1
0
mirror of https://github.com/moparisthebest/curl synced 2024-12-24 17:18:48 -05:00
curl/docs/MQTT.md
JP Mens 19ec94d944
docs/MQTT: replace confusing 80 by 75
I was a bit surprised by the `80`: first thought: what's HTTP doing
here? ;)

Closes #5236
2020-04-14 23:08:43 +02:00

62 lines
1.7 KiB
Markdown

# MQTT in curl
## Experimental!
MQTT support in curl is considered **EXPERIMENTAL** until further notice. It
needs to be enabled at build-time. See below.
After the initial merge, further development and tweaking of the MQTT support
in curl will happen in the master branch using pull-requests, just like
ordinary changes.
Experimental support for MQTT means that we **do not guarantee** that the
current protocol functionality will remain or remain this way going forward.
There are no API or ABI promises for experimental features as for regular curl
features.
Do not ship anything with this enabled.
## Build
./configure --enable-mqtt
## 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.