jiti-meet/react/features/base/storage/PersistenceRegistry.js

281 lines
9.0 KiB
JavaScript

// @flow
import md5 from 'js-md5';
import logger from './logger';
declare var __DEV__;
/**
* The name of the {@code localStorage} store where the app persists its values.
*/
const PERSISTED_STATE_NAME = 'jitsi-state';
/**
* Mixed type of the element (subtree) config. If it's a {@code boolean} (and is
* {@code true}), we persist the entire subtree. If it's an {@code Object}, we
* perist a filtered subtree based on the properties of the config object.
*/
declare type ElementConfig = boolean | Object;
/**
* The type of the name-config pairs stored in {@code PersistenceRegistry}.
*/
declare type PersistencyConfigMap = { [name: string]: ElementConfig };
/**
* A registry to allow features to register their redux store subtree to be
* persisted and also handles the persistency calls too.
*/
class PersistenceRegistry {
_checksum: string;
_defaultStates: { [name: string ]: ?Object} = {};
_elements: PersistencyConfigMap = {};
/**
* Returns the persisted redux state. Takes the {@link #_elements} into
* account as we may have persisted something in the past that we don't want
* to retreive anymore. The next {@link #persistState} will remove such
* values.
*
* @returns {Object}
*/
getPersistedState() {
let filteredPersistedState = {};
// localStorage key per feature
for (const subtreeName of Object.keys(this._elements)) {
// Assumes that the persisted value is stored under the same key as
// the feature's redux state name.
// TODO We'll need to introduce functions later that can control the
// persist key's name. Similar to control serialization and
// deserialization. But that should be a straightforward change.
const persistedSubtree
= this._getPersistedSubtree(
subtreeName,
this._elements[subtreeName],
this._defaultStates[subtreeName]);
if (persistedSubtree !== undefined) {
filteredPersistedState[subtreeName] = persistedSubtree;
}
}
// legacy
if (Object.keys(filteredPersistedState).length === 0) {
const { localStorage } = window;
let persistedState = localStorage.getItem(PERSISTED_STATE_NAME);
if (persistedState) {
try {
persistedState = JSON.parse(persistedState);
} catch (error) {
logger.error(
'Error parsing persisted state',
persistedState,
error);
persistedState = {};
}
filteredPersistedState = this._getFilteredState(persistedState);
// Store into the new format and delete the old format so that
// it's not used again.
this.persistState(filteredPersistedState);
localStorage.removeItem(PERSISTED_STATE_NAME);
}
}
// Initialize the checksum.
this._checksum = this._calculateChecksum(filteredPersistedState);
if (typeof __DEV__ !== 'undefined' && __DEV__) {
logger.info('redux state rehydrated as', filteredPersistedState);
}
return filteredPersistedState;
}
/**
* Initiates a persist operation, but its execution will depend on the
* current checksums (checks changes).
*
* @param {Object} state - The redux state.
* @returns {void}
*/
persistState(state: Object) {
const filteredState = this._getFilteredState(state);
const checksum = this._calculateChecksum(filteredState);
if (checksum !== this._checksum) {
for (const subtreeName of Object.keys(filteredState)) {
try {
window.localStorage.setItem(
subtreeName,
JSON.stringify(filteredState[subtreeName]));
} catch (error) {
logger.error(
'Error persisting redux subtree',
subtreeName,
error);
}
}
logger.info(
`redux state persisted. ${this._checksum} -> ${checksum}`);
this._checksum = checksum;
}
}
/**
* Registers a new subtree config to be used for the persistency.
*
* @param {string} name - The name of the subtree the config belongs to.
* @param {ElementConfig} config - The config {@code Object}, or
* {@code boolean} if the entire subtree needs to be persisted.
* @param {Object} defaultState - The default state of the component. If
* it's provided, the rehydrated state will be merged with it before it gets
* pushed into Redux.
* @returns {void}
*/
register(
name: string,
config?: ElementConfig = true,
defaultState?: Object) {
this._elements[name] = config;
this._defaultStates[name] = defaultState;
}
/**
* Calculates the checksum of a specific state.
*
* @param {Object} state - The redux state to calculate the checksum of.
* @private
* @returns {string} The checksum of the specified {@code state}.
*/
_calculateChecksum(state: Object) {
try {
return md5.hex(JSON.stringify(state) || '');
} catch (error) {
logger.error('Error calculating checksum for state', error);
return '';
}
}
/**
* Prepares a filtered state from the actual or the persisted redux state,
* based on this registry.
*
* @param {Object} state - The actual or persisted redux state.
* @private
* @returns {Object}
*/
_getFilteredState(state: Object) {
const filteredState = {};
for (const name of Object.keys(this._elements)) {
if (state[name]) {
filteredState[name]
= this._getFilteredSubtree(
state[name],
this._elements[name]);
}
}
return filteredState;
}
/**
* Prepares a filtered subtree based on the config for persisting or for
* retrieval.
*
* @param {Object} subtree - The redux state subtree.
* @param {ElementConfig} subtreeConfig - The related config.
* @private
* @returns {Object}
*/
_getFilteredSubtree(subtree, subtreeConfig) {
let filteredSubtree;
if (typeof subtreeConfig === 'object') {
// Only a filtered subtree gets persisted as specified by
// subtreeConfig.
filteredSubtree = {};
for (const persistedKey of Object.keys(subtree)) {
if (subtreeConfig[persistedKey]) {
filteredSubtree[persistedKey] = subtree[persistedKey];
}
}
} else if (subtreeConfig) {
// Persist the entire subtree.
filteredSubtree = subtree;
}
return filteredSubtree;
}
/**
* Retreives a persisted subtree from the storage.
*
* @param {string} subtreeName - The name of the subtree.
* @param {Object} subtreeConfig - The config of the subtree from
* {@link #_elements}.
* @param {Object} subtreeDefaults - The defaults of the persisted subtree.
* @private
* @returns {Object}
*/
_getPersistedSubtree(subtreeName, subtreeConfig, subtreeDefaults) {
let persistedSubtree = window.localStorage.getItem(subtreeName);
if (persistedSubtree) {
try {
persistedSubtree = JSON.parse(persistedSubtree);
const filteredSubtree
= this._getFilteredSubtree(persistedSubtree, subtreeConfig);
if (filteredSubtree !== undefined) {
return this._mergeDefaults(
filteredSubtree, subtreeDefaults);
}
} catch (error) {
logger.error(
'Error parsing persisted subtree',
subtreeName,
persistedSubtree,
error);
}
}
return undefined;
}
/**
* Merges the persisted subtree with its defaults before rehydrating the
* values.
*
* @private
* @param {Object} subtree - The Redux subtree.
* @param {?Object} defaults - The defaults, if any.
* @returns {Object}
*/
_mergeDefaults(subtree: Object, defaults: ?Object) {
if (!defaults) {
return subtree;
}
// If the subtree is an array, we don't need to merge it with the
// defaults, because if it has a value, it will overwrite it, and if
// it's undefined, it won't be even returned, and Redux will natively
// use the default values instead.
if (!Array.isArray(subtree)) {
return {
...defaults,
...subtree
};
}
}
}
export default new PersistenceRegistry();