Signing a tuple (struct) for ECDSA.recover

Question

I'm using web3js, and I'm trying to sign a tuple correctly.

Below you can see the solidity code for verification. I'm using draft-EIP712Upgradeable.sol

struct NFTVoucher {
    uint256 tokenId;
    uint256 minPrice; // in wei
    string uri;       // IPFS uri of metadata file
    bytes signature;  // the EIP-712 signature of all other fields in the NFTVoucher struct.
}

function _verify(NFTVoucher calldata voucher) public view returns (address) {
    bytes32 digest = _hash(voucher);
    return ECDSAUpgradeable.recover(digest, voucher.signature);
}

function _hash(NFTVoucher calldata voucher) internal view returns (bytes32) {
     return _hashTypedDataV4(keccak256(abi.encode(
         keccak256("NFTVoucher(uint256 tokenId,uint256 minPrice,string uri)"),
         voucher.tokenId,
         voucher.minPrice,
         keccak256(bytes(voucher.uri))
     )));
}

The frontend is built on ReactJs, web3js. The code you can find below 👇

let newHash = web3.utils.soliditySha3(
  web3.eth.abi.encodeParameters(
    [
      'uint256',
      'uint256',
      'string'
    ], 
    [
      tokenId,
      priceNumber,
      imageURL
    ]
  )
)

let sig = await web3.eth.sign(newHash, account); // "account" is the address of signer

---

So how should I change in the frontend code to pass the verification? If you need any other information please tell me. Any help is welcome. Thank youu!✌

Answer 1

Here is the solution guys:

let msgHash = web3.utils.soliditySha3(
    { type: "uint256", value: tokenId },
    { type: "uint256", value: priceNumber },
    { type: "string", value: imageURL }
)

let sig = await web3.eth.sign(msgHash, account);

:)