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starlette/middleware/limits.py

@@ -11,7 +11,7 @@ def __init__(self, max_body_size: int) -> None:
         self.max_body_size = max_body_size
 
 
-class LimitRequestMiddleware:
+class LimitRequestSizeMiddleware:
     def __init__(
         self, app: ASGIApp, max_body_size: int = DEFAULT_MAX_BODY_SIZE
     ) -> None:
@@ -22,17 +22,6 @@ async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
         if scope["type"] != "http":  # pragma: no cover
             return await self.app(scope, receive, send)
 
-        headers = Headers(scope=scope)
-        content_length = headers.get("content-length")
-        if content_length is not None:
-            if int(content_length) > self.max_body_size:
-                return await _content_too_large_app(scope)(scope, receive, send)
-
-            # NOTE: The server makes sure that the content-length header sent by the
-            #   client is the same as the length of the body.
-            #   Ref.: https://github.com/django/asgiref/issues/422
-            return await self.app(scope, receive, send)
-
         total_size = 0
         response_started = False
 
@@ -52,15 +41,21 @@ async def wrap_receive() -> Message:
                     raise ContentTooLarge(self.max_body_size)
             return message
 
+        headers = Headers(scope=scope)
+        content_length = headers.get("content-length")
+        if content_length is not None:
+            if int(content_length) > self.max_body_size:
+                return await _content_too_large_app()(scope, receive, send)
+
         try:
             await self.app(scope, wrap_receive, wrap_send)
         except ContentTooLarge as exc:
             # NOTE: If response has already started, we can't return a 413, because the
             #   headers have already been sent.
             if not response_started:
-                return await _content_too_large_app(scope)(scope, receive, send)
+                return await _content_too_large_app()(scope, receive, send)
             raise exc
 
 
-def _content_too_large_app(scope: Scope) -> PlainTextResponse:
+def _content_too_large_app() -> PlainTextResponse:
     return PlainTextResponse("Content Too Large", status_code=413)

tests/middleware/test_limits.py

@@ -4,7 +4,7 @@
 
 from starlette.applications import Starlette
 from starlette.middleware import Middleware
-from starlette.middleware.limits import ContentTooLarge, LimitRequestMiddleware
+from starlette.middleware.limits import ContentTooLarge, LimitRequestSizeMiddleware
 from starlette.requests import Request
 from starlette.routing import Route
 from starlette.testclient import TestClient
@@ -24,7 +24,7 @@ async def echo_app(scope: Scope, receive: Receive, send: Send) -> None:
             break
 
 
-app = LimitRequestMiddleware(echo_app, max_body_size=1024)
+app = LimitRequestSizeMiddleware(echo_app, max_body_size=1024)
 
 
 def test_no_op(test_client_factory: Callable[..., TestClient]) -> None:
@@ -81,10 +81,20 @@ async def read_body_endpoint(request: Request) -> None:
 
     app = Starlette(
         routes=[Route("/", read_body_endpoint, methods=["POST"])],
-        middleware=[Middleware(LimitRequestMiddleware, max_body_size=1024)],
+        middleware=[Middleware(LimitRequestSizeMiddleware, max_body_size=1024)],
     )
     client = test_client_factory(app)
 
     response = client.post("/", content=[b"X" * 1024, b"X"])
     assert response.status_code == 413
     assert response.text == "Content Too Large"
+
+
+def test_content_too_large_and_content_length_mismatch(
+    test_client_factory: Callable[..., TestClient]
+) -> None:
+    client = test_client_factory(app)
+
+    response = client.post("/", content="X" * 1025, headers={"Content-Length": "1024"})
+    assert response.status_code == 413
+    assert response.text == "Content Too Large"