🛡️ User Authentication Service

A robust and scalable microservice for user authentication, authorization, and token validation, built using Spring Boot, JWT, Kafka, and Spring Security. Designed to serve as a core authentication module in a distributed e-commerce platform.

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🔧 Tech Stack

• Spring Boot 3.4.3
• Spring Security
• JWT (jjwt)
• MySQL & JPA (Hibernate)
• Kafka (for async email notifications)
• Eureka Client (for service discovery)
• Lombok (boilerplate reduction)

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📦 Features

• ✅ User Signup (with default + custom roles)
• ✅ Secure Login with hashed password & JWT token generation
• ✅ Stateless session management using JWT
• ✅ Token validation with expiry handling
• ✅ Kafka-based email notifications on signup/login
• ✅ Spring Security integration (for authentication/authorization)
• ✅ Exception handling with @ControllerAdvice
• ✅ Eureka registration for microservice communication

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🔐 Endpoints

Method	Endpoint	Description
POST	/auth/signup	Register a new user
POST	/auth/login	Login user and receive JWT token
POST	/auth/validate	Validate JWT for a given user ID
GET	/users/{id}	Get user details by ID

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🛠️ Setup & Run

Prerequisites

• Java 17
• MySQL running & DB created
• Kafka broker running locally
• Eureka server running at http://localhost:8761/

Configure application.properties

spring.datasource.url=jdbc:mysql://localhost:3306/YOUR_DB_NAME
spring.datasource.username=YOUR_DB_USERNAME
spring.datasource.password=YOUR_DB_PASSWORD
email.id=your-email@example.com
eureka.client.service-url.defaultZone=http://localhost:8761/eureka/

Run the application

  mvn spring-boot:run

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🧪 Testing

Run unit and integration tests with:

  mvn test

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📡 Kafka Setup (for Email Notifications)

• Topics used:
  • signup
  • login

Make sure a Kafka broker is running, and configure a consumer for the signup & login topics to listen for EmailDto messages.

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🧱 Folder Structure

src/
├── clients/           # Kafka producer
├── configuration/     # Spring security config
├── controllers/       # REST endpoints
├── dtos/              # Data Transfer Objects
├── exceptions/        # Custom exception classes
├── models/            # Entity classes (User, Role, Session)
├── repositories/      # Spring Data JPA interfaces
├── security/          # JWT and UserDetails config
├── services/          # Business logic

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📬 Kafka EmailDto Structure

{
  "to": "user@example.com",
  "from": "your-email@example.com",
  "subject": "Welcome to Chitraveda",
  "body": "Enjoy shopping!"
}

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📚 Future Enhancements

• Role-based access control (RBAC) using Spring Security
• Refresh tokens & logout API
• OTP-based login support
• Add Swagger documentation

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👤 Author

Harshal Kalewar
🔗 LinkedIn

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📝 License

This project is licensed under the MIT License.