Fix middleware and add tests

fastapi/applications.py

@@ -810,7 +810,7 @@ class FastAPI(Starlette):
                 """
             ),
         ] = True,
-        ignore_trailing_whitespaces: Annotated[
+        ignore_trailing_slash: Annotated[
             bool,
             Doc(
                 """
@@ -950,7 +950,7 @@ class FastAPI(Starlette):
             include_in_schema=include_in_schema,
             responses=responses,
             generate_unique_id_function=generate_unique_id_function,
-            ignore_trailing_whitespaces=ignore_trailing_whitespaces,
+            ignore_trailing_slash=ignore_trailing_slash,
         )
         self.exception_handlers: Dict[
             Any, Callable[[Request, Any], Union[Response, Awaitable[Response]]]
@@ -970,11 +970,14 @@ class FastAPI(Starlette):
         )
         self.middleware_stack: Union[ASGIApp, None] = None
 
-        if ignore_trailing_whitespaces:
-            async def middleware_ignore_tailing_whitespace(request: Request, call_next):
-                request.scope["path"] = request.scope["path"].rstrip("/")
-                return await call_next(request)
-            self.add_middleware(BaseHTTPMiddleware, dispatch=middleware_ignore_tailing_whitespace)
+        if ignore_trailing_slash:
+            def ignore_trailing_whitespace_middleware(app):
+                async def ignore_trailing_whitespace_wrapper(scope, receive, send):
+                    scope["path"] = scope["path"].rstrip("/")
+                    await app(scope, receive, send)
+                return ignore_trailing_whitespace_wrapper
+            self.add_middleware(ignore_trailing_whitespace_middleware)
+
         self.setup()
 
     def openapi(self) -> Dict[str, Any]:

fastapi/routing.py

@@ -811,7 +811,7 @@ class APIRouter(routing.Router):
                 """
             ),
         ] = Default(generate_unique_id),
-        ignore_trailing_whitespaces: Annotated[
+        ignore_trailing_slash: Annotated[
             bool,
             Doc(
                 """
@@ -843,7 +843,7 @@ class APIRouter(routing.Router):
         self.route_class = route_class
         self.default_response_class = default_response_class
         self.generate_unique_id_function = generate_unique_id_function
-        self.ignore_trailing_whitespaces = ignore_trailing_whitespaces
+        self.ignore_trailing_slash = ignore_trailing_slash
 
     def route(
         self,
@@ -852,7 +852,7 @@ class APIRouter(routing.Router):
         name: Optional[str] = None,
         include_in_schema: bool = True,
     ) -> Callable[[DecoratedCallable], DecoratedCallable]:
-        if self.ignore_trailing_whitespaces:
+        if self.ignore_trailing_slash:
             path = path.rstrip("/")
         def decorator(func: DecoratedCallable) -> DecoratedCallable:
             self.add_route(
@@ -900,7 +900,7 @@ class APIRouter(routing.Router):
             Callable[[APIRoute], str], DefaultPlaceholder
         ] = Default(generate_unique_id),
     ) -> None:
-        if self.ignore_trailing_whitespaces:
+        if self.ignore_trailing_slash:
             path = path.rstrip("/")
         route_class = route_class_override or self.route_class
         responses = responses or {}
@@ -1020,7 +1020,7 @@ class APIRouter(routing.Router):
         *,
         dependencies: Optional[Sequence[params.Depends]] = None,
     ) -> None:
-        if self.ignore_trailing_whitespaces:
+        if self.ignore_trailing_slash:
             path = path.rstrip("/")
         current_dependencies = self.dependencies.copy()
         if dependencies:
@@ -1105,7 +1105,7 @@ class APIRouter(routing.Router):
     def websocket_route(
         self, path: str, name: Union[str, None] = None
     ) -> Callable[[DecoratedCallable], DecoratedCallable]:
-        if self.ignore_trailing_whitespaces:
+        if self.ignore_trailing_slash:
             path = path.rstrip("/")
         def decorator(func: DecoratedCallable) -> DecoratedCallable:
             self.add_websocket_route(path, func, name=name)
@@ -1265,7 +1265,7 @@ class APIRouter(routing.Router):
             responses = {}
         for route in router.routes:
             path = route.path
-            if self.ignore_trailing_whitespaces:
+            if self.ignore_trailing_slash:
                 path = path.rstrip("/")
             if isinstance(route, APIRoute):
                 combined_responses = {**responses, **route.responses}

tests/test_ignore_trailing_slash.py

@@ -1,29 +1,45 @@
-from fastapi import FastAPI
+from fastapi import FastAPI, WebSocket, APIRouter
 from fastapi.testclient import TestClient
 
-recognizing_app = FastAPI()
-ignoring_app = FastAPI(ignore_trailing_whitespaces=True)
+app = FastAPI(ignore_trailing_slash=True)
+router = APIRouter()
 
-@recognizing_app.get("/example")
-@ignoring_app.get("/example")
-async def return_data():
-    return {"msg": "Reached the route!"}
+@app.get("/example")
+async def example_endpoint():
+    return {"msg": "Example"}
 
-recognizing_client = TestClient(recognizing_app)
-ignoring_client = TestClient(ignoring_app)
+@app.websocket("/websocket")
+async def websocket_endpoint(websocket: WebSocket):
+    await websocket.accept()
+    await websocket.send_text("Websocket")
+    await websocket.close()
 
-def test_recognizing_trailing_slash():
-    response = recognizing_client.get("/example", follow_redirects=False)
-    assert response.status_code == 200
-    assert response.json()["msg"] == "Reached the route!"
-    response = recognizing_client.get("/example/", follow_redirects=False)
-    assert response.status_code == 307
-    assert response.headers["location"].endswith("/example")
+@router.get("/example")
+def route_endpoint():
+    return {"msg": "Routing Example"}
+
+app.include_router(router, prefix="/router")
+
+client = TestClient(app)
 
 def test_ignoring_trailing_slash():
-    response = ignoring_client.get("/example", follow_redirects=False)
+    response = client.get("/example", follow_redirects=False)
+    assert response.status_code == 200
+    assert response.json()["msg"] == "Example"
+    response = client.get("/example/", follow_redirects=False)
+    assert response.status_code == 200
+    assert response.json()["msg"] == "Example"
+
+def test_ignoring_trailing_shlash_ws():
+    with client.websocket_connect("/websocket") as websocket:
+        assert websocket.receive_text() == "Websocket"
+    with client.websocket_connect("/websocket/") as websocket:
+        assert websocket.receive_text() == "Websocket"
+
+def test_ignoring_trailing_routing():
+    response = client.get("router/example", follow_redirects=False)
     assert response.status_code == 200
-    assert response.json()["msg"] == "Reached the route!"
-    response = ignoring_client.get("/example/", follow_redirects=False)
+    assert response.json()["msg"] == "Routing Example"
+    response = client.get("router/example/", follow_redirects=False)
     assert response.status_code == 200
-    assert response.json()["msg"] == "Reached the route!"
+    assert response.json()["msg"] == "Routing Example"