封装前端缓存操作

import CryptoJS from 'crypto-js';

// 十六位十六进制数作为密钥
const SECRET_KEY = CryptoJS.enc.Utf8.parse('3333e6e143439161');
// 十六位十六进制数作为密钥偏移量
const SECRET_IV = CryptoJS.enc.Utf8.parse('e3bbe7e3ba84431a');

// 类型 window.localStorage,window.sessionStorage,
const config = {
  type: 'sessionStorage', // 本地存储类型 localStorage sessionStorage
  prefix: 'xxx_0.0.1', // 名称前缀 建议：项目名 + 项目版本
  expire: 0, //过期时间 单位：秒
  isEncrypt: false // 默认加密 为了调试方便, 开发过程中可以不加密
};

// 判断是否支持 Storage
export const isSupStorage = () => {
  if (!window) {
    throw new Error('当前环境非浏览器，无法消费全局window实例。');
  }
  if (!window.localStorage) {
    throw new Error('当前环境非无法使用localStorage');
  }
  if (!window.sessionStorage) {
    throw new Error('当前环境非无法使用sessionStorage');
  }

  return typeof Storage !== 'undefined' ? true : false;
};

// 设置 setStorage
export const setStorage = (key, value, expire = 0) => {
  if (value === '' || value === null || value === undefined) {
    value = null;
  }

  if (isNaN(expire) || expire < 0) throw new Error('Expire must be a number');

  expire = (expire ? expire : config.expire) * 1000;
  let data = {
    value: value, // 存储值
    time: Date.now(), //存值时间戳
    expire: expire // 过期时间
  };
  const encryptString = config.isEncrypt
    ? encrypt(JSON.stringify(data))
    : JSON.stringify(data);
  window[config.type].setItem(autoAddPrefix(key), encryptString);
};

// 获取 getStorage
export const getStorage = key => {
  let value = null;
  key = autoAddPrefix(key);
  // key 不存在判断
  if (
    !window[config.type].getItem(key) ||
    JSON.stringify(window[config.type].getItem(key)) === 'null'
  ) {
    return null;
  }

  // 优化 持续使用中续期
  const storage = config.isEncrypt
    ? JSON.parse(decrypt(window[config.type].getItem(key)))
    : JSON.parse(window[config.type].getItem(key));
  const nowTime = Date.now();
  // 过期删除
  if (storage.expire && storage.expire < nowTime - storage.time) {
    removeStorage(key);
    return null;
  } else {
    // // 未过期期间被调用 则自动续期 进行保活
    // setStorage(autoRemovePrefix(key), storage.value);
    if (isJson(storage.value)) {
      value = JSON.parse(storage.value);
    } else {
      value = storage.value;
    }
    return value;
  }
};

// 是否存在 hasStorage
export const hasStorage = key => {
  key = autoAddPrefix(key);
  let arr = getStorageAll().filter(item => {
    return item.key === key;
  });
  return arr.length ? true : false;
};

// 获取所有key
export const getStorageKeys = () => {
  let items = getStorageAll();
  let keys = [];
  for (let index = 0; index < items.length; index++) {
    keys.push(items[index].key);
  }
  return keys;
};

// 根据索引获取key
export const getStorageForIndex = index => {
  return window[config.type].key(index);
};

// 获取localStorage长度
export const getStorageLength = () => {
  return window[config.type].length;
};

// 获取全部 getAllStorage
export const getStorageAll = () => {
  const len = getStorageLength(); // 获取长度
  let arr = []; // 定义数据集
  for (let i = 0; i < len; i++) {
    const key = window[config.type].key(i);
    // 获取key 索引从0开始
    const getKey = autoRemovePrefix(key);
    // 获取key对应的值
    const storage = config.isEncrypt
      ? JSON.parse(decrypt(window[config.type].getItem(key)))
      : JSON.parse(window[config.type].getItem(key));

    const nowTime = Date.now();
    if (storage.expire && nowTime - storage.time > storage.expire) {
      removeStorage(getKey);
    } else {
      let getVal = storage.value;
      // console.log(Object.prototype.toString.call(value));
      if (isJson(getVal)) {
        getVal = JSON.parse(getVal);
      }
      // 放进数组
      arr.push({ key: getKey, val: getVal });
    }
  }
  return arr;
};

// 删除 removeStorage
export const removeStorage = key => {
  window[config.type].removeItem(autoAddPrefix(key));
};

// 清空 clearStorage
export const clearStorage = () => {
  window[config.type].clear();
};

// 判断是否可用 JSON.parse
export const isJson = value => {
  if (Object.prototype.toString.call(value) === '[object String]') {
    try {
      const obj = JSON.parse(value);
      const objType = Object.prototype.toString.call(obj);
      return objType === '[object Object]' || objType === '[object Array]';
    } catch (e) {
      // console.log('error：' + value + '!!!' + e);
      return false;
    }
  }
  return false;
};

// 名称前自动添加前缀
const autoAddPrefix = key => {
  const prefix = config.prefix ? config.prefix + '_' : '';
  return prefix + key;
};

// 移除已添加的前缀
const autoRemovePrefix = key => {
  const len = config.prefix ? config.prefix.length + 1 : '';
  return key.substr(len);
};

/**
 * 加密方法
 * @param data
 * @returns {string}
 */
const encrypt = data => {
  if (typeof data === 'object') {
    try {
      data = JSON.stringify(data);
    } catch (error) {
      console.log('encrypt error:', error);
    }
  }
  const dataHex = CryptoJS.enc.Utf8.parse(data);
  const encrypted = CryptoJS.AES.encrypt(dataHex, SECRET_KEY, {
    iv: SECRET_IV,
    mode: CryptoJS.mode.CBC,
    padding: CryptoJS.pad.Pkcs7
  });
  return encrypted.ciphertext.toString();
};

/**
 * 解密方法
 * @param data
 * @returns {string}
 */
const decrypt = data => {
  const encryptedHexStr = CryptoJS.enc.Hex.parse(data);
  const str = CryptoJS.enc.Base64.stringify(encryptedHexStr);
  const decrypt = CryptoJS.AES.decrypt(str, SECRET_KEY, {
    iv: SECRET_IV,
    mode: CryptoJS.mode.CBC,
    padding: CryptoJS.pad.Pkcs7
  });
  const decryptedStr = decrypt.toString(CryptoJS.enc.Utf8);
  return decryptedStr.toString();
};

export default {
  install(Vue) {
    // 挂载全局
    if (!Vue.$storage) {
      Vue.$storage = {
        set: setStorage,
        get: getStorage,
        getAll: getStorageAll,
        getLen: getStorageLength,
        isSub: isSupStorage,
        isJson: isJson,
        has: hasStorage,
        del: removeStorage,
        clear: clearStorage
      };
    } else {
      Vue.$storage.set = setStorage;
      Vue.$storage.get = getStorage;
      Vue.$storage.getAll = getStorageAll;
      Vue.$storage.getLen = getStorageLength;
      Vue.$storage.isSub = isSupStorage;
      Vue.$storage.isJson = isJson;
      Vue.$storage.has = hasStorage;
      Vue.$storage.del = removeStorage;
      Vue.$storage.clear = clearStorage;
    }
    Vue.mixin({
      created: function () {
        this.$storage = Vue.$storage;
      }
    });
  }
};