Fire Home Assistant events

[lisz8]

I know no card that can directly trigger Home Assistant events, like:

- event: name_of_event
  event_data: [optional data]

Is it because it's completely impossible? Or maybe there is some "javascript hack" we could use in a custom button - or even make it a separate action?

[RomRider]

AFAIK, this is not exposed in frontend directly but you can call a script which will fire the event.

[lisz8]

I see, it's a pity :) Script – yes, but the event name can't be a variable, so a new script is needed for each event. So I hoped we could create a generic method in a custom button.

[lisz8]

I found a method that I think is good enough: rest_command. Unlike a script, a single command covers all possible events with all possible data.

1. First you need to create a long lived access token and put it into secrets.yaml, e.g.
   events: Bearer your_very_long_access_token
2. Next, rest command:

event:
  url: "http://localhost:8123/api/events/{{ ev_name }}"
  content_type: 'application/json'
  verify_ssl: false
  headers:
    authorization: !secret events
    content-type: 'application/json'
  method: 'post'
  payload: "{{ ev_data|default({},true)|to_json }}"

Important: if configured with an SSL certificate, the URL should look like this: "https://localhost/api/events/{{ env_name }}"
This rest_command requires 2 parameters: ev_name (string) and optionally ev_data (object/dictionary). Now you can fire events from cards, with any name and data:

tap_action:
  action: perform-action
  perform_action: rest_command.event
  data:
    ev_name: my_super_event
    ev_data:
      field1: value1
      field2:
        - element1
        - element2

Or javascript action:

tap_action:
  action: javascript
  javascript: |
    [[[
      let data = {
        ev_name: 'my_super_event',
        ev_data: {
          field1: 'value1',
          field2: ['element1','element2'],
        }
      };
      hass.callService('rest_command','event', data);
    ]]]