private void ValidateTx(
RelayResponse returnedTx,
TransactionInput transaction,
BigInteger txFee,
BigInteger gasPrice,
BigInteger gasLimit,
BigInteger nonce,
string relayHubAddress,
string relayAddress)
{
var tx = returnedTx.ToTransaction();
var signer = tx.Key.GetPublicAddress();
var functionEncodingService = new FunctionMessageEncodingService <RelayCallFunction>();
var relayCall = functionEncodingService.DecodeInput(new RelayCallFunction(), returnedTx.Input);
var returnedTxHash = GetTransactionHash(
relayCall.From,
relayCall.To,
relayCall.EncodedFunction.ToHex(),
relayCall.TransactionFee,
relayCall.GasPriceParam,
relayCall.GasLimit,
relayCall.NonceParam,
returnedTx.To,
signer);
var hash = GetTransactionHash(
transaction.From,
transaction.To,
transaction.Data,
txFee,
transaction.GasPrice.Value,
transaction.Gas.Value,
nonce,
relayHubAddress,
relayAddress);
if (returnedTxHash.EnsureHexPrefix().ToLower() != hash.EnsureHexPrefix().ToLower() ||
signer.EnsureHexPrefix().ToLower() != relayAddress.EnsureHexPrefix().ToLower())
{
throw new GSNRelayInvalidResponseException();
}
}
private async Task <string> SendViaRelay(
string relayUrl,
TransactionInput transaction,
BigInteger txFee,
BigInteger gasPrice,
BigInteger gasLimit,
BigInteger nonce,
string relayHubAddress,
string relayAddress,
string signature,
string approvalData,
BigInteger relayMaxNonce)
{
var requestData = new RelayRequest
{
EncodedFunction = transaction.Data,
Signature = signature.HexToByteArray(),
ApprovalData = approvalData.HexToByteArray(),
From = transaction.From,
To = transaction.To,
GasPrice = gasPrice,
GasLimit = gasLimit,
RelayFee = txFee,
RecipientNonce = nonce,
RelayMaxNonce = relayMaxNonce,
RelayHubAddress = relayHubAddress,
UserAgent = _options.UserAgent
};
RelayResponse relayResponse = await _relayClient.RelayAsync(new Uri(relayUrl), requestData)
.ConfigureAwait(false);
if (!string.IsNullOrEmpty(relayResponse.Error))
{
throw new Exception(relayResponse.Error);
}
if (relayResponse.Nonce.Value.IsZero)
{
throw new Exception("Empty body received from server, or neither 'error' nor 'nonce' fields present.");
}
ValidateTx(
relayResponse,
transaction,
txFee,
gasPrice,
gasLimit,
nonce,
relayHubAddress,
relayAddress);
var tx = relayResponse.ToTransaction();
string hash = string.Empty;
var ethSendTransaction = new EthSendRawTransaction(_client);
try
{
hash = await ethSendTransaction.SendRequestAsync(tx.GetRLPEncoded().ToHex().EnsureHexPrefix())
.ConfigureAwait(false);
}
catch (Exception ex)
{
if (!ex.Message.Contains("the tx doesn't have the correct nonce") &&
!ex.Message.Contains("known transaction") &&
!ex.Message.Contains("nonce too low"))
{
throw ex;
}
}
var txHash = relayResponse.Hash;
if (!string.IsNullOrEmpty(hash) &&
relayResponse.Hash.EnsureHexPrefix().ToLower() != hash.EnsureHexPrefix().ToLower())
{
txHash = hash;
}
return(txHash);
}