public async Task HandleSubscription <T>(
IStreamingClient client,
RpcStreamingSubscriptionObservableHandler <T> subscription,
Func <Task> subscribeFunc,
Action <T> onNext,
Func <Task> subscribeResponseFunc,
CancellationToken cancellationToken)
{
subscription.GetSubscriptionDataResponsesAsObservable().Subscribe(onNext);
var subscribed = false;
subscription.GetSubscribeResponseAsObservable().Subscribe(async id =>
{
subscribed = true;
subscribeResponseFunc?.Invoke();
await _messagingService.SendLogMessage($"Subscribed ID: {id}");
});
subscription.GetUnsubscribeResponseAsObservable().Subscribe(async r =>
{
subscribed = false;
await _messagingService.SendLogMessage($"Unsubscribed result: {r}");
});
await client.StartAsync();
await subscribeFunc();
SpinWait.SpinUntil(() => subscribed && cancellationToken.IsCancellationRequested);
await subscription.UnsubscribeAsync();
SpinWait.SpinUntil(() => !subscribed);
}
public async Task <T> SendQuery <T>(Dictionary <string, string> variableTypes = null, Dictionary <string, object> filters = null, Dictionary <string, HashSet <string> > exclusions = null, object variables = null, string operationName = null, CancellationToken cancellationToken = default)
{
using var graphQLClient = new GraphQLHttpClient(_batBotOptions.UniswapSubgraphUrl, new SystemTextJsonSerializer());
await _messagingService.SendLogMessage($"⚡ Sending Graph query '{typeof(T).GetCustomAttribute<DescriptionAttribute>()?.Description}' with variables '{variables}'");
return((await graphQLClient.SendQueryAsync <T>(new GraphQLRequest(BuildQuery(typeof(T), variableTypes, filters, exclusions), variables, operationName), cancellationToken)).Data);
}
public async Task Protect(Func <Task> action)
{
try
{
await _policyCircuitBreaker.ExecuteAsync(action);
}
catch (BrokenCircuitException e)
{
await _messagingService.SendLogMessage($"Exception: '{e.Message}'.");
}
catch (RpcResponseException e)
{
await _messagingService.SendLogMessage($"Exception: '{e.Message}'.");
}
catch (RpcClientUnknownException e)
{
await _messagingService.SendLogMessage($"Exception: '{e.Message}'.");
}
}
public async Task Subscribe(CancellationToken cancellationToken)
{
// http://docs.nethereum.com/en/latest/nethereum-subscriptions-streaming/
using var streamingClient = new StreamingWebSocketClient(_batBotOptions.BlockchainEndpointWssUrl);
var subscription = new EthNewPendingTransactionObservableSubscription(streamingClient);
await _ethereumService.HandleSubscription(streamingClient, subscription, async() => await subscription.SubscribeAsync(), async th =>
{
await _messagingService.SendLogMessage($"Pending Transaction Hash: {th}");
// Don't process transactions (discard) when one is being processed for front running.
if (_backoffService.BackOff())
{
return;
}
await _backoffService.Protect(async() => await _transactionProcessorService.Process(await _ethereumService.GetSwap(th), cancellationToken));
}, null, cancellationToken);
}