Python 无法在fastapi中管理多个用户的websocket连接

Your FastAPI WebSocket route does not seem to have an event loop to continuously handle incoming or outgoing messages for each connected client.
Meaning: as soon as the function websocket_endpoint finishes executing, the WebSocket connection is automatically closed by FastAPI, leading to the unexpected ASGI message error.

将connections字典outside放在函数范围内将允许跨不同的函数调用存储和访问多个WebSocket连接.

您需要一个while True:循环来确保WebSocket连接保持打开，从而允许连续发送和接收消息.

添加一些错误处理并不是一个坏主意:这将有助于通过WebSocketDisconnect优雅地处理客户端断开连接.这样，当客户端断开连接时，可以从connections字典中删除该连接.

from fastapi import FastAPI, WebSocket, WebSocketDisconnect
from typing import Dict

app = FastAPI()
connections: Dict[str, WebSocket] = {}

@app.websocket("/ws/{client_id}")
async def websocket_endpoint(websocket: WebSocket, client_id: str):
    await websocket.accept()
    connections[client_id] = websocket

    try:
        while True:
            data = await websocket.receive_text()
            # Do something with received data (optional)
            
            for uid, ws in connections.items():
                await ws.send_text(f"Client {client_id} says: {data}")

    except WebSocketDisconnect:
        del connections[client_id]

例如，该代码将来自任何客户端的传入消息发送到所有连接的客户端.您可以根据您的用例需要对其进行定制.

新工作流程:

   +---------------------+
   |  websocket_endpoint |
   +-------+-------------+
           |
           |
   +-------v-----------------+
   |await websocket.accept() |
   +-------+-----------------+
           |
           |
   +-------v----------------------------+
   | connections[client_id] = websocket |
   +-------+----------------------------+
           |
           |
           |<-------------------------------------------+
           |                                            |
   +-------v----------+                        +--------+------------+
   |   while True:    |                        | WebSocketDisconnect |
   +-------+----------+                        +--------+------------+
           |                                            |
           |                                            |
   +-------v-------------------------------+   +--------v-------------------+
   | data = await websocket.receive_text() |<--| del connections[client_id] |
   +-------+-------------------------------+   +----------------------------+
           |
           |
   +-------v-----------------------------+
   | for uid, ws in connections.items(): |
   +-------+-----------------------------+
           |
           |
   +-------v--------------+          +--------------------+
   | await ws.send_text() |---...--->|     while True:    |
   +-------+--------------+          +--------------------+