wikimedia/mediawiki-extensions-Wikibase

<?php declare( strict_types=1 );

namespace Wikibase\Repo\RestApi\RouteHandlers;

use MediaWiki\MediaWikiServices;
use MediaWiki\Rest\Handler;
use MediaWiki\Rest\RequestInterface;
use MediaWiki\Rest\Response;
use MediaWiki\Rest\ResponseInterface;
use MediaWiki\Rest\SimpleHandler;
use MediaWiki\Rest\StringStream;
use Wikibase\Repo\RestApi\Application\Serialization\StatementSerializer;
use Wikibase\Repo\RestApi\Application\UseCases\GetItemStatement\GetItemStatement;
use Wikibase\Repo\RestApi\Application\UseCases\GetItemStatement\GetItemStatementRequest;
use Wikibase\Repo\RestApi\Application\UseCases\GetStatement\GetStatementResponse;
use Wikibase\Repo\RestApi\Application\UseCases\ItemRedirect;
use Wikibase\Repo\RestApi\Application\UseCases\UseCaseError;
use Wikibase\Repo\RestApi\RouteHandlers\Middleware\AuthenticationMiddleware;
use Wikibase\Repo\RestApi\RouteHandlers\Middleware\MiddlewareHandler;
use Wikibase\Repo\RestApi\RouteHandlers\Middleware\UserAgentCheckMiddleware;
use Wikibase\Repo\RestApi\WbRestApi;
use Wikimedia\ParamValidator\ParamValidator;

/**
 * @license GPL-2.0-or-later
 */
class GetItemStatementRouteHandler extends SimpleHandler {

    public const ITEM_ID_PATH_PARAM = 'item_id';
    public const STATEMENT_ID_PATH_PARAM = 'statement_id';
    public const ROUTE = '/wikibase/v0/entities/items/{item_id}/statements/{statement_id}';

    private GetItemStatement $getStatement;
    private StatementSerializer $statementSerializer;
    private ResponseFactory $responseFactory;
    private MiddlewareHandler $middlewareHandler;

    public function __construct(
        GetItemStatement $getStatement,
        StatementSerializer $statementSerializer,
        ResponseFactory $responseFactory,
        MiddlewareHandler $middlewareHandler
    ) {
        $this->getStatement = $getStatement;
        $this->statementSerializer = $statementSerializer;
        $this->responseFactory = $responseFactory;
        $this->middlewareHandler = $middlewareHandler;
    }

    public static function factory(): Handler {
        $responseFactory = new ResponseFactory();
        return new self(
            WbRestApi::getGetItemStatement(),
            WbRestApi::getStatementSerializer(),
            $responseFactory,
            new MiddlewareHandler( [
                WbRestApi::getUnexpectedErrorHandlerMiddleware(),
                new UserAgentCheckMiddleware(),
                new AuthenticationMiddleware( MediaWikiServices::getInstance()->getUserIdentityUtils() ),
                WbRestApi::getPreconditionMiddlewareFactory()->newPreconditionMiddleware(
                    fn( RequestInterface $request ): string => $request->getPathParam( self::ITEM_ID_PATH_PARAM )
                ),
                WbRestApi::getStatementRedirectMiddlewareFactory()->newStatementRedirectMiddleware(
                    self::STATEMENT_ID_PATH_PARAM,
                    self::ITEM_ID_PATH_PARAM
                ),
            ] )
        );
    }

    /**
     * @param mixed ...$args
     */
    public function run( ...$args ): Response {
        return $this->middlewareHandler->run( $this, [ $this, 'runUseCase' ], $args );
    }

    public function runUseCase( string $itemId, string $statementId ): Response {
        try {
            return $this->newSuccessHttpResponse(
                $this->getStatement->execute(
                    new GetItemStatementRequest( $itemId, $statementId )
                )
            );
        } catch ( UseCaseError $e ) {
            return $this->responseFactory->newErrorResponseFromException( $e );
        } catch ( ItemRedirect $e ) {
            return $this->responseFactory
                ->newErrorResponseFromException( UseCaseError::newResourceNotFound( 'statement' ) );
        }
    }

    public function getParamSettings(): array {
        return [
            self::ITEM_ID_PATH_PARAM => [
                self::PARAM_SOURCE => 'path',
                ParamValidator::PARAM_TYPE => 'string',
                ParamValidator::PARAM_REQUIRED => true,
            ],
            self::STATEMENT_ID_PATH_PARAM => [
                self::PARAM_SOURCE => 'path',
                ParamValidator::PARAM_TYPE => 'string',
                ParamValidator::PARAM_REQUIRED => true,
            ],
        ];
    }

    public function needsWriteAccess(): bool {
        return false;
    }

    /**
     * Preconditions are checked via {@link PreconditionMiddleware}
     */
    public function checkPreconditions(): ?ResponseInterface {
        return null;
    }

    private function newSuccessHttpResponse( GetStatementResponse $useCaseResponse ): Response {
        $httpResponse = $this->getResponseFactory()->create();
        $httpResponse->setHeader( 'Content-Type', 'application/json' );
        $httpResponse->setHeader(
            'Last-Modified',
            wfTimestamp( TS_RFC2822, $useCaseResponse->getLastModified() )
        );
        $this->setEtagFromRevId( $httpResponse, $useCaseResponse->getRevisionId() );
        $httpResponse->setBody(
            new StringStream(
                json_encode( $this->statementSerializer->serialize( $useCaseResponse->getStatement() ) )
            )
        );

        return $httpResponse;
    }

    private function setEtagFromRevId( Response $httpResponse, int $revId ): void {
        $httpResponse->setHeader( 'ETag', "\"$revId\"" );
    }
}