40 lines
1.6 KiB
Markdown
40 lines
1.6 KiB
Markdown
---
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author: J. Nick Koston
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authorURL: https://github.com/bdraco
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title: "Replacing `async_track_state_change` with `async_track_state_change_event`"
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---
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`async_track_state_change` is deprecated and will be removed in Home Assistant 2025.5. `async_track_state_change_event` should be used instead.
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`async_track_state_change` always creates a top-level listener for `EVENT_STATE_CHANGED`, which would have to reject all state changes that did not match the desired entities. This design presented a performance problem when there were many integrations using `async_track_state_change`. `async_track_state_change` has been phased out in `core` since the introduction of `async_track_state_change_event`, with the last instance being removed in 2024.5.
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Example with `async_track_state_change`:
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```python
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from homeassistant.core import State, callback
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from homeassistant.helper.event import async_track_state_change
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@callback
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def _async_on_change(entity_id: str, old_state: State | None, new_state: State | None) -> None:
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...
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unsub = async_track_state_change(hass, "sensor.one", _async_on_change)
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unsub()
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```
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Example replacement with `async_track_state_change_event`:
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```python
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from homeassistant.core import Event, EventStateChangedData, callback
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from homeassistant.helper.event import async_track_state_change_event
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@callback
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def _async_on_change(event: Event[EventStateChangedData]) -> None:
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entity_id = event.data["entity_id"]
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old_state = event.data["old_state"]
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new_state = event.data["new_state"]
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...
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unsub = async_track_state_change_event(hass, "sensor.one", _async_on_change)
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unsub()
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``` |