chore(event_handler): only apply serialization at the end

Author: rubenfonseca

aws_lambda_powertools/event_handler/api_gateway.py

@@ -788,6 +788,8 @@ def build(self, event: ResponseEventT, cors: Optional[CORSConfig] = None) -> Dic
             logger.debug("Encoding bytes response with base64")
             self.response.base64_encoded = True
             self.response.body = base64.b64encode(self.response.body).decode()
+        elif self.response.is_json():
+            self.response.body = self.serializer(self.response.body)
 
         # We only apply the serializer when the content type is JSON and the
         # body is not a str, to avoid double encoding

tests/functional/event_handler/test_api_gateway.py

@@ -367,7 +367,7 @@ def test_override_route_compress_parameter():
     # AND the Response object with compress=False
     app = ApiGatewayResolver()
     mock_event = {"path": "/my/request", "httpMethod": "GET", "headers": {"Accept-Encoding": "deflate, gzip"}}
-    expected_value = '{"test": "value"}'
+    expected_value = {"test": "value"}
 
     @app.get("/my/request", compress=True)
     def with_compression() -> Response:
@@ -381,7 +381,7 @@ def handler(event, context):
 
     # THEN the response is not compressed
     assert result["isBase64Encoded"] is False
-    assert result["body"] == expected_value
+    assert json.loads(result["body"]) == expected_value
     assert result["multiValueHeaders"].get("Content-Encoding") is None
 
 
@@ -681,7 +681,7 @@ def another_one():
 def test_no_content_response():
     # GIVEN a response with no content-type or body
     response = Response(status_code=204, content_type=None, body=None, headers=None)
-    response_builder = ResponseBuilder(response)
+    response_builder = ResponseBuilder(response, serializer=json.dumps)
 
     # WHEN calling to_dict
     result = response_builder.build(APIGatewayProxyEvent(LOAD_GW_EVENT))
@@ -1482,7 +1482,7 @@ def get_lambda() -> Response:
     # THEN call the exception_handler
     assert result["statusCode"] == 500
     assert result["multiValueHeaders"]["Content-Type"] == [content_types.APPLICATION_JSON]
-    assert result["body"] == "CUSTOM ERROR FORMAT"
+    assert result["body"] == '"CUSTOM ERROR FORMAT"'
 
 
 def test_exception_handler_not_found():
@@ -1778,11 +1778,11 @@ def test_route_match_prioritize_full_match():
 
     @router.get("/my/{path}")
     def dynamic_handler() -> Response:
-        return Response(200, content_types.APPLICATION_JSON, json.dumps({"hello": "dynamic"}))
+        return Response(200, content_types.APPLICATION_JSON, {"hello": "dynamic"})
 
     @router.get("/my/path")
     def static_handler() -> Response:
-        return Response(200, content_types.APPLICATION_JSON, json.dumps({"hello": "static"}))
+        return Response(200, content_types.APPLICATION_JSON, {"hello": "static"})
 
     app.include_router(router)
 

tests/functional/event_handler/test_base_path.py

@@ -21,7 +21,7 @@ def handle():
 
     result = app(event, {})
     assert result["statusCode"] == 200
-    assert result["body"] == ""
+    assert result["body"] == '""'
 
 
 def test_base_path_api_gateway_http():
@@ -38,7 +38,7 @@ def handle():
 
     result = app(event, {})
     assert result["statusCode"] == 200
-    assert result["body"] == ""
+    assert result["body"] == '""'
 
 
 def test_base_path_alb():
@@ -53,7 +53,7 @@ def handle():
 
     result = app(event, {})
     assert result["statusCode"] == 200
-    assert result["body"] == ""
+    assert result["body"] == '""'
 
 
 def test_base_path_lambda_function_url():
@@ -70,7 +70,7 @@ def handle():
 
     result = app(event, {})
     assert result["statusCode"] == 200
-    assert result["body"] == ""
+    assert result["body"] == '""'
 
 
 def test_vpc_lattice():
@@ -85,7 +85,7 @@ def handle():
 
     result = app(event, {})
     assert result["statusCode"] == 200
-    assert result["body"] == ""
+    assert result["body"] == '""'
 
 
 def test_vpc_latticev2():
@@ -100,4 +100,4 @@ def handle():
 
     result = app(event, {})
     assert result["statusCode"] == 200
-    assert result["body"] == ""
+    assert result["body"] == '""'