v0.0.3, add local storage cache.

.eslintrc.js

@@ -16,6 +16,7 @@ module.exports = {
     rules: {
         '@typescript-eslint/no-var-requires': 0,
         '@typescript-eslint/explicit-module-boundary-types': 0,
-        '@typescript-eslint/no-unused-vars': 0
+        '@typescript-eslint/no-unused-vars': 0,
+        'no-useless-catch': 0
     }
 };

package.json

@@ -1,6 +1,6 @@
 {
   "name": "casbin.js",
-  "version": "0.0.2",
+  "version": "0.0.3",
   "main": "./lib/index.js",
   "types": "./lib/index.d.ts",
   "repository": "https://github.com/casbin/casbin.js.git",

src/Authorizer.ts

@@ -2,6 +2,7 @@ import axios from 'axios';
 import Cookies from 'js-cookie';
 import Permission from './Permission';
 import { StringKV } from './types';
+import * as Cache from './Cache'
 
 interface BaseResponse {
     message: string;
@@ -16,23 +17,28 @@ export class Authorizer {
     private user : string | undefined;
     private permission = new Permission();
     private cookieKey : string | undefined = undefined;
+    private cacheExpiredTime  = 60; // Seconds
 
     /**
      * 
      * @param mode "auto", "cookies" or "manual"
      * "auto": Specify the casbin server endpoint, and Casbin.js will load permission from it when the identity changes
      * "cookies": Casbin.js load the permission data from the cookie "casbin_permission" or the specified cookie key.
      * "manual": Load the permission mannually with "setPermission"
-     * @param args.endpoint Casbin service endpoint, required when mode == "auto"
+     * @param args.endpoint Casbin service endpoint, REQUIRED when mode == "auto"
+     * @param args.cacheExpiredTime The expired time of local cache, Unit: seconds, Default: 60s, activated when mode == "auto" 
      * @param args.cookieKey The cookie key when loading permission, activated when mode == "cookies"
      */
-    constructor(mode: Mode = "manual", args: {endpoint?: string, cookieKey?: string} = {}) {
+    constructor(mode: Mode = "manual", args: {endpoint?: string, cookieKey?: string, cacheExpiredTime?: number} = {}) {
         if (mode == 'auto') {
             if (!args.endpoint) {
                 throw new Error("Specify the endpoint when initializing casbin.js with mode == 'auto'");
             } else {
                 this.mode = mode;
                 this.endpoint = args.endpoint;
+                if (args.cacheExpiredTime !== null && args.cacheExpiredTime !== undefined) {
+                    this.cacheExpiredTime = args.cacheExpiredTime; 
+                }
             }
         } else if (mode == 'cookies') {
             this.mode = mode;
@@ -53,7 +59,7 @@ export class Authorizer {
      * Get the permission.
      */
     public getPermission() : StringKV {
-        return this.permission.getPermissionJson();
+        return this.permission.getPermissionJsonObject();
     }
 
     public setPermission(permission : Record<string, unknown> | string) : void{
@@ -67,7 +73,6 @@ export class Authorizer {
         if (this.endpoint !== undefined && this.endpoint !== null) {
             const resp = await axios.get<BaseResponse>(`${this.endpoint}?casbin_subject=${this.user}`);
             this.permission.load(resp.data.data);
-            console.log("syncUserPermission is called")
         }
     }
 
@@ -79,7 +84,13 @@ export class Authorizer {
         // Sync with the server and fetch the latest permission of the new user
         if (this.mode == 'auto' && user != this.user) {
             this.user = user;
-            await this.syncUserPermission()
+            const permStr = Cache.loadFromLocalStorage(user);
+            if (permStr === null) {
+                await this.syncUserPermission();
+                Cache.saveToLocalStorage(user, this.permission.getPermissionString(), this.cacheExpiredTime);
+            } else {
+                this.permission.load(permStr);
+            }
         }        
     }
 

src/Cache.ts

@@ -0,0 +1,53 @@
+const isLocalStorageAvailable: boolean = (() => {
+    try {
+        const key = "fUjXn2r59"; // A random key
+        const value = "test";
+        localStorage.setItem(key, value);
+        const gotValue = localStorage.getItem(key);
+        localStorage.removeItem(key);
+        return true;
+    } catch (e) {
+        return false;
+    }
+})();
+
+export function saveToLocalStorage(key: string, value: string, expired: number): number{
+    if (!isLocalStorageAvailable) {
+        return -1;
+    }
+    const savedItem = {
+        value: value,
+        expired: Date.now() + 1000 * expired
+    };
+    console.log(savedItem);
+    try {
+        localStorage.setItem(`casbinjs_${key}`, JSON.stringify(savedItem));
+    } catch (e) {
+        throw(e)
+        // TODO: Process the quotaExceededError
+    }
+    return 0;
+}
+
+/***
+ * return: a string. 
+ * If ret == null, it means there is no such user permission.
+ */
+export function loadFromLocalStorage(key: string): string | null{
+    if (!isLocalStorageAvailable) {
+        return null;
+    }
+    const itemStr = localStorage.getItem(`casbinjs_${key}`);
+    // No cache
+    if (itemStr === null) {
+        return null;
+    }
+    const item = JSON.parse(itemStr);
+
+    if (Date.now() > item["expired"]){
+        localStorage.removeItem(`casbinjs_${key}`);
+        return null;
+    } else {
+        return item['value'];
+    }
+}

src/Permission.ts

@@ -8,7 +8,6 @@ export default class Permission {
         this.actObjData = new Map<string, Array<string>>();
         this.objActData = new Map<string, Array<string>>();
     }
-
 
     public load(permission : string | Record<string, unknown>) : void {
         let p : StringKV;
@@ -39,7 +38,7 @@ export default class Permission {
 
     }
 
-    public getPermissionJson() : StringKV {
+    public getPermissionJsonObject() : StringKV {
         const obj : StringKV = {};
         this.actObjData.forEach((value, key) => (obj[key] = value));
         return obj;
@@ -49,7 +48,7 @@ export default class Permission {
         Parse the permission into JSON string
     */
     public getPermissionString() : string {
-        return JSON.stringify(this.getPermissionJson());
+        return JSON.stringify(this.getPermissionJsonObject());
     }
 
     public getTargetsFromAction(action: string) : Array<string> {

src/__test__/cache.test.ts

@@ -0,0 +1,11 @@
+import * as Cache from '../Cache';
+import * as utils from '../utils';
+
+test("Cache unit test", async () => {
+    Cache.saveToLocalStorage("test", "test", 1);
+    expect(Cache.loadFromLocalStorage("test")).toBe("test");
+    expect(localStorage.getItem("casbinjs_test")).not.toBeNull();
+    await utils.sleep(2000);
+    expect(Cache.loadFromLocalStorage("test")).toBeNull();
+    expect(localStorage.getItem("casbinjs_test")).toBeNull();
+})

src/__test__/permission.test.ts

@@ -10,7 +10,7 @@ describe('Permission unit test', () => {
     test('Load permission from JSON object', () => {
         const s = JSON.stringify(policyExample);
         permission.load(policyExample);
-        const t = permission.getPermissionJson();
+        const t = permission.getPermissionJsonObject();
         expect(t).toMatchObject(policyExample);
     })
 

src/utils.ts

@@ -0,0 +1,3 @@
+export function sleep(ms: number) {
+    return new Promise(resolve => setTimeout(resolve, ms));
+}

tsconfig.json

@@ -6,7 +6,7 @@
     // "incremental": true,                   /* Enable incremental compilation */
     "target": "es5",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019', 'ES2020', or 'ESNEXT'. */
     "module": "commonjs",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', 'es2020', or 'ESNext'. */
-    "lib": ["es6"],                             /* Specify library files to be included in the compilation. */
+    "lib": ["es6", "DOM"],                             /* Specify library files to be included in the compilation. */
     // "allowJs": true,                       /* Allow javascript files to be compiled. */
     // "checkJs": true,                       /* Report errors in .js files. */
     // "jsx": "preserve",                     /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */