「树莓派玩转物联网」之树莓派连接「百度天工」测试

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预安装环境

本工程需要使用Python 3以上版本。本工程在Windows、Linux和Mac上均可运行。

下载项目文件

从http://iot-demo.cdn.bcebos.com/SampleCode/TestMQTTPython.zip处下载工程文件，并解压至磁盘。

• 问题1
  pi@raspberrypi:~/TestMQTTPython$ python server.py
  Traceback (most recent call last):
  File “server.py”, line 1, in
  import paho.mqtt.client as mqtt
  ImportError: No module named paho.mqtt.client

• 解决办法：pip install paho-mqtt==1.2

• 问题2
  

• 解决办法：msg = str(msg.payload, ‘utf-8’)，改为msg = str(msg.payload)，再次运行python server.py ，如下图

总结

通过MQTT.FX客户端给云端百度云天工发送消息，能够转发至Raspberry Pi。

以下代码，实现了对百度云天工-该主题（demoTopic）的subscribe。

import paho.mqtt.client as mqtt
import sys
import uuid

broker = 'iotfreetest.mqtt.iot.gz.baidubce.com'
port = 1883
username = 'iotfreetest/thing01'
password = 'YU7Tov8zFW+WuaLx9s9I3MKyclie9SGDuuNkl6o9LXo='
clientid = 'test_mqtt_python_' + str(uuid.uuid4())
topic = 'demoTopic'

def on_connect(client, userdata, rc):
    print('Connected. Client id is: ' + clientid)
    client.subscribe(topic)
    print('Subscribed to topic: ' + topic)

    client.publish(topic, 'Message from Baidu IoT demo')
    print('MQTT message published.')

def on_message(client, userdata, msg):
    msg = str(msg.payload, 'utf-8')
    print('MQTT message received: ' + msg)
    if msg == 'exit':
        sys.exit()

client = mqtt.Client(clientid)
client.on_connect = on_connect
client.on_message = on_message
client.username_pw_set(username, password)

print('Connecting to broker: ' + broker)
client.connect(broker, port)

client.loop_forever()