python对mqtt进行封装成类函数

下面是一个简单的Python类函数，用于封装MQTT：

import paho.mqtt.client as mqtt

class MQTT:

    def __init__(self, broker_address, username=None, password=None):
        self.client = mqtt.Client()
        if username and password:
            self.client.username_pw_set(username, password)
        self.client.connect(broker_address)

    def publish(self, topic, payload, qos=0, retain=False):
        self.client.publish(topic, payload, qos, retain)

    def subscribe(self, topic, qos=0):
        self.client.subscribe(topic, qos)

    def on_message(self, callback):
        self.client.on_message = callback

    def loop_forever(self):
        self.client.loop_forever()

使用示例：

def on_message(client, userdata, message):
    print(message.topic + " " + str(message.payload))

mqtt = MQTT("localhost")
mqtt.subscribe("test/topic")
mqtt.on_message(on_message)
mqtt.loop_forever()

这个类函数封装了MQTT的连接、发布、订阅和消息处理等功能，可以方便地在Python中使用MQTT。