Websocket Service

WebSocket Service — 实时通信服务

Goal

Trigger

见 description 中的触发时机

见 ## Workflow

设计和实现可靠的 WebSocket 实时通信系统。

Workflow

1. 需求分析 — 通信模式 (点对点/广播/房间)、消息格式
2. 选择方案 — Socket.IO / ws / 原生 WebSocket
3. 设计协议 — 消息类型、心跳、重连
4. 实现服务 — 连接管理、消息路由、房间管理
5. 部署运维 — 负载均衡、水平扩展、监控

核心实现

Socket.IO Server (Node.js)

const { Server } = require('socket.io');
const io = new Server(httpServer, {
  cors: { origin: '*' },
  pingTimeout: 60000,
  pingInterval: 25000,
});

// 房间管理
io.on('connection', (socket) => {
  console.log(`User connected: ${socket.id}`);

  // 加入房间
  socket.on('join:room', (roomId) => {
    socket.join(roomId);
    socket.to(roomId).emit('user:joined', { userId: socket.id });
  });

  // 房间消息
  socket.on('message:room', ({ roomId, message }) => {
    io.to(roomId).emit('message:new', {
      userId: socket.id,
      message,
      timestamp: Date.now(),
    });
  });

  // 私聊
  socket.on('message:private', ({ targetId, message }) => {
    socket.to(targetId).emit('message:private', {
      from: socket.id,
      message,
    });
  });

  socket.on('disconnect', () => {
    console.log(`User disconnected: ${socket.id}`);
  });
});

Python FastAPI WebSocket

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

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

@app.websocket("/ws/{room_id}")
async def websocket_endpoint(websocket: WebSocket, room_id: str):
    await websocket.accept()

    if room_id not in rooms:
        rooms[room_id] = set()
    rooms[room_id].add(websocket)

    try:
        while True:
            data = await websocket.receive_json()
            # 广播给房间内其他人
            for ws in rooms[room_id]:
                if ws != websocket:
                    await ws.send_json(data)
    except WebSocketDisconnect:
        rooms[room_id].remove(websocket)

消息协议

{
  "type": "chat | system | ack | error",
  "payload": {},
  "timestamp": 1704067200000,
  "id": "uuid"
}

Example

用户: 实现一个多人聊天室

输出:
1. Socket.IO server，支持房间管理
2. 客户端: join:room, message:room 事件
3. 心跳检测: ping/pong 25s 间隔
4. 断线重连: 指数退避，最多 5 次
5. 消息持久化: Redis pub/sub 跨实例广播

参考

• Socket.IO: references/socketio.md
• WebSocket 协议: references/websocket-protocol.md