python+emqx实现mqtt协议传输数据_msg.payload.decode()

目录

安装

发布端

订阅端

存在问题

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安装

1.下载安装emqx开源框架

下载 EMQX

这个是windows版本的，我用的4.4版本

2.下载后，解压到你想要的文件夹就行

3.把bin目录加入环境变量，很多人都不用加，但是我不加不能用

4.用管理员权限进入bin目录

5.安装emqx

emqx install

安装成功会报成功

6.开始执行

emqx start

4.4版本执行不会报成功

7.进入后台

http://localhost:18083/

默认用户名和密码：admin public进去就能改

这就好了，可以编写python程序去运行了

8.如果要停止服务

emqx stop

如果要卸载服务，就先停止服务，在删除根目录所有内容即可。

发布端

# # python 3.8
#
import time
from paho.mqtt import client as mqtt
# client在可以发布和订阅消息之前必须要先连接到broker代理
# 连接由client发起
# broke地址
broker = "ip"
# 端口
port = 1883
 
# 消息所属话题， 消息的类型，Subscribe后，就会收到payload
# topic = '$oc/test'
# 回调客户机实例
client_id = f'user'
 
# 发布端
# 连接回调函数
 
def on_connect(client, userdata, flags, rc):
    if rc == 0:
        print("Connected to MQTT Broker!")
    else:
        print("Failed to connect, return code %d\n", rc)
 
#   断开链接回调
def on_disconnect(client, userdata, rc):
    print("Unexpected disconnection rc = " + str(rc))
    pass
 
def on_message(client, userdata, msg):
    print(msg.topic + " " + str(msg.payload))
 
#   订阅回调
def on_subscribe(client, userdata, mid, granted_qos):
    print("On Subscribed: qos = %d" % granted_qos)
    pass
 
 
#   取消订阅回调
def on_unsubscribe(client, userdata, mid, granted_qos):
    print("On unSubscribed: qos = %d" % granted_qos)
    pass
 
 
#   发布消息回调
def on_publish(client, userdata, mid):
    print("On onPublish: qos = %d" % mid)
    pass
 
# 发布消息回调
def publish(client):
    msg_count = 0
    while True:
        time.sleep(1)
        result = client.publish(topic, str(a), qos=0)
        status = result[0]
        if status == 0:
            print(f"Send `{a}` to topic `{topic}`")
        else:
            print(f"Failed to send message to topic {topic}")
        msg_count += 1
 
 
def run():
    # 初始化客户机
    client = mqtt.Client()
    # 调用连接回调函数
    client.on_connect = on_connect
    client.on_message = on_message
    client.on_publish = on_publish
    client.on_disconnect = on_disconnect
    client.on_unsubscribe = on_unsubscribe
    client.on_subscribe = on_subscribe
    # 连接
    client.connect(broker, port)
    # 启用进程保持连接
    client.loop_start()
    # client.username_pw_set(username, password=None)
    # 调用完loop之后再调用publish
    publish(client)
 
 
if __name__ == '__main__':
    run()

发布端连接代理，就是我们刚才整的emqx，topic是订阅的消息，订阅端只有订阅了该消息头才能接收到这一类的消息

订阅端

 
broker = "ip"
port = 1883
# topic = '$oc/devices/{CN}/user/rsu/info/up'
topic = '$oc/ccc'
# generate client ID with pub prefix randomly
client_id = f'user_client'
 
#   断开链接回调
def on_disconnect(client, userdata, rc):
    print("Unexpected disconnection rc = " + str(rc))
    pass
 
def on_connect(client, userdata, flags, rc):
    if rc == 0:
        print("Connected to MQTT Broker!")
    else:
        print("Failed to connect, return code %d\n", rc)
 
 
#   订阅回调
def on_subscribe(client, userdata, mid, granted_qos):
    print("On Subscribed: qos = %d" % granted_qos)
    pass
 
 
#   取消订阅回调
def on_unsubscribe(client, userdata, mid):
    print("On unSubscribed: qos = %d" % mid)
    pass
 
def on_message(client, userdata, msg):
    try:
        print(msg.topic)
        print(msg.payload.decode('utf-8'))
    # print(f"Received `{msg.payload.decode()}` from `{msg.topic}` topic")
    except:
        pass
    pass
 
 
 
def run():
    client = mqtt_client.Client(client_id)
    client.on_connect = on_connect
    client.on_unsubscribe = on_unsubscribe
    client.on_subscribe = on_subscribe
    client.connect(broker, port)
    client.subscribe(topic, qos=0)
    client.on_message = on_message  # 返回订阅消息的回调函数
    client.loop_forever()
 
 
if __name__ == '__main__':
    run()

存在问题

理论上就可以使用了，但是经过实际测试，只有在本地上使用的时候是正确的，如果我把订阅端放到另一个电脑上，双方电脑能ping通，但是在订阅端会报socket超时错误。