Subscribe & Unsubscribe - stodev-com-br/tasmota GitHub Wiki

  » v6.5.0

This feature is not included in precompiled binaries.
To use it you must compile your build. Add the following to user_config_override.h:

#ifndef SUPPORT_MQTT_EVENT
#define SUPPORT_MQTT_EVENT
#endif

Subscribes to an MQTT topic and assigns an Event name to it.

Subscribe <eventName>, <mqttTopic> [, <key>]

The command without any parameters will list all currently subscribed topics.

The <key> parameter is optional. It is specified to parse a key/value pair from a JSON payload in the MQTT message. In order to parse a value from a multi-level JSON pair, you can use one dot (.) syntax to split the key into sections. You can subscribe a MQTT topic and assign an event name. Once we received subscribed MQTT message, an event will be automatically triggered. So you can set up a rule with ON EVENT#<event_name> DO ... ENDON to do whatever you want based on this MQTT message. The payload is passed as a parameter once the event has been triggered. If the payload is in JSON format, you are able to get the value of specified key as a parameter.

For example, if you have a Tasmota based thermostat and multiple temperature sensors in different locations, usually you have to set up a home automation system like Domoticz to control the thermostat. Right now, with this new feature, you can write a rule to do this.

Examples:

Rule1
  ON mqtt#initialized DO Subscribe BkLight, stat/%topic%/POWER ENDON
  ON Event#BkLight=ON DO <command> ENDON

Rule1
  ON mqtt#initialized DO Subscribe DnTemp, stat/%topic%/SENSOR, DS18B20.Temperature ENDON
  ON Event#DnTemp>=21 DO <command> ENDON

where the MQTT message payload is `{"Time":"2017-02-16T10:13:52", "DS18B20":{"Temperature":20.6}}`

Unsubscribe from topics which were subscribed to using the Subscribe command.

Unsubscribe from a specific MQTT topic
Unsubscribe <eventName>

The command without a parameter will unsubscribe from all currently subscribed topics.