public void Subscribe(IActorRef subscriber, string stream, long?from, int max,
Func <ResolvedEvent, object> resolved)
{
if (!_subscriptions.TryGetValue(subscriber, out var subscriptions))
{
subscriptions = new HashSet <EventStoreCatchUpSubscription>();
_subscriptions.Add(subscriber, subscriptions);
_context.WatchWith(subscriber, new Unsubscribe(stream, subscriber));
}
try
{
// need to have this since ES Catchup Subscription needs null for from when user wants to
// read from begging of the stream
long?nullable = null;
var self = _context.Self;
var subscription = _conn.SubscribeToStreamFrom(
stream,
from.HasValue && from.Value == 0 ? nullable : from,
new CatchUpSubscriptionSettings(max * 2, 500, false, true),
(sub, @event) =>
{
var p = resolved(@event);
if (p != null)
{
subscriber.Tell(p, self);
}
},
_ => subscriber.Tell(CaughtUp.Instance, self),
(_, reason, exception) =>
{
var msg = $"Subscription dropped due reason {reason.ToString()}";
subscriber.Tell(new SubscriptionDroppedException(msg, exception), self);
});
subscriptions.Add(subscription);
}
catch (Exception)
{
if (subscriptions.Count == 0)
{
_context.Unwatch(subscriber);
}
throw;
}
}