persist local-storage state in external json-file

Signed-off-by: Roman <ixrock@gmail.com>

src/renderer/hooks/useStorage.ts

@@ -1,7 +1,7 @@
 import { useState } from "react";
-import { createStorage, IStorageHelperOptions } from "../utils";
+import { createStorage, StorageHelperOptions } from "../utils";
 
-export function useStorage<T>(key: string, initialValue?: T, options?: IStorageHelperOptions) {
+export function useStorage<T>(key: string, initialValue?: T, options?: StorageHelperOptions<T>) {
   const storage = createStorage(key, initialValue, options);
   const [storageValue, setStorageValue] = useState(storage.get());
   const setValue = (value: T) => {

src/renderer/utils/createStorage.ts

@@ -1,73 +1,210 @@
-// Helper to work with browser's local/session storage api
+// Helper for work with persistent local storage (default: window.localStorage)
+// TODO: write unit/integration tests
 
-export interface IStorageHelperOptions {
-  addKeyPrefix?: boolean;
-  useSession?: boolean; // use `sessionStorage` instead of `localStorage`
-}
+import { app, remote } from "electron";
+import path from "path";
+import { ensureDirSync, readJsonSync, writeJson } from "fs-extra";
+import type { CreateObservableOptions } from "mobx/lib/api/observable";
+import { action, comparer, observable, reaction, toJS, when } from "mobx";
+import produce, { Draft, setAutoFreeze } from "immer";
+import { isEqual, isFunction, isObject } from "lodash";
 
-export function createStorage<T>(key: string, defaultValue?: T, options?: IStorageHelperOptions) {
+setAutoFreeze(false); // allow to merge observables
+
+export function createStorage<T>(key: string, defaultValue?: T, options?: StorageHelperOptions<T>) {
   return new StorageHelper(key, defaultValue, options);
 }
 
-export class StorageHelper<T> {
-  static keyPrefix = "lens_";
+export interface StorageHelperOptions<T> extends StorageConfiguration<T> {
+  autoInit?: boolean; // default: true
+}
 
-  static defaultOptions: IStorageHelperOptions = {
-    addKeyPrefix: true,
-    useSession: false,
+export interface StorageConfiguration<T> {
+  storage?: StorageAdapter<T>;
+  observable?: CreateObservableOptions;
+}
+
+export interface StorageAdapter<T> {
+  [metadata: string]: any;
+  getItem(key: string): T; // import
+  setItem(key: string, value: T): void; // export
+  removeItem?(key: string): void; // if not provided setItem(key,undefined) will be used
+  onChange?(data: { key: string, value: T, oldValue?: T }): void;
+}
+
+export class StorageHelper<T> {
+  static defaultOptions: StorageHelperOptions<any> = {
+    autoInit: true,
+    get storage() {
+      return jsonFileSyncStorageAdapter;
+    },
+    observable: {
+      deep: true,
+      equals: comparer.shallow,
+    }
   };
 
-  constructor(protected key: string, protected defaultValue?: T, protected options?: IStorageHelperOptions) {
-    this.options = Object.assign({}, StorageHelper.defaultOptions, options);
+  private data = observable.box<T>();
+  @observable.ref storage: StorageAdapter<T>;
+  @observable initialized = false;
+  whenReady = when(() => this.initialized);
 
-    if (this.options.addKeyPrefix) {
-      this.key = StorageHelper.keyPrefix + key;
+  constructor(readonly key: string, readonly defaultValue?: T, readonly options: StorageHelperOptions<T> = {}) {
+    this.options = { ...StorageHelper.defaultOptions, ...options };
+    this.configure();
+    this.reset();
+
+    if (this.options.autoInit) {
+      this.init();
     }
   }
 
-  protected get storage() {
-    if (this.options.useSession) return window.sessionStorage;
+  @action
+  init() {
+    if (this.initialized) return;
 
-    return window.localStorage;
+    try {
+      const value = this.load();
+      const notEmpty = value != null;
+      const notDefault = !this.isDefaultValue(value);
+
+      if (notEmpty && notDefault) {
+        this.merge(value);
+      }
+      this.initialized = true;
+    } catch (error) {
+      console.error(`[init]: ${error}`, this);
+    }
+  }
+
+  isDefaultValue(value: T): boolean {
+    return isEqual(value, this.defaultValue);
+  }
+
+  @action
+  private configure({ storage, observable }: StorageConfiguration<T> = this.options): this {
+    if (storage) this.storage = storage;
+    if (observable) this.configureObservable(observable);
+
+    return this;
+  }
+
+  @action
+  private configureObservable(options: CreateObservableOptions = {}) {
+    this.data = observable.box<T>(this.data.get(), {
+      ...StorageHelper.defaultOptions.observable, // inherit default observability options
+      ...options,
+    });
+    this.data.observe(change => {
+      const { newValue, oldValue } = toJS(change, { recurseEverything: true });
+
+      this.onChange(newValue, oldValue);
+    });
+  }
+
+  protected onChange(value: T, oldValue?: T) {
+    if (!this.initialized) return;
+
+    this.storage.onChange?.({ value, oldValue, key: this.key });
+    this.storage.setItem(this.key, value);
+  }
+
+  load(): T {
+    return this.storage.getItem(this.key);
   }
 
   get(): T {
-    const strValue = this.storage.getItem(this.key);
-
-    if (strValue != null) {
-      try {
-        return JSON.parse(strValue);
-      } catch (e) {
-        console.error(`Parsing json failed for pair: ${this.key}=${strValue}`);
-      }
-    }
-
-    return this.defaultValue;
+    return this.data.get();
   }
 
   set(value: T) {
-    this.storage.setItem(this.key, JSON.stringify(value));
-
-    return this;
+    this.data.set(value);
   }
 
-  merge(value: Partial<T>) {
-    const currentValue = this.get();
-
-    return this.set(Object.assign(currentValue, value));
+  reset() {
+    this.set(this.defaultValue);
   }
 
   clear() {
-    this.storage.removeItem(this.key);
-
-    return this;
+    this.data.set(null);
   }
 
-  getDefaultValue() {
-    return this.defaultValue;
+  merge(value: Partial<T> | ((draft: Draft<T>) => Partial<T> | void)) {
+    const updater = isFunction(value) ? value : (state: Draft<T>) => {
+      if (isObject(state)) return Object.assign(state, value);
+
+      return value;
+    };
+    const currentValue = this.toJS();
+    const nextValue = produce(currentValue, updater) as T;
+
+    this.set(nextValue);
   }
 
-  restoreDefaultValue() {
-    return this.set(this.defaultValue);
+  toJS() {
+    return toJS(this.get(), { recurseEverything: true });
   }
 }
+
+export const localStorageAdapter: StorageAdapter<object> = {
+  getItem(key: string) {
+    return JSON.parse(localStorage.getItem(key));
+  },
+  setItem(key: string, value: any) {
+    localStorage.setItem(key, JSON.stringify(value));
+  },
+  removeItem(key: string) {
+    localStorage.removeItem(key);
+  }
+};
+
+// TODO: remove after merge https://github.com/lensapp/lens/pull/2269
+export const jsonFileSyncStorageAdapter: StorageAdapter<object> = {
+  cwd: path.resolve((app || remote.app).getPath("userData"), "lens-local-storage"),
+  data: observable.map<string, any>([], { deep: false }),
+  initialized: false,
+
+  get filePath() {
+    const clusterId = location.hostname.split(".").slice(-2, -1)[0];
+
+    return path.resolve(this.cwd, `${clusterId ?? "app"}.json`);
+  },
+
+  init() {
+    if (this.initialized) return;
+
+    try {
+      ensureDirSync(this.cwd, { mode: 0o755 });
+      const data = readJsonSync(this.filePath, { throws: false }) || {};
+
+      this.data.replace(data);
+      this.bindAutoSave();
+    } catch (error) {
+      console.error(`[init]: ${this.filePath} failed: ${error}`, this);
+    } finally {
+      this.initialized = true;
+    }
+  },
+
+  bindAutoSave() {
+    return reaction(() => this.data.toJSON(), async (data) => {
+      try {
+        await writeJson(this.filePath, data, { spaces: 2 });
+      } catch (error) {
+        console.error(`[save]: ${this.filePath} failed: ${error}`, this);
+      }
+    });
+  },
+
+  getItem(key: string) {
+    this.init();
+
+    return this.data.get(key);
+  },
+  setItem(key: string, value: any) {
+    this.data.set(key, value);
+  },
+  removeItem(key: string) {
+    this.data.delete(key);
+  }
+};