public IObservable <DealRowViewModel> GetDealUpdates(Guid dealId)
{
//Subscribe to the EventStream looking for the DealId
var streamName = StreamNames.DealStreamName(dealId);
return(_eventStoreClient.GetEvents(streamName)
.Scan <ResolvedEvent, DealRowViewModel>(null, AccumlateDealEvents));
}
protected override async Task ProcessJsonAsync(string json, CancellationToken token = default)
{
try
{
//string streamName;
//IJsonStreamObserver[] subscribers;
// NOTE: Avoid locking... allowing for eventual consistency of subscribers.
//lock (_sync)
//{
var jObject = JObject.Parse(json);
// Get stream name.
var streamName = jObject["stream"]?.Value <string>();
if (streamName != null)
{
// Get JSON data.
var data = jObject["data"]?.ToString(Formatting.None);
if (data == null)
{
Logger?.LogError($"{nameof(BinanceWebSocketStream)}: No JSON 'data' in message: \"{json}\" [thread: {Thread.CurrentThread.ManagedThreadId}]");
return; // ignore.
}
json = data;
}
if (streamName == null)
{
// Get stream name.
streamName = StreamNames.FirstOrDefault();
if (streamName == null)
{
Logger?.LogError($"{nameof(BinanceWebSocketStream)}: No subscribed streams. [thread: {Thread.CurrentThread.ManagedThreadId}]");
return; // ignore.
}
}
if (!Subscribers.TryGetValue(streamName, out var observers))
{
return; // ignore.
}
// Get subscribers.
var subscribers = observers?.ToArray();
//}
await NotifyListenersAsync(subscribers, streamName, json, token)
.ConfigureAwait(false);
}
catch (OperationCanceledException) { /* ignored */ }
catch (Exception e)
{
if (!token.IsCancellationRequested)
{
Logger?.LogError(e, $"{nameof(BinanceWebSocketStream)}: Failed processing JSON message. [thread: {Thread.CurrentThread.ManagedThreadId}]");
}
}
}
private async Task ProcessNext()
{
//TODO: Allow cancellation
var cmd = await _messageBusClient.Dequeue <CreateDealCommand>();
//Run slow just for fun
await Task.Delay(TimeSpan.FromSeconds(2));
//Create the DealCreatedEvent in the new Deal-GUID stream.
var streamName = StreamNames.DealStreamName(cmd.DealId);
var eventId = Guid.NewGuid(); //Is this correct? Or should it be cmd.DealId? Or something else?
var payload = cmd.ToJson();
await _eventStoreClient.SaveEvent(streamName, ExpectedVersion.NoStream, eventId, "DealCreated", payload);
//We will use Projections to merge them together.
}
public async Task <int> GetDealUpdatesHead(Guid dealId)
{
var streamName = StreamNames.DealStreamName(dealId);
return(await _eventStoreClient.GetHeadVersion(streamName));
}