public async Task <ISubscription> Subscribe(IEventHandlerFactory factory, object[] args = null)
{
if (!factory.SupportedEventTypes.Contains <TEvent>())
{
throw new InvalidOperationException(
$"Event Handler Factory seems not to support this Event. {typeof(TEvent).Name}");
}
// uhhh and we need to know from when...
Type checkpointRepo = typeof(ICheckpointRepository <,>).MakeGenericType(_schema.Type, typeof(TEvent));
var repo = (ICheckpointEventRepository <TEvent>)_serviceProvider.GetService(checkpointRepo);
string streamName = $"$et-{typeof(TEvent).Name}";
var lastCheckpoint = await repo.GetLastCheckpoint();
StreamRevision start = StreamRevision.Start;
if (!lastCheckpoint.HasValue)
{
// this is the first time we run this processor.
var(globalPosition, streamRevision) = await _eventStore.GetLastStreamPosition(streamName);
start = streamRevision;
await repo.SaveCheckpoint(start.ToUInt64());
}
else
{
start = new StreamRevision(lastCheckpoint.Value + 1);
}
Subscription s = new Subscription();
await _eventStore.SubscribeToStreamAsync(streamName, start,
async (s, r, c) =>
{
using (var scope = factory.Scope())
{
var handler = scope.CreateHandler <TEvent>();
var(m, e) = _eventConverter.Convert <TEvent>(r);
await handler.Execute(m, e);
await repo.SaveCheckpoint(r.Link.EventNumber.ToUInt64());
}
}, ss => s.MakeLive(), true);
return(s);
}
protected DeleteExistingStreamSpecification(StreamRevision expectedStreamRevision) : this(
new DeleteReq.Types.Options {
Revision = expectedStreamRevision.ToUInt64(),
})
{
}
