nodejs中express+mongodb+middleware如何实现密码哈希

UserSchema.pre('save', function (next) {  var user = this;  if (user.isModified('password')) {    bcrypt.genSalt(10, (err, salt) => {      bcrypt.hash(user.password, salt, (err, hash) => {        user.password = hash;        next();      });    });  } else {    next();  }});

var mongoose = require('mongoose');var express = require('express');var bodyParser = require('body-parser');const {ObjectID} = require('mongodb');var _ = require('lodash');const validator = require('validator');const jwt = require('jsonwebtoken');const bcrypt = require('bcryptjs');//appvar app = express();const port = process.env.PORT || 3000;//express middleware  Jonson对象与字符串转换。app.use(bodyParser.json());//mongoose.Promise = global.Promise;//连接mogodbmongoose.connect(process.env.MONGODB_URI || 'mongodb://localhost:27017/TodoApp');//模版var Todo = mongoose.model('Todo',{    text:{      type:String,  //类型      required:true, //必须要有      minlength:1, //最小长度      trim:true   //去除空格    },    completed:{      type:Boolean,      default:false  //默认值    },    completedAt:{      type:Number,      default:null    }});var UserSchema = new mongoose.Schema({  email: {    type: String,    required: true,    trim: true,    minlength: 1,    unique: true,    validate: {      validator: validator.isEmail,      message: '{VALUE} is not a valid email'    }  },  password: {    type: String,    require: true,    minlength: 6  },  tokens: [{    access: {      type: String,      required: true    },    token: {      type: String,      required: true    }  }]});UserSchema.methods.toJSON = function () {  var user = this;  var userObject = user.toObject();  return _.pick(userObject, ['_id', 'email']);};UserSchema.methods.generateAuthToken = function () {  var user = this;  var access = 'auth';  var token = jwt.sign({_id: user._id.toHexString(), access}, 'abc123').toString();  user.tokens = user.tokens.concat([{access,token}]);  return user.save().then(() => {    return token;  //返回token  });};UserSchema.statics.findByToken = function (token) {  var User = this;  var decoded;  try {    decoded = jwt.verify(token, 'abc123');  } catch (e) {    return Promise.reject();  }  return User.findOne({    '_id': decoded._id,    'tokens.token': token,    'tokens.access': 'auth'  });};//在保存之前执行操作。UserSchema.pre('save', function (next) {  var user = this;//保存时对于密码的更新  if (user.isModified('password')) {    bcrypt.genSalt(10, (err, salt) => {      //密码变为了hash      bcrypt.hash(user.password, salt, (err, hash) => {        user.password = hash;        next();      });    });  } else {    next();  }});var User = mongoose.model('User', UserSchema);//auth middlewirevar authenticate = (req, res, next) => {  var token = req.header('x-auth');  User.findByToken(token).then((user) => {    if (!user) {      return Promise.reject();    }    req.user = user;    req.token = token;    next();  }).catch((e) => {    res.status(401).send();  });};app.get('/users/me', authenticate, (req, res) => {  res.send(req.user);});//express routeapp.post('/todos',(req,res)=>{//  console.log(req.body);    //建立对象document    var todo = new Todo({        text:req.body.text    });    //保存      todo.save().then((doc)=>{      res.send(doc);    },(e)=>{        res.status(400).send(e);    });})//获取所有属性app.get('/todos', (req, res) => {  Todo.find().then((todos) => {    res.send({todos});  }, (e) => {    res.status(400).send(e);  })});//查询idapp.get('/todos/:id', (req, res) => {  var id = req.params.id;  if (!ObjectID.isValid(id)) {    return res.status(404).send();  }  Todo.findById(id).then((todo) => {    if (!todo) {      return res.status(404).send();    }    res.send({todo});  }).catch((e) => {    res.status(400).send();  });});//删除app.delete('/todos/:id', (req, res) => {  var id = req.params.id;  if (!ObjectID.isValid(id)) {    return res.status(404).send();  }  Todo.findByIdAndRemove(id).then((todo) => {    if (!todo) {      return res.status(404).send();    }    res.send({todo});  }).catch((e) => {    res.status(400).send();  });});//更新app.patch('/todos/:id', (req, res) => {  var id = req.params.id;  var body = _.pick(req.body, ['text', 'completed']);  if (!ObjectID.isValid(id)) {    return res.status(404).send();  }  if (_.isBoolean(body.completed) && body.completed) {    body.completedAt = new Date().getTime();  } else {    body.completed = false;    body.completedAt = null;  }  Todo.findByIdAndUpdate(id, {$set: body}, {new: true}).then((todo) => {    if (!todo) {      return res.status(404).send();    }    res.send({todo});  }).catch((e) => {    res.status(400).send();  })});// POST /usersapp.post('/users', (req, res) => {  var body = _.pick(req.body, ['email', 'password']);  var user = new User(body);  user.save().then(() => {    return user.generateAuthToken(); //调用方法，产生auth token并保存。  }).then((token) => {    res.header('x-auth', token).send(user); //设置了响应头  }).catch((e) => {    res.status(400).send(e);  })});//监听app.listen(port,()=>{    console.log(`Start on port ${port}`);});module.exports = {   app,   Todo}

1、打开mongoDB > ./mongod -dbpath /Users/jackson/Downloads/mongodb-data2、运行 >node postman.js3、打开postman 选择post 输入 >localhost:3000/usersBody中填入：{	"email": "zhuimengshaonian07@gmail.com",	"password" : "123abc!"}返回：{    "_id": "5bfe716591e78c6a4ad8c164",    "email": "zhuimengshaonian07@gmail.com"}header:x-auth →eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJfaWQiOiI1YmZlNzE2NTkxZTc4YzZhNGFkOGMxNjQiLCJhY2Nlc3MiOiJhdXRoIiwiaWF0IjoxNTQzNDAxODI5fQ.wOKNzkls_w_jA5YVkCo0r9gFZ4-KtD6GarRiCDpAPr84、查看studio 3T 发现密码变为了hash之后的数字。