Python 脚本没有在树莓派上显示 nodemcu 数据（树莓派角色是 mqtt 代理）

Question

对不起，我的英语不好。 我在树莓派 3 上安装 mqtt(mosquitto) 并将 nodemcu 数据发送到代理。当我在终端中编写“mosquitto_sub -d -t tester”时，它会显示 nodemcu 数据，但我有一个 python3 脚本在我运行时运行但不显示任何内容，我不知道是什么问题

nodemcu 代码：

#include <ESP8266WiFi.h> 
#include <PubSubClient.h> 

const char* ssid = "ssid";
const char* wifi_password = "wifi_password";


const char* mqtt_server = "192.168.1.103";
const char* mqtt_topic = "/tmp/room";
const char* clientID = "123";

WiFiClient wifiClient;
PubSubClient client(mqtt_server, 1883, wifiClient); 

void setup() {
  Serial.begin(115200);

  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.begin(ssid, wifi_password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("WiFi connected");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());

  if (client.connect(clientID)) {
    Serial.println("Connected to MQTT Broker!");
  }
  else {
    Serial.println("Connection to MQTT Brokers pressed down");
    // (i.e. if the state of the b failed...");
  }

}

void loop() {
 char ldr_value [10] = {'b', 'd', 'l', 't', 'd'};

  delay(5000);
  client.publish(mqtt_topic, ldr_value);
}

python3 脚本：

    import paho.mqtt.client as mqtt
    mqtt_topic = "/tmp/room"
    mqtt_broker_ip = "localhost"
    client = mqtt.Client()

    def on_connect(client, userdata, rc):
        print("Connected!", str(rc))
        client.subscribe(mqtt_topic)

    def on_message(client, userdata, msg):
        print("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))

    client.on_connect = on_connect
    client.on_message = on_message
    client.connect(mqtt_broker_ip, 1883)
    client.loop_forever()
    client.disconnect()

我删除了 include_dir 行 /etc/mosquitto/mosquitto.conf 并编写 linstener 1883

我的操作系统：2018-11-13-raspbian-stretch

Answer 1

您使用的 on_connect 方法不正确。我已经修改了您的代码并对其进行了测试。它的工作原理

import paho.mqtt.client as mqtt

client = mqtt.Client("123")

def on_connect(client, userdata, flags, rc):
  print("Connected!", str(rc))
  client.subscribe("test")

def on_message(client, userdata, msg):
   print("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))

client.on_connect = on_connect
client.on_message = on_message
client.connect("localhost", 1883, 60)
client.loop_forever()