Websocket Routes Only Work on FastAPI, not APIRouter

[azurelotus0926]

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Example Code

app = FastAPI()

ws_router = APIRouter()
@ws_router.websocket("/ws")
async def websocket_endpoint(websocket: WebSocket):
    await manager.connect(websocket)

    while websocket.client_state.CONNECTED:
        try:
            await websocket.send_json({"Hello": "World!"})
            time.sleep(3)
        except (WebSocketDisconnect, ConnectionClosed):
            await manager.disconnect(websocket)
            break

file_router = APIRouter()
@filerouter.post("/fetch-all",
             response_model=FetchItemResponse)
async def fetch_all_items(
        credentials: Annotated[HTTPAuthorizationCredentials, Depends(security)],
        userid: Annotated[str, Form()],
        upload_repo: UploadRepository = Depends(get_mongodb_repo(UploadRepository))
    ):
    try:
        print("userid", userid)
        item_list, total = upload_repo.list_items(userid=userid)
        print(item_list)
        return FetchItemResponse(itemlist=[FetchModel(id=item.id,originname=item.originname, filepath=item.filepath, createdat=item.createdat, status=item.status) for item in item_list])
    except Exception as e:
        print(e)
        return None
app.include_router(file_router, prefix="/files", tags=["files"])
app.include_router(ws_router, prefix="/ws", tags=["websocket"])

Description

Similarity
The same issue as this closed issue. (#98)
It was closed because an owner declared that this issue was fixed. But I have same issue now with latest fastapi version and python stable version.
Describe the bug
I developed a full-stack project using fastapi, websocket and Next. I can fetch all file items when I include file_router only, but it fails when I include both routers. When I trace the request in Network tab in Google Inspect panel, I find its status is pending and has no response. Nothing happens in fastapi server, whether or not I send post request.

Operating System

Windows

Operating System Details

No response

FastAPI Version

0.111.0

Pydantic Version

2.7.4

Python Version

3.12.4

Additional Context

No response

[YuriiMotov]

You are using time.sleep(3) inside of async function (websocket endpoint). It slows down your app. I guess this is probably the root of your issue

[azurelotus0926]

I'm sorry but it's the same when I delete the line.

[YuriiMotov]

Try changing time.sleep(3) to await asyncio.sleep(3).
time.sleep is blocking function, in async functions you should use await asyncio.sleep instead.

If this doesn't help, you probably have errors in the implementation of manager.

[azurelotus0926]

Thanks, it works.