Azure topic and sending message over MQTT

Question

Is it possible to send messages to azure to any custom topic via mqtt. All example that I've found so far work with standard topics

'devices/' + hubName + '/messages/events/'
'devices/' + hubName + '/messages/devicebound/#'

Btw, I tried to send/subscribe on the topic/subscription above with MQTT.fx application and never received messages, although the connection was successful.

What did you mean about 'never received messages'? Did it mean that the back end can not receive the messages which sent from MQTT.fx(Device-To-Cloud), or MQTT.fx can not receive the messages which sent from service(Cloud-To-Device)? — Michael Xu - MSFT
MQTT.fx being subscribed on devices/mydevice/messages/devicebound/#, never received messages sent from MQTT.fx to devices/mydevice/messages/events/ (I use the application as sender and receiver). Connection is established (green light turned on) — amplifier

Michael Xu - MSFT Michael Xu - MSFT · Accepted Answer · 2018-07-03T02:24:38

The topic filter of devices/{device_id}/messages/devicebound/# is to subscribe receiving message from IoT Hub(Cloud-To-Device message), it think you need to understand the difference about device-to-cloud message and cloud-to-device message from here. The topic of devices/{device_id}/messages/events/ is for sending a device-to-cloud message from device.

You can use Device Explorer to test this issue. When you send a message to device with the tool, MQTT.fx will receive the message.

Azure topic and sending message over MQTT

1 Answers