public async Task ScanCancelByEventsAsync()
{
string latestScannedBlockKey = "CancelLatestScannedBlock";
var abi = await _abiProvider.GetCrowdsaleAbiAsync();
var contract = _nethereumClient.Eth.GetContract(abi, _ethSettings.EtherDeltaContractAddress);
var cancelEvent = contract.GetEvent("Cancel");
var blockNumHex = await _nethereumClient.Eth.Blocks.GetBlockNumber.SendRequestAsync();
var blockNumLong = Convert.ToInt64(blockNumHex.Value.ToString());
//to avoid races conditions between services
blockNumLong -= 5;
var latestScannedBlock = await _parametersService.GetLatestScannedBlockAsync(latestScannedBlockKey);
var fromBlock = new BlockParameter(Convert.ToUInt64(latestScannedBlock + 1));
var filterInput = cancelEvent.CreateFilterInput(fromBlock);
var logs = await _etherscanService.GetEventsAsync(filterInput, latestScannedBlock + 1, blockNumLong);
var eventLogsAll = cancelEvent.DecodeAllEventsForEvent <CancelEvent>(logs);
var detectedTransactionHashes = eventLogsAll.Select(l => l.Log.TransactionHash).ToList();
var existingDbTransactions = _context.CancelEvent
.Where(t => detectedTransactionHashes.Contains(t.TransactionHash))
.ToDictionary(t => t.TransactionHash, t => t);
foreach (var eventEntry in eventLogsAll)
{
if (existingDbTransactions.TryGetValue(eventEntry.Log.TransactionHash, out var dbTransaction))
{
continue;
}
var transaction = await _nethereumClient.Eth.Transactions.GetTransactionByHash.SendRequestAsync(eventEntry.Log.TransactionHash);
var receipt = await _nethereumClient.Eth.Transactions.GetTransactionReceipt.SendRequestAsync(eventEntry.Log.TransactionHash);
var block = await _nethereumClient.Eth.Blocks.GetBlockWithTransactionsByNumber.SendRequestAsync(transaction.BlockNumber);
var epoch = Convert.ToInt64(block.Timestamp.Value.ToString());
var dbEvent = new CancelEventModel
{
TokenGet = eventEntry.Event.TokenGet,
AmountGet = eventEntry.Event.AmountGet.ToString(),
TokenGive = eventEntry.Event.TokenGive,
AmountGive = eventEntry.Event.AmountGive.ToString(),
Expires = eventEntry.Event.Expires.ToString(),
Nonce = eventEntry.Event.Nonce.ToString(),
User = eventEntry.Event.User,
Hash = ComputeHash(eventEntry.Event as CancelEvent),
TransactionHash = eventEntry.Log.TransactionHash,
Timestamp = DateTimeOffset.FromUnixTimeSeconds(epoch),
BlockNum = Convert.ToInt64(transaction.BlockNumber.Value.ToString()),
GasPriceWei = Convert.ToInt64(transaction.GasPrice.Value.ToString()),
GasUsed = Convert.ToInt64(receipt.GasUsed.Value.ToString()),
};
await _context.CancelEvent.AddAsync(dbEvent);
}
await _parametersService.SetLatestScannedBlockAsync(latestScannedBlockKey, blockNumLong);
await _context.SaveChangesAsync();
}
