feat(event_handler): add route-level custom response validation in OpenAPI utility

aws_lambda_powertools/event_handler/api_gateway.py

@@ -319,6 +319,7 @@ def __init__(
         security: list[dict[str, list[str]]] | None = None,
         openapi_extensions: dict[str, Any] | None = None,
         deprecated: bool = False,
+        custom_response_validation_http_code: HTTPStatus | None = None,
         middlewares: list[Callable[..., Response]] | None = None,
     ):
         """
@@ -360,8 +361,11 @@ def __init__(
             Additional OpenAPI extensions as a dictionary.
         deprecated: bool
             Whether or not to mark this route as deprecated in the OpenAPI schema
+        custom_response_validation_http_code: HTTPStatus | None, optional
+            Whether to have custom http status code for this route if response validation fails
         middlewares: list[Callable[..., Response]] | None
             The list of route middlewares to be called in order.
+        # TODO
         """
         self.method = method.upper()
         self.path = "/" if path.strip() == "" else path
@@ -397,6 +401,8 @@ def __init__(
         # _body_field is used to cache the dependant model for the body field
         self._body_field: ModelField | None = None
 
+        self.custom_response_validation_http_code = custom_response_validation_http_code
+
     def __call__(
         self,
         router_middlewares: list[Callable],
@@ -505,7 +511,7 @@ def body_field(self) -> ModelField | None:
 
         return self._body_field
 
-    def _get_openapi_path(
+    def _get_openapi_path(  # noqa: PLR0912
         self,
         *,
         dependant: Dependant,
@@ -565,6 +571,14 @@ def _get_openapi_path(
             },
         }
 
+        # Add custom response validation response, if exists
+        if self.custom_response_validation_http_code:
+            http_code = self.custom_response_validation_http_code.value
+            operation_responses[http_code] = {
+                "description": "Response Validation Error",
+                "content": {"application/json": {"schema": {"$ref": f"{COMPONENT_REF_PREFIX}ResponseValidationError"}}},
+            }
+
         # Add the response to the OpenAPI operation
         if self.responses:
             for status_code in list(self.responses):
@@ -942,6 +956,7 @@ def route(
         security: list[dict[str, list[str]]] | None = None,
         openapi_extensions: dict[str, Any] | None = None,
         deprecated: bool = False,
+        custom_response_validation_http_code: int | HTTPStatus | None = None,
         middlewares: list[Callable[..., Any]] | None = None,
     ) -> Callable[[AnyCallableT], AnyCallableT]:
         raise NotImplementedError()
@@ -1003,6 +1018,7 @@ def get(
         security: list[dict[str, list[str]]] | None = None,
         openapi_extensions: dict[str, Any] | None = None,
         deprecated: bool = False,
+        custom_response_validation_http_code: int | HTTPStatus | None = None,
         middlewares: list[Callable[..., Any]] | None = None,
     ) -> Callable[[AnyCallableT], AnyCallableT]:
         """Get route decorator with GET `method`
@@ -1043,6 +1059,7 @@ def lambda_handler(event, context):
             security,
             openapi_extensions,
             deprecated,
+            custom_response_validation_http_code,
             middlewares,
         )
 
@@ -1062,6 +1079,7 @@ def post(
         security: list[dict[str, list[str]]] | None = None,
         openapi_extensions: dict[str, Any] | None = None,
         deprecated: bool = False,
+        custom_response_validation_http_code: int | HTTPStatus | None = None,
         middlewares: list[Callable[..., Any]] | None = None,
     ) -> Callable[[AnyCallableT], AnyCallableT]:
         """Post route decorator with POST `method`
@@ -1103,6 +1121,7 @@ def lambda_handler(event, context):
             security,
             openapi_extensions,
             deprecated,
+            custom_response_validation_http_code,
             middlewares,
         )
 
@@ -1122,6 +1141,7 @@ def put(
         security: list[dict[str, list[str]]] | None = None,
         openapi_extensions: dict[str, Any] | None = None,
         deprecated: bool = False,
+        custom_response_validation_http_code: int | HTTPStatus | None = None,
         middlewares: list[Callable[..., Any]] | None = None,
     ) -> Callable[[AnyCallableT], AnyCallableT]:
         """Put route decorator with PUT `method`
@@ -1163,6 +1183,7 @@ def lambda_handler(event, context):
             security,
             openapi_extensions,
             deprecated,
+            custom_response_validation_http_code,
             middlewares,
         )
 
@@ -1182,6 +1203,7 @@ def delete(
         security: list[dict[str, list[str]]] | None = None,
         openapi_extensions: dict[str, Any] | None = None,
         deprecated: bool = False,
+        custom_response_validation_http_code: int | HTTPStatus | None = None,
         middlewares: list[Callable[..., Any]] | None = None,
     ) -> Callable[[AnyCallableT], AnyCallableT]:
         """Delete route decorator with DELETE `method`
@@ -1222,6 +1244,7 @@ def lambda_handler(event, context):
             security,
             openapi_extensions,
             deprecated,
+            custom_response_validation_http_code,
             middlewares,
         )
 
@@ -1241,6 +1264,7 @@ def patch(
         security: list[dict[str, list[str]]] | None = None,
         openapi_extensions: dict[str, Any] | None = None,
         deprecated: bool = False,
+        custom_response_validation_http_code: int | HTTPStatus | None = None,
         middlewares: list[Callable] | None = None,
     ) -> Callable[[AnyCallableT], AnyCallableT]:
         """Patch route decorator with PATCH `method`
@@ -1284,6 +1308,7 @@ def lambda_handler(event, context):
             security,
             openapi_extensions,
             deprecated,
+            custom_response_validation_http_code,
             middlewares,
         )
 
@@ -1303,6 +1328,7 @@ def head(
         security: list[dict[str, list[str]]] | None = None,
         openapi_extensions: dict[str, Any] | None = None,
         deprecated: bool = False,
+        custom_response_validation_http_code: int | HTTPStatus | None = None,
         middlewares: list[Callable] | None = None,
     ) -> Callable[[AnyCallableT], AnyCallableT]:
         """Head route decorator with HEAD `method`
@@ -1345,6 +1371,7 @@ def lambda_handler(event, context):
             security,
             openapi_extensions,
             deprecated,
+            custom_response_validation_http_code,
             middlewares,
         )
 
@@ -2108,6 +2135,29 @@ def swagger_handler():
                 body=body,
             )
 
+    def _validate_route_response_validation_error_http_code(
+        self,
+        custom_response_validation_http_code: int | HTTPStatus | None,
+    ) -> HTTPStatus | None:
+        if custom_response_validation_http_code and not self._enable_validation:
+            msg = (
+                "'custom_response_validation_http_code' cannot be set for route when enable_validation is False "
+                "on resolver."
+            )
+            raise ValueError(msg)
+
+        if (
+            not isinstance(custom_response_validation_http_code, HTTPStatus)
+            and custom_response_validation_http_code is not None
+        ):
+            try:
+                custom_response_validation_http_code = HTTPStatus(custom_response_validation_http_code)
+            except ValueError:
+                msg = f"'{custom_response_validation_http_code}' must be an integer representing an HTTP status code or an enum of type HTTPStatus."  # noqa: E501
+                raise ValueError(msg) from None
+
+        return custom_response_validation_http_code
+
     def route(
         self,
         rule: str,
@@ -2125,10 +2175,15 @@ def route(
         security: list[dict[str, list[str]]] | None = None,
         openapi_extensions: dict[str, Any] | None = None,
         deprecated: bool = False,
+        custom_response_validation_http_code: int | HTTPStatus | None = None,
         middlewares: list[Callable[..., Any]] | None = None,
     ) -> Callable[[AnyCallableT], AnyCallableT]:
         """Route decorator includes parameter `method`"""
 
+        custom_response_validation_http_code = self._validate_route_response_validation_error_http_code(
+            custom_response_validation_http_code,
+        )
+
         def register_resolver(func: AnyCallableT) -> AnyCallableT:
             methods = (method,) if isinstance(method, str) else method
             logger.debug(f"Adding route using rule {rule} and methods: {','.join(m.upper() for m in methods)}")
@@ -2154,6 +2209,7 @@ def register_resolver(func: AnyCallableT) -> AnyCallableT:
                     security,
                     openapi_extensions,
                     deprecated,
+                    custom_response_validation_http_code,
                     middlewares,
                 )
 
@@ -2523,15 +2579,22 @@ def _call_exception_handler(self, exp: Exception, route: Route) -> ResponseBuild
             )
 
         # OpenAPIValidationMiddleware will only raise ResponseValidationError when
-        # 'self._response_validation_error_http_code' is not None
+        # 'self._response_validation_error_http_code' is not None or
+        # when route has custom_response_validation_http_code
         if isinstance(exp, ResponseValidationError):
-            http_code = self._response_validation_error_http_code
+            # route validation must take precedence over app validation
+            route_response_validation_http_code = route.custom_response_validation_http_code
+            http_code = (
+                route_response_validation_http_code
+                if route_response_validation_http_code
+                else self._response_validation_error_http_code
+            )
             errors = [{"loc": e["loc"], "type": e["type"]} for e in exp.errors()]
             return self._response_builder_class(
                 response=Response(
                     status_code=http_code.value,
                     content_type=content_types.APPLICATION_JSON,
-                    body={"statusCode": self._response_validation_error_http_code, "detail": errors},
+                    body={"statusCode": http_code, "detail": errors},
                 ),
                 serializer=self._serializer,
                 route=route,
@@ -2682,6 +2745,7 @@ def route(
         security: list[dict[str, list[str]]] | None = None,
         openapi_extensions: dict[str, Any] | None = None,
         deprecated: bool = False,
+        custom_response_validation_http_code: int | HTTPStatus | None = None,
         middlewares: list[Callable[..., Any]] | None = None,
     ) -> Callable[[AnyCallableT], AnyCallableT]:
         def register_route(func: AnyCallableT) -> AnyCallableT:
@@ -2708,6 +2772,7 @@ def register_route(func: AnyCallableT) -> AnyCallableT:
                 frozen_security,
                 frozen_openapi_extensions,
                 deprecated,
+                custom_response_validation_http_code,
             )
 
             # Collate Middleware for routes
@@ -2794,6 +2859,7 @@ def route(
         security: list[dict[str, list[str]]] | None = None,
         openapi_extensions: dict[str, Any] | None = None,
         deprecated: bool = False,
+        custom_response_validation_http_code: int | HTTPStatus | None = None,
         middlewares: list[Callable[..., Any]] | None = None,
     ) -> Callable[[AnyCallableT], AnyCallableT]:
         # NOTE: see #1552 for more context.
@@ -2813,6 +2879,7 @@ def route(
             security,
             openapi_extensions,
             deprecated,
+            custom_response_validation_http_code,
             middlewares,
         )
 

aws_lambda_powertools/event_handler/bedrock_agent.py

@@ -14,6 +14,7 @@
 from aws_lambda_powertools.event_handler.openapi.constants import DEFAULT_API_VERSION, DEFAULT_OPENAPI_VERSION
 
 if TYPE_CHECKING:
+    from http import HTTPStatus
     from re import Match
 
     from aws_lambda_powertools.event_handler.openapi.models import Contact, License, SecurityScheme, Server, Tag
@@ -109,6 +110,7 @@ def get(  # type: ignore[override]
         operation_id: str | None = None,
         include_in_schema: bool = True,
         deprecated: bool = False,
+        custom_response_validation_http_code: int | HTTPStatus | None = None,
         middlewares: list[Callable[..., Any]] | None = None,
     ) -> Callable[[Callable[..., Any]], Callable[..., Any]]:
         openapi_extensions = None
@@ -129,6 +131,7 @@ def get(  # type: ignore[override]
             security,
             openapi_extensions,
             deprecated,
+            custom_response_validation_http_code,
             middlewares,
         )
 
@@ -148,6 +151,7 @@ def post(  # type: ignore[override]
         operation_id: str | None = None,
         include_in_schema: bool = True,
         deprecated: bool = False,
+        custom_response_validation_http_code: int | HTTPStatus | None = None,
         middlewares: list[Callable[..., Any]] | None = None,
     ):
         openapi_extensions = None
@@ -168,6 +172,7 @@ def post(  # type: ignore[override]
             security,
             openapi_extensions,
             deprecated,
+            custom_response_validation_http_code,
             middlewares,
         )
 
@@ -187,6 +192,7 @@ def put(  # type: ignore[override]
         operation_id: str | None = None,
         include_in_schema: bool = True,
         deprecated: bool = False,
+        custom_response_validation_http_code: int | HTTPStatus | None = None,
         middlewares: list[Callable[..., Any]] | None = None,
     ):
         openapi_extensions = None
@@ -207,6 +213,7 @@ def put(  # type: ignore[override]
             security,
             openapi_extensions,
             deprecated,
+            custom_response_validation_http_code,
             middlewares,
         )
 
@@ -226,6 +233,7 @@ def patch(  # type: ignore[override]
         operation_id: str | None = None,
         include_in_schema: bool = True,
         deprecated: bool = False,
+        custom_response_validation_http_code: int | HTTPStatus | None = None,
         middlewares: list[Callable] | None = None,
     ):
         openapi_extensions = None
@@ -246,6 +254,7 @@ def patch(  # type: ignore[override]
             security,
             openapi_extensions,
             deprecated,
+            custom_response_validation_http_code,
             middlewares,
         )
 
@@ -265,6 +274,7 @@ def delete(  # type: ignore[override]
         operation_id: str | None = None,
         include_in_schema: bool = True,
         deprecated: bool = False,
+        custom_response_validation_http_code: int | HTTPStatus | None = None,
         middlewares: list[Callable[..., Any]] | None = None,
     ):
         openapi_extensions = None
@@ -285,6 +295,7 @@ def delete(  # type: ignore[override]
             security,
             openapi_extensions,
             deprecated,
+            custom_response_validation_http_code,
             middlewares,
         )
 

aws_lambda_powertools/event_handler/middlewares/openapi_validation.py

@@ -150,6 +150,7 @@ def _handle_response(self, *, route: Route, response: Response):
             response.body = self._serialize_response(
                 field=route.dependant.return_param,
                 response_content=response.body,
+                has_route_custom_response_validation=route.custom_response_validation_http_code is not None,
             )
 
         return response
@@ -165,6 +166,7 @@ def _serialize_response(
         exclude_unset: bool = False,
         exclude_defaults: bool = False,
         exclude_none: bool = False,
+        has_route_custom_response_validation: bool = False,
     ) -> Any:
         """
         Serialize the response content according to the field type.
@@ -173,8 +175,16 @@ def _serialize_response(
             errors: list[dict[str, Any]] = []
             value = _validate_field(field=field, value=response_content, loc=("response",), existing_errors=errors)
             if errors:
+                # route-level validation must take precedence over app-level
+                if has_route_custom_response_validation:
+                    raise ResponseValidationError(
+                        errors=_normalize_errors(errors),
+                        body=response_content,
+                        source="route",
+                    )
                 if self._has_response_validation_error:
-                    raise ResponseValidationError(errors=_normalize_errors(errors), body=response_content)
+                    raise ResponseValidationError(errors=_normalize_errors(errors), body=response_content, source="app")
+
                 raise RequestValidationError(errors=_normalize_errors(errors), body=response_content)
 
             if hasattr(field, "serialize"):