Backend Kotlin Spring Boot - Notes Application

This project is a backend for a CRUD Notes application, developed using Kotlin and Spring Boot. It follows a standard MVC architecture, featuring controllers, services, repositories, and models. The application is secured with JWT-based authentication and user session management, and uses MongoDB as its database.

Features

• User registration with email/password validation
• Secure login returning JWT tokens
• Refresh token mechanism for session maintenance
• Password hashing for security
• JWT-based authentication and session management
• CRUD operations for notes
• Modular MVC structure
• Global validation handling
• Ready for integration with databases and security modules

API Endpoints

Auth Endpoints

• POST /auth/register — Register a new user (with email/password validation)
• POST /auth/login — Login and receive JWT access and refresh tokens
• POST /auth/refresh — Refresh access token using a valid refresh token

Notes Endpoints

• GET /notes — Retrieve all notes for the authenticated user
• POST /notes — Create a new note
• DELETE /notes/{id} — Delete a note by ID

Token Expiry

• Access Token: Valid for 15 minutes
• Refresh Token: Valid for 15 days

If the refresh token expires, MongoDB will automatically generate and update the refresh token. Access tokens can be regenerated using a valid refresh token.

Project Structure

├── build.gradle.kts           # Gradle build script (Kotlin DSL)
├── src/
│   ├── main/
│   │   ├── kotlin/            # Application source code
│   │   │   └── com/tandon_ksb/backend_kotlin_springboot/
│   │   │       ├── controller/
│   │   │       ├── database/
│   │   │       ├── security/
│   │   │       ├── BackendKotlinSpringbootApplication.kt
│   │   │       └── GlobalValidationHandler.kt
│   │   └── resources/
│   │       └── application.properties
│   └── test/
│       └── kotlin/            # Test source code
│           └── com/tandon_ksb/backend_kotlin_springboot/
│               └── BackendKotlinSpringbootApplicationTests.kt
├── gradle/                    # Gradle wrapper files
├── build/                     # Build output (generated)
└── ...

Getting Started

Prerequisites

• JDK 17+
• Gradle (or use the included wrapper)
• MongoDB Atlas or local MongoDB instance

Environment Variables

Create a .env file or set the following environment variables:

MONGODB_CONNECTION_STRING=mongodb+srv://<username>:<pswd>@<project_name>.2fqeq6f.mongodb.net/notes?retryWrites=true&w=majority&appName=tandonExpCKO&tls=true&socketTimeoutMS=6000000&connectTimeoutMS=3000000&tlsAllowInvalidCertificates=true&tlsAllowInvalidHostnames=true

JWT_SECRET_BASE64=b3F5ZHV0ZXI3ODIzeXI4OTM2N3J0MjM4ZGVyeTg5MjN5ZTc4MmY=

• Replace <uname> and <pswd> with your MongoDB Atlas credentials.

Build & Run

./gradlew build
./gradlew bootRun

The application will start on http://localhost:8080 by default.

Configuration

Edit src/main/resources/application.properties to configure application settings.

Testing

You can test the API endpoints using Postman. Import the API collection and use the provided endpoints for authentication and notes management.

Run tests with:

./gradlew test

License

This project is licensed under the MIT License.