Add basic streaming support

Buffer and parse streamed requests.

.flake8

@@ -0,0 +1,2 @@
+[flake8]
+extend-ignore = E203

llsd_asgi/middleware.py

@@ -107,14 +107,9 @@ async def receive_with_llsd(self) -> Message:
         assert message["type"] == "http.request"
 
         body = message["body"]
-        more_body = message.get("more_body", False)
-        if more_body:
-            # Some implementations (e.g. HTTPX) may send one more empty-body message.
-            # Make sure they don't send one that contains a body, or it means
-            # that clients attempt to stream the request body.
+        while message.get("more_body", False):
             message = await self.receive()
-            if message["body"] != b"":  # pragma: no cover
-                raise NotImplementedError("Streaming the request body isn't supported yet")
+            body += message["body"]
 
         message["body"] = json.dumps(self.parse(body), cls=JSONEncoder).encode()
 

tests/test_middleware.py

@@ -51,6 +51,33 @@ async def app(scope: Scope, receive: Receive, send: Send) -> None:
         )
 
 
+@pytest.mark.asyncio
+async def test_streaming_request() -> None:
+    async def app(scope: Scope, receive: Receive, send: Send) -> None:
+        request = Request(scope, receive=receive)
+        body = await request.json()
+        text = f"message={body['message']!r}"
+
+        response = PlainTextResponse(text)
+        await response(scope, receive, send)
+
+    app = LLSDMiddleware(app)
+
+    async def stream_bytes(content):
+        b = llsd.format_xml(content)
+        for chunk in range(0, len(b), 2):
+            yield b[chunk : chunk + 2]
+
+    async with httpx.AsyncClient(app=app, base_url="http://testserver") as client:
+        r = await client.post(
+            "/",
+            content=stream_bytes({"message": "Hello, world!"}),
+            headers={"content-type": "application/llsd+xml"},
+        )
+        assert r.status_code == 200
+        assert r.text == "message='Hello, world!'"
+
+
 @pytest.mark.asyncio
 async def test_non_llsd_request() -> None:
     async def app(scope: Scope, receive: Receive, send: Send) -> None: