Step 13: Update documentation for skinning

pull/21833/head
Travis Ralston 2022-03-28 15:17:40 -06:00
parent ea6e6429ee
commit bd1fd0a734
3 changed files with 14 additions and 74 deletions

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@ -65,10 +65,6 @@ practices that anyone working with the SDK needs to be be aware of and uphold:
component is a view or a structure, and then a broad functional grouping
(e.g. 'rooms' here)
* After creating a new component you must run `yarn reskindex` to regenerate
the `component-index.js` for the SDK (used in future for skinning)
<!-- TODO: Remove this once this approach to skinning is replaced -->
* The view's CSS file MUST have the same name (e.g. view/rooms/MessageTile.css).
CSS for matrix-react-sdk currently resides in
https://github.com/vector-im/element-web/tree/master/src/skins/vector/css/matrix-react-sdk.
@ -158,9 +154,6 @@ cd matrix-react-sdk
git checkout develop
yarn link matrix-js-sdk
yarn install
# Generate the `component-index.js` file.
yarn reskindex
```
See the [help for `yarn link`](https://classic.yarnpkg.com/docs/cli/link) for

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@ -1,71 +1,18 @@
# Skinning
The react-sdk can be skinned to replace presentation components, CSS, or
other relevant parts of the SDK. Typically consumers will replace entire
components and get the ability for custom CSS as a result.
Skinning in the context of the react-sdk is component replacement rather than CSS. This means you can override (replace)
any accessible component in the project to implement custom behaviour, look & feel, etc. Depending on your approach,
overriding CSS classes to apply custom styling is also possible, though harder to do.
This doc isn't exhaustive on how skinning works, though it should cover
some of the more complicated parts such as component replacement.
At present, the react-sdk offers no stable interface for components - this means properties and state can and do change
at any time without notice. Once we determine the react-sdk to be stable enough to use as a proper SDK, we will adjust
this policy. In the meantime, skinning is done completely at your own risk.
## Loading a skin
The approach you take is up to you - we suggest using a module replacement plugin, as found in
[webpack](https://webpack.js.org/plugins/normal-module-replacement-plugin/), though you're free to use whichever build
system works for you. The react-sdk does not have any particular functions to call to load skins, so simply replace or
extend the components/stores/etc you're after and build. As a reminder though, this is done completely at your own risk
as we cannot guarantee a stable interface at this time.
1. Generate a `component-index.js` (preferably using the tools that the react-sdk
exposes). This can typically be done with a npm script like `"reskindex -h src/header"`.
2. In your app's entry point, add something like this code:
```javascript
import {loadSkin} from "matrix-react-sdk";
loadSkin(import("component-index").components);
// The rest of your imports go under this.
```
3. Import the remainder of the SDK and bootstrap your app.
It is extremely important that you **do not** import anything else from the
SDK prior to loading your skin as otherwise the skin might not work. Loading
the skin should be one of the first things your app does, if not the very
first thing.
Additionally, **do not** provide `loadSkin` with the react-sdk components
themselves otherwise the app might explode. The SDK is already aware of its
components and doesn't need to be told.
## Replacing components
Components that replace the react-sdk ones MUST have a `replaces` static
key on the component's class to describe which component it overrides. For
example, if your `VectorAuthPage` component is meant to replace the react-sdk
`AuthPage` component then you'd add `static replaces = 'views.auth.AuthPage';`
to the `VectorAuthPage` class.
Other than that, the skin just needs to be loaded normally as mentioned above.
Consumers of the SDK likely will not be interested in the rest of this section.
### SDK developer notes
Components in the react-sdk MUST be decorated with the `@replaceableComponent`
function. For components that can't use the decorator, they must use a
variation that provides similar functionality. The decorator gives consumers
an opportunity to load skinned components by abusing import ordering and
behaviour.
Decorators are executed at import time which is why we can abuse the import
ordering behaviour: importing `loadSkin` doesn't trigger any components to
be imported, allowing the consumer to specify a skin. When the consumer does
import a component (for example, `MatrixChat`), it starts to pull in all the
components via `import` statements. When the components get pulled in the
decorator checks with the skinned components to see if it should be replacing
the component being imported. The decorator then effectively replaces the
components when needed by specifying the skinned component as an override for
the SDK's component, which should in theory override critical functions like
`render()` and lifecycle event handlers.
The decorator also means that older usage of `getComponent()` is no longer
required because components should be replaced by the decorator. Eventually
the react-sdk should only have one usage of `getComponent()`: the decorator.
The decorator assumes that if `getComponent()` returns null that there is
no skinned version of the component and continues on using the SDK's component.
In previous versions of the SDK, the function would throw an error instead
because it also expected the skin to list the SDK's components as well, however
that is no longer possible due to the above.
In short, components should always be `import`ed.
Taking a look at [element-web](https://github.com/vector-im/element-web)'s approach to skinning may be worthwhile, as it
overrides some relatively simple components.

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@ -254,7 +254,7 @@ legend {
}
// These are magic constants which are excluded from tinting, to let themes
// (which only have CSS, unlike skins) tell the app what their non-tinted
// (which only have CSS) tell the app what their non-tinted
// colourscheme is by inspecting the stylesheet DOM.
//
// They are not used for layout!!