JWT MongoDB User Authentication

A Spring Boot application that provides JWT-based authentication with MongoDB as the database.

Features

• User registration and login
• JWT token generation and validation
• Password encryption using BCrypt
• MongoDB integration
• Input validation
• Protected endpoints

Prerequisites

• Java 21
• MongoDB running on localhost:27017
• Maven

Getting Started

1. Start MongoDB

   # Make sure MongoDB is running on localhost:27017
   mongod

2. Run the application

   ./mvnw spring-boot:run

3. The application will start on port 8080

API Endpoints

Public Endpoints

Register a new user

POST /auth/register
Content-Type: application/json

{
    "username": "testuser",
    "email": "test@example.com",
    "password": "password123"
}

Login

POST /auth/login
Content-Type: application/json

{
    "username": "testuser",
    "password": "password123"
}

Response:

{
    "token": "eyJhbGciOiJIUzI1NiJ9..."
}

Test endpoint

GET /auth/test

Protected Endpoints

Protected endpoint (requires JWT token)

GET /auth/protected
Authorization: Bearer <your-jwt-token>

Configuration

The application uses the following configuration in application.properties:

• MongoDB URI: mongodb://localhost:27017/userdb
• JWT Secret: Base64 encoded secret key
• JWT Expiration: 1 hour (3600000 ms)

Security

• Passwords are encrypted using BCrypt
• JWT tokens are signed with HS256 algorithm
• Protected endpoints require valid JWT token in Authorization header
• Input validation for user registration

Database

The application creates a userdb database in MongoDB with a users collection.

User document structure:

{
    "_id": "ObjectId",
    "username": "string (unique)",
    "email": "string (unique)",
    "password": "string (encrypted)",
    "role": "string (default: USER)"
}

Testing with curl

1. Register a user:

curl -X POST http://localhost:8080/auth/register \
  -H "Content-Type: application/json" \
  -d '{"username":"testuser","email":"test@example.com","password":"password123"}'

2. Login:

curl -X POST http://localhost:8080/auth/login \
  -H "Content-Type: application/json" \
  -d '{"username":"testuser","password":"password123"}'

3. Access protected endpoint:

curl -X GET http://localhost:8080/auth/protected \
  -H "Authorization: Bearer YOUR_JWT_TOKEN_HERE"