import paho.mqtt.client as mqtt

def on_connect(client, userdata, flags, rc):
    client.subscribe("topic/status")

def on_message(client, userdata, msg):
    print(f"Received: {msg.payload.decode()}")

client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message
client.connect("broker.example.com", 1883)
client.loop_forever()

// 请求端
const mqtt = require('mqtt')
const client = mqtt.connect('mqtt://broker.example.com')

client.publish('request/topic', 'request_data', {qos: 1})

// 响应端
client.subscribe('request/topic')
client.on('message', (topic, message) => {
    if(topic === 'request/topic') {
        client.publish('response/topic', 'response_data')
    }
})

MqttMessage message = new MqttMessage("request".getBytes());
message.setResponseTopic("response/topic");
client.publish("request/topic", message);

# 确保可靠连接的示例
client = mqtt.Client(client_id="my_client", clean_session=False)
client.connect("broker.example.com", 1883, keepalive=60)