gnidan / guestbook-712

Example Guestbook contract using EIP-712 signatures

guestbook-712

Example Guestbook contract using EIP-712 signatures

Contents

This repository houses a Truffle project.

It contains the following core components:

• Guestbook.sol smart contract in Solidity using @openzeppelin/contracts for EIP-712 verification.
• guestbookUtils.js helpers for performing signature operations for a given deployed Guestbook

Notes about this Truffle project

• There's no Migrations.sol. Yep, that file is completely optional.
• Compiler version is specified as version: "pragma". Did you know you could do that? 😄
• Ignore the weird RPC URL. No secret unreleased features here. 🤫
• The console: section in truffle-config.js is recent new functionality. Pretty handy!

Guestbook contract

Aggregates signed log entries. This contract defines an EIP-712 schema and verifies the validity of the signature for each entry.

Anyone may spend gas to submit a signed guestbook log from anyone else, as long as the signature and message match.

guestbookUtils.js module

This module serves as a truffle console "require" hook, adding the forGuestbook global function to the console scope.

Usage

1. Run truffle console or truffle develop

2. Ensure you have run migrations (i.e. with truffle migrate command)

3. Initialize utils:

   // get deployed guestbook
   truffle(develop)> const guestbook = await Guestbook.deployed();
   
   // pass instance to function defined by "require" hook
   truffle(develop)> const utils = forGuestbook(guestbook);
   
   // read current guestbook logs
   truffle(develop)> utils.read();
   
   // sign message and capture result to variable
   truffle(develop)> const signedMessage = await utils.sign("hi!");
   
   // submit signed message in transaction to save
   truffle(develop)> utils.submit(signedMessage);
   
   // read guestbook logs again and see new entry
   truffle(develop)> utils.read();