Add possibility to send an empty payload

[henriksvensson]

Problem or use case

I'm using mqtt-cli to communicate with a device running the Tasmota firmware. One feature of Tasmota is the ability to request a status update by sending an empty message to a command topic, see Tasmota MQTT documentation.

From what I understand of mqtt-cli, it is not possible to send and empty payload to a topic, though it seems supported by MQTT brokers. It would be great to be able to do this!

Preferred solution or suggestions

Maybe the most straight-forward solution would be to let the -m parameter on the pub command be optional and send an empty payload if not set. Another option could be to add another parameter --no-message or similar to make it explicit that this is actually what the user wishes to do.

Thanks for a great tool!

[gitseti]

Hi @henriksvensson & thank you for your request! :)

Have you tried mqtt pub -t topic -m "" -h <your-broker-address>?

[henriksvensson]

Hi @gitseti and thanks for a quick reply! I did try it and failed yesterday, but when I ran it again just know it works as expected. My bad, PEBKAC =).

Thanks again for a great tool!