codePaste - Pastebin Application

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Overview

codePaste is a Pastebin-like application designed to demonstrate system design skills, focusing on building a scalable, maintainable, and efficient backend service. This project showcases how to handle data persistence, caching, security, and API design in a real-world scenario.

Purpose

This project is primarily a demonstration of system design capabilities including:

• Designing RESTful APIs for creating, retrieving, and managing text pastes.
• Implementing security with authentication and access controls.
• Managing data storage with MongoDB for flexibility and scalability.
• Leveraging caching mechanisms to improve performance.
• Handling paste expiration and password protection features.
• Applying clean architecture and separation of concerns.

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Features

• Create & Retrieve Pastes: Store and access text snippets via unique paste IDs.
• Password Protection: Secure pastes with optional password-based access.
• Expiration: Support paste expiry after a configurable duration.
• Access Control: Public and private pastes with access restrictions.
• Caching: Performance optimization via caching frequently accessed data.
• Basic Authentication: Secure endpoints with HTTP Basic Auth.
• RESTful API: Well-structured API design to facilitate client integrations.

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Tech Stack

• Backend: Java, Spring Boot
• Database: MongoDB
• Security: Spring Security (Basic Auth, BCrypt password encoding)
• Caching: Spring Cache abstraction (e.g., with Redis or in-memory)
• Build & Dependency: Maven
• Testing: Postman (for API testing and visualization)

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System Design Highlights

• Modular service and controller layers to separate business logic.
• Use of caching annotations (@Cacheable, @CacheEvict, @CachePut) to balance consistency and performance.
• Thoughtful data modeling with MongoDB documents for pastes.
• Secure password storage using BCrypt hashing.
• Expiry mechanism with timestamp checks and background cleanup.
• Selective authentication configuration allowing public and protected endpoints.

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Project Structure

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Getting Started

Prerequisites

• Java 17 or above installed.
• MongoDB installed and running.
• Maven build tool.

Installation & Setup

1. Clone the repository:

   git clone [https://github.com/Jay-1409/codePaste.git](https://github.com/Jay-1409/codePaste.git)
   cd codePaste

2. Configure MongoDB: Update src/main/resources/application.properties with your MongoDB URI:

   spring.data.mongodb.uri=mongodb://localhost:27017/codepaste

3. Build the project:

   ./mvnw clean install

4. Run the application:

   ./mvnw spring-boot:run

Authentication

The app uses Basic Authentication. Default user credentials are:

• Username: user
• Password: password

You can customize this in the SecurityConfig class. By default all apis are set to be allowed without authentication.

API Endpoints

• POST /paste/addPaste — Create a new paste.
• GET /paste/{pasteId} — Retrieve a paste by its ID.
• DELETE /paste/deletePaste?pasteId=xxx — Delete a paste by ID.

Additional endpoints are secured except those explicitly configured to be public.

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Future Improvements

• Implement user registration and paste ownership.
• Add richer metadata and search functionality.
• Integrate rate limiting and abuse prevention.
• Provide a frontend client for better UX.

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Contribution

This repository is mainly for demonstration and learning purposes. Feel free to fork and experiment.

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License

This project is open-source and free to use.

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Built with ❤️ by Jay-1409