feat(event_handler): add support for multiValueQueryStringParameters in OpenAPI schema (#3667)

* Initial code for multivalue querystring

* Adding tests and improving code

* Adding tests and improving code

* Refactoging to avoid abstraction leaky

* Making Pydanticv2 happy

* Adding documentation

* Addressing Ruben's feedback

* Addressing Ruben's feedback

* Mypy....

Author: leandrodamascena

aws_lambda_powertools/event_handler/middlewares/openapi_validation.py

@@ -16,6 +16,7 @@
     _regenerate_error_with_loc,
     get_missing_field_error,
 )
+from aws_lambda_powertools.event_handler.openapi.dependant import is_scalar_field
 from aws_lambda_powertools.event_handler.openapi.encoders import jsonable_encoder
 from aws_lambda_powertools.event_handler.openapi.exceptions import RequestValidationError
 from aws_lambda_powertools.event_handler.openapi.params import Param
@@ -68,10 +69,16 @@ def handler(self, app: EventHandlerInstance, next_middleware: NextMiddleware) ->
             app.context["_route_args"],
         )
 
+        # Normalize query values before validate this
+        query_string = _normalize_multi_query_string_with_param(
+            app.current_event.resolved_query_string_parameters,
+            route.dependant.query_params,
+        )
+
         # Process query values
         query_values, query_errors = _request_params_to_args(
             route.dependant.query_params,
-            app.current_event.query_string_parameters or {},
+            query_string,
         )
 
         values.update(path_values)
@@ -344,3 +351,29 @@ def _get_embed_body(
         received_body = {field.alias: received_body}
 
     return received_body, field_alias_omitted
+
+
+def _normalize_multi_query_string_with_param(query_string: Optional[Dict[str, str]], params: Sequence[ModelField]):
+    """
+    Extract and normalize resolved_query_string_parameters
+
+    Parameters
+    ----------
+    query_string: Dict
+        A dictionary containing the initial query string parameters.
+    params: Sequence[ModelField]
+        A sequence of ModelField objects representing parameters.
+
+    Returns
+    -------
+    A dictionary containing the processed multi_query_string_parameters.
+    """
+    if query_string:
+        for param in filter(is_scalar_field, params):
+            try:
+                # if the target parameter is a scalar, we keep the first value of the query string
+                # regardless if there are more in the payload
+                query_string[param.name] = query_string[param.name][0]
+            except KeyError:
+                pass
+    return query_string

aws_lambda_powertools/utilities/data_classes/alb_event.py

@@ -1,4 +1,4 @@
-from typing import Dict, List, Optional
+from typing import Any, Dict, List, Optional
 
 from aws_lambda_powertools.shared.headers_serializer import (
     BaseHeadersSerializer,
@@ -35,6 +35,13 @@ def request_context(self) -> ALBEventRequestContext:
     def multi_value_query_string_parameters(self) -> Optional[Dict[str, List[str]]]:
         return self.get("multiValueQueryStringParameters")
 
+    @property
+    def resolved_query_string_parameters(self) -> Optional[Dict[str, Any]]:
+        if self.multi_value_query_string_parameters:
+            return self.multi_value_query_string_parameters
+
+        return self.query_string_parameters
+
     @property
     def multi_value_headers(self) -> Optional[Dict[str, List[str]]]:
         return self.get("multiValueHeaders")

aws_lambda_powertools/utilities/data_classes/api_gateway_proxy_event.py

@@ -118,6 +118,13 @@ def multi_value_headers(self) -> Dict[str, List[str]]:
     def multi_value_query_string_parameters(self) -> Optional[Dict[str, List[str]]]:
         return self.get("multiValueQueryStringParameters")
 
+    @property
+    def resolved_query_string_parameters(self) -> Optional[Dict[str, Any]]:
+        if self.multi_value_query_string_parameters:
+            return self.multi_value_query_string_parameters
+
+        return self.query_string_parameters
+
     @property
     def request_context(self) -> APIGatewayEventRequestContext:
         return APIGatewayEventRequestContext(self._data)
@@ -299,3 +306,13 @@ def http_method(self) -> str:
 
     def header_serializer(self):
         return HttpApiHeadersSerializer()
+
+    @property
+    def resolved_query_string_parameters(self) -> Optional[Dict[str, Any]]:
+        if self.query_string_parameters is not None:
+            query_string = {
+                key: value.split(",") if "," in value else value for key, value in self.query_string_parameters.items()
+            }
+            return query_string
+
+        return {}

aws_lambda_powertools/utilities/data_classes/bedrock_agent_event.py

@@ -108,3 +108,7 @@ def query_string_parameters(self) -> Optional[Dict[str, str]]:
         # In Bedrock Agent events, query string parameters are passed as undifferentiated parameters,
         # together with the other parameters. So we just return all parameters here.
         return {x["name"]: x["value"] for x in self["parameters"]} if self.get("parameters") else None
+
+    @property
+    def resolved_query_string_parameters(self) -> Optional[Dict[str, str]]:
+        return self.query_string_parameters

aws_lambda_powertools/utilities/data_classes/common.py

@@ -103,6 +103,17 @@ def headers(self) -> Dict[str, str]:
     def query_string_parameters(self) -> Optional[Dict[str, str]]:
         return self.get("queryStringParameters")
 
+    @property
+    def resolved_query_string_parameters(self) -> Optional[Dict[str, str]]:
+        """
+        This property determines the appropriate query string parameter to be used
+        as a trusted source for validating OpenAPI.
+
+        This is necessary because different resolvers use different formats to encode
+        multi query string parameters.
+        """
+        return self.query_string_parameters
+
     @property
     def is_base64_encoded(self) -> Optional[bool]:
         return self.get("isBase64Encoded")

aws_lambda_powertools/utilities/data_classes/vpc_lattice.py

@@ -141,6 +141,10 @@ def query_string_parameters(self) -> Dict[str, str]:
         """The request query string parameters."""
         return self["query_string_parameters"]
 
+    @property
+    def resolved_query_string_parameters(self) -> Optional[Dict[str, str]]:
+        return self.query_string_parameters
+
 
 class vpcLatticeEventV2Identity(DictWrapper):
     @property
@@ -251,3 +255,7 @@ def request_context(self) -> vpcLatticeEventV2RequestContext:
     def query_string_parameters(self) -> Optional[Dict[str, str]]:
         """The request query string parameters."""
         return self.get("queryStringParameters")
+
+    @property
+    def resolved_query_string_parameters(self) -> Optional[Dict[str, str]]:
+        return self.query_string_parameters

docs/core/event_handler/api_gateway.md

@@ -400,6 +400,16 @@ In the following example, we use a new `Query` OpenAPI type to add [one out of m
 
     1. `completed` is still the same query string as before, except we simply state it's an string. No `Query` or `Annotated` to validate it.
 
+=== "working_with_multi_query_values.py"
+
+    If you need to handle multi-value query parameters, you can create a list of the desired type.
+
+    ```python hl_lines="23"
+    --8<-- "examples/event_handler_rest/src/working_with_multi_query_values.py"
+    ```
+
+    1. `example_multi_value_param` is a list containing values from the `ExampleEnum` enumeration.
+
 <!-- markdownlint-enable MD013 -->
 
 #### Validating path parameters

examples/event_handler_rest/src/working_with_multi_query_values.py

@@ -0,0 +1,34 @@
+from enum import Enum
+from typing import List
+
+from aws_lambda_powertools.event_handler import APIGatewayRestResolver
+from aws_lambda_powertools.event_handler.openapi.params import Query
+from aws_lambda_powertools.shared.types import Annotated
+from aws_lambda_powertools.utilities.typing import LambdaContext
+
+app = APIGatewayRestResolver(enable_validation=True)
+
+
+class ExampleEnum(Enum):
+    """Example of an Enum class."""
+
+    ONE = "value_one"
+    TWO = "value_two"
+    THREE = "value_three"
+
+
+@app.get("/todos")
+def get(
+    example_multi_value_param: Annotated[
+        List[ExampleEnum],  # (1)!
+        Query(
+            description="This is multi value query parameter.",
+        ),
+    ],
+):
+    """Return validated multi-value param values."""
+    return example_multi_value_param
+
+
+def lambda_handler(event: dict, context: LambdaContext) -> dict:
+    return app.resolve(event, context)

tests/events/albMultiValueQueryStringEvent.json

@@ -0,0 +1,38 @@
+{
+  "requestContext": {
+    "elb": {
+      "targetGroupArn": "arn:aws:elasticloadbalancing:eu-central-1:1234567890:targetgroup/alb-c-Targe-11GDXTPQ7663S/804a67588bfdc10f"
+    }
+  },
+  "httpMethod": "GET",
+  "path": "/todos",
+  "multiValueQueryStringParameters": {
+    "parameter1": ["value1","value2"],
+    "parameter2": ["value"]
+  },
+  "multiValueHeaders": {
+    "accept": [
+      "*/*"
+    ],
+    "host": [
+      "alb-c-LoadB-14POFKYCLBNSF-1815800096.eu-central-1.elb.amazonaws.com"
+    ],
+    "user-agent": [
+      "curl/7.79.1"
+    ],
+    "x-amzn-trace-id": [
+      "Root=1-62fa9327-21cdd4da4c6db451490a5fb7"
+    ],
+    "x-forwarded-for": [
+      "123.123.123.123"
+    ],
+    "x-forwarded-port": [
+      "80"
+    ],
+    "x-forwarded-proto": [
+      "http"
+    ]
+  },
+  "body": "",
+  "isBase64Encoded": false
+}

tests/events/lambdaFunctionUrlEventWithHeaders.json

@@ -0,0 +1,51 @@
+{
+   "version":"2.0",
+   "routeKey":"$default",
+   "rawPath":"/",
+   "rawQueryString":"",
+   "headers":{
+      "sec-fetch-mode":"navigate",
+      "x-amzn-tls-version":"TLSv1.2",
+      "sec-fetch-site":"cross-site",
+      "accept-language":"pt-BR,pt;q=0.9",
+      "x-forwarded-proto":"https",
+      "x-forwarded-port":"443",
+      "x-forwarded-for":"123.123.123.123",
+      "sec-fetch-user":"?1",
+      "accept":"text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9",
+      "x-amzn-tls-cipher-suite":"ECDHE-RSA-AES128-GCM-SHA256",
+      "sec-ch-ua":"\" Not A;Brand\";v=\"99\", \"Chromium\";v=\"102\", \"Google Chrome\";v=\"102\"",
+      "sec-ch-ua-mobile":"?0",
+      "x-amzn-trace-id":"Root=1-62ecd163-5f302e550dcde3b12402207d",
+      "sec-ch-ua-platform":"\"Linux\"",
+      "host":"<url-id>.lambda-url.us-east-1.on.aws",
+      "upgrade-insecure-requests":"1",
+      "cache-control":"max-age=0",
+      "accept-encoding":"gzip, deflate, br",
+      "sec-fetch-dest":"document",
+      "user-agent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/102.0.0.0 Safari/537.36"
+   },
+   "queryStringParameters": {
+      "parameter1": "value1,value2",
+      "parameter2": "value"
+    },
+   "requestContext":{
+      "accountId":"anonymous",
+      "apiId":"<url-id>",
+      "domainName":"<url-id>.lambda-url.us-east-1.on.aws",
+      "domainPrefix":"<url-id>",
+      "http":{
+         "method":"GET",
+         "path":"/",
+         "protocol":"HTTP/1.1",
+         "sourceIp":"123.123.123.123",
+         "userAgent":"agent"
+      },
+      "requestId":"id",
+      "routeKey":"$default",
+      "stage":"$default",
+      "time":"05/Aug/2022:08:14:39 +0000",
+      "timeEpoch":1659687279885
+   },
+   "isBase64Encoded":false
+}

tests/events/vpcLatticeV2EventWithHeaders.json

@@ -0,0 +1,36 @@
+{
+    "version": "2.0",
+    "path": "/newpath",
+    "method": "GET",
+    "headers": {
+      "user_agent": "curl/7.64.1",
+      "x-forwarded-for": "10.213.229.10",
+      "host": "test-lambda-service-3908sdf9u3u.dkfjd93.vpc-lattice-svcs.us-east-2.on.aws",
+      "accept": "*/*"
+    },
+    "queryStringParameters": {
+      "parameter1": [
+        "value1",
+        "value2"
+      ],
+      "parameter2": [
+        "value"
+      ]
+    },
+    "body": "{\"message\": \"Hello from Lambda!\"}",
+    "isBase64Encoded": false,
+    "requestContext": {
+        "serviceNetworkArn": "arn:aws:vpc-lattice:us-east-2:123456789012:servicenetwork/sn-0bf3f2882e9cc805a",
+        "serviceArn": "arn:aws:vpc-lattice:us-east-2:123456789012:service/svc-0a40eebed65f8d69c",
+        "targetGroupArn": "arn:aws:vpc-lattice:us-east-2:123456789012:targetgroup/tg-6d0ecf831eec9f09",
+        "identity": {
+          "sourceVpcArn": "arn:aws:ec2:region:123456789012:vpc/vpc-0b8276c84697e7339",
+          "type" : "AWS_IAM",
+          "principal": "arn:aws:sts::123456789012:assumed-role/example-role/057d00f8b51257ba3c853a0f248943cf",
+          "sessionName": "057d00f8b51257ba3c853a0f248943cf",
+          "x509SanDns": "example.com"
+        },
+        "region": "us-east-2",
+        "timeEpoch": "1696331543569073"
+    }
+}

tests/functional/event_handler/test_openapi_params.py

@@ -184,6 +184,20 @@ def handler(page: Annotated[str, Query(include_in_schema=False)]):
     assert get.parameters is None
 
 
+def test_openapi_with_list_param():
+    app = APIGatewayRestResolver()
+
+    @app.get("/")
+    def handler(page: Annotated[List[str], Query()]):
+        return page
+
+    schema = app.get_openapi_schema()
+    assert len(schema.paths.keys()) == 1
+
+    get = schema.paths["/"].get
+    assert get.parameters[0].schema_.type == "array"
+
+
 def test_openapi_with_description():
     app = APIGatewayRestResolver()