LeetCode Clone Backend

A backend service for a LeetCode-like platform, featuring user management, RESTful APIs, PostgreSQL integration, and Redis caching for improved performance.

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Table of Contents

• Features
• Project Structure
• Local Development
  • Manual Setup
  • Docker
  • Docker Compose
• Environment Variables
• Scripts
• Additional Notes

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Features

• User authentication and management
• RESTful API endpoints
• PostgreSQL integration with Prisma ORM
• Redis caching for user data, authentication, and problem management
• Session management and data persistence
• (Add more features as your app grows)

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Project Structure

backend/
  ├── src/
  │   ├── config/
  │   │   └── redis.ts          # Redis client configuration
  │   ├── controllers/
  │   ├── middlewares/
  │   ├── models/
  │   ├── routes/
  │   ├── services/             # Business logic with Redis caching
  │   ├── utils/
  │   └── index.ts
  ├── prisma/
  ├── public/
  ├── Dockerfile
  ├── docker-compose.yaml
  ├── package.json
  └── ...

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Local Development

You can run the backend locally using one of the following methods:

Manual Setup

1. Clone the repository:

   git clone <repo-url>
   cd backend

2. Install dependencies:

   pnpm install
   # or
   npm install -g pnpm && pnpm install

3. Set up environment variables:

   • Create a .env file in the root directory. Example:

     PORT=5001
     DATABASE_URL=postgres://leetcode:leetcode@localhost:5432/leetcode_db
     REDIS_HOST=localhost
     REDIS_PORT=6379
     # Add other variables as needed (see .env.example)
     

4. Start PostgreSQL:

   • You must have a PostgreSQL server running.
     You can use an existing instance, or start one with Docker:

     docker run --name leetcode-postgres -e POSTGRES_USER=leetcode -e POSTGRES_PASSWORD=leetcode -e POSTGRES_DB=leetcode_db -p 5432:5432 -d postgres:16.9-alpine

5. Start Redis:

   • You must have a Redis server running. You can use an existing instance, or start one with Docker:

     docker run --name leetcode-redis -p 6379:6379 -d redis

6. Generate Prisma client:

   pnpm prisma generate

7. Build and start the server:

   pnpm build && pnpm start
   # or for development
   pnpm dev

• The backend will be available at http://localhost:5001
• Redis will be available at localhost:6379

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Docker

1. Start PostgreSQL and Redis containers:

   docker run --name leetcode-postgres -e POSTGRES_USER=leetcode -e POSTGRES_PASSWORD=leetcode -e POSTGRES_DB=leetcode_db -p 5432:5432 -d postgres:16.9-alpine
   
   docker run --name leetcode-redis -p 6379:6379 -d redis:7.2-alpine

   Or use your own PostgreSQL and Redis instances and update the environment variables in .env.

2. Build the backend Docker image:

   docker build -t leetcode-backend .

3. Run the backend container:

   docker run --env-file .env -p 5001:5001 leetcode-backend

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Docker Compose

1. Create a .env file in the root directory (see .env.example).

2. Start all services:

   docker-compose up --build

• This will start the backend, PostgreSQL, and Redis instances.
• The backend will be available at http://localhost:5001.
• PostgreSQL will be available inside the Docker network as postgres:5432.
• Redis will be available inside the Docker network as my-redis:6379.

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Environment Variables

Variable	Description	Example
PORT	Port for the backend server	5001
DATABASE_URL	PostgreSQL connection string	postgres://leetcode:leetcode@localhost:5432/leetcode_db
REDIS_HOST	Redis server host	localhost
REDIS_PORT	Redis server port	6379
(others)	See your .env file for more

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Scripts

• pnpm build – Build the TypeScript project
• pnpm start – Start the backend (after build)
• pnpm dev – Start in development mode (watch & auto-restart)
• pnpm prettier – Format code

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Additional Notes

• Use pnpm for dependency management (recommended).
• For code formatting, run pnpm prettier.
• Redis is used for caching user data, authentication tokens, and problem data to improve API response times.
• The Redis client is automatically initialized when the server starts.
• For any issues, please check the logs or open an issue.
• For production, review and secure your environment variables.