[help wanted] nothing receive after publishing message with MQTT5 properties

[oceanlvr]

Environment:

• MQTT.js version: ^4.2.8
• Node 14
• Tested on EMQX and HiveMQ broker

Dear dev, I write some demo to test publish API (with MQTT5 properties), and nothing was received when I set the IClientPublishOptions['properties']. Here is the code

const mqtt = require('mqtt')

const host = 'broker.mqttdashboard.com' // or broker.mqttdashboard.com
const port = '8000' // 8000 for broker.mqttdashboard.com
const protocol = 'ws' // ws for broker.mqttdashboard.com
const connectUrl = `${protocol}://${host}:${port}`

const clientId = `mqtt_${Math.random().toString(16).slice(3)}`

const client = mqtt.connect(connectUrl, {
  clientId,
  clean: true,
  connectTimeout: 4000,
  reconnectPeriod: 1000,
  protocolVersion: 5,
  path: '/mqtt', // for broker.mqttdashboard.com
})

const topic = '/nodejs/mqtt'

client.on('connect', () => {
  console.log('Connected')
  client.subscribe([topic], () => {
    console.log(`Subscribe to topic '${topic}'`)
    client.publish(topic, 'nodejs mqtt test', {
      qos: 2,
     // ⚠⚠ help wanted, properties affect on message event and we can't send message with properties successfully
      properties: {
        topicAlias: 'test',
      userProperties: {
        myprop: "myprop value"
      }
      },
      retain: false
    }, (error) => {
      if (error) {
        console.error(error)
      }
    })
  })
})

client.on('message', (topic, payload, packet) => {
  console.log(`=====Received Message=====
from topic: ${topic}
payload:    ${payload.toString()}
packet:     ${packet.toString()}
properties: ${packet.properties}
`)
})

publish properties affect message events and we can't send messages with properties successfully.
Nothing receives, and we expect at least a message like nodejs mqtt test, then I pub some other message on this topic, nothing receive either.

Did I miss any details? Or is it just a bug? Waiting for your reply. THANKS!! :)

Here is my test repo, please try this to get more detail:

https://github.com/oceanlvr/mqtt5-publish-props

Maybe relative:

• User properties in MQTT protocol version 5 #1303
• The IClientPublishOptions interface is missing the properties attribute #1074
• Added MQTT 5 properties object to publish options #1103

[oceanlvr]

I'm sorry to bother you, Did I miss any details? Or is it just a bug? Waiting for your reply. THANKS!! :) @YoDaMa

[oceanlvr]

I also test on MQTT.js version: 4.0.0

and Also can't send an message with properties:

const mqtt = require('mqtt')

const host = 'broker.mqttdashboard.com' // or broker.mqttdashboard.com
const port = '8000' // 8000 for broker.mqttdashboard.com
const protocol = 'ws' // ws for broker.mqttdashboard.com
const connectUrl = `${protocol}://${host}:${port}`

const clientId = `mqtt_${Math.random().toString(16).slice(3)}`

const client = mqtt.connect(connectUrl, {
  clientId,
  clean: true,
  connectTimeout: 4000,
  reconnectPeriod: 1000,
  protocolVersion: 5,
  path: '/mqtt', // for broker.mqttdashboard.com
})

const topic = '/nodejs/mqtt'

client.on('message', (topic, payload, packet) => {
  console.log(`=====Received Message=====
from topic: ${topic}
payload:    ${payload.toString()}
packet:     ${JSON.stringify(packet)}
properties: ${packet.properties}
`)
})

client.on('connect', () => {
  console.log('Connected')
  client.subscribe([topic], () => {
    console.log(`Subscribe to topic '${topic}'`)
    client.publish(topic, 'nodejs mqtt test', {
      qos: 2,
      properties: {
        topicAlias: 'test',
        userProperties: {
          myprop: "myprop value"
        }
      },
      retain: false
    }, (error) => {
      if (error) {
        console.error(error)
      }
    })
  })
})

result

---

after delete properties:

client.on('connect', () => {
  console.log('Connected')
  client.subscribe([topic], () => {
    console.log(`Subscribe to topic '${topic}'`)
    client.publish(topic, 'nodejs mqtt test', {
      qos: 2,
-      properties: {
-      topicAlias: 'test',
-      userProperties: {
-      myprop: "myprop value"
-      }
-     },
      retain: false
    }, (error) => {
      if (error) {
        console.error(error)
      }
    })
  })
})

Message send normally.

[YoDaMa]

@oceanlvr thanks for your patience. looking at this issue now.

There is a bug in the typings of topicAlias, it should be a number. This is fixed in this PR: https://github.com/mqttjs/MQTT.js/pull/1359/files

So make sure to use a number for your topicAlias.

[YoDaMa]

@oceanlvr did you find this solved?

[oceanlvr]

Yes, problem solved! :)