Implementing authentication and authorization with MongoDB requires using features available in MongoDB and additional software libraries as per your chosen programming language. Here we’ll instigate how to achieve this using Mongoose in Node.js along with a library for handling JSON Web Tokens (JWT). Passport.js can be used for more complex and diverse authentication methods.
1. Setup MongoDB database: Firstly, you should have a MongoDB server running either on your local system or on the cloud. You can download MongoDB compass for managing your database.
1. Connect database with your project: You need to establish a connection to the MongoDB server from your Node.js application. Use the MongoDB Node.js driver or a tool like Mongoose.
1. Implement the registration and login flow: Create a User model using Mongoose that has at least fields for the username and password. Take care to hash the password using a library like bcrypt before saving it to the database.
\`\`\`js const mongoose = require(‘mongoose’); const bcrypt = require(‘bcrypt’); const UserSchema = new mongoose.Schema({ username: { type: String, required: true, }, password: { type: String, required: true, }, }); UserSchema.pre(‘save’, function (next) { const user = this; if (!user.isModified(‘password’)) return next(); bcrypt.hash(user.password, 10, (err, hashed) => { if (err) return next(err); user.password = hashed; next(); }); }); module.exports = mongoose.model(‘User’, UserSchema); \`\`\` Then, create routes for registering and logging in users. The registration route should create a new User, and the login route should compare the entered password with the hashed password stored in the database. \`\`\`js const express = require(‘express’); const User = require(‘./models/User’); const bcrypt = require(‘bcrypt’); const jwt = require(‘jsonwebtoken’); const router = express.Router(); router.post(‘/register’, (req, res) => { const newUser = new User(req.body); newUser.save((err) => { if (err) return res.status(500).send(err); return res.status(200).send(newUser); }); }); router.post(‘/login’, async (req, res) => { const user = await User.findOne({ username: req.body.username }); bcrypt.compare(req.body.password, user.password, (err, result) => { if(err) return res.status(500).send(err); if(!result) return res.status(401).send(‘Invalid password’); const token = jwt.sign({ id: user.\_id }, ‘yourPrivateKey’); return res.status(200).json({ user, token }); }); }); module.exports = router; \`\`\`1. Implement Authorization middleware: Create a middleware function in Express that checks for a valid JWT and attaches the user object to the request if the token is valid:
\`\`\`js const jwt = require(‘jsonwebtoken’); const User = require(‘./models/User’); function auth(req, res, next) { const token = req.header(‘auth-token’); if (!token) return res.status(401).send(‘Access Denied’); try { const verified = jwt.verify(token, ‘yourPrivateKey’); req.user = await User.findById(verified.id); next(); } catch (err) { res.status(400).send(‘Invalid Token’); } } module.exports = auth; \`\`\`Use SSL/TLS to transmit sensitive data like passwords and token securely over the network and always keep your database and server environment secure. The security of your application depends on much more than just the code you write.
