How to properly logout with JWT using Passport Strategies? - authentication

Question

I am new to JWT and Passport so I started following a MERN tutorial on Youtube by NoobCoder that deals with authentication and authorization using JWT. I reached the part where the route deals with '/logout' and I get Unauthorized as a reply from Postman. The code so far is exactly the same by the looks of it. Can someone help me understand what is wrong here?
I have attached the code in the bottom. Please let me know if more information is required.
Here is the code:
app.js
const express = require('express');
const app = express();
const cookieParser = require('cookie-parser');
const mongoose = require('mongoose');
app.use(cookieParser());
app.use(express.json());
mongoose.connect('mongodb://localhost:27017/mernauth', {useNewUrlParser: true, useUnifiedTopology: true}, () => {
console.log('Successfully connected to DB');
});
const userRouter = require('./routes/User');
app.use('/user', userRouter);
app.listen(5000, () => {
console.log('express server started');
});
passport.js
const passport = require('passport');
const LocalStrategy = require('passport-local').Strategy;
const JwtStrategy = require('passport-jwt').Strategy;
const User = require('./models/User');
const cookieExtractor = req => {
let token = null;
if(req && req.cookies) {
token = req.cookies['access_token'];
}
return token;
}
// Authorization
passport.use(new JwtStrategy({
jwtFromRequest: cookieExtractor,
secretOrKey: 'NoobCoder'
}, (payload, done) => {
User.findById({_id: payload.sub}, (err, user) => {
if(err) {
return done(err, false);
}
if(user) {
return done(null, user);
}
else {
return done(null, false);
}
})
}));
// Authenticated local strategy using username and password
passport.use(new LocalStrategy((username, password, done) => {
User.findOne({username}, (err, user) => {
// Something went wrong with DB
if(err) {
return done(err);
}
// If no user exists; null = no error; false = user does not exist
if(!user) {
return done(null, false);
}
// Check if password is correct; callback cb = done
user.comparePassword(password, done);
});
}));
User.js (route)
const express = require('express');
const userRouter = express.Router();
const passport = require('passport');
const passportConfig = require('../passport');
const JWT = require('jsonwebtoken');
const User = require('../models/User');
const Todo = require('../models/Todo');
const signToken = userID => {
return JWT.sign({
iss: "NoobCoder",
sub: userID
}, "NoobCoder", {expiresIn: "1h"});
}
userRouter.post('/register', (req, res) => {
const {username, password, role} = req.body;
User.findOne({username}, (err, user) => {
if(err) {
res.status(500).json({message: {msgBody: "Error has occured", msgError: true}})
}
if(user) {
res.status(400).json({message: {msgBody: "Username is already taken", msgError: true}})
}
else {
const newUser = new User({username, password, role});
newUser.save(err => {
if(err) {
res.status(500).json({message: {msgBody: "Error has occured", msgError: true}})
}
else {
res.status(201).json({message: {msgBody: "Account Successfully Created", msgError: false}})
}
})
}
})
});
userRouter.post('/login', passport.authenticate('local', {session: false}), (req, res) => {
if(req.isAuthenticated()) {
const {_id, username, role} = req.user;
const token = signToken(_id);
res.cookie('access_token', token, {httpOnly: true, sameSite: true});
res.status(200).json({isAuthenticated: true, user: {username, role}})
}
});
userRouter.get('/logout', passport.authenticate('jwt', {session: false}), (req, res) => {
res.clearCookie('access_token');
res.json({user: {username: '', role: ''}, success: true});
});
module.exports = userRouter;
User.js (model)
const mongoose = require('mongoose');
const bcrypt = require('bcrypt');
const UserSchema = new mongoose.Schema({
username: {
type: String,
required: true,
min: 6,
max: 15
},
password: {
type: String,
required: true,
},
role: {
type: String,
enum: ['user', 'admin'],
required: true
},
todos: [{type: mongoose.Schema.Types.ObjectId, ref: 'Todo'}]
});
UserSchema.pre('save', function(next) {
if(!this.isModified('password')) {
return next()
}
bcrypt.hash(this.password, 10, (err, passwordHash) => {
if(err) {
return next(err);
}
this.password = passwordHash;
next();
});
});
UserSchema.methods.comparePassword = function(password, cb) {
bcrypt.compare(password, this.password, (err, isMatch) => {
if(err) {
return cb(err);
}
else {
if(!isMatch) {
return cb(null, isMatch)
}
return cb(null, this);
}
})
};
module.exports = mongoose.model('User', UserSchema);

Answer 1

Perhaps the /logout route is unauthorised because the JWT token is not present?
JWT token presence can be verified by ensuring that the cookieExtractor function is returning a token

Answer 2

app.get('/logout', function(req, res){
req.logout();
res.redirect('/');
});
Source