Data: Add persistence via data plugin interface (#8341)

* Data: Add persistence via data plugin interface

* Data: Integrate persistence as first-party plugin

* Data: Restore deprecated persistence behaviors

* Data: Return default persisted by caught error

* Data: Initialize persistence by plugin options

* Data: Remove string form variation on use

* Data: Refactor persistence as dispatch enhancer

* Data: Remove middlewares / enhancers support for store

* Data: Remove unused variable

* Data: Improve objectStorage spec compliancy

Should (a) return null if not set, (b) assign value as string

* Data: Fix persistence handling of null value

* Data: Fix deprecation key to persist

1. Wrong property accessed used
2. Reducer is already wrapped at point registerStore is called. Detect from plugin instead.

* Data: Add tests for WPDataRegistry#use

* Data: Remove _ prefix from local variable

Not conventional

* Data: Update plugins documentation to avoid mention of string usage

edit-post/index.js

@@ -3,7 +3,7 @@
  */
 import { registerCoreBlocks } from '@wordpress/core-blocks';
 import { render, unmountComponentAtNode } from '@wordpress/element';
-import { dispatch, setupPersistence } from '@wordpress/data';
+import { dispatch } from '@wordpress/data';
 import deprecated from '@wordpress/deprecated';
 
 /**
@@ -15,11 +15,6 @@ import store from './store';
 import { initializeMetaBoxState } from './store/actions';
 import Editor from './editor';
 
-/**
- * Module Constants
- */
-const STORAGE_KEY = `WP_EDIT_POST_DATA_${ window.userSettings.uid }`;
-
 /**
  * Reinitializes the editor after the user chooses to reboot the editor after
  * an unhandled error occurs, replacing previously mounted editor element using
@@ -93,5 +88,3 @@ export { default as PluginPostStatusInfo } from './components/sidebar/plugin-pos
 export { default as PluginPrePublishPanel } from './components/sidebar/plugin-pre-publish-panel';
 export { default as PluginSidebar } from './components/sidebar/plugin-sidebar';
 export { default as PluginSidebarMoreMenuItem } from './components/header/plugin-sidebar-more-menu-item';
-
-setupPersistence( STORAGE_KEY );

edit-post/store/index.js

@@ -1,10 +1,7 @@
 /**
  * WordPress Dependencies
  */
-import {
-	registerStore,
-	restrictPersistence,
-} from '@wordpress/data';
+import { registerStore } from '@wordpress/data';
 
 /**
  * Internal dependencies
@@ -13,11 +10,12 @@ import reducer from './reducer';
 import applyMiddlewares from './middlewares';
 import * as actions from './actions';
 import * as selectors from './selectors';
+
 const store = registerStore( 'core/edit-post', {
-	reducer: restrictPersistence( reducer, 'preferences' ),
+	reducer,
 	actions,
 	selectors,
-	persist: true,
+	persist: [ 'preferences' ],
 } );
 
 applyMiddlewares( store );

lib/client-assets.php

@@ -210,6 +210,22 @@ function gutenberg_register_scripts_and_styles() {
 		filemtime( gutenberg_dir_path() . 'build/data/index.js' ),
 		true
 	);
+	wp_add_inline_script(
+		'wp-data',
+		implode( "\n", array(
+			// TODO: Transferring old storage should be removed at v3.7.
+			'( function() {',
+			'	var userId = window.userSettings.uid;',
+			'	var oldStorageKey = "WP_EDIT_POST_DATA_" + userId;',
+			'	var storageKey = "WP_DATA_USER_" + userId;',
+			'	if ( localStorage[ oldStorageKey ] ) {',
+			'		localStorage[ storageKey ] = localStorage[ oldStorageKey ];',
+			'		delete localStorage[ oldStorageKey ];',
+			'	}',
+			'	wp.data.use( wp.data.plugins.persistence, { storageKey: storageKey } );',
+			'} )()',
+		) )
+	);
 	wp_register_script(
 		'wp-core-data',
 		gutenberg_url( 'build/core-data/index.js' ),

packages/data/src/deprecated.js

@@ -11,7 +11,7 @@ import deprecated from '@wordpress/deprecated';
 /**
  * Internal dependencies
  */
-import { getPersistenceStorage } from './persist';
+import * as persistence from './plugins/persistence';
 
 /**
  * Adds the rehydration behavior to redux reducers.
@@ -63,12 +63,14 @@ export function loadAndPersist( store, reducer, reducerKey, storageKey ) {
 		hint: 'See https://github.com/WordPress/gutenberg/pull/8146 for more details',
 	} );
 
+	const persist = persistence.createPersistenceInterface( { storageKey } );
+
 	// Load initially persisted value
-	const persistedString = getPersistenceStorage().getItem( storageKey );
-	if ( persistedString ) {
+	const persisted = persist.get();
+	if ( persisted ) {
 		const persistedState = {
 			...get( reducer( undefined, { type: '@@gutenberg/init' } ), reducerKey ),
-			...JSON.parse( persistedString ),
+			...JSON.parse( persisted ),
 		};
 
 		store.dispatch( {
@@ -85,7 +87,50 @@ export function loadAndPersist( store, reducer, reducerKey, storageKey ) {
 		if ( newStateValue !== currentStateValue ) {
 			currentStateValue = newStateValue;
 			const stateToSave = get( reducer( store.getState(), { type: 'SERIALIZE' } ), reducerKey );
-			getPersistenceStorage().setItem( storageKey, JSON.stringify( stateToSave ) );
+			persist.set( stateToSave );
 		}
 	} );
 }
+
+/**
+ * Higher-order reducer used to persist just one key from the reducer state.
+ *
+ * @param {function} reducer    Reducer function.
+ * @param {string} keyToPersist The reducer key to persist.
+ *
+ * @return {function} Updated reducer.
+ */
+export function restrictPersistence( reducer, keyToPersist ) {
+	deprecated( 'wp.data.restrictPersistence', {
+		alternative: 'registerStore persist option with persistence plugin',
+		version: '3.7',
+		plugin: 'Gutenberg',
+		hint: 'See https://github.com/WordPress/gutenberg/pull/8341 for more details',
+	} );
+
+	reducer.__deprecatedKeyToPersist = keyToPersist;
+
+	return reducer;
+}
+
+/**
+ * Sets a different persistence storage.
+ *
+ * @param {Object} storage Persistence storage.
+ */
+export function setPersistenceStorage( storage ) {
+	deprecated( 'wp.data.setPersistenceStorage', {
+		alternative: 'persistence plugin with storage option',
+		version: '3.7',
+		plugin: 'Gutenberg',
+		hint: 'See https://github.com/WordPress/gutenberg/pull/8341 for more details',
+	} );
+
+	const originalCreatePersistenceInterface = persistence.createPersistenceInterface;
+	persistence.createPersistenceInterface = ( options ) => {
+		originalCreatePersistenceInterface( {
+			storage,
+			...options,
+		} );
+	};
+}

packages/data/src/index.js

@@ -7,12 +7,19 @@ import { combineReducers } from 'redux';
  * Internal dependencies
  */
 import defaultRegistry from './default-registry';
-export { restrictPersistence, setPersistenceStorage } from './persist';
+import * as plugins from './plugins';
+
 export { default as withSelect } from './components/with-select';
 export { default as withDispatch } from './components/with-dispatch';
 export { default as RegistryProvider } from './components/registry-provider';
 export { createRegistry } from './registry';
-export { withRehydration, loadAndPersist } from './deprecated';
+export {
+	withRehydration,
+	loadAndPersist,
+	restrictPersistence,
+	setPersistenceStorage,
+} from './deprecated';
+export { plugins };
 
 /**
  * The combineReducers helper function turns an object whose values are different
@@ -35,3 +42,4 @@ export const registerActions = defaultRegistry.registerActions;
 export const registerSelectors = defaultRegistry.registerSelectors;
 export const registerResolvers = defaultRegistry.registerResolvers;
 export const setupPersistence = defaultRegistry.setupPersistence;
+export const use = defaultRegistry.use;

packages/data/src/plugins/README.md

@@ -0,0 +1,17 @@
+Data Plugins
+============
+
+Included here are a set of default plugin integrations for the WordPress data module.
+
+## Usage
+
+For any of the plugins included here as directories, call the `use` method to include its behaviors in the registry.
+
+```js
+// npm Usage
+import { plugins, use } from '@wordpress/data';
+use( plugins.persistence );
+
+// WordPress Globals Usage
+wp.data.use( wp.data.plugins.persistence );
+```

packages/data/src/plugins/index.js

@@ -0,0 +1 @@
+export { default as persistence } from './persistence';

packages/data/src/plugins/persistence/README.md

@@ -0,0 +1,36 @@
+Persistence Plugin
+==================
+
+The persistence plugin enhances a registry to enable registered stores to opt in to persistent storage.
+
+By default, persistence occurs by [`localStorage`](https://developer.mozilla.org/en-US/docs/Web/API/Window/localStorage). This can be changed using the [`setStorage` function](#api) defined on the plugin. Unless set otherwise, state will be persisted on the `WP_DATA` key in storage.
+
+## Usage
+
+Call the `use` method on the default or your own registry to include the persistence plugin:
+
+```js
+wp.data.use( wp.data.plugins.persistence, { storageKey: 'example' } );
+```
+
+Then, when registering a store, set a `persist` property as `true` (persist all state) or an array of state keys to persist.
+
+```js
+wp.data.registerStore( 'my-plugin', {
+	// ...
+
+	persist: [ 'preferences' ],
+} );
+```
+
+## Options
+
+### `storage`
+
+Persistent storage implementation. This must at least implement `getItem` and `setItem` of the Web Storage API.
+
+See: https://developer.mozilla.org/en-US/docs/Web/API/Storage
+
+### `storageKey`
+
+The key on which to set in persistent storage.