mqtt 代理中的數據解析

Question

我有一個 python 代碼，用於從 mqtt 訂閱者接收數據。來自 mqtt 訂閱者的消息根據收到的字符串作為字符串發送，我正在處理結果。 但是代碼每次都只針對 else 情況。

    import paho.mqtt.client as mqtt
    MQTT_ADDRESS = '192.168.103.5'
    MQTT_USER = 'user'
    MQTT_PASSWORD = '12345678'
    MQTT_TOPIC = 'home/+/+'
    def on_connect(client, userdata, flags, rc):
        """ The callback for when the client receives a CONNACK response from the server."""
        print('Connected with result code ' + str(rc))
        client.subscribe(MQTT_TOPIC)
    candidate1 = 0
    candidate2 = 0
    candidate3 = 0
    total_count = 0
    def on_message(client, userdata, msg):
        """The callback for when a PUBLISH message is received from the server."""
        global candidate1
        global candidate2
        global candidate3
        global total_count
        print(msg.topic + ' ' + str(msg.payload))
        msg1 = "Candidate1:"
        print(msg1)
        rx_msg = str(msg.payload)
        print(rx_msg)
        msg2 = "Candidate2:"
        print(msg2)
        total_count = total_count + 1
        f_total = open("total_count.txt","w")
        f_total.write(str(total_count))
        f_total.close()
        if msg1 == rx_msg:
            candidate1 = candidate1+1
            f_c1 = open("candidate1.txt","w")
            f_c1.write(str(candidate1))
            f_c1.close()
        elif msg2 == rx_msg:
            candidate2 = candidate2+1
            f_c2 = open("candidate2.txt","w")
            f_c2.write(str(candidate2))
            f_c2.close()
        else:
            candidate3 = candidate3+1
            f_c3 = open("candidate3.txt","w")
            f_c3.write(str(candidate3))
            f_c3.close()
    
    
    def parse_message(msg):
        """This callback parses input is received"""
    
    def main():
        mqtt_client = mqtt.Client()
        mqtt_client.username_pw_set(MQTT_USER, MQTT_PASSWORD)
        mqtt_client.on_connect = on_connect
        mqtt_client.on_message = on_message
    
        mqtt_client.connect(MQTT_ADDRESS, 1883)
        mqtt_client.loop_forever()
    
    
    if __name__ == '__main__':
        print('MQTT to InfluxDB bridge')
        main()

代碼有什么問題嗎？

Answer 1

我運行代碼，你的所有問題都是

 str(msg.payload)

它將字節轉換為帶有前綴b和' '字符串，例如b'Candidate1:' ， b'Candidate2:'

你應該使用

 msg.payload.decode()

---

坦率地說，我不知道你為什么沒有看到print(msg.topic + ' ' + str(msg.payload)給出類似的東西

 home/x/x b'Candidate1:'