push notification with fastapi get error RuntimeError: no running event loop

[bobwatcherx]

Question

i'm trying to make a push notification with api . and when I post a request to fastapi. with the socket connected, an automatic alert should appear on the flet screen later. and the message from the fastapi request post. but i got an error

Code sample

server.py

from fastapi import FastAPI, WebSocket, WebSocketDisconnect
import asyncio

app = FastAPI()

class ConnectionManager:
    def __init__(self):
        self.active_connections = []

    async def connect(self, websocket: WebSocket):
        await websocket.accept()
        self.active_connections.append(websocket)

    def disconnect(self, websocket: WebSocket):
        self.active_connections.remove(websocket)

    async def send_notification(self, message: str):
        for connection in self.active_connections:
            try:
                await connection.send_text(message)
            except:
                pass  # Skip if connection is closed

manager = ConnectionManager()

@app.websocket("/ws")
async def websocket_endpoint(websocket: WebSocket):
    await manager.connect(websocket)
    try:
        while True:
            data = await websocket.receive_text()
            await manager.send_notification(data)
            await asyncio.sleep(0)  # Allow time for sending before next loop iteration
    except WebSocketDisconnect:
        pass  # Disconnect will be handled here
    finally:
        manager.disconnect(websocket)

@app.post("/send_notification/")
async def send_notification(msg: str):
    await manager.send_notification(msg)
    return {"message": "Notification sent"}

main.py


from flet import *
import asyncio
import websockets

def main(page: Page):
    page.window_width = 300
    notif = AlertDialog(
        title=Text("New Notif", weight="bold"),
        content=Text(size=30, weight="bold")
    )

    async def receive_notifications(page, notif):
        uri = "ws://localhost:8000/ws"
        page.dialog = notif

        async with websockets.connect(uri) as websocket:
            while True:
                try:
                    message = await websocket.recv()
                    notif.content.value = Text(message)
                    notif.open = True
                    print(f"Received notification: {message}")
                    page.update()
                except websockets.ConnectionClosed:
                    print("WebSocket connection closed")
                    notif.open = False
                    page.update()
                    break

    # Memulai event loop dari framework Flet
    asyncio.create_task(receive_notifications(page, notif))

    page.add(
        Column([
            Text("listen notif from server",
                 size=30, weight="bold"
            )
        ])
    )

flet.app(target=main)

Error message

/usr/local/lib/python3.10/dist-packages/flet/flet.py:322: RuntimeWarning: coroutine 'main.<locals>.receive_notifications' was never awaited
  page.error(f"There was an error while processing your request: {e}")
RuntimeWarning: Enable tracemalloc to get the object allocation traceback
Unhandled error processing page session : Traceback (most recent call last):
  File "/usr/local/lib/python3.10/dist-packages/flet/flet.py", line 316, in on_session_created
    session_handler(page)
  File "/home/miop/belajar/fletpushnotif/main.py", line 31, in main
    asyncio.create_task(receive_notifications(page, notif))
  File "/usr/lib/python3.10/asyncio/tasks.py", line 336, in create_task
    loop = events.get_running_loop()
RuntimeError: no running event loop

Unhandled error processing page session : Traceback (most recent call last):
  File "/usr/local/lib/python3.10/dist-packages/flet/flet.py", line 316, in on_session_created
    session_handler(page)
  File "/home/miop/belajar/fletpushnotif/main.py", line 31, in main
    asyncio.create_task(receive_notifications(page, notif))
  File "/usr/lib/python3.10/asyncio/tasks.py", line 336, in create_task
    loop = events.get_running_loop()
RuntimeError: no running event loop

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• I have searched for answers to my question both in the issues and in previous discussions.