NodeJS-订阅所有MQTT主题

Question

我使用的是NodeJS的mqtt模块。一切正常，即发布、订阅特定主题、处理连接错误等。问题是，当我尝试订阅所有主题时，通常以client.subscribe('#',callback)的形式完成，它不订阅任何主题。

这是相关代码：

// Connecting to a specific topic
client = mqtt.connect(broker,options)
console.log("MQTT Connected")
client.on('connect',()=>{
client.subscribe('mytopic/topic1',(err,granted)=>{
if(err){
console.log(err)
}
console.log(granted)
console.log("Subscribed to mytopic/topic1")
})
listenIncoming()
})
client.on('error',err=>{
console.log("ERROR in MQTT: ",err)
})

订阅所有主题的代码：

client = mqtt.connect(broker,options)
console.log("MQTT Connected")
client.on('connect',()=>{
client.subscribe('#',(err,granted)=>{
if(err){
console.log(err)
}
console.log(granted)
console.log("Subscribed to all topics")
})
listenIncoming()
})
client.on('error',err=>{
console.log("ERROR in MQTT: ",err)
})

这就是listenIncoming()函数，它在收到消息时打印出消息：

function listenIncoming(){
client.on('message',(topic,payload,packet)=>{
var topics = subscribedTopics
console.log(topics,payload) //prints it when specific topic is subscribed. Doesn't when subscribing to '#'
})
}

如何使用此订阅所有主题？我使用的经纪人是hivemq(mqtt://broker.hivemq.com)

Answer 1

不允许在broker.hivemq.com上订阅#。

通过使用mosquitto_sub可以看出

$ mosquitto_sub -v -t '#' -h broker.hivemq.com
All subscription requests were denied.

或者，您的代码显示了128的qos(来自规范(。

$ node test.js 
MQTT Connected
[ { topic: '#', qos: 128 } ]
Subscribed to all topics