Create a EIP712 TypedData signature

[OnChainArt]

Hi,

I need to do a EIP712 signature in my app. I saw that web3swift allowed EIP712 but when I saw the test file https://github.com/skywinder/web3swift/blob/e733e077a613cba3a68ec7b480f1f7ef1a22d316/Tests/web3swiftTests/localTests/EIP712Tests.swift I saw that it uses a predetermined Gnosis SafeTX. I would like to know how to change the parameters of the safetx to be able to create a correct signature.

[JeneaVranceanu]

Hello, @OnChainArt !
Looks like Web3Signer.signEIP712 must accept any EIP712Hashable object and not just SafeTx. That's a mistake on the side of the library. I've just updated locally the type of the first input argument of that function, ran tests and can confirm that it will fix the issue.
We will fix that in the upcoming release.

Temporarily you can use the implementation from Web3Signer.signEIP712 in a place where you need to construct a signature or you can create a copy of that function temporarily if you need that in multiple places:

public func signEIP712(_ eip712HashableMessage: EIP712Hashable,
                       keystore: BIP32Keystore,
                       verifyingContract: EthereumAddress,
                       account: EthereumAddress,
                       password: String? = nil,
                       chainId: BigUInt? = nil) throws -> Data {

    let domainSeparator: EIP712DomainHashable = EIP712Domain(chainId: chainId, verifyingContract: verifyingContract)

    let password = password ?? ""
    let hash = try eip712encode(domainSeparator: domainSeparator, message: eip712HashableMessage)

    guard let signature = try Web3Signer.signPersonalMessage(hash, keystore: keystore, account: account, password: password) else {
        throw Web3Error.dataError
    }

    return signature
}

You can even copy-paste this function outside of any class/struct to make it accessible globally.
I'll post updates here as PR will be opened and merged.

[JeneaVranceanu]

Looks like you'll have to wait until this fix is released as eip712encode function is not public.

[OnChainArt]

Looks like you'll have to wait until this fix is released as eip712encode function is not public.

Thanks for your reply! I hope it gets fixed soon as it is really relevant for my app.