48 lines
3.0 KiB
Markdown
48 lines
3.0 KiB
Markdown
---
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title: Image entity
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sidebar_label: Image
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---
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An image entity can display a static image. Derive a platform entity from [`homeassistant.components.image.ImageEntity`](https://github.com/home-assistant/core/blob/dev/homeassistant/components/image/__init__.py).
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The image entity is a simplified version of the [`camera`](/docs/core/entity/camera) entity, and supports serving a static image or an image URL that can be fetched.
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An implementation can provide either a URL from where an image will automatically be fetched or image data as `bytes`. When providing a URL, the fetched image will be cached in `self._cached_image`, set `self._cached_image` to `None` to invalidate the cache.
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## Properties
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:::tip
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Properties should always only return information from memory and not do I/O (like network requests). Implement `update()` or `async_update()` to fetch data.
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:::
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| Name | Type | Default | Description |
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| -------------------| --------------------------------- | ------------ | -------------------------------------------------------------------------------------------------------- |
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| content_type | str | `image/jpeg` | The content-type of the image, set automatically if the image entity provides a URL. |
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| image_last_updated | <code>datetime.datetime | None</code> | `None` | Timestamp of when the image was last updated. Used to determine `state`. Frontend will call `image` or `async_image` after this changes. |
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| image_url | <code>str | None</code> | `UNDEFINED` | Optional URL from where the image should be fetched. |
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## Methods
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### Image
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Implement `async_image` or `image` if your entity returns bytes of the image instead of providing a URL. Frontend will call `async_image` or `image` to fetch the image. If the image is fetched remotely, image data should be cached and the cache invalidated when `image_last_updated` is changed.
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Note that:
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- The image entity's `async_image` or `image` method is only called when frontend fetches the image.
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- Frontend will:
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- Fetch the image once when a page with an image entity is loaded
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- Refetch the image when the image entity's state changed by the image entity changing `image_last_updated`
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This means it's incorrect to bump the `image_last_updated` property inside `async def async_image`. Instead, the image entity should, when an updated image is available or periodically if the image should be refetched after some time, update the `image_last_updated` timestamp. This can for example happen as part of an entity coordinator update.
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```python
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class MyImage(ImageEntity):
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# Implement one of these methods.
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def image(self) -> bytes | None:
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"""Return bytes of image."""
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async def async_image(self) -> bytes | None:
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"""Return bytes of image."""
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```
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