MQTT for Clarion

1

I have a client that needs our app to communicate to their field units via MQTT. Has anyone dealt with MQTT from Clarion before?

Thanks
Matthys

2

libcurl supports mqtt protocol.

3

Thanks Mike, I didn’t know that libcurl supports it. I’ll look at your libcurl repo on GitHub to see how it can be done.

4

MQTT in curl

Usage

A plain “GET” subscribes to the topic and prints all published messages.
Doing a “POST” publishes the post data to the topic and exits.

Example subscribe:

curl mqtt://host.home/bedroom/temp

Example publish:

curl -d 75 mqtt://host.home/bedroom/dimmer

What does curl deliver as a response to a subscribe

It outputs two bytes topic length (MSB | LSB), the topic followed by the
payload.

Caveats

Remaining limitations:

  • Only QoS level 0 is implemented for publish
  • No way to set retain flag for publish
  • No TLS (mqtts) support
  • Naive EAGAIN handling will not handle split messages
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5

Hi Mike,

Can a call to LibCurl work inside a IDLE() hook procedure ?

6

I never tried that, I’m sure you are able to check it yourself.

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7

I’ve used the Mosquitto libraries in C6

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