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Node.js check if user already exists

Hello guys I am trying to check if a user already exists in the database, I have managed to stop creating a user if one already exists with the same name, however I do not seem to get the error message displayed. I am not too sure why my error is not being handled correctly. Here is my code:
// Register User
router.post('/register', function(req, res){
var name = req.body.name;
var email = req.body.email;
var username = req.body.username;
var password = req.body.password;
var password2 = req.body.password2;
//Validation
req.checkBody('name', 'Name is required').notEmpty();
req.checkBody('email', 'Email is required').notEmpty();
req.checkBody('email', 'Email is not valid').isEmail();
req.checkBody('username', 'Username is required').notEmpty();
req.checkBody('password', 'Password is required').notEmpty();
req.checkBody('password2', 'Passwords do not match').equals(req.body.password);
var errors = req.validationErrors();
if(errors){
res.render('register',{
errors:errors
});
}else{var newUser = new User({
name: name,
email:email,
username: username,
password: password
});
User.getUserByUsername(username, function(err, user){
if(err) throw err;
if(user){
return new Error('User already exists!');
}else{
User.createUser(newUser, function(err, user){
if(err) throw err;
console.log(user);
});
}
});
req.flash('success_msg', 'You are registered and can now login');
res.redirect('/users/login');
}
});

This will work exactly as you wish.I had the same issue trying to make it work and I assure you it does. Cheers!
User.getUserByUsername(username, function(err, user){ //must check if user exists
if(err) throw err;
if(user){
console.log('existing...'); //may be deleted
req.flash('error_msg', 'This username already exists');
res.redirect('/users/register');
} else {
User.createUser(newUser, function(err, user){
if(err) throw err;
console.log(user);//may be deleted
});
req.flash('success_msg', 'You registered successfuly and you can now login');
res.redirect('/users/login');
}
})

Two things I see wrong:
You're doing synchronous operations after passing off the control to an asynchronous callback
You're not doing anything useful with the errors inside your asynchronous callback
Here the asynchronous callback is the function you pass to User.getUserByUsername
router.post('/register', function(req, res) {
...
User.getUserByUsername(username, function(err, user) {
// Any errors get thrown here need to be dealt with here
// Also you can't simply "throw" or "return" errors from this,
// You need to use Express's "next" method to handle these errors
})
// And since you've gone asynchronous above (User.getUserByUsername)
// you can't do the following here:
req.flash('success_msg', 'You are registered and can now login')
res.redirect('/users/login')
// otherwise these will ALWAYS get executed,
// regardless of what the result of `User.getUserByUsername` may be
})
You need to do something like this:
router.post('/register', function(req, res, next) { // use `next` to handle errors
...
User.getUserByUsername(username, function(err, user) {
if (err) {
next(err)
} else if (user) {
next(new Error('User already exists!'))
} else {
req.flash('success_msg', 'You are registered and can now login')
res.redirect('/users/login')
}
})
})
PS: Also you're not saving newUser (at least not in the code you've posted)

If you only want to check if user with given username exist or not, then I have used this simple trick.
What I am doing is while registering, if some error occurs then I am checking if this error is UserExistError(which is related to mongodb, and you can see it when it occurs in terminal)
If err is equal to UserExistError then I am rendering an alert which is in separate file.
register(new User({username:req.body.username}),req.body.password,function(err,user){
if(err)
{ var chk=1;
console.log(err);
if(err=='UserExistsError');
console.log("error is here");
return res.render("register",{chk:chk});
}
passport.authenticate("local")(req,res,function(){
res.redirect("/dashboard");
})
});

var candidateName = username;
var queryforUsername = {};
queryforUsername['username'] = candidateName;
User.find(queryforUsername, function(err, item){
if(err) throw (err);
if(item.length > 0){
req.flash('error_msg', 'User with username '+username+' already exists!');
res.redirect('register');
}else if(item.length == 0){
User.createUser(newUser, function(err, user){
if(err) throw err;
console.log(user);
req.flash('success_msg', 'You are registered and can now login');
res.redirect('/users/login');
});
}
});

const { usuario } = req.body;
let user = await User.findOne({ usuario});
if (user) {
return res.status(400).json({ ok: false, msg: 'El usuario ya existe' });
}
//crear nuevo user
user = new User(req.body);

The right way to connect to query database mongodb multiples times

im building a website in my free time using nodejs/Handlebars.js/mongodb(mongoose),
i didnt study any web developement lessons, and i dont know the right way to do things efficiently and securely.
so in this project, i stumbled upon a problem where i had to query in the database if email already exists or no if it does, it queries again if the username already exists or not, if it does exists the user can be registred to the databse. yes it gets the job done but im not satisfyied with this approach, it seems to be unprofessional and not secure.
so can you please tell me the right way to do it ?
this is the part where i think i ve done it the wrong way
//check for errors in Req.validation and push them to errors Array
if(valErrors){
for (var i = 0; i < valErrors.length; i++) {
errors.push(valErrors[i])
}
}
//check if the username submitted exists in the database
User.findOne({'username':username}, function (err, user) {
if(user)
{
errors.push({msg:"username is already in use!"})
res.render('user/register',{
errors:errors
});
}
//if the username is not in use already check if the email is in
//use
else {
User.findOne({'email':email}, function (err, user) {
if(user){
errors.push({msg:'email is already in use !'})
res.render('user/register',{
errors:errors
});
} //if the email doesnt exists too then register this //user
else{
var coins = new Coins()
var newUser = new User({
name: name,
email:email,
username: username,
password: password,
coins:coins.encryptcoins('0'),
joindate:getDate()
});
User.createUser(newUser, function(err, user){
if(err) throw err;
});
req.flash('success_msg', 'You are registered and can now login');
res.redirect('/user/login');
}
});
}
});
})
EDIT:
user Schema
var mongoose = require('mongoose');
var bcrypt = require('bcryptjs');
// User Schema
var UserSchema = mongoose.Schema({
username: {
type: String,
index:true,
required:true
},
password: {
type: String,
required:true
},
email: {
type: String,
required:true
},
name: {
type: String,
required:true
},
coins: {
type:String,
required:true
},
joindate: {
type:String,
required:true
},
orders: {
type:Array,
required:false
}
},{collection:'Users'});
var User = module.exports = mongoose.model('User', UserSchema);
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);
});
}
this is the whole code
var express = require('express');
var router = express.Router();
var passport = require('passport');
var LocalStrategy = require('passport-local').Strategy;
var User = require('../models/users');
const ensureLoggedIn = require('connect-ensure-login').ensureLoggedIn();
const ensureLoggedOut = require('connect-ensure-login').ensureLoggedOut();
var Coins = require('../models/coins');
// Register
router.get('/register',ensureLoggedOut, function(req, res){
res.render('user/register');
});
// Login
router.get('/login',ensureLoggedOut, function(req, res){
res.render('user/login');
});
// Register User
router.post('/register', function(req, res){
var name = req.body.name;
var email = req.body.email;
var username = req.body.username;
var password = req.body.password;
var password2 = req.body.password2;
console.log(email)
console.log(username)
// Validation
req.checkBody('name', 'Name is required').notEmpty();
req.checkBody('email', 'Email is required').notEmpty();
req.checkBody('email', 'Email is not valid').isEmail();
req.checkBody('username', 'Username is required').notEmpty();
req.checkBody('password', 'Password is required').notEmpty();
req.checkBody('password2', 'Passwords do not match').equals(req.body.password);
//Error handling
var errors = [];
var valErrors = req.validationErrors()
//check for errors in Req.validation and push them to errors Array
if(valErrors){
for (var i = 0; i < valErrors.length; i++) {
errors.push(valErrors[i])
}
}
//check if the username submitted exists in the database
User.findOne({'username':username}, function (err, user) {
if(user)
{
errors.push({msg:"username is already in use!"})
res.render('user/register',{
errors:errors
});
}
//if the username is not in use already check if the email is in
//use
else {
User.findOne({'email':email}, function (err, user) {
if(user){
errors.push({msg:'email is already in use !'})
res.render('user/register',{
errors:errors
});
} //if the email doesnt exists too then register this //user
else{
var coins = new Coins()
var newUser = new User({
name: name,
email:email,
username: username,
password: password,
coins:coins.encryptcoins('0'),
joindate:getDate()
});
User.createUser(newUser, function(err, user){
if(err) throw err;
});
req.flash('success_msg', 'You are registered and can now login');
res.redirect('/user/login');
}
});
}
});
})
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);
});
});
router.post('/login',
passport.authenticate('local', {successReturnToOrRedirect: '/', failureRedirect:'/user/login',failureFlash: true}),
function(req, res) {
res.redirect('/');
});
router.get('/logout',ensureLoggedIn, function(req, res){
req.logout();
req.session.destroy();
res.redirect('/');
});
module.exports = router;
function getDate(){
var d = new Date()
return ("date: "+d.getDate()+"/"+(d.getMonth()+1)+"/" +d.getFullYear() + " time GMT+1: "+(d.getHours()+1)+":"+(d.getMinutes())).toString()
}
// replaced with Ensure loging in library !
// function ensureLoggedIn(req, res, next) {
// if(req.user){
// return next()
// }else{
// res.redirect('/user/login');
// }
// }
// function ensureLoggedOut(req, res, next) {
// if(!req.user){
// return next()
// }else{
// res.redirect('/');
// }
// }

In general, for a logical unit of work send to a Database Management System (DBMS) (i.e., MongoDB server), it is imperative to group the individual operations in a single transaction. This way, you can avoid inconsistencies that might result from concurrent user creation in your database.
To be more precise, in your project the registration process checks for the following:
Check if email exists
Check if username exists
If queries 1 and 2 returned an empty result set, register a new user
In essence, those 3 steps need to take place in an atomic fashion, which means that they occur as a single logical unit (Transaction). If not, in the extreme case that 2 concurrent clients try to register users with the same usernames, then your database will result with two users with the same username.
Therefore, you should update your code to do the following:
Initiate a transaction
Check for users with the given email (user_email) and or usernamae (user_name)
If the query of step 2 returned a user, then rollback the transaction; Otherwise, insert a new user with user_email and user_name.
Commit Transaction
I am not sure whether MongoDB supports Transactional Consistency, and this is one of the reasons that I suggested using an RDBMS. Also, if it doesn't, I am sure that you can figure out a schema that identifies a single user based on email/username and try to perform the registration as a transaction.
Finally, it is considered good practice to have most of the processing take place in the DBMS side with the use of Stored Procedures.
I hope this helps.

NodeJS and Mongodb findOneAndUpdate

I need help to figure this out. The update function is called to reset a password on database. I got this error.
TypeError: Cannot read property 'password' of undefined
module.exports.update = function (token, req, res) {
User.findOneAndUpdate({resetPasswordToken: token, password: req.body.password, resetPasswordExpires: {$gt: Date.now()}}, function(err) {
if (err) throw err;
return res.sendStatus(200);
console.log(User);
});
}
router.post('/forgot', function (req, res) {
var password = req.body.passwordnew;
var password2 = req.body.passwordnew2;
var update = User.update(password, password2, function (err, user) {
//userToken = token;
if (!update) {
console.log("token2 = " + req.params.resetPasswordToken);
req.flash('error', 'Password reset token is invalid or has expired.');
return res.redirect('forgot');
}
else {
user.save(function (err) {
user.password = password;
user.password2 = password2;
user.resetPasswordToken = undefined;
user.resetPasswordExpires = undefined;
});
console.log("save new password");
}
});
//}
})

when you use update method of mongoose 1st parameter will be query( by which you can find that doccument in collection) and 2nd will be what you want to update ..
So what query you make is not make sense , it will be like :
var userId=user; //mongoId
var newPassWord=req.body.passwordnew;
User.update({_id:userId}, {password:newPassWord}, callbackFunction);
this will update password of that perticular user.
Thanks

Node with Passport: Compare Password throws error undefined is not a function, when it returns return done(null, user);

I have read all the related questions and responses and still can't fix this issue. Please see the code below and help me understand why terminal is throwing 'undefined is not a function'.
For a rundown of the functions:
The query section looks up SQL gets the users PW from DB. Parse results gets just the pw and eliminates the 'key' from the key value pair. Move pw function is there just as a buffer so that compare PW will not execute until we have retrieved the pw to compare with.
I have been stuck on this for a while, any help is much appreciated. To see the running app, go here...a working un/pw combo are user5 1234, but bc of the error it will look up username, password, verify that its a match (the compare pw and the look up pw functions actually do work and tell you if its a existing pw and un combo, but when i try and return done(user, null) to the passport login route, it crashes...
https://[redacted].com/
var express = require('express');
var router = express.Router();
var passport = require('passport');
var LocalStrategy = require('passport-local').Strategy;
var db = require('../database');
var returnedPw;
var flash = require('connect-flash');
var session = require('express-session');
var mysql = require('mysql');
var connection = mysql.createConnection({
host : 's',
user : 'n',
password : '',
database : 's'
});
//stripped credentioals
// Include User Model
var User = require('../models/user');
// Include Student Model
var Client = require('../models/client');
// Include Instructor Model
var Company = require('../models/company');
router.get('/signup', function(req, res, next) {
res.render('users/signup');
});
router.post('/signup', function(req, res, next){
// Get Form Values
console.log('starting post and making new user');
var first_name = req.body.first_name;
var last_name = req.body.last_name;
var street_address = req.body.street_address;
var city = req.body.city;
var state = req.body.state;
var zip = req.body.zip;
var email = req.body.email;
var username = req.body.username;
var password = req.body.password;
var password2 = req.body.password2;
var type = req.body.type;
// Form Field Validation
req.checkBody('first_name', 'First name field is required').notEmpty();
req.checkBody('last_name', 'Last name field is required').notEmpty();
req.checkBody('email', 'Email field is required').notEmpty();
req.checkBody('email', 'Email must be a valid email address').isEmail();
req.checkBody('username', 'Username field is required').notEmpty();
req.checkBody('password', 'Password field is required').notEmpty();
req.checkBody('password2', 'Passwords do not match').equals(req.body.password);
var errors = req.validationErrors();
if(errors){
res.render('users/signup', {
errors: errors,
first_name: first_name,
last_name: last_name,
street_address: street_address,
city: city,
state: state,
zip: zip,
email: email,
username: username,
password: password,
password2: password2
});
} else {
var newUser = new User({
email: email,
username:username,
password: password,
type: type
});
console.log('calling post to database file to receive new user:' + newUser)
// THIS IS WHERE WE ARE POSTING THE NEW USER TO THE DATABASE!!!
db.postUsers(newUser);
var newClient = new Client({
first_name: first_name,
last_name: last_name,
address: [{
street_address: street_address,
city: city,
state: state,
zip: zip
}],
email: email,
username:username
});
if(type == 'client'){
//User.saveClient(newUser, newClient, function(err, user){
// console.log('Client created');
///}); works but replacing w sql
} else {
var newCompany = new Company({
first_name: first_name,
last_name: last_name,
address: [{
street_address: street_address,
city: city,
state: state,
zip: zip
}],
email: email,
username:username
});
//works but replacing w sql
//User.saveCompany(newUser, newCompany, function(err, user){
// console.log('Company created');
//});
//sql save function
console.log('calling sql save..');
//db.postUsers(newUser, newClient);
}
req.flash('success','User added');
res.redirect('/');
}
});
<!--//// -USER AUTH SECTION- \\\\--!><!--//// -USER AUTH SECTION- \\\\--!><!--//// -USER AUTH SECTION- \\\\--!>
/*
passport.serializeUser(function(user, done) {
done(null, user._id);
});
passport.deserializeUser(function(id, done) {
User.getUserById(id, function (err, user) {
done(err, user);
});
}); */
passport.serializeUser(function(user, done) {
done(null, user);
});
passport.deserializeUser(function(user, done) {
done(null, user);
});
router.post('/login',passport.authenticate('local',{failureRedirect:'/', failureFlash:'Wrong Username or Password'}), function(req, res){
req.flash('success','You are now logged in');
var usertype = req.user.type;
res.redirect('/'/*+usertype+'s/classes' */);
});
passport.use(new LocalStrategy(
function(username, password, done ) {
console.log('in users the username is ' + username)
connection.query('SELECT password FROM t_user WHERE username = ?', username, function(err, user) {
parseResults(user, done);
});// end query
function parseResults(user, done) {
Object.keys(user)[0];
var key = Object.keys(user)[0];
user[key];
var storedPw = user[key];
for(var i in storedPw){
returnedPw = storedPw[i];
}
console.log('returnedPw is defined here ' +returnedPw);
movePw(returnedPw, done);
}// end function
var candidatePassword = password;
function movePw (returnedPw, done) {
if (returnedPw ) {
User.comparePassword(candidatePassword, returnedPw, function(err, isMatch) {
if (err) return done(err);
if(isMatch) {
//return done(null, user);
// req.flash('success','User Access Granted');
//console.log('go head')
user = username;
return done(null, user);
//done(null, user);
//notifyOuterScope();
//return true;
} else {
console.log('Invalid Password');
// Success Message
req.flash('failureFlash','User Access Denied. False Password');
return done(null, false, { message: 'Invalid password' });
}
});
}
else {console.log('return PW not defined')}
}
}// end outer function ?
));//end passport
// Log User Out
router.get('/logout', function(req, res){
req.logout();
// Success Message
req.flash('success', "You have logged out");
res.redirect('/');
});
function ensureAuthenticated(req, res, next) {
if (req.isAuthenticated()) {
return next();
}
res.redirect('/')
}
/* COMPARING PASSWORDS */
/* where are we returning the password from the user db profile?
bcrypt.hash('mypassword', 10, function(err, hash) {
if (err) { throw (err); }
bcrypt.compare('mypassword', hash, function(err, result) {
if (err) { throw (err); }
console.log(result);
});
});
*/
module.exports = router;

The code is a working example of using SQL and passport.js with node. I was having difficulty using the Local Strategy required for passport (using sql commands instead of mongodb commands that you see in most passport documentation), and it turns out the reason is because I wasn't passing the correct variables/ was also passing in unnecessary variables.
I corrected it above. Instead of using the User.FindOne Mongo db query in local strategy, this is an example of how to do the same username/ password querys using SQL, within passport local strategy. There isn't much documentation on using SQL and passport / node.

Unexpected results with MongooseJS findOne()

Using Mongoose as an ODM with NodeJS, but not fully understanding how the error handling works. It works, but doesn't look right, and isn't in line with the documentation, so I'm worried that going down this road will haunt me later on.
For example, here is a basic signin route:
app.post('/signin', function(req, res){
var email = req.body.email;
var password = req.body.password;
mongoose.model('User').findOne({
email: email,
password: password
}, function(err, user){
if (err){
console.log('Database Error')
return res.json({error: 'Database Error'})
} else {
if (!user) {
console.log('User not found.');
return res.json({error: 'Email and/or password incorrect.'})
} else {
console.log('User ' + user.email + ' found. Logging in.');
res.json({
token: jwt.sign({}, 'top-secret', {subject: user}),
data: data[user]
})
}
}
})
})
I'm especially worried about:
if (err) {
//do something
} else {
if (!user){
//do something else
} else {
//log the user in
}
}
Haven't really used Mongo before today, but this feels like a lot of conditional error handling. Is there something that I'm not understanding properly here?

Was going to post as a comment but it was easier to paste this as an answer..
You can simplify the if-else nesting since you are returning at the end of each conditional, like so:
app.post('/signin', function (req, res) {
var email = req.body.email;
var password = req.body.password;
mongoose.model('User').findOne({
email: email,
password: password
}, function (err, user) {
if (err) {
console.log('Database Error');
return res.json({error: 'Database Error'});
}
if (!user) {
console.log('User not found.');
return res.json({error: 'Email and/or password incorrect.'});
}
console.log('User ' + user.email + ' found. Logging in.');
res.json({
token: jwt.sign({}, 'top-secret', {subject: user}),
data: data[user]
});
});
});