Merge "REST: Modify GetItem to use exceptions"

repo/rest-api/src/RouteHandlers/GetItemRouteHandler.php

@@ -2,7 +2,6 @@
 
 namespace Wikibase\Repo\RestApi\RouteHandlers;
 
-use LogicException;
 use MediaWiki\Rest\Handler;
 use MediaWiki\Rest\RequestInterface;
 use MediaWiki\Rest\Response;
@@ -16,10 +15,10 @@
 use Wikibase\Repo\RestApi\RouteHandlers\Middleware\UserAgentCheckMiddleware;
 use Wikibase\Repo\RestApi\Serialization\ItemDataSerializer;
 use Wikibase\Repo\RestApi\UseCases\GetItem\GetItem;
-use Wikibase\Repo\RestApi\UseCases\GetItem\GetItemErrorResponse;
 use Wikibase\Repo\RestApi\UseCases\GetItem\GetItemRequest;
-use Wikibase\Repo\RestApi\UseCases\GetItem\GetItemSuccessResponse;
-use Wikibase\Repo\RestApi\UseCases\ItemRedirectResponse;
+use Wikibase\Repo\RestApi\UseCases\GetItem\GetItemResponse;
+use Wikibase\Repo\RestApi\UseCases\ItemRedirectException;
+use Wikibase\Repo\RestApi\UseCases\UseCaseException;
 use Wikibase\Repo\RestApi\WbRestApi;
 use Wikimedia\ParamValidator\ParamValidator;
 
@@ -78,20 +77,19 @@ public function run( ...$args ): Response {
 
 	public function runUseCase( string $id ): Response {
 		$fields = explode( ',', $this->getValidatedParams()[self::FIELDS_QUERY_PARAM] );
-		$useCaseResponse = $this->getItem->execute( new GetItemRequest( $id, $fields ) );
-
-		if ( $useCaseResponse instanceof GetItemSuccessResponse ) {
-			return $this->newSuccessHttpResponse( $useCaseResponse );
-		} elseif ( $useCaseResponse instanceof ItemRedirectResponse ) {
-			return $this->newRedirectHttpResponse( $useCaseResponse );
-		} elseif ( $useCaseResponse instanceof GetItemErrorResponse ) {
-			return $this->responseFactory->newErrorResponse( $useCaseResponse );
-		} else {
-			throw new LogicException( 'Received an unexpected use case result in ' . __CLASS__ );
+
+		try {
+			return $this->newSuccessHttpResponse(
+				$this->getItem->execute( new GetItemRequest( $id, $fields ) )
+			);
+		} catch ( ItemRedirectException $e ) {
+			return $this->newRedirectHttpResponse( $e );
+		} catch ( UseCaseException $e ) {
+			return $this->responseFactory->newErrorResponseFromException( $e );
 		}
 	}
 
-	private function newSuccessHttpResponse( GetItemSuccessResponse $useCaseResponse ): Response {
+	private function newSuccessHttpResponse( GetItemResponse $useCaseResponse ): Response {
 		$httpResponse = $this->getResponseFactory()->create();
 		$httpResponse->setHeader( 'Content-Type', 'application/json' );
 		$httpResponse->setHeader( 'Last-Modified', wfTimestamp( TS_RFC2822, $useCaseResponse->getLastModified() ) );
@@ -103,12 +101,12 @@ private function newSuccessHttpResponse( GetItemSuccessResponse $useCaseResponse
 		return $httpResponse;
 	}
 
-	private function newRedirectHttpResponse( ItemRedirectResponse $useCaseResponse ): Response {
+	private function newRedirectHttpResponse( ItemRedirectException $e ): Response {
 		$httpResponse = $this->getResponseFactory()->create();
 		$httpResponse->setHeader(
 			'Location',
 			$this->getRouteUrl(
-				[ self::ITEM_ID_PATH_PARAM => $useCaseResponse->getRedirectTargetId() ],
+				[ self::ITEM_ID_PATH_PARAM => $e->getRedirectTargetId() ],
 				$this->getRequest()->getQueryParams()
 			)
 		);

repo/rest-api/src/UseCases/GetItem/GetItem.php

@@ -6,7 +6,8 @@
 use Wikibase\Repo\RestApi\Domain\Services\ItemDataRetriever;
 use Wikibase\Repo\RestApi\Domain\Services\ItemRevisionMetadataRetriever;
 use Wikibase\Repo\RestApi\UseCases\ErrorResponse;
-use Wikibase\Repo\RestApi\UseCases\ItemRedirectResponse;
+use Wikibase\Repo\RestApi\UseCases\ItemRedirectException;
+use Wikibase\Repo\RestApi\UseCases\UseCaseException;
 
 /**
  * @license GPL-2.0-or-later
@@ -28,28 +29,29 @@ public function __construct(
 	}
 
 	/**
-	 * @return GetItemSuccessResponse|GetItemErrorResponse|ItemRedirectResponse
+	 * @throws UseCaseException
+	 * @throws ItemRedirectException
 	 */
-	public function execute( GetItemRequest $itemRequest ) {
-		$validationError = $this->validator->validate( $itemRequest );
-
-		if ( $validationError ) {
-			return GetItemErrorResponse::newFromValidationError( $validationError );
-		}
+	public function execute( GetItemRequest $itemRequest ): GetItemResponse {
+		$this->validator->assertValidRequest( $itemRequest );
 
 		$itemId = new ItemId( $itemRequest->getItemId() );
 		$latestRevisionMetadata = $this->revisionMetadataRetriever->getLatestRevisionMetadata( $itemId );
 
 		if ( !$latestRevisionMetadata->itemExists() ) {
-			return new GetItemErrorResponse(
+			throw new UseCaseException(
 				ErrorResponse::ITEM_NOT_FOUND,
 				"Could not find an item with the ID: {$itemRequest->getItemId()}"
 			);
-		} elseif ( $latestRevisionMetadata->isRedirect() ) {
-			return new ItemRedirectResponse( $latestRevisionMetadata->getRedirectTarget()->getSerialization() );
 		}
 
-		return new GetItemSuccessResponse(
+		if ( $latestRevisionMetadata->isRedirect() ) {
+			throw new ItemRedirectException(
+				$latestRevisionMetadata->getRedirectTarget()->getSerialization()
+			);
+		}
+
+		return new GetItemResponse(
 			$this->itemDataRetriever->getItemData( $itemId, $itemRequest->getFields() ),
 			$latestRevisionMetadata->getRevisionTimestamp(),
 			$latestRevisionMetadata->getRevisionId()

repo/rest-api/src/UseCases/GetItem/GetItemSuccessResponse.php → repo/rest-api/src/UseCases/GetItem/GetItemResponse.php

@@ -7,7 +7,7 @@
 /**
  * @license GPL-2.0-or-later
  */
-class GetItemSuccessResponse {
+class GetItemResponse {
 
 	private ItemData $itemData;
 

repo/rest-api/src/UseCases/GetItem/GetItemValidator.php

@@ -3,34 +3,50 @@
 namespace Wikibase\Repo\RestApi\UseCases\GetItem;
 
 use Wikibase\Repo\RestApi\Domain\ReadModel\ItemData;
+use Wikibase\Repo\RestApi\UseCases\ErrorResponse;
+use Wikibase\Repo\RestApi\UseCases\UseCaseException;
 use Wikibase\Repo\RestApi\Validation\ItemIdValidator;
-use Wikibase\Repo\RestApi\Validation\ValidationError;
 
 /**
  * @license GPL-2.0-or-later
  */
 class GetItemValidator {
-	public const CODE_INVALID_FIELD = 'invalid-field';
 
-	public const CONTEXT_FIELD_VALUE = 'field-value';
+	public const CODE_INVALID_FIELD = 'invalid-field';
 
 	private ItemIdValidator $itemIdValidator;
 
 	public function __construct( ItemIdValidator $itemIdValidator ) {
 		$this->itemIdValidator = $itemIdValidator;
 	}
 
-	public function validate( GetItemRequest $request ): ?ValidationError {
-		return $this->itemIdValidator->validate( $request->getItemId() )
-			?: $this->validateFields( $request->getFields() );
+	/**
+	 * @throws UseCaseException
+	 */
+	public function assertValidRequest( GetItemRequest $request ): void {
+		$validationError = $this->itemIdValidator->validate( $request->getItemId() );
+
+		if ( $validationError ) {
+			throw new UseCaseException(
+				ErrorResponse::INVALID_ITEM_ID,
+				'Not a valid item ID: ' . $validationError->getContext()[ItemIdValidator::CONTEXT_VALUE]
+			);
+		}
+
+		$this->validateFields( $request->getFields() );
 	}
 
-	private function validateFields( array $fields ): ?ValidationError {
+	/**
+	 * @throws UseCaseException
+	 */
+	private function validateFields( array $fields ): void {
 		foreach ( $fields as $field ) {
 			if ( !in_array( $field, ItemData::VALID_FIELDS ) ) {
-				return new ValidationError( self::CODE_INVALID_FIELD, [ self::CONTEXT_FIELD_VALUE => $field ] );
+				throw new UseCaseException(
+					ErrorResponse::INVALID_FIELD,
+					'Not a valid field: ' . $field
+				);
 			}
 		}
-		return null;
 	}
 }

repo/rest-api/tests/phpunit/Presentation/Presenters/ErrorJsonPresenterTest.php

@@ -5,7 +5,6 @@
 use PHPUnit\Framework\TestCase;
 use Wikibase\Repo\RestApi\Presentation\Presenters\ErrorJsonPresenter;
 use Wikibase\Repo\RestApi\UseCases\ErrorResponse;
-use Wikibase\Repo\RestApi\UseCases\GetItem\GetItemErrorResponse;
 
 /**
  * @covers \Wikibase\Repo\RestApi\Presentation\Presenters\ErrorJsonPresenter
@@ -17,7 +16,7 @@
 class ErrorJsonPresenterTest extends TestCase {
 
 	public function testGetJson_withoutContext(): void {
-		$error = new GetItemErrorResponse( ErrorResponse::ITEM_NOT_FOUND, 'Could not find an item with the ID Q123' );
+		$error = new ErrorResponse( ErrorResponse::ITEM_NOT_FOUND, 'Could not find an item with the ID Q123' );
 
 		$presenter = new ErrorJsonPresenter();