HTTP Gateway V2: Remove use of obsolete multiValueHeaders (#216)

IlyaSukhanov · web-flow · commit a589465492b3 · 2022-01-11T20:27:46.000-06:00
HTTP Gateway V2 drops both the multiValueHeaders and multiValueQueryStringParameters elements. With this change: * Cookies passed to request and response as cookie element containing list of all cookie values. * Headers with multiple values are concatenated through comma and passed under Headers element instead of the obsolete multiValueHeaders. https://medium.com/@lancers/amazon-api-gateway-explaining-lambda-payload-version-2-0-in-http-api-24b0b4db5d36 https://aws.amazon.com/blogs/compute/building-better-apis-http-apis-now-generally-available/ Addresses issue #215.
diff --git a/mangum/handlers/aws_http_gateway.py b/mangum/handlers/aws_http_gateway.py
@@ -1,6 +1,6 @@
 import base64
 import urllib.parse
-from typing import Dict, Any
+from typing import Dict, Any, List, Tuple
 
 from . import AwsApiGateway
 from .. import Response, Request
@@ -122,37 +122,65 @@ def transform_response(self, response: Response) -> Dict[str, Any]:
 
         https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api-develop-integrations-lambda.html#http-api-develop-integrations-lambda.response
         """
+        if self.event_version == "1.0":
+            return self.transform_response_v1(response)
+        elif self.event_version == "2.0":
+            return self.transform_response_v2(response)
+        raise RuntimeError(  # pragma: no cover
+            "Misconfigured event unable to return value, unsupported version."
+        )
+
+    def transform_response_v1(self, response: Response) -> Dict[str, Any]:
         headers, multi_value_headers = self._handle_multi_value_headers(
             response.headers
         )
 
-        if self.event_version == "1.0":
-            body, is_base64_encoded = self._handle_base64_response_body(
-                response.body, headers
-            )
-            return {
-                "statusCode": response.status,
-                "headers": headers,
-                "multiValueHeaders": multi_value_headers,
-                "body": body,
-                "isBase64Encoded": is_base64_encoded,
-            }
-        elif self.event_version == "2.0":
-            # The API Gateway will infer stuff for us, but we'll just do that inference
-            # here and keep the output consistent
-            if "content-type" not in headers and response.body is not None:
-                headers["content-type"] = "application/json"
+        body, is_base64_encoded = self._handle_base64_response_body(
+            response.body, headers
+        )
+        return {
+            "statusCode": response.status,
+            "headers": headers,
+            "multiValueHeaders": multi_value_headers,
+            "body": body,
+            "isBase64Encoded": is_base64_encoded,
+        }
+
+    def _combine_headers_v2(
+        self, input_headers: List[List[bytes]]
+    ) -> Tuple[Dict[str, str], List[str]]:
+        output_headers: Dict[str, str] = {}
+        cookies: List[str] = []
+        for key, value in input_headers:
+            normalized_key: str = key.decode().lower()
+            normalized_value: str = value.decode()
+            if normalized_key == "set-cookie":
+                cookies.append(normalized_value)
+            else:
+                if normalized_key in output_headers:
+                    normalized_value = (
+                        f"{output_headers[normalized_key]},{normalized_value}"
+                    )
+                output_headers[normalized_key] = normalized_value
+        return output_headers, cookies
 
-            body, is_base64_encoded = self._handle_base64_response_body(
-                response.body, headers
-            )
-            return {
-                "statusCode": response.status,
-                "headers": headers,
-                "multiValueHeaders": multi_value_headers,
-                "body": body,
-                "isBase64Encoded": is_base64_encoded,
-            }
-        raise RuntimeError(  # pragma: no cover
-            "Misconfigured event unable to return value, unsupported version."
+    def transform_response_v2(self, response_in: Response) -> Dict[str, Any]:
+        # The API Gateway will infer stuff for us, but we'll just do that inference
+        # here and keep the output consistent
+
+        headers, cookies = self._combine_headers_v2(response_in.headers)
+
+        if "content-type" not in headers and response_in.body is not None:
+            headers["content-type"] = "application/json"
+
+        body, is_base64_encoded = self._handle_base64_response_body(
+            response_in.body, headers
         )
+        response_out = {
+            "statusCode": response_in.status,
+            "body": body,
+            "headers": headers or None,
+            "cookies": cookies or None,
+            "isBase64Encoded": is_base64_encoded,
+        }
+        return {key: value for key, value in response_out.items() if value is not None}
diff --git a/tests/conftest.py b/tests/conftest.py
@@ -65,7 +65,7 @@ def mock_aws_api_gateway_event(request):
 
 
 @pytest.fixture
-def mock_http_api_event(request):
+def mock_http_api_event_v2(request):
     method = request.param[0]
     body = request.param[1]
     multi_value_query_parameters = request.param[2]
@@ -120,6 +120,67 @@ def mock_http_api_event(request):
     return event
 
 
+@pytest.fixture
+def mock_http_api_event_v1(request):
+    method = request.param[0]
+    body = request.param[1]
+    multi_value_query_parameters = request.param[2]
+    query_string = request.param[3]
+    event = {
+        "version": "1.0",
+        "routeKey": "$default",
+        "rawPath": "/my/path",
+        "path": "/my/path",
+        "httpMethod": method,
+        "rawQueryString": query_string,
+        "cookies": ["cookie1", "cookie2"],
+        "headers": {
+            "accept-encoding": "gzip,deflate",
+            "x-forwarded-port": "443",
+            "x-forwarded-proto": "https",
+            "host": "test.execute-api.us-west-2.amazonaws.com",
+        },
+        "queryStringParameters": {
+            k: v[-1] for k, v in multi_value_query_parameters.items()
+        }
+        if multi_value_query_parameters
+        else None,
+        "multiValueQueryStringParameters": {
+            k: v for k, v in multi_value_query_parameters.items()
+        }
+        if multi_value_query_parameters
+        else None,
+        "requestContext": {
+            "accountId": "123456789012",
+            "apiId": "api-id",
+            "authorizer": {
+                "jwt": {
+                    "claims": {"claim1": "value1", "claim2": "value2"},
+                    "scopes": ["scope1", "scope2"],
+                }
+            },
+            "domainName": "id.execute-api.us-east-1.amazonaws.com",
+            "domainPrefix": "id",
+            "http": {
+                "protocol": "HTTP/1.1",
+                "sourceIp": "192.168.100.1",
+                "userAgent": "agent",
+            },
+            "requestId": "id",
+            "routeKey": "$default",
+            "stage": "$default",
+            "time": "12/Mar/2020:19:03:58 +0000",
+            "timeEpoch": 1583348638390,
+        },
+        "body": body,
+        "pathParameters": {"parameter1": "value1"},
+        "isBase64Encoded": False,
+        "stageVariables": {"stageVariable1": "value1", "stageVariable2": "value2"},
+    }
+
+    return event
+
+
 @pytest.fixture
 def mock_lambda_at_edge_event(request):
     method = request.param[0]
diff --git a/tests/handlers/test_aws_http_gateway.py b/tests/handlers/test_aws_http_gateway.py
@@ -605,6 +605,5 @@ async def app(scope, receive, send):
         "statusCode": 200,
         "isBase64Encoded": res_base64_encoded,
         "headers": {"content-type": content_type.decode()},
-        "multiValueHeaders": {},
         "body": res_body,
     }
diff --git a/tests/test_http.py b/tests/test_http.py
@@ -253,7 +253,7 @@ async def app(scope, receive, send):
 
 
 @pytest.mark.parametrize(
-    "mock_http_api_event",
+    "mock_http_api_event_v2",
     [
         (["GET", None, None, ""]),
         (["GET", None, {"name": ["me"]}, "name=me"]),
@@ -267,9 +267,9 @@ async def app(scope, receive, send):
             ]
         ),
     ],
-    indirect=["mock_http_api_event"],
+    indirect=["mock_http_api_event_v2"],
 )
-def test_set_cookies(mock_http_api_event) -> None:
+def test_set_cookies_v2(mock_http_api_event_v2) -> None:
     async def app(scope, receive, send):
         assert scope == {
             "asgi": {"version": "3.0"},
@@ -279,15 +279,17 @@ async def app(scope, receive, send):
                 "version": "2.0",
                 "routeKey": "$default",
                 "rawPath": "/my/path",
-                "rawQueryString": mock_http_api_event["rawQueryString"],
+                "rawQueryString": mock_http_api_event_v2["rawQueryString"],
                 "cookies": ["cookie1", "cookie2"],
                 "headers": {
                     "accept-encoding": "gzip,deflate",
                     "x-forwarded-port": "443",
                     "x-forwarded-proto": "https",
                     "host": "test.execute-api.us-west-2.amazonaws.com",
                 },
-                "queryStringParameters": mock_http_api_event["queryStringParameters"],
+                "queryStringParameters": mock_http_api_event_v2[
+                    "queryStringParameters"
+                ],
                 "requestContext": {
                     "accountId": "123456789012",
                     "apiId": "api-id",
@@ -331,7 +333,127 @@ async def app(scope, receive, send):
             "http_version": "1.1",
             "method": "GET",
             "path": "/my/path",
-            "query_string": mock_http_api_event["rawQueryString"].encode(),
+            "query_string": mock_http_api_event_v2["rawQueryString"].encode(),
+            "raw_path": None,
+            "root_path": "",
+            "scheme": "https",
+            "server": ("test.execute-api.us-west-2.amazonaws.com", 443),
+            "type": "http",
+        }
+
+        await send(
+            {
+                "type": "http.response.start",
+                "status": 200,
+                "headers": [
+                    [b"content-type", b"text/plain; charset=utf-8"],
+                    [b"set-cookie", b"cookie1=cookie1; Secure"],
+                    [b"set-cookie", b"cookie2=cookie2; Secure"],
+                    [b"multivalue", b"foo"],
+                    [b"multivalue", b"bar"],
+                ],
+            }
+        )
+        await send({"type": "http.response.body", "body": b"Hello, world!"})
+
+    handler = Mangum(app, lifespan="off")
+    response = handler(mock_http_api_event_v2, {})
+    assert response == {
+        "statusCode": 200,
+        "isBase64Encoded": False,
+        "headers": {
+            "content-type": "text/plain; charset=utf-8",
+            "multivalue": "foo,bar",
+        },
+        "cookies": ["cookie1=cookie1; Secure", "cookie2=cookie2; Secure"],
+        "body": "Hello, world!",
+    }
+
+
+@pytest.mark.parametrize(
+    "mock_http_api_event_v1",
+    [
+        (["GET", None, None, ""]),
+        (["GET", None, {"name": ["me"]}, "name=me"]),
+        (["GET", None, {"name": ["me", "you"]}, "name=me&name=you"]),
+        (
+            [
+                "GET",
+                None,
+                {"name": ["me", "you"], "pet": ["dog"]},
+                "name=me&name=you&pet=dog",
+            ]
+        ),
+    ],
+    indirect=["mock_http_api_event_v1"],
+)
+def test_set_cookies_v1(mock_http_api_event_v1) -> None:
+    async def app(scope, receive, send):
+        assert scope == {
+            "asgi": {"version": "3.0"},
+            "aws.eventType": "AWS_HTTP_GATEWAY",
+            "aws.context": {},
+            "aws.event": {
+                "version": "1.0",
+                "routeKey": "$default",
+                "rawPath": "/my/path",
+                "path": "/my/path",
+                "httpMethod": "GET",
+                "rawQueryString": mock_http_api_event_v1["rawQueryString"],
+                "cookies": ["cookie1", "cookie2"],
+                "headers": {
+                    "accept-encoding": "gzip,deflate",
+                    "x-forwarded-port": "443",
+                    "x-forwarded-proto": "https",
+                    "host": "test.execute-api.us-west-2.amazonaws.com",
+                },
+                "queryStringParameters": mock_http_api_event_v1[
+                    "queryStringParameters"
+                ],
+                "multiValueQueryStringParameters": mock_http_api_event_v1[
+                    "multiValueQueryStringParameters"
+                ],
+                "requestContext": {
+                    "accountId": "123456789012",
+                    "apiId": "api-id",
+                    "authorizer": {
+                        "jwt": {
+                            "claims": {"claim1": "value1", "claim2": "value2"},
+                            "scopes": ["scope1", "scope2"],
+                        }
+                    },
+                    "domainName": "id.execute-api.us-east-1.amazonaws.com",
+                    "domainPrefix": "id",
+                    "http": {
+                        "protocol": "HTTP/1.1",
+                        "sourceIp": "192.168.100.1",
+                        "userAgent": "agent",
+                    },
+                    "requestId": "id",
+                    "routeKey": "$default",
+                    "stage": "$default",
+                    "time": "12/Mar/2020:19:03:58 +0000",
+                    "timeEpoch": 1_583_348_638_390,
+                },
+                "body": None,
+                "pathParameters": {"parameter1": "value1"},
+                "isBase64Encoded": False,
+                "stageVariables": {
+                    "stageVariable1": "value1",
+                    "stageVariable2": "value2",
+                },
+            },
+            "client": (None, 0),
+            "headers": [
+                [b"accept-encoding", b"gzip,deflate"],
+                [b"x-forwarded-port", b"443"],
+                [b"x-forwarded-proto", b"https"],
+                [b"host", b"test.execute-api.us-west-2.amazonaws.com"],
+            ],
+            "http_version": "1.1",
+            "method": "GET",
+            "path": "/my/path",
+            "query_string": mock_http_api_event_v1["rawQueryString"].encode(),
             "raw_path": None,
             "root_path": "",
             "scheme": "https",
@@ -353,7 +475,7 @@ async def app(scope, receive, send):
         await send({"type": "http.response.body", "body": b"Hello, world!"})
 
     handler = Mangum(app, lifespan="off")
-    response = handler(mock_http_api_event, {})
+    response = handler(mock_http_api_event_v1, {})
     assert response == {
         "statusCode": 200,
         "isBase64Encoded": False,

Original file line number	Diff line number	Diff line change
`@@ -605,6 +605,5 @@ async def app(scope, receive, send):`
`605`	`605`	`"statusCode": 200,`
`606`	`606`	`"isBase64Encoded": res_base64_encoded,`
`607`	`607`	`"headers": {"content-type": content_type.decode()},`
`608`		`- "multiValueHeaders": {},`
`609`	`608`	`"body": res_body,`
`610`	`609`	`}`