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Python实现MQTT通信的示例代码

作者：weixin_43182240

本文主要介绍了Python实现MQTT通信的示例代码,文中通过示例代码介绍的非常详细,对大家的学习或者工作具有一定的参考学习价值,需要的朋友们下面随着小编来一起学习学习吧

 适用于物联网设备、传感器数据采集等场景

1. 安装paho-mqtt库‌

安装Python的MQTT客户端库 paho-mqtt，支持MQTT v3.1/v3.1.1协议，兼容性强

pip install paho-mqtt==1.6.1  # 推荐使用1.6.1版本避免兼容性问题

2. 搭建MQTT代理服务器（Broker）‌

选择本地搭建或使用公共Broker：

‌本地搭建（以EMQX为例）‌

下载并解压EMQX开源版。Directory listing for EMQX: /v5.3.2/ | EMQ

配置EMQX，EMQX的配置文件位于etc\emqx.conf，可以根据需要修改配置文件，例如更改端口号、添加插件等：18083 EMQX Dashboard 管理控制台端口

在命令行中进入安装目录的 bin 文件夹，执行以下命令启动服务

检查启动状态emqx_ctl status

访问 http://localhost:18083 进入管理界面（默认账号：admin/public）

公共Broker（如HiveMQ）‌

使用免费公共服务器： 

broker_address = "broker.hivemq.com"  
broker_port = 1883

‌3. Python实现基础通信功能‌

分为 ‌发布者（Publisher）‌ 和 ‌订阅者（Subscriber）‌ 两类客户端：

‌3.1 发布者代码示例publisher.py

# python 3.8

import random
import time

from paho.mqtt import client as mqtt_client


broker = 'broker.emqx.io'
port = 1883
broker = '127.0.0.1'
port = 1883
topic = "python/mqtt"
# generate client ID with pub prefix randomly
client_id = f'python-mqtt-{random.randint(0, 1000)}'
username = 'emqx'
password = '**********'


def connect_mqtt():
    def on_connect(client, userdata, flags, rc,properties):
        if rc == 0:
            print("Connected to MQTT Broker!")
        else:
            print("Failed to connect, return code %d\n", rc)

    # client = mqtt_client.Client(client_id)
    client = mqtt_client.Client(client_id=client_id, callback_api_version=mqtt_client.CallbackAPIVersion.VERSION2)
    # client.tls_set(ca_certs='./server-ca.crt')
    # client.username_pw_set(username, password)
    client.username_pw_set('admin', 'public')
    client.on_connect = on_connect
    client.connect(broker, port)
    return client


def publish(client):
    msg_count = 0
    while True:
        time.sleep(1)
        msg = f"messages: {msg_count}"
        result = client.publish(topic, msg)
        # result: [0, 1]
        status = result[0]
        if status == 0:
            print(f"Send `{msg}` to topic `{topic}`")
        else:
            print(f"Failed to send message to topic {topic}")
        msg_count += 1


def run():
    client = connect_mqtt()
    client.loop_start()
    publish(client)


if __name__ == '__main__':
    run()

3.2 订阅者代码示例subscriber.py

# python3.8

import random

from paho.mqtt import client as mqtt_client


broker = 'broker.emqx.io'
port = 1883
broker = '127.0.0.1'
port = 1883
topic = "python/mqtt"
# generate client ID with pub prefix randomly
client_id = f'python-mqtt-{random.randint(0, 100)}'
username = 'emqx'
password = '**********'


def connect_mqtt() -> mqtt_client:
    def on_connect(client, userdata, flags, rc,properties):
        if rc == 0:
            print("Connected to MQTT Broker!")
        else:
            print("Failed to connect, return code %d\n", rc)

    # client = mqtt_client.Client(client_id)
    client = mqtt_client.Client(client_id=client_id, callback_api_version=mqtt_client.CallbackAPIVersion.VERSION2)
    # client.tls_set(ca_certs='./server-ca.crt')
    # client.username_pw_set(username, password)
    client.username_pw_set('admin', 'public')
    client.on_connect = on_connect
    client.connect(broker, port)
    return client


def subscribe(client: mqtt_client):
    def on_message(client, userdata, msg):
        print(f"Received `{msg.payload.decode()}` from `{msg.topic}` topic")

    client.subscribe(topic)
    client.on_message = on_message


def run():
    client = connect_mqtt()
    subscribe(client)
    client.loop_forever()


if __name__ == '__main__':
    run()

3.3或者放同一个文件：

from paho.mqtt import client as mqtt_client
from threading import Thread
import time

broker = '127.0.0.1'
port = 1883
# broker = 'broker.emqx.io'
# port = 1883
su_topic = [("python_mqtt_server", 2), ("python_mqtt_command", 2)]  # 订阅频道,数组格式为(topic，qos)
pu_topic = ["python_mqtt_server"]  # 发布频道
client_id = 'websocket_publisher_001'


# 将连接与订阅绑在一起，防止复用client导致连接冲突
def connect_mqtt():
    # For paho-mqtt 2.0.0, you need to add the properties parameter.
    def on_connect(client, userdata, flags, rc, properties):
        if rc == 0:
            print("Connected to MQTT Broker!")
        else:
            print("Failed to connect, return code %d\n", rc)

    # For paho-mqtt 2.0.0, you need to set callback_api_version.
    client = mqtt_client.Client(client_id=client_id, callback_api_version=mqtt_client.CallbackAPIVersion.VERSION2)

    client.username_pw_set('admin', 'public')
    client.on_connect = on_connect
    client.connect(broker, port)
    subscribe_many(client)
    print("订阅完成")
    return client


# 订阅多个频道
def subscribe_many(client):
    # 根据client源码可知，订阅支持的数组格式是(topic,qos)
    client.subscribe(su_topic)


# 收到信息的回调函数
def on_message(client, userdata, msg):
    print(f"Received `{msg.payload.decode()}` from `{msg.topic}` topic")
    # 这里可以编写一些收到信息后的处理,比如收到什么信息开启什么任务，任务完成后再调publish发布信息给终端等等........
    # ----------处理例子------------------
    r_msg = msg.payload.decode()
    if int(r_msg) % 2 == 0:
        print("收到偶数")
    # -----------------------------------


# 发布信息函数
def publish(client):
    for i in range(1, 11):
        time.sleep(1)
        msg = f"{i}"
        result = client.publish(pu_topic[0], msg)
        # result: [0, 1]
        status = result[0]
        if status == 0:
            print(f"Send `{msg}` to topic `{pu_topic[0]}`")
        else:
            print(f"Failed to send message to topic {pu_topic[0]}")


if __name__ == '__main__':
    client = connect_mqtt()
    client.username_pw_set('admin','public')
    client.on_message = on_message  # 重写回调函数,可以在方法体里，根据需求改收到信息后干什么
    # 多线程，这里启动一个发布任务的线程，模拟有一个发布消息的客户端
    thread1 = Thread(target=publish, args=(client,))
    # --*如要要实现流水线式的收发，则可以将线程内方法改为任务队列处理，用一个全局变量管理任务执行，执行后再publish
    thread1.start()

    client.loop_forever()  # 这个要加,监听(on_message)与loop_forever配套

关键配置说明

订阅所有传感器子主题

client.subscribe("sensors/#", qos=1) ‌

‌WebSocket协议支持‌

‌QoS与消息保留‌

‌异常处理‌

4. 关键功能扩展

异步通信，使用多线程实现非阻塞操作：

from threading import Thread  

  def start_async(client):  
      Thread(target=client.loop_start).start()

服务质量（QoS）设置 支持至多一次（0）、至少一次（1）、恰好一次（2）三种级别：

client.publish(topic, payload, qos=1)  # 设置QoS为1

5. 注意事项‌

  1. ‌连接安全性‌：若需SSL加密，可使用 client.tls_set() 方法。
  2. ‌主题设计‌：遵循分层结构（如 sensor/room1/temp），支持通配符 +（单层）和 #（多层）。
  3. ‌异常处理‌：添加 on_disconnect 回调函数实现断线重连逻辑。

‌完整示例流程‌

  1. 启动EMQX Broker服务。
  2. 运行订阅者代码监听主题 home/sensor/temp。
  3. 运行发布者代码发送温度数据。
  4. 在EMQX管理界面验证消息收发状态

到此这篇关于Python实现MQTT通信的示例代码的文章就介绍到这了,更多相关Python MQTT通信内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家！ 

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