将flask socketio发送到特定用户

from flask import Flask, render_template
from flask_socketio import SocketIO, emit

app = Flask(__name__)
socketio = SocketIO(app)

@socketio.on('message')
def handle_message(data):
    user_id = data['user_id']
    message = data['message']
    # 发送消息到特定用户
    emit('message', message, room=user_id)

if __name__ == '__main__':
    socketio.run(app)

<script src="//cdnjs.cloudflare.com/ajax/libs/socket.io/2.3.1/socket.io.js"></script>
<script>
    var socket = io.connect('http://localhost:5000');

    socket.on('message', function(message) {
        // 处理接收到的消息
        console.log(message);
    });

    // 发送消息到服务器
    function sendMessage() {
        var user_id = '特定用户的会话ID';
        var message = '要发送的消息';
        socket.emit('message', {user_id: user_id, message: message});
    }
</script>