Listly Backend API

A robust RESTful API backend built with NestJS for managing listings, users, categories, and messages. This application provides a scalable foundation for a marketplace or listing platform.

🚀 Features

• User Management: Create, read, update, and delete users
• Listings Management: Full CRUD operations for product/service listings
• Category System: Organize listings with categories
• Messaging System: User-to-user messaging functionality
• Rate Limiting: Built-in protection against API abuse (10 requests per 60 seconds)
• Input Validation: Automatic request validation using DTOs
• Error Handling: Comprehensive error handling with appropriate HTTP status codes
• Type Safety: Full TypeScript support with Prisma ORM

🛠️ Tech Stack

• Framework: NestJS (v11.0.1)
• Language: TypeScript
• Database: PostgreSQL
• ORM: Prisma
• Validation: class-validator, class-transformer
• Rate Limiting: @nestjs/throttler

📋 Prerequisites

Before you begin, ensure you have the following installed:

• Node.js (v18 or higher)
• npm or yarn
• PostgreSQL (v12 or higher)
• Prisma CLI (included as dev dependency)

🔧 Installation

1. Clone the repository

   git clone <repository-url>
   cd Listly_Backend

2. Install dependencies

   npm install

3. Set up environment variables

   Create a .env file in the root directory:

   DATABASE_URL="postgresql://username:password@localhost:5432/listly_db?schema=public"
   PORT=4000

4. Set up the database

   # Generate Prisma Client
   npx prisma generate
   
   # Run database migrations
   npx prisma migrate dev
   
   # (Optional) Seed the database
   npx prisma db seed

🚀 Running the Application

Development Mode

Start the application in watch mode (auto-reload on file changes):

npm run start:dev

The API will be available at http://localhost:4000 (or the port specified in your .env file).

Production Mode

1. Build the application

   npm run build

2. Start the production server

   npm run start:prod

Other Commands

# Start without watch mode
npm run start

# Start in debug mode
npm run start:debug

# Format code
npm run format

# Lint code
npm run lint

📚 API Endpoints

Users

• GET /users - Get all users
• GET /users?id={id} - Get user by ID
• POST /users - Create a new user
• PUT /users/:id - Update a user
• DELETE /users/:id - Delete a user

Listings

• GET /listings - Get all listings
• GET /listings?id={id} - Get listing by ID
• GET /listings?user={userId} - Get listings by user
• GET /listings?category={categoryName} - Get listings by category
• POST /listings - Create a new listing
• PUT /listings/:id - Update a listing
• DELETE /listings/:id - Delete a listing

Categories

• GET /categories - Get all categories
• POST /categories - Create a new category
• DELETE /categories/:id - Delete a category

Messages

• GET /messages?sender={senderId} - Get messages by sender
• GET /messages?sender={senderId}&recipient={recipientId} - Get messages between users
• POST /messages - Create a new message
• DELETE /messages/:id - Delete a message

🔒 Rate Limiting

The API implements rate limiting to protect against abuse:

• Limit: 10 requests per 60 seconds per IP address
• Response: HTTP 429 (Too Many Requests) when limit is exceeded
• Window: Sliding window based on first request timestamp

To customize rate limits, modify the configuration in src/app.module.ts:

ThrottlerModule.forRoot([{
  ttl: 60000, // Time window in milliseconds
  limit: 10,  // Maximum requests per window
}]),

📁 Project Structure

src/
├── app.module.ts          # Root application module
├── main.ts                # Application entry point
├── prisma.service.ts      # Prisma database service
├── users/                 # User module
│   ├── users.controller.ts
│   ├── users.service.ts
│   └── dto/
├── listings/              # Listing module
│   ├── listings.controller.ts
│   ├── listings.service.ts
│   └── dto/
├── categories/            # Category module
│   ├── categories.controller.ts
│   ├── categories.service.ts
│   └── dto/
└── messages/             # Message module
    ├── messages.controller.ts
    ├── messages.service.ts
    └── dto/

🧪 Testing

# Unit tests
npm run test

# E2E tests
npm run test:e2e

# Test coverage
npm run test:cov

# Watch mode
npm run test:watch

🗄️ Database Management

Prisma Commands

# View database in Prisma Studio
npx prisma studio

# Create a new migration
npx prisma migrate dev --name migration_name

# Reset database (⚠️ deletes all data)
npx prisma migrate reset

# Generate Prisma Client after schema changes
npx prisma generate

⚠️ Error Handling

The API uses standard HTTP status codes:

• 200 - Success
• 201 - Created
• 400 - Bad Request (validation errors)
• 404 - Not Found
• 409 - Conflict (e.g., duplicate email)
• 429 - Too Many Requests (rate limit exceeded)

🔐 Security Features

• Input validation on all endpoints
• Rate limiting to prevent abuse
• SQL injection protection (via Prisma ORM)
• Type-safe database queries

📄 License

This project is private and unlicensed.

🤝 Contributing

This is a private project. For questions or issues, please contact the project maintainer.

📞 Support

For NestJS-related questions:

• NestJS Documentation
• NestJS Discord

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Built with ❤️ using NestJS