Ethereum Auction dApp

A decentralized auction application built with Solidity smart contracts and Next.js. This project demonstrates a complete blockchain application that allows users to create auctions, place bids, and manage the auction lifecycle.

Features

Smart Contract Functionality

• Timed auctions with automatic ending
• Highest bid tracking
• Automatic refund of outbid participants
• Secure funds transfer to beneficiary on auction completion

Frontend Interface

• Connect MetaMask wallet
• View current auction status
• Place bids with ETH
• Withdraw previous bids if outbid
• End auction when time expires

Technologies Used

Smart Contracts

• Solidity ^0.8.28
• Hardhat development environment
• Hardhat Ignition for deployments
• TypeScript for type-safe deployment scripts

Frontend

• Next.js React framework
• Ethers.js v5.8.0 for blockchain interactions
• TypeScript for type safety
• Styled-JSX for component styling

Testing

• Hardhat testing framework
• Chai assertion library

Project Structure

Prerequisites

• Node.js v16+ and npm
• MetaMask or another Ethereum wallet browser extension
• Basic knowledge of Ethereum and smart contracts

Installation & Setup

1. Clone the repository.
2. Install dependencies.
3. Compile contracts.
4. Generate TypeScript contract types.

Usage

Local Development

1. Start a local Ethereum node.
2. Deploy the auction contract.
3. Update the contract address in index.tsx with the deployed contract address.
4. Start the frontend.
5. Access the application at http://localhost:3000 with MetaMask installed.

Configuring MetaMask

1. Open MetaMask and add a new network:
   • Network Name: Hardhat Local
   • New RPC URL: http://127.0.0.1:8545
   • Chain ID: 31337
   • Currency Symbol: ETH
2. Import one of the private keys shown when you started the Hardhat node to interact with the dApp.

Testing

Run the test suite with:

npx hardhat test

Smart Contract Details

SimpleAuction Contract

The SimpleAuction contract implements a time-limited auction with the following main functions:

• constructor(uint _biddingTime, address payable _beneficiary) - Creates a new auction.
• bid() - Submit a bid (payable function).
• withdraw() - Withdraw funds from previous outbid.
• auctionEnd() - End the auction and transfer funds to the beneficiary.

Events

• HighestBidIncreased(address bidder, uint amount) - Emitted when a new highest bid is placed.
• AuctionEnded(address winner, uint amount) - Emitted when the auction ends.

Troubleshooting

Common Issues

MetaMask Connection Problems

• Ensure MetaMask is connected to the correct network.
• Refresh the page.
• Check console logs for specific errors.

Dependency Conflicts

• This project uses ethers v5.8.0, which may conflict with other packages requiring ethers v6.
• Use the --legacy-peer-deps flag if needed when installing new packages.

Contract Deployment Failures

• Ensure your Hardhat node is running.
• Clear Ignition cache if needed: rm -rf .ignition.

License

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

Acknowledgments

• Hardhat
• Next.js
• Ethers.js
• TypeChain

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

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