eip712

Generates Solidity code to verify [EIP-712] style signatures.

Usage

First, create an abstract contract implementing the functionality you want:

```solidity // SPDX-License-Identifier: CC0-1.0

pragma solidity ^0.8.11;

abstract contract NameRegistry { mapping (string => address) public nameToAddress; mapping (address => string) public addressToName;

// This `claim` function implements the functionality you want to expose
// via an EIP-712 signature.
//
// Importantly, the first argument must be the sender's address, and
// the function must be internal.
function claim(address sender, string memory name) internal {
    require(bytes(addressToName[sender]).length == 0, "address already registered");
    require(nameToAddress[name] == address(0), "name already registered");

    addressToName[sender] = name;
    nameToAddress[name] = sender;
}

// You can optionally expose your functionality using `msg.sender`.
function claim(string memory name) external {
    claim(msg.sender, name);
}

// Finally, you should declare an abstract function that accepts a signature.
//
// The implementation will be generated for you.
function claim(string memory name, uint8 v, bytes32 r, bytes32 s) external virtual;

} ```

On the Command Line

Install eip712-cli:

bash $ cargo install eip712-cli

Then run it with:

bash $ eip712 \ --base NameRegistry \ --signing-domain NameRegistry \ --version 1 \ --output /tmp/output.sol \ NameRegistry.json

As a Library

For advanced uses, this crate can be used as a library from Rust or JavaScript.

Rust

```rust use eip712::Eip712;

use std::io::Write;

fn main() { // Read the ABI file (normally generated by solc.) let abi = include_str!("NameRegistry.json");

let mut output = String::new();

// Configure and run the generator.
Eip712::<()>::new("NameRegistry")       // Name of the base contract.
    .signing_domain("NameRegistry")     // Name for the EIP-712 domain.
    .version("1")                       // Contract version.
    .read_str(abi)
    .unwrap()
    .generate(&mut output)
    .unwrap();

std::io::stdout().write_all(output.as_bytes()).unwrap();

} ```

JavaScript

```javascript import { default as eip712, Eip712 } from './eip712.js';

async function main() { await eip712();

// Read the ABI file (normally generated by `solc`.)
const resp = await fetch("./NameRegistry.json");
const abi = await resp.text();

// Configure and run the generator.
const output = new Eip712("NameRegistry")   // Name of the base contract.
    .error(console.log)                     // Error handler.
    .warning(console.log)                   // Warning handler.
    .signing_domain("NameRegistry")         // Name for the EIP-712 domain.
    .version("1")                           // Contract version.
    .read_str(abi)
    .generate();

let elem = document.createElement('pre');
elem.innerText = output;
document.body.appendChild(elem);

}

main(); ```