Fixes Request.json() Hangs Forever

starlette/requests.py

@@ -205,10 +205,33 @@ def method(self) -> str:
     def receive(self) -> Receive:
         return self._receive
 
+    @property
+    def _stream(self) -> typing.List[bytes]:
+        try:
+            return self.scope["extensions"]["starlette"]["stream"]
+        except KeyError:
+            raise AttributeError("_stream")
+
+    @_stream.setter
+    def _stream(self, chunks: typing.List[bytes]) -> None:
+        if "starlette" not in self.scope["extensions"]:
+            self.scope["extensions"]["starlette"] = {}
+        self.scope["extensions"]["starlette"]["stream"] = chunks
+
+    async def _cache_stream(self) -> typing.AsyncGenerator[bytes, None]:
+        _stream: typing.List[bytes] = []
+
+        async for chunk in self.stream():
+            _stream.append(chunk)
+            yield chunk
+
+        if not hasattr(self, "_stream"):
+            self._stream = _stream
+
     async def stream(self) -> typing.AsyncGenerator[bytes, None]:
-        if hasattr(self, "_body"):
-            yield self._body
-            yield b""
+        if hasattr(self, "_stream"):
+            for chunk in self._stream:
+                yield chunk
             return
 
         if self._stream_consumed:
@@ -229,18 +252,14 @@ async def stream(self) -> typing.AsyncGenerator[bytes, None]:
         yield b""
 
     async def body(self) -> bytes:
-        if not hasattr(self, "_body"):
-            chunks = []
-            async for chunk in self.stream():
-                chunks.append(chunk)
-            self._body = b"".join(chunks)
-        return self._body
+        chunks = []
+        async for chunk in self._cache_stream():
+            chunks.append(chunk)
+        return b"".join(chunks)
 
     async def json(self) -> typing.Any:
-        if not hasattr(self, "_json"):
-            body = await self.body()
-            self._json = json.loads(body)
-        return self._json
+        body = await self.body()
+        return json.loads(body)
 
     async def form(self) -> FormData:
         if not hasattr(self, "_form"):

tests/test_requests.py

@@ -158,6 +158,21 @@ async def app(scope, receive, send):
     assert response.json() == {"body": "<stream consumed>", "stream": "abc"}
 
 
+def test_request_body_then_request_body(test_client_factory):
+    async def app(scope, receive, send):
+        request = Request(scope, receive)
+        body = await request.body()
+        request2 = Request(scope, request.receive)
+        body2 = await request2.body()
+        response = JSONResponse({"body": body.decode(), "body2": body2.decode()})
+        await response(scope, receive, send)
+
+    client = test_client_factory(app)
+
+    response = client.post("/", data="abc")
+    assert response.json() == {"body": "abc", "body2": "abc"}
+
+
 def test_request_json(test_client_factory):
     async def app(scope, receive, send):
         request = Request(scope, receive)