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Update settings documentation for features

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Travis Ralston 2020-08-17 13:32:33 -06:00
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docs/settings.md
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@ -9,13 +9,13 @@ of dealing with the different levels and exposes easy to use getters and setters
## Levels
Granular Settings rely on a series of known levels in order to use the correct value for the scenario. These levels, in
order of prioirty, are:
order of priority, are:
* `device` - The current user's device
* `room-device` - The current user's device, but only when in a specific room
* `room-account` - The current user's account, but only when in a specific room
* `account` - The current user's account
* `room` - A specific room (setting for all members of the room)
* `config` - Values are defined by the `settingDefaults` key (usually) in `config.json`
* `config` - Values are defined by the `settingDefaults` key (usually) in `config.tson`
* `default` - The hardcoded default for the settings
Individual settings may control which levels are appropriate for them as part of the defaults. This is often to ensure
@ -25,33 +25,10 @@ that room administrators cannot force account-only settings upon participants.
## Settings
Settings are the different options a user may set or experience in the application. These are pre-defined in
`src/settings/Settings.js` under the `SETTINGS` constant and have the following minimum requirements:
```
// The ID is used to reference the setting throughout the application. This must be unique.
"theSettingId": {
// The levels this setting supports is required. In `src/settings/Settings.js` there are various pre-set arrays
// for this option - they should be used where possible to avoid copy/pasting arrays across settings.
supportedLevels: [...],
`src/settings/Settings.ts` under the `SETTINGS` constant, and match the `ISetting` interface as defined there.
// The default for this setting serves two purposes: It provides a value if the setting is not defined at other
// levels, and it serves to demonstrate the expected type to other developers. The value isn't enforced, but it
// should be respected throughout the code. The default may be any data type.
default: false,
// The display name has two notations: string and object. The object notation allows for different translatable
// strings to be used for different levels, while the string notation represents the string for all levels.
displayName: _td("Change something"), // effectively `displayName: { "default": _td("Change something") }`
displayName: {
"room": _td("Change something for participants of this room"),
// Note: the default will be used if the level requested (such as `device`) does not have a string defined here.
"default": _td("Change something"),
}
}
```
Settings that support the config level can be set in the config file under the `settingDefaults` key (note that some settings, like the "theme" setting, are special cased in the config file):
Settings that support the config level can be set in the config file under the `settingDefaults` key (note that some
settings, like the "theme" setting, are special cased in the config file):
```json
{
...
@ -119,38 +96,29 @@ for you. If a display name cannot be found, it will return `null`.
## Features
Occasionally some parts of the application may be undergoing testing and are not quite production ready. These are
commonly known to be behind a "labs flag". Features behind lab flags must go through the granular settings system, and
look and act very much normal settings. The exception is that they must supply `isFeature: true` as part of the setting
definition and should go through the helper functions on `SettingsStore`.
Feature flags are just like regular settings with some underlying semantics for how they are meant to be used. Usually
a feature flag is used when a portion of the application is under development or not ready for full release yet, such
as new functionality or experimental ideas. In these cases, the feature name *should* be named with the `feature_*`
convention and must be tagged with `isFeature: true` in the setting definition. By doing so, the feature will automatically
appear in the "labs" section of the user's settings.
Although features have levels and a default value, the calculation of those options is blocked by the feature's state.
A feature's state is determined from the `SdkConfig` and is a little complex. If `enableLabs` (a legacy flag) is `true`
then the feature's state is `labs`, if it is `false`, the state is `disable`. If `enableLabs` is not set then the state
is determined from the `features` config, such as in the following:
Features can be controlled at the config level using the following structure:
```json
"features": {
"feature_lazyloading": "labs"
"feature_lazyloading": true
}
```
In this example, `feature_lazyloading` is in the `labs` state. It may also be in the `enable` or `disable` state with a
similar approach. If the state is invalid, the feature is in the `disable` state. A feature's levels are only calculated
if it is in the `labs` state, therefore the default only applies in that scenario. If the state is `enable`, the feature
is always-on.
Once a feature flag has served its purpose, it is generally recommended to remove it and the associated feature flag
checks. This would enable the feature implicitly as it is part of the application now.
When `true`, the user will see the feature as enabled. Similarly, when `false` the user will see the feature as disabled.
The user will only be able to change/see these states if `showLabsSettings: true` is in the config.
### Determining if a feature is enabled
A simple call to `SettingsStore.isFeatureEnabled` will tell you if the feature is enabled. This will perform all the
required calculations to determine if the feature is enabled based upon the configuration and user selection.
Call `SettingsStore.getValue()` as you would for any other setting.
### Enabling a feature
Features can only be enabled if the feature is in the `labs` state, otherwise this is a no-op. To find the current set
of features in the `labs` state, call `SettingsStore.getLabsFeatures`. To set the value, call
`SettingsStore.setFeatureEnabled`.
Call `SettingsStore.setValue("feature_name", null, SettingLevel.DEVICE, true)`.
## Setting controllers
@ -162,7 +130,7 @@ kept up to date with the setting where it is otherwise not possible. An example
they can only be considered enabled if the platform supports notifications, and enabling notifications requires
additional steps to actually enable notifications.
For more information, see `src/settings/controllers/SettingController.js`.
For more information, see `src/settings/controllers/SettingController.ts`.
## Local echo
@ -222,7 +190,7 @@ The `SettingsStore` uses the hardcoded `LEVEL_ORDER` constant to ensure that it
The array is checked from left to right, simulating the behaviour of overriding values from the higher levels. Each
level should be defined in this array, including `default`.
Handlers (`src/settings/handlers/SettingsHandler.js`) represent a single level and are responsible for getting and
Handlers (`src/settings/handlers/SettingsHandler.ts`) represent a single level and are responsible for getting and
setting values at that level. Handlers also provide additional information to the `SettingsStore` such as if the level
is supported or if the current user may set values at the level. The `SettingsStore` will use the handler to enforce
checks and manipulate settings. Handlers are also responsible for dealing with migration patterns or legacy settings for
@ -230,7 +198,7 @@ their level (for example, a setting being renamed or using a different key from
Handlers are provided to the `SettingsStore` via the `LEVEL_HANDLERS` constant. `SettingsStore` will optimize lookups by
only considering handlers that are supported on the platform.
Local echo is achieved through `src/settings/handlers/LocalEchoWrapper.js` which acts as a wrapper around a given
Local echo is achieved through `src/settings/handlers/LocalEchoWrapper.ts` which acts as a wrapper around a given
handler. This is automatically applied to all defined `LEVEL_HANDLERS` and proxies the calls to the wrapped handler
where possible. The echo is achieved by a simple object cache stored within the class itself. The cache is invalidated
immediately upon the proxied save call succeeding or failing.
@ -240,20 +208,7 @@ Controllers are notified of changes by the `SettingsStore`, and are given the op
### Features
Features automatically get considered as `disabled` if they are not listed in the `SdkConfig` or `enableLabs` is
false/not set. Features are always checked against the configuration before going through the level order as they have
the option of being forced-on or forced-off for the application. This is done by the `features` section and looks
something like this:
```
"features": {
"feature_groups": "enable",
"feature_pinning": "disable", // the default
"feature_presence": "labs"
}
```
If `enableLabs` is true in the configuration, the default for features becomes `"labs"`.
See above for feature reference.
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