Mongoose create() resolved before async middleware is finished - node.js

Question

var mongoose = require('mongoose');
var bcrypt = require('bcrypt-nodejs');
var UserSchema = new mongoose.Schema({
email: {
type: string,
unique: true,
required: true,
trim: true
},
password: {
type: string,
required: true
},
authtokens: {
type: [{ type: mongoose.Schema.Types.ObjectId, ref: 'AuthToken' }]
}
});
//hashing a password before saving it to the database
UserSchema.pre('save', function (next) {
if (this.isNew) {
bcrypt.gensalt(10, function(err, salt) {
if (err) return next(err);
bcrypt.hash(this.password, salt, null, function (err, hash){
if (err) return next(err);
this.password = hash;
console.log('user.password ', this.password);
next();
});
});
} else next();
});
I call this from a controller:
'use strict';
var mongoose = require('mongoose'),
User = mongoose.model('User'),
AuthToken = mongoose.model('AuthToken');
exports.createUser = function(req, res, next) {
if (req.body.email && req.body.password && req.body.passwordConf) {
var userData = {
email: req.body.email,
password: req.body.password,
passwordConf: req.body.passwordConf
};
//use schema.create to insert data into the db
User.create(userData, function (err, user) {
console.log('user created ', user.password);
if (err) {
return next(err);
} else {
return res.redirect('/profile');
}
});
} else {
var err = new Error("Missing parameters");
err.status = 400;
next(err);
}
};
When a createUser is called with email user#email.com, password password, I get the output:
user.password $2a$10$wO.6TPUm5b1j6lvHdCi/JOTeEXHWhYernWU.ZzA3hfYhyWoOeugcq
user created password
Also, looking directly in the database, I see this user with plain text password -> password.
Why is user having plaintext password in the database. How can I store the hash instead?

Answer 1

In short, you forgot you were going into a callback which has a different functional scope and you're still referring to this, which is at that time not actually the "model" instance.
To correct this, take a copy of this before you do anything like launching another function with a callback:
UserSchema.pre('save', function(next) {
var user = this; // keep a copy
if (this.isNew) {
bcrypt.genSalt(10, function(err,salt) {
if (err) next(err);
bcrypt.hash(user.password, salt, null, function(err, hash) {
if (err) next(err);
user.password = hash;
next();
});
});
}
});
An alternate approach of course is to modernize things and use Promise results with async/await. The bcrypt library which is actually the "core" and not a fork does this right out of the box:
UserSchema.pre('save', async function() {
if (this.isNew) {
let salt = await bcrypt.genSalt(10);
let hash = await bcrypt.hash(this.password, salt);
this.password = hash;
}
});
Aside from the modern approach being generally cleaner code, you also don't need to change the scope of this since we don't "dive in" to another function call. Everything gets changed in the same scope, and of course awaits the async calls before continuing.
Full Example - Callback
const { Schema } = mongoose = require('mongoose');
const bcrypt = require('bcrypt-nodejs');
const uri = 'mongodb://localhost/crypto';
var userSchema = new Schema({
email: String,
password: String
});
userSchema.pre('save', function(next) {
var user = this; // keep a copy
if (this.isNew) {
bcrypt.genSalt(10, function(err,salt) {
if (err) next(err);
bcrypt.hash(user.password, salt, null, function(err, hash) {
if (err) next(err);
user.password = hash;
next();
});
});
}
});
const log = data => console.log(JSON.stringify(data, undefined, 2));
const User = mongoose.model('User', userSchema);
(async function() {
try {
const conn = await mongoose.connect(uri);
await Promise.all(Object.entries(conn.models).map(([k,m]) => m.remove()));
await User.create({ email: 'ted#example.com', password: 'password' });
let result = await User.findOne();
log(result);
} catch(e) {
console.error(e)
} finally {
process.exit()
}
})()
Full Example - Promise async/await
const { Schema } = mongoose = require('mongoose');
const bcrypt = require('bcrypt');
const uri = 'mongodb://localhost/crypto';
var userSchema = new Schema({
email: String,
password: String
});
userSchema.pre('save', async function() {
if (this.isNew) {
let salt = await bcrypt.genSalt(10);
let hash = await bcrypt.hash(this.password, salt);
this.password = hash;
}
});
const log = data => console.log(JSON.stringify(data, undefined, 2));
const User = mongoose.model('User', userSchema);
(async function() {
try {
const conn = await mongoose.connect(uri);
await Promise.all(Object.entries(conn.models).map(([k,m]) => m.remove()));
await User.create({ email: 'ted#example.com', password: 'password' });
let result = await User.findOne();
log(result);
} catch(e) {
console.error(e)
} finally {
process.exit()
}
})()
Both show the password correctly encrypted, since we actually set the value in the model instance:
{
"_id": "5aec65f4853eed12050db4d9",
"email": "ted#example.com",
"password": "$2b$10$qAovc0m0VtmtpLg7CRZmcOXPDNi.2WbPjSFkfxSUqh8Pu5lyN4p7G",
"__v": 0
}