javascript - 如何在nodeJS中使用 mqtt.Client(streamBuilder, options) 构造函数

Question

我正在尝试使用 npm 包“mqtt.js”构建简单的 MQTT 应用程序。我尝试过 mqtt.connect() 构造函数，它工作正常，但我想探索 MQTT 的更多功能，因此我想使用 mqtt.client() 构造函数。官方文档没有示例，所以我很困惑。 这是我到目前为止所尝试过的
var mqtt = require('mqtt')

客户端1:-

var mqtt = require('mqtt')

client = mqtt.connect('http://localhost:1883',{clientId :'client1', clean: false});

  client.on('connect', function () {
    client.subscribe('presence',{QoS:2});
    client.subscribe('offline',{QoS:2});
    console.log('connected');
  });
  client.on('message', function (topic, message) {
    console.log(message.toString());
  });

客户端2:-

var mqtt = require('mqtt')

client = mqtt.connect('http://localhost:1883',{clientId :'client2', clean: false,will:{topic:'offline',payload:'off',qos:2}});

   client.on('connect', function () {
    client.publish('presence', '{message:hello,id:1}',{QoS:2});

  });

任何例子都会有帮助。
谢谢。

Answer 1

您可以直接在 connect() 调用中传递客户端连接选项，如以下代码片段所示:

// Connect with unique clientId and set clean to false, so as to receive any
// missed QOS 1 or 2 messages received at broker when this worker was down.
this.MqttClient = mqtt.connect(this.tls_url,{clientId : this.myClientId, clean: false});

this.MqttClient.on('connect', function(connack){
    // do stufff       
});