Subscribe to events trough REST API

Setup, Configuration and Use Scripts & Rules
1

Hi, I’m working on an node.js module for heating control in our house. Now it is working with a “polling” concept where all relevant items (thermostats, temp sensors, etc) are checked every minute.

I’ve started to add event driven actions - and subscribing to item events is pretty much straight forward with "/rest/events?topics=smarthome/items/{itemName}

The next step is to subscribe to events from all members of a group (eg. all temp sensors and thermostats), but I am not able to find out how to do this trough the REST API. What I am looking for is something like the “Member of {groupName} changed” in the built in rules engine.

Thanks

Olav

2

OpenHAB 2 or 3?

3

OpenHAB 2

4

@Spaceman_Spiff does that with HABApp in Python 3. Perhaps he has some tips.

5

You have to subscribe to the group item and then you should get the corresponding events through the API.
Probably you have to subscribe to the group members as well …

1 Like
6

Thanks for the guiding.

After some more investigation, I found the following:

  • A group which is defined without itemtype (and function) will not emit any events.
  • After I defined the aThermostat group like this:
    “Group:Number:SUM gThermostats”, a group event is emitted when the sum of values for all group items are changed

Source for the information: Items | openHAB

The path to the event(s): /rest/events?topics=smarthome/items/gThermostats

Example of event:
{
topic: ‘smarthome/items/gThermostats/Thermostat_Kitchen_Room/statechanged’,
payload: ‘{“type”:“Decimal”,“value”:“30”,“oldType”:“Decimal”,“oldValue”:“40”}’,
type: ‘GroupItemStateChangedEvent’
}

Thanks to all

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