public async Task <string> SendTransactionAsync(TransactionInput transactionInput)
{
if (transactionInput == null)
{
throw new ArgumentNullException(nameof(transactionInput));
}
if (string.IsNullOrEmpty(transactionInput.From))
{
throw new Exception("From address is null of empty");
}
if (string.IsNullOrEmpty(transactionInput.To))
{
throw new Exception("Cannot deploy a new contract via the GSN");
}
var value = transactionInput.Value.HexValue;
if (value != "0" && value != "0x0")
{
throw new Exception("Cannot send funds via the GSN");
}
var relayHubAddress = await _relayHubManager
.GetHubAddressAsync(_contractAddress)
.ConfigureAwait(false);
await ValidateRecipientBalance(
relayHubAddress,
transactionInput.To,
transactionInput.Gas.Value,
transactionInput.GasPrice.Value,
new BigInteger(0))
.ConfigureAwait(false);
var relays = await _relayHubManager
.GetRelaysAsync(relayHubAddress, _relayPolicy)
.ConfigureAwait(false);
foreach (var lazyRelay in relays)
{
var relay = lazyRelay.Value;
if (!relay.Ready ||
relay.MinGasPrice.CompareTo(transactionInput.GasPrice.Value) == 1)
{
continue;
}
try
{
var hash = await RelayTransaction(relay, transactionInput, relayHubAddress)
.ConfigureAwait(false);
await _relayPolicy.GraceAsync(relay).ConfigureAwait(false);
return(hash);
}
catch
{
await _relayPolicy.PenalizeAsync(relay).ConfigureAwait(false);
continue;
}
}
return(null);
}
public async Task <string> Relay(
TransactionInput transaction,
Func <Relay, TransactionInput, string, Task <string> > relayFunc)
{
var relayHubAddress = await _relayHubManager
.GetHubAddressAsync(transaction.To)
.ConfigureAwait(false);
await _balanceValidator.Validate(
relayHubAddress,
transaction.To,
transaction.Gas.Value,
transaction.GasPrice.Value,
new BigInteger(0))
.ConfigureAwait(false);
var relays = await _relayHubManager
.GetRelaysAsync(relayHubAddress, _relayPolicy)
.ConfigureAwait(false);
BigInteger gasPrice = transaction.GasPrice;
BigInteger minGasPrice = default;
foreach (var lazyRelay in relays)
{
var relay = lazyRelay.Value;
if (minGasPrice == default)
{
minGasPrice = relay.MinGasPrice;
}
if (!relay.Ready ||
relay.MinGasPrice.CompareTo(gasPrice) == 1)
{
minGasPrice = BigInteger.Min(minGasPrice, relay.MinGasPrice);
continue;
}
try
{
var nonce = await _relayHubManager
.GetNonceAsync(relayHubAddress, transaction.From)
.ConfigureAwait(false);
transaction.Nonce = new HexBigInteger(nonce);
var hash = await relayFunc(relay, transaction, relayHubAddress)
.ConfigureAwait(false);
await _relayPolicy.GraceAsync(relay).ConfigureAwait(false);
return(hash);
}
catch
{
await _relayPolicy.PenalizeAsync(relay).ConfigureAwait(false);
continue;
}
}
var message = minGasPrice.CompareTo(gasPrice) == 1 ?
$"Relay not found. Minimum relay gas price is {minGasPrice}, provided {gasPrice}" :
null;
throw new GSNRelayNotFoundException(message);
}