This is the final project for the 2021 Consensys Blockchain Developer course.

This project demonstrates how to use a VRF oracle to run a raffle. Oversubscribed projects in the NFT space and elsewhere currently struggle with fair distribution, and avoiding botting. Free-for-all mints result in incredibly high gas fees, with none of that cost going to the creator. By using a verifiable random function to select from a set of addresses we can improve this. In production, a cost-per-address or anti-botting measure could be added.

This project can be accessed at https://wpg-blockchain-course.netlify.app (as of 30/11/21).

This project is based on the React Truffle box.

• client - contains the frontend code, based on create-react-app.
• contracts - the Solidity code. Raffle.sol is the key file describing the contract.
• migrations - used by Truffle for deployment.
• test - contains Truffle tests for the Solidity code.

The project relies on Truffle, installed globally with npm install -g truffle.

To install the project dependencies, run npm install from the project root.

Run the development console with truffle develop.

Within the Truffle development environment, compile with compile and migrate with migrate (use migrate --network rinkeby --reset to re-deploy on the testnet). Run tests with test.

The contract code can be verified on Etherscan with truffle run verify Raffle --network rinkeby.

To run the frontend locally, install frontend dependencies with npm install from /client and npm run start to start the React app.

See the below screen recording for a demonstration of the project, including compilation, migration, testing, and interacting with the frontend.

https://www.loom.com/share/31ddc9df6e8e4610be1bcdd2551340a5

My address is 0xb6c5D999E32C806468A2fF165c2E679dDbD6e569 (williamgrant.eth).

• better react interface, better handling of errors (propagate to frontend)
• some anti-bot measure
• allow for multiple winners
• make contract upgradable with UUPS.
• listen to emitted events, update frontend