无法在Express中导出功能

Question

我正在尝试实现passport.js，问题是在模型中导出函数的方式:

用户模型文件(User .js)看起来像:

var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var passportLocalMongoose = require('passport-local-mongoose');
var bcrypt = require('bcrypt');
var userSchema = mongoose.Schema({
  username: String,
  password: String
});
userSchema.plugin(passportLocalMongoose);
userSchema.methods = {
    getUserByUsername: function(username, callback){
        var query = {username: username};
        userSchema.findOne(query, callback);
        /*userSchema.findOne(query, function(err, user) {
            callback(err, user);
        }); */
    },
    getUserById: function(id, callback){
        userSchema.findById(id, callback);
    },
    comparePassword: function(candidatePassword, hash, callback){
        bcrypt.compare(candidatePassword, hash, function(err, isMatch) {
            if(err) throw err;
            callback(null, isMatch);
        });
    }
}
module.exports = mongoose.model('User', userSchema);

我调用模型(app.js):

// user schema/model
var User = require('./models/user.js');

和我试图使用导出的功能在护照(app.js):

passport.use(new localStrategy(
  function(username, password, done) {
    User.getUserByUsername(username, function(err, user){
      if(err) throw err;
      if(!user){
        return done(null, false, {message: 'Unknown User'});
    }
    User.comparePassword(password, user.password, function(err, isMatch){
      if(err) throw err;
      if(isMatch){
        return done(null, user);
      } else {
        return done(null, false, {message: 'Invalid password'});
      }
    });
   });
  }));
passport.serializeUser(function(user, done) {
  done(null, user.id);
});
passport.deserializeUser(function(id, done) {
  User.getUserById(id, function(err, user) {
    done(err, user);
  });
});

我得到TypeError: User.getUserByUsername is not a function

我试图定义一个关于docs的函数:

User.methods.getUserByUsername = function(username, callback){
        var query = {username: username};
        User.findOne(query, callback);
    }

和相同的错误出现在控制台中，当我试图登录…

编辑:我说:

var User = mongoose.model('User', userSchema);
module.exports = {
  User: User
};

现在它与方法定义一起工作:

module.exports.getUserByUsername()

所以最终的模型文件看起来像:

// user model
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var passportLocalMongoose = require('passport-local-mongoose');
var bcrypt = require('bcrypt');
var userSchema = mongoose.Schema({
  username: String,
  password: String
});
userSchema.plugin(passportLocalMongoose);
var User = mongoose.model('User', userSchema);
module.exports = {
  User: User
};
module.exports.createUser = function(newUser, callback){
    bcrypt.genSalt(10, function(err, salt) {
        bcrypt.hash(newUser.password, salt, function(err, hash) {
            newUser.password = hash;
            newUser.save(callback);
        });
    });
}
module.exports.getUserByUsername = function(username, callback){
    var query = {username: username};
    User.findOne(query, callback);
}
module.exports.getUserById = function(id, callback){
    User.findById(id, callback);
}
module.exports.comparePassword = function(candidatePassword, hash, callback){
    bcrypt.compare(candidatePassword, hash, function(err, isMatch) {
        if(err) throw err;
        callback(null, isMatch);
    });
}

谢谢大家的帮助

Answer 1

代替

module.exports.getUserByUsername = ...

或

User.methods.getUserByUsername = ...

使用

User.statics.getUserByUsername = ...

见http://mongoosejs.com/docs/2.7.x/docs/methods-statics.html

Answer 2

如果你是NodeJS的新手，那么理解模块。exports和exports可能有点混淆。清楚地了解这个概念是很重要的，因为如果你还在认真地进行nodejs开发，你会经常遇到这个问题。我不打算在这里解释在nodejs中导出是如何工作的，因为在web中有很多教程。如;

按照我下面的代码来解决你的问题。

//UserModel.js
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var bcrypt = require('bcrypt');
var passportLocalMongoose = require('passport-local-mongoose');
var userSchema = mongoose.schema({
      username: String,
      password: String
});
userSchema.plugin(passportLocalMongoose);
userSchema.methods = {
    createUser: function(...){..},
    getUserByUsername: function(..){..},
    getUserById: function(..){..},
    comparePassword: function(..),{}
}
module.exports = mongoose.model('User', userSchema);

你可以从你的UserSchema中访问方法:

//Controller.js
var User  = require('path/to/UserModel.js');
User.createUser(..,..)

更多细节，你可以参考我的仓库，看看我是怎么做的。