//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}");
};
Action <EventStoreCatchUpSubscription, ResolvedEvent> EventAppeared(Projection projection)
=> (_, e) =>
{
// always double check if it is a system event ;)
if (e.OriginalEvent.EventType.StartsWith("$"))
{
return;
}
// get the configured clr type name for deserializing the event
if (!_typeMapper.TryGetType(e.Event.EventType, out var eventType))
{
Log.Debug("Failed to find clr type for {eventType}. Skipping...", e.Event.EventType);
}
else
{
// deserialize event
var domainEvent = _serializer.Deserialize(e.Event.Data, eventType);
// try to execute the projection
if (projection.CanHandle(domainEvent))
{
projection.Handle(domainEvent).GetAwaiter().GetResult();
Log.Debug("{projection} handled {event}", projection, domainEvent);
}
}
// store the current checkpoint
_checkpointStore.SetCheckpoint(e.OriginalPosition, projection).GetAwaiter().GetResult();
};
private Action <EventStoreCatchUpSubscription, ResolvedEvent> EventAppeared(Projection projection) =>
async(_, e) =>
{
// always double check if it is a system event ;)
if (e.OriginalEvent.EventType.StartsWith("$"))
{
return;
}
// get the configured clr type name for deserializing the event
var eventType = _typeMapper.GetType(e.Event.EventType);
// try to execute the projection
await projection.Handle(_serializer.Deserialize(e.Event.Data, eventType));
// store the current checkpoint
await _checkpointStore.SetCheckpoint(e.OriginalPosition, projection);
};