File Storage System

A blockchain-backed file storage application built with Solidity smart contracts, Hardhat for development, and React for the frontend. Files are stored on IPFS via Pinata, with metadata tracked on-chain.

Features

• Upload files to IPFS through Pinata
• Store file metadata on Ethereum blockchain
• Retrieve and display uploaded files
• Local blockchain testing with Hardhat

Prerequisites

• Node.js (v16 or higher)
• npm or yarn
• Git
• MetaMask (for interacting with the deployed contracts)

Installation

1. Clone the repository

git clone https://github.com/yourusername/file-storage-system.git
cd file-storage-system

2. Install dependencies

# Install root dependencies
npm install

# Install client dependencies
cd client
npm install

3. Configure environment variables

Backend Configuration (Hardhat)

Create a .env file in the project root:

API_URL=https://eth-sepolia.g.alchemy.com/v2/your-api-key
PRIVATE_KEY=your-wallet-private-key

Frontend Configuration (React)

Create a .env file in the client directory:

REACT_APP_PINATA_API_KEY=your_pinata_api_key
REACT_APP_PINATA_SECRET_API_KEY=your_pinata_secret_key

Security Warning: Never commit .env files to version control. Add them to .gitignore.

Running the Project

Start Local Blockchain

In one terminal window:

cd client
npx hardhat node

This starts a local Ethereum node at http://127.0.0.1:8545/

Deploy Smart Contracts

In another terminal window:

cd client
npx hardhat run scripts/deploy.js --network localhost

Copy the deployed contract address from the output.

Start React Application

cd client
npm start

The app will open at http://localhost:3000

Project Structure

file-storage-system/
├── client/
│   ├── contracts/          # Solidity smart contracts
│   ├── scripts/            # Deployment scripts
│   ├── src/                # React application source
│   ├── hardhat.config.js   # Hardhat configuration
│   └── package.json
├── .gitignore
├── package.json
└── README.md

Environment Variables

Required Variables

Variable	Location	Description
API_URL	Root .env	Alchemy or Infura RPC URL
PRIVATE_KEY	Root .env	Wallet private key for deployment
REACT_APP_PINATA_API_KEY	client/.env	Pinata API key
REACT_APP_PINATA_SECRET_API_KEY	client/.env	Pinata secret key

Security Best Practices

• Add .env files to .gitignore
• Use .env.example files for templates
• Never hardcode secrets in source code
• REACT_APP_* variables are exposed in the browser bundle
• For production, use a backend proxy for sensitive API operations

Testing

Run smart contract tests:

cd client
npx hardhat test

Deployment

Deploy to Testnet (Sepolia)

1. Ensure you have testnet ETH in your wallet
2. Configure API_URL in .env with your Alchemy/Infura endpoint
3. Deploy:

cd client
npx hardhat run scripts/deploy.js --network sepolia

Deploy Frontend

The React app can be deployed to:

• Vercel: vercel deploy
• Netlify: netlify deploy
• GitHub Pages: Configure in package.json

Remember to set environment variables in your hosting platform's dashboard.

Contributing

Contributions are welcome! Please follow these steps:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Hardhat - Ethereum development environment
• Pinata - IPFS pinning service
• OpenZeppelin - Secure smart contract libraries