curl/docs/MQTT.md

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:

• No username support
• Only QoS level 0 is implemented for publish
• No way to set retain flag for publish
• No username/password support
• No TLS (mqtts) support
• Naive EAGAIN handling won't handle split messages

Work

1. Write a mqtt server for the test suite
2. Create a few tests verifying the existing mqtt functionality
3. Work on fixing some of the worst limitations - with accompanying tests
4. Consider replacing the client-side MQTT code with wolfMQTT

Credits

The initial MQTT patch was authored by Björn Stenberg. This work is built upon that patch and has been expanded since.