NFT Ticketing Event Marketplace - Backend Hardhat

📌 Table of Contents

• Overview
• Features
• Tech Stack
• Architecture
• Smart contracts
• Getting Started
• Testing
• Deployment
• Gas Optimization
• Security Considerations
• Future Enhancements
• Contributing
• License

🌟 Overview

This project implements the backend for an NFT Ticketing Event Marketplace. By leveraging NFTs (Non-Fungible Tokens), this cutting-edge decentralized application (dApp) provide a secure, transparent, and efficient platform for event organizers to create and sell tickets, while offering attendees a unique and verifiable digital asset.

🚀 Features

• Event Creation: Organizers can easily create and manage events with customizable parameters.
• NFT Ticket Minting: Generate unique NFT tickets for each event with embedded metadata.
• Secure Marketplace: List, buy, and sell NFT tickets with built-in royalties for organizers.
• Ticket Verification: Blockchain-based verification ensures ticket authenticity and prevents fraud.
• Secondary Market: Enable secure peer-to-peer ticket reselling with price caps to prevent scalping.
• Event Discovery: Users can browse and search for events using various filters.
• Smart Contract Automation: Automate ticket sales, distributions, and refunds using smart contracts.

💻 Tech Stack

• Blockchain: Ethereum, Polygon (Amoy Testnet)
• Smart Contract: Solidity ^0.8.19
• Development Environment: Hardhat
• Testing: Chai, Mocha
• Frontend: Next.js 13 (separate repository)
• Styling: TailwindCSS
• Version Control: Git, GitHub

🏗 Architecture

A[Frontend - Next.js] -->|Web3.js| B(Blockchain)
B --> C[Smart Contracts]
C -->|Manages| D[NFT.sol]
C -->|Manages| E[Marketplace.sol]
D -->|Mints| F[NFT Tickets]
E -->|Lists/Sells| F
E -->|Creates| G[Events]

📜 Smart Contracts

1. NFT.sol:

• Implements ERC721 standard for NFT tickets
• Custom minting function with metadata support
• Royalty mechanism for secondary sales

2. Marketplace.sol:

• Event creation and management
• Ticket listing and sales functionality
• Secondary market controls
• Revenue distribution to relevant parties

🏁 Getting Started

1. Clone the repository

git clone https://github.com/adelamare-blockchain/Web3_Ticketing-Event-NFT-Marketplace_backend.git
cd backend

2. Install dependencies:

yarn install

3. Set up environment variables:

cp .env.example .env
# Edit .env with your configuration

4. Compile smart contracts:

npx hardhat compile

🧪 Testing

We've implemented comprehensive tests to ensure the reliability and security of our smart contracts. Run the test suite with:

npx hardhat test

Test Coverage

| File | % Stmts | % Branch | % Funcs | % Lines |
|------------|--------|---------|--------|--------|
| Marketplace.sol | 100% | 95.45% | 100% | 100% |
| NFT.sol | 100% | 100% | 100% | 100% |

Key Test Results

Marketplace
Deployment
✓ Should deploy the contract correctly
✓ Should track name and symbol of the nft collection
✓ Should update the listing price
Event Creation
✓ Should create an event
✓ Should return all created events of the marketplace
NFT Minting
✓ Should track 3 new minted NFTs
✓ Should fail if ticketPrice is not equal to listingPrice
Market Operations
✓ Should transfer minted NFTs from seller to marketplace
✓ Should emit offered event for 2 new NFTs on marketplace
✓ Should return all the fetched market items
✓ Should return the fetch market items of one creator (addr1)
✓ Should return the fetch market items of one event (event1)
Sales
✓ Should update item as sold, pay seller, transfer NFT to buyer, and charge fees
✓ Should return the sold market item bought by addr3 with fetchMyNFTs()
✓ Should return all the unsold fetched market items

15 passing (7s)

🚀 Deployment

To deploy to Polygon Amoy testnet:

1. Ensure your .env file is configured with the correct private key and RPC URL

2. Run the deployment script:

npx hardhat run scripts/deploy.js --network amoy

3. Verify the contract on PolygonScan:

npx hardhat verify --network amoy DEPLOYED_CONTRACT_ADDRESS "Constructor argument 1"

⛽ Gas Optimization

We've implemented several gas optimization techniques to ensure efficient contract execution:

• Use of uint256 instead of uint8, uint16, etc.
• Appropriate use of view and pure functions
• Minimized storage reads/writes
• Use of events for off-chain tracking

** Gas Usage Report

·----------------------------------------|---------------------------|-------------|-----------------------------·
|           Solc version: 0.8.19         ·  Optimizer enabled: true  ·  Runs: 200  ·  Block limit: 30000000 gas  │
·········································|···························|·············|······························
|  Methods                                                                                                       │
·················|······················|·············|·············|·············|···············|··············
|  Contract      ·  Method               ·  Min        ·  Max        ·  Avg        ·  # calls      ·  eur (avg)  │
·················|······················|·············|·············|·············|···············|··············
|  Marketplace   ·  createEvent          ·     302821  ·     319801  ·     311311  ·           30  ·          -  │
·················|······················|·············|·············|·············|···············|··············
|  Marketplace   ·  createMarketSale     ·     130575  ·     130587  ·     130581  ·            4  ·          -  │
·················|······················|·············|·············|·············|···············|··············
|  Marketplace   ·  createMarketTicket   ·     222138  ·     261150  ·     234870  ·           46  ·          -  │
·················|······················|·············|·············|·············|···············|··············
|  Marketplace   ·  updateListingPrice   ·          -  ·          -  ·      29770  ·            1  ·          -  │
·················|······················|·············|·············|·············|···············|··············
|  NFT           ·  mintNFT              ·      85807  ·     139907  ·     117832  ·           60  ·          -  │
·················|······················|·············|·············|·············|···············|··············
|  Deployments                           ·                                         ·  % of limit   ·             │
·········································|·············|·············|·············|···············|··············
|  Marketplace                           ·          -  ·          -  ·    2227441  ·        7.4 %  ·          -  │
·········································|·············|·············|·············|···············|··············
|  NFT                                   ·    1374951  ·    1374963  ·    1374962  ·        4.6 %  ·          -  │
·----------------------------------------|-------------|-------------|-------------|---------------|-------------·

🔒 Security Considerations

• Implemented reentrancy guards using OpenZeppelin's ReentrancyGuard
• Used SafeMath library for arithmetic operations
• Access control implemented with Ownable contract
• Thorough input validation in all public functions
• Events emitted for all critical state changes

🔮 Future Enhancements

1. Integration with decentralized identity solutions for KYC/AML compliance
2. Implementation of a governance token for community-driven decision making
3. Cross-chain compatibility for multi-blockchain support
4. Integration with layer-2 solutions for improved scalability

🤝 Contributing

We welcome contributions to the NFT Ticketing Event Marketplace! Any contributions you make are greatly appreciated. Don't forget to give the project a star! Thanks again!

📄 License

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

🚀 Developed with ❤️ by Antoine Delamare