45 lines
1.7 KiB
Markdown
45 lines
1.7 KiB
Markdown
Jitsi Meet - redux state persistence
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====================================
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Jitsi Meet has a persistence layer that persists specific subtrees of the redux
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store/state into window.localStorage (on Web) or AsyncStorage (on mobile).
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Usage
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=====
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If a subtree of the redux store should be persisted (e.g.
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`'features/base/settings'`), then persistence for that subtree should be
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requested by registering the subtree with `PersistenceRegistry`.
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For example, to register the field `displayName` of the redux subtree
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`'features/base/settings'` to be persisted, use:
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```javascript
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PersistenceRegistry.register('features/base/settings', {
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displayName: true
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});
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```
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in the `reducer.js` of the `base/settings` feature.
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If the second parameter is omitted, the entire feature state is persisted.
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When it's done, Jitsi Meet will automatically persist these subtrees and
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rehydrate them on startup.
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Throttling
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==========
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To avoid too frequent write operations in the storage, we utilize throttling in
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the persistence layer, meaning that the storage gets persisted only once every 2
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seconds, even if multiple redux state changes occur during this period. The
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throttling timeout can be configured in
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```
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react/features/base/storage/middleware.js#PERSIST_STATE_DELAY
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```
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Serialization
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=============
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The API JSON.stringify() is currently used to serialize feature states,
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therefore its limitations affect the persistency feature too. E.g. complex
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objects, such as Maps (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map)
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or Sets (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set)
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cannot be automatically persisted at the moment. The same applies to Functions
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(which is not a good practice to store in Redux anyhow).
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