diff --git a/docs/internals/MQTT.md b/docs/internals/MQTT.md index a1bc4b349e..58a3585662 100644 --- a/docs/internals/MQTT.md +++ b/docs/internals/MQTT.md @@ -9,19 +9,35 @@ SPDX-License-Identifier: 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. + +### Subscribing +Command usage: + + curl mqtt://host/topic + Example subscribe: curl mqtt://host.home/bedroom/temp +This will send an MQTT SUBSCRIBE packet for the topic `bedroom/temp` and listen in for incoming PUBLISH packets. + +### Publishing +Command usage: + + curl -d payload mqtt://host/topic + Example publish: curl -d 75 mqtt://host.home/bedroom/dimmer +This will send an MQTT PUBLISH packet to the topic `bedroom/dimmer` with the payload `75`. + ## What does curl deliver as a response to a subscribe -It outputs two bytes topic length (MSB | LSB), the topic followed by the +Whenever a PUBLISH packet is received, curl outputs two bytes topic length (MSB | LSB), the topic followed by the payload. ## Caveats