//https://eventstore.org/blog/20130306/getting-started-part-3-subscriptions/
//SubscribeToAllFrom(this IEventStoreConnection target,
// Position? lastCheckpoint,
// CatchUpSubscriptionSettings settings,
// Action<EventStoreCatchUpSubscription, ResolvedEvent> eventAppeared,
// Action<EventStoreCatchUpSubscription> liveProcessingStarted = null,
// Action<EventStoreCatchUpSubscription, SubscriptionDropReason, Exception> subscriptionDropped = null,
// UserCredentials userCredentials = null)
private Action <EventStoreCatchUpSubscription, ResolvedEvent> eventAppeared(Projection projection)
=> async(_, e) =>
{
// check system events and ignore them...
if (e.OriginalEvent.EventType.StartsWith("$"))
{
return;
}
// find event type
var eventType = eventTypeMapper.GetEventType(e.Event.EventType);
if (eventType == null)
{
return;
}
// deserialize the event.
var domainEvent = serializer.Deserialize(e.Event.Data, eventType);
//build your projection
await projection.Handle(domainEvent);
//store current checkpoint
checkpointStore.SetCheckpoint(e.OriginalPosition.Value, projection);
Console.WriteLine($"{domainEvent} projected into {projection}");
};
public async Task <Snapshot> GetSnapshotAsync <T>(Type type, Guid aggregateId)
{
Snapshot snapshot = default(Snapshot);
var stream = getStreamName(type, aggregateId.ToString());
Console.WriteLine("getting snapshot stream name:" + stream);
var streamEvents = await eventStoreConnection.ReadStreamEventsBackwardAsync(stream, StreamPosition.End, 1, false);
Console.WriteLine("found events:" + streamEvents.Events.Length);
if (streamEvents.Events.Any())
{
var result = streamEvents.Events.FirstOrDefault();
var t = eventTypeMapper.GetEventType(result.Event.EventType);
Console.WriteLine("Typeof" + t.FullName);
Console.WriteLine("Typeof" + Encoding.ASCII.GetString(result.OriginalEvent.Data));
snapshot = (Snapshot)serializer.Deserialize(result.OriginalEvent.Data, t);
Console.WriteLine("build snapshot:" + snapshot.AggregateId);
return(snapshot);
}
return(null);
}
