Implement entity area property

Testing with Home Assistant 2023.3.6 There doesn't seem an easy way anymore to get the area of an entity.

Get areas:

{
    "type": "config/area_registry/list",
    "id": 4
}

Result (sample):

{
    "id": 4,
    "type": "result",
    "success": true,
    "result": [
        {
            "aliases": [],
            "area_id": "living_room",
            "name": "Living Room",
            "picture": null
        },
        {
            "aliases": [],
            "area_id": "kitchen",
            "name": "Kitchen",
            "picture": null
        },
        {
            "aliases": [],
            "area_id": "bedroom",
            "name": "Bedroom",
            "picture": null
        }
    ]
}

So far so good. But how do we get the entities in an area_id?

There's the entity registry:

{
    "type": "config/entity_registry/list",
    "id": 5
}

Result (sample):

        {
            "area_id": null,
            "config_entry_id": "18c9ecbd442b0fad06359ece6efe4bbe",
            "device_id": "3d293c15b9646fa6ee3c4659a3b17317",
            "disabled_by": null,
            "entity_category": null,
            "entity_id": "light.esstisch",
            "has_entity_name": false,
            "hidden_by": null,
            "icon": null,
            "id": "f5bb2da87a4a4de5ea257d282d672f96",
            "name": null,
            "options": {},
            "original_name": "Esstisch",
            "platform": "hue",
            "translation_key": null,
            "unique_id": "3fd17309-9d07-4b50-8e6c-a8b78d20e84a"
        }

Buth light.esstisch is in a defined area:

Interestingly the manually defined power switch to control a Sonos speaker has an area:

        {
            "area_id": "essen",
            "config_entry_id": null,
            "device_id": null,
            "disabled_by": null,
            "entity_category": null,
            "entity_id": "switch.mystrom_switch",
            "has_entity_name": false,
            "hidden_by": null,
            "icon": null,
            "id": "00212855345302ed74851d23db636556",
            "name": "Sonos Esstisch",
            "options": {},
            "original_name": "myStrom Switch",
            "platform": "mystrom",
            "translation_key": null,
            "unique_id": "30AEA491D184"
        }

This doesn't seem to work: from my 100+ entities all except 3 return "area_id": null 👎 But I have assigned many many more entities to areas! Where are they? I remember that retrieving the area was working about 3+ years ago when we were implementing the onboarding for the YIO remote...

Looks like that quite a few things have changed. My current understanding:

entities belonging to devices. The device is linked to an area. This seems to be the standard case.
entities can also be directly linked to areas

Only example I've found: https://developers.home-assistant.io/docs/frontend/custom-ui/custom-strategy/#full-example

Then let's try with the device registry:

{
    "type": "config/device_registry/list",
    "id": 6
}

Bingo! area_id for the light.esstisch entity with device_id: 3d293c15b9646fa6ee3c4659a3b17317 shown above is finally set:

        {
            "area_id": "essen",
            "configuration_url": null,
            "config_entries": [
                "18c9ecbd442b0fad06359ece6efe4bbe"
            ],

            "id": "3d293c15b9646fa6ee3c4659a3b17317",

            "name": "Esstisch",
            "sw_version": "1.101.2",
            "via_device_id": "ee5dbf4b9197e2863380054b26dcc3ed"
        },

So, no more easy way to get the area, now we have an additional indirection to deal with...

unfoldedcircle / integration-home-assistant

Implement entity area property #2