRemoteIdSerialization(), $this->lookupCache );
        } );
    }

    /**
     * @param FederatedPropertyId[] $ids
     * @return array the json_decoded part of the wbgetentities API response for the entity.
     */
    private function getEntities( array $ids ) {
        if ( !$ids ) {
            return [];
        }
        Assert::parameterElementType( FederatedPropertyId::class, $ids, '$entityIds' );

        $entityIds = $this->getFederatedEntityIdsWithoutPrefix( $ids );

        $response = $this->api->get( [
            'action' => 'wbgetentities',
            'ids' => implode( '|', $entityIds ),
            'props' => 'labels|descriptions|datatype',
            'format' => 'json',
        ] );

        // @phan-suppress-next-line PhanTypeArraySuspiciousNullable The API response will be JSON here
        return json_decode( $response->getBody()->getContents(), true )[ 'entities' ];
    }

    /**
     * Getter for the federated entity result data.
     * If not currently in cache it will make a new request.
     * @param FederatedPropertyId $id
     * @return array containing the part of the wbgetentities response for the given entity id
     */
    public function getResultPartForId( FederatedPropertyId $id ): array {
        if ( !array_key_exists( $id->getRemoteIdSerialization(), $this->lookupCache ) ) {
            wfDebugLog( 'Wikibase', 'Entity ' . $id->getSerialization() . ' not prefetched.' );
            $this->fetchEntities( [ $id ] );
        }

        return $this->lookupCache[ $id->getRemoteIdSerialization() ];
    }

    /**
     * @param FederatedPropertyId[] $federatedEntityIds
     * @return string[]
     */
    public function getFederatedEntityIdsWithoutPrefix( array $federatedEntityIds ): array {
        return array_map( function ( FederatedPropertyId $id ): string {
            return $id->getRemoteIdSerialization();
        }, $federatedEntityIds );
    }

}