node.js - ESP8266 模块发布消息，但订阅者没有通过 MQTT 获得任何信息

Question

我是 IoT 和 MQTT 的新手。我有一个 ESP8266 模块，它想要连接到 Web 应用程序并向其发布消息，为此我使用模块的 pubsub 客户端库和服务器端的 NodeJs MQTT 和 HiveMQ.com 作为代理。模块可以随机成功发布消息，但订阅者（服务器端）无法获取任何消息。有什么问题？

模块

const char* ssid = "Knight";
const char* password = "0520298926";
const char* mqtt_server = "broker.hivemq.com";

WiFiClient espClient;
PubSubClient client(espClient);
unsigned long lastMsg = 0;
#define MSG_BUFFER_SIZE  (50)
char msg[MSG_BUFFER_SIZE];
int value = 0;

void setup_wifi() {

  delay(10);
  // We start by connecting to a WiFi network
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);

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

  randomSeed(micros());

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

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();

  // Switch on the LED if an 1 was received as first character
  if ((char)payload[0] == '1') {
    digitalWrite(BUILTIN_LED, LOW);   // Turn the LED on (Note that LOW is the voltage level
    // but actually the LED is on; this is because
    // it is active low on the ESP-01)
  } else {
    digitalWrite(BUILTIN_LED, HIGH);  // Turn the LED off by making the voltage HIGH
  }

}

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Create a random client ID
    String clientId = "clientId-xnHbRALbr5";
    // Attempt to connect
    if (client.connect(clientId.c_str())) {
      Serial.println("connected");
      // Once connected, publish an announcement...
      client.publish("doorphone/connected", "true");
      // ... and resubscribe
      client.subscribe("doorphone/close");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void setup() {
  pinMode(BUILTIN_LED, OUTPUT);     // Initialize the BUILTIN_LED pin as an output
  Serial.begin(115200);
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
}

void loop() {

  if (!client.connected()) {
    reconnect();
  }
  client.loop();

//  unsigned long now = millis();
// 
//    lastMsg = now;
    ++value;
    snprintf (msg, MSG_BUFFER_SIZE, "hello world #%ld", value);
    Serial.print("Publish message: ");
    Serial.println(msg);
    client.publish("doorphone/open", msg);

}

服务器端

const mqtt = require('mqtt')
var options = [{
    port: 1883,
    host: 'mqtt://broker.hivemq.com',
    clientId: '',
}];
const client = mqtt.connect('mqtt://broker.hivemq.com', options)

/**
* The state of the doorphone, defaults to closed
* Possible states : closed, opening, open, closing
*/


client.on('connect', () => {
  client.subscribe('doorphone/open')
  client.subscribe('doorphone/close')

  // Inform controllers that doorphone is connected
  client.subscribe('doorphone/connected', 'true')
})

client.on('message', (topic, message) => {
    console.log('received message %s %s', topic, message)
    switch (topic) {
        case 'doorphone/open':
          return handleOpenRequest(message)
        case 'doorphone/close':
          return handleCloseRequest(message)
        case 'doorphone/connected':
            console.log(message)
      }
})


function handleOpenRequest (message) {
    console.log('opening doorphone door %s', message)
}


function handleCloseRequest (message) {
    console.log('closing doorphone door %s', message)
}

标签： node.jstcpmqttmicrocontrolleriot