Chat Backend Service 🚀

A Spring Boot REST API service for managing chat rooms and messages. This service handles all chat operations and validates JWT tokens from the auth service.

Features ✨

• Chat Room Management: Create, retrieve, and delete chat rooms
• Message Management: Send and retrieve messages within chat rooms
• JWT Authentication: Validates tokens from the Python auth service
• H2 In-Memory Database: No external database setup required
• REST API: Full REST endpoints for chat operations
• CORS Support: Configured for Angular frontend communication

Technology Stack

• Java 17
• Spring Boot 3.1.5
• Spring Data JPA
• H2 Database
• JWT (JJWT)
• Maven

Prerequisites

• Java 17 or higher
• Maven 3.6+

Installation & Setup

1. Navigate to the project directory:

   cd chat-backend

2. Build the project:

   mvn clean install

3. Run the application:

   mvn spring-boot:run

The service will start on http://localhost:8080/api

API Endpoints

Chat Rooms

• Create Room (requires JWT)

  POST /api/rooms
  Authorization: Bearer <jwt_token>
  Content-Type: application/json
  
  {
    "name": "General",
    "description": "General discussion room"
  }
  

• Get All Rooms

  GET /api/rooms
  

• Get Room by ID (requires JWT)

  GET /api/rooms/{id}
  Authorization: Bearer <jwt_token>
  

• Delete Room (requires JWT)

  DELETE /api/rooms/{id}
  Authorization: Bearer <jwt_token>
  

Messages

• Send Message (requires JWT)

  POST /api/messages
  Authorization: Bearer <jwt_token>
  Content-Type: application/json
  
  {
    "roomId": 1,
    "content": "Hello everyone!"
  }
  

• Get Messages by Room

  GET /api/messages?roomId=1
  

• Get Message by ID (requires JWT)

  GET /api/messages/{id}
  Authorization: Bearer <jwt_token>
  

• Delete Message (requires JWT)

  DELETE /api/messages/{id}
  Authorization: Bearer <jwt_token>
  

Authentication

• Verify Token (called by Auth Service)

  GET /api/auth/verify
  Authorization: Bearer <jwt_token>
  

Configuration

Edit src/main/resources/application.yml to customize:

server:
  port: 8080                    # Change port if needed
  servlet:
    context-path: /api          # API base path

jwt:
  secret: your-secret-key       # Change this in production!
  expiration: 86400000          # 24 hours in milliseconds

auth-service:
  url: http://localhost:8000    # Auth service URL

Database

The application uses H2 in-memory database. Access the H2 console at:

http://localhost:8080/api/h2-console

Default credentials:

• JDBC URL: jdbc:h2:mem:chatdb
• Username: sa
• Password: (leave blank)

Inter-Service Communication

This service validates JWT tokens and can verify users through the auth service:

1. Frontend → Sends JWT in Authorization: Bearer <token> header
2. Backend → Validates JWT signature using configured secret
3. Auth Service → Can be called by backend for additional verification

Project Structure

chat-backend/
├── pom.xml
├── src/main/
│   ├── java/com/chatapp/
│   │   ├── ChatBackendApplication.java
│   │   ├── config/
│   │   │   ├── JwtConfig.java
│   │   │   ├── JwtUtil.java
│   │   │   └── CorsConfig.java
│   │   ├── controllers/
│   │   │   ├── ChatRoomController.java
│   │   │   ├── MessageController.java
│   │   │   └── AuthController.java
│   │   ├── services/
│   │   │   ├── ChatRoomService.java
│   │   │   ├── MessageService.java
│   │   │   └── AuthVerificationService.java
│   │   ├── repositories/
│   │   │   ├── ChatRoomRepository.java
│   │   │   └── MessageRepository.java
│   │   └── models/
│   │       ├── ChatRoom.java
│   │       └── Message.java
│   └── resources/
│       └── application.yml
└── README.md

Troubleshooting

Port 8080 already in use?

# Change port in application.yml or run with:
mvn spring-boot:run -Dspring-boot.run.arguments="--server.port=8081"

JWT validation failing?

• Ensure the JWT secret matches the auth service
• Check token hasn't expired
• Verify token format: Bearer <token>

CORS errors?

• Frontend must be running on http://localhost:4200
• Adjust CORS settings in CorsConfig.java if needed

Notes

• All timestamps are stored in UTC
• Messages are ordered by creation time
• Room names must be unique
• User information is extracted from JWT claims

License

MIT