Don't send 0 as the response size for streaming responses

Send nothing instead.

Author: ruohola

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Don't send 0 as the response size for streaming responses, send nothing instead.
+
 ## [1.2.0] - 2022-01-31
 
 ### Added

apilytics/django.py

@@ -52,8 +52,9 @@ def __call__(self, request: django.http.HttpRequest) -> django.http.HttpResponse
             integrated_library=f"django/{django.__version__}",
         ) as sender:
             response = self.get_response(request)
+            content = getattr(response, "content", None)
             sender.set_response_info(
                 status_code=response.status_code,
-                response_size=len(getattr(response, "content", ())),
+                response_size=len(content) if content is not None else None,
             )
         return response

apilytics/fastapi.py

@@ -60,8 +60,9 @@ async def dispatch(
             integrated_library=f"fastapi/{fastapi.__version__}",
         ) as sender:
             response = await call_next(request)
+            size = response.headers.get("content-length")
             sender.set_response_info(
                 status_code=response.status_code,
-                response_size=int(response.headers.get("content-length", 0)),
+                response_size=int(size) if size is not None else None,
             )
         return response

tests/django/app/views.py

@@ -15,7 +15,7 @@ def streaming_view(
     request: django.http.HttpRequest,
 ) -> django.http.StreamingHttpResponse:
     return django.http.StreamingHttpResponse(
-        status=200, streaming_content=(b"first", b"second")
+        status=200, streaming_content=(b"first", b" ", b"second")
     )
 
 

tests/django/test_django.py

@@ -71,7 +71,7 @@ def test_middleware_should_send_query_params(
     assert isinstance(data["timeMillis"], int)
 
 
-def test_middleware_should_send_zero_request_and_response_sizes(
+def test_middleware_should_handle_zero_request_and_response_sizes(
     mocked_urlopen: unittest.mock.MagicMock,
 ) -> None:
     client.handler.load_middleware()
@@ -85,7 +85,7 @@ def test_middleware_should_send_zero_request_and_response_sizes(
     assert data["responseSize"] == 0
 
 
-def test_middleware_should_send_non_zero_request_and_response_sizes(
+def test_middleware_should_handle_non_zero_request_and_response_sizes(
     mocked_urlopen: unittest.mock.MagicMock,
 ) -> None:
     client.handler.load_middleware()
@@ -107,6 +107,9 @@ def test_middleware_should_work_with_streaming_response(
     client.handler.load_middleware()
     response = client.get("/streaming")
     assert response.status_code == 200
+    # Ignore: The attribute *does* exist on StreamingHTTPResponse.
+    content = b"".join(response.streaming_content)  # type: ignore[attr-defined]
+    assert content == b"first second"
 
     assert mocked_urlopen.call_count == 1
     __, call_kwargs = mocked_urlopen.call_args
@@ -116,14 +119,12 @@ def test_middleware_should_work_with_streaming_response(
         "method",
         "statusCode",
         "requestSize",
-        "responseSize",
         "timeMillis",
     }
     assert data["path"] == "/streaming"
     assert data["method"] == "GET"
     assert data["statusCode"] == 200
     assert data["requestSize"] == 0
-    assert data["responseSize"] == 0  # Can't get body size from a streaming response.
     assert isinstance(data["timeMillis"], int)
 
 

tests/fastapi/app.py

@@ -26,7 +26,9 @@ async def streaming_route(
     request: fastapi.Request,
 ) -> starlette.responses.StreamingResponse:
     return starlette.responses.StreamingResponse(
-        status_code=fastapi.status.HTTP_200_OK, content=(b"first", b"second")
+        status_code=fastapi.status.HTTP_200_OK,
+        content=iter([b"first", b" ", b"second"]),
+        media_type="application/octet-stream",
     )
 
 

tests/fastapi/test_fastapi.py

@@ -70,7 +70,7 @@ def test_middleware_should_send_query_params(
     assert isinstance(data["timeMillis"], int)
 
 
-def test_middleware_should_send_zero_request_and_response_sizes(
+def test_middleware_should_handle_zero_request_and_response_sizes(
     mocked_urlopen: unittest.mock.MagicMock,
 ) -> None:
     response = client.post("/empty")
@@ -80,10 +80,10 @@ def test_middleware_should_send_zero_request_and_response_sizes(
     __, call_kwargs = mocked_urlopen.call_args
     data = tests.conftest.decode_request_data(call_kwargs["data"])
     assert data["requestSize"] == 0
-    assert data["responseSize"] == 0
+    assert "responseSize" not in data  # In FastAPI 0 content-length is not set.
 
 
-def test_middleware_should_send_non_zero_request_and_response_sizes(
+def test_middleware_should_handle_non_zero_request_and_response_sizes(
     mocked_urlopen: unittest.mock.MagicMock,
 ) -> None:
     response = client.post("/dummy?some=query", json={"hello": "world"})
@@ -99,8 +99,10 @@ def test_middleware_should_send_non_zero_request_and_response_sizes(
 def test_middleware_should_work_with_streaming_response(
     mocked_urlopen: unittest.mock.MagicMock,
 ) -> None:
-    response = client.get("/streaming")
+    response = client.get("/streaming", stream=True)
     assert response.status_code == 200
+    content = b"".join(response.iter_content())
+    assert content == b"first second"
 
     assert mocked_urlopen.call_count == 1
     __, call_kwargs = mocked_urlopen.call_args
@@ -110,14 +112,12 @@ def test_middleware_should_work_with_streaming_response(
         "method",
         "statusCode",
         "requestSize",
-        "responseSize",
         "timeMillis",
     }
     assert data["path"] == "/streaming"
     assert data["method"] == "GET"
     assert data["statusCode"] == 200
     assert data["requestSize"] == 0
-    assert data["responseSize"] == 0  # Can't get body size from a streaming response.
     assert isinstance(data["timeMillis"], int)