const redis = require('redis');

// cache.jsconst redis = require('redis');const config = require('config');const logger = require('winston');const redisObj = {  client: null,  connect: function () {    this.client = redis.createClient(config.redis);    this.client.on('error', function (err) {      logger.error('redisCache Error ' + err);    });    this.client.on('ready', function () {      logger.info('redisCache connection succeed');    });  },  init: function () {    this.connect(); // 創(chuàng)建連接    const instance = this.client;    // 主要重寫(xiě)了一下三個(gè)方法。可以根據(jù)需要定義。    const get = instance.get;    const set = instance.set;    const setex = instance.setex;    instance.set = function (key, value, callback) {      if (value ！== undefined) {        set.call(instance, key, JSON.stringify(value), callback);      }    };    instance.get = function (key, callback) {      get.call(instance, key, (err, val) => {        if (err) {          logger.warn('redis.get: ', key, err);        }        callback(null, JSON.parse(val));      });    };    // 可以不用傳遞expires參數(shù)。在config文件里進(jìn)行配置。    instance.setex = function (key, value, callback) {      if (value !== undefined) {        setex.call(instance, key, config.cache.maxAge, JSON.stringify(value), callback);      }    };    return instance;  },};// 返回的是一個(gè)redis.client的實(shí)例module.exports = redisObj.init();

const cache = require('./cache');cache.get(key, (err, val) => {  if (val) {    // do something  } else {    // do otherthing  }});cache.set(key, val, (err, res) => {  // do something});cache.setex(key, val, (err, res) => {  // do something})