/// <summary>
/// Attempts to get the aggregate root entity associated with the aggregate identifier.
/// </summary>
/// <param name="identifier">The aggregate identifier.</param>
/// <param name="cancellationToken"></param>
/// <returns>The found <typeparamref name="TAggregateRoot"/>, or empty if not found.</returns>
public async Task <Optional <TAggregateRoot> > GetOptionalAsync(string identifier, CancellationToken cancellationToken)
{
if (_unitOfWork.TryGet(identifier, out var aggregate))
{
return(new Optional <TAggregateRoot>((TAggregateRoot)aggregate.Root));
}
var snapshot = await _eventStore.Advanced
.GetSnapshotAsync(identifier, Int32.MaxValue, cancellationToken)
.ConfigureAwait(false);
if (snapshot != null)
{
using (var stream = await _eventStore
.OpenStreamAsync(snapshot, Int32.MaxValue, cancellationToken)
.ConfigureAwait(false))
{
var root = _rootFactory();
root.RestoreSnapshot(snapshot.Payload);
root.Initialize(stream.CommittedEvents.Select(eventMessage => eventMessage.Body));
_unitOfWork.Attach(new Aggregate(identifier, stream.StreamRevision, root));
return(new Optional <TAggregateRoot>(root));
}
}
using (var stream = await _eventStore
.OpenStreamAsync(identifier, cancellationToken, 0)
.ConfigureAwait(false))
{
if (stream.StreamRevision == 0)
{
return(Optional <TAggregateRoot> .Empty);
}
var root = _rootFactory();
root.Initialize(stream.CommittedEvents.Select(eventMessage => eventMessage.Body));
_unitOfWork.Attach(new Aggregate(identifier, stream.StreamRevision, root));
return(new Optional <TAggregateRoot>(root));
}
}
/// <summary>
/// Reads the stream indicated from the minimum revision specified up to the maximum revision specified or creates
/// an empty stream if no commits are found and a minimum revision of zero is provided.
/// </summary>
/// <param name="storeEvents">The store events instance.</param>
/// <param name="bucketId">The value which uniquely identifies bucket the stream belongs to.</param>
/// <param name="streamId">The value which uniquely identifies the stream within the bucket to be created.</param>
/// <param name="cancellationToken"></param>
/// <param name="minRevision">The minimum revision of the stream to be read.</param>
/// <param name="maxRevision">The maximum revision of the stream to be read.</param>
/// <returns>A series of committed events represented as a stream.</returns>
/// <exception cref="StorageException" />
/// <exception cref="StorageUnavailableException" />
/// <exception cref="StreamNotFoundException" />
public static Task <IEventStream> OpenStreamAsync(this IStoreEvents storeEvents, string bucketId, Guid streamId, CancellationToken cancellationToken, int minRevision = int.MinValue, int maxRevision = int.MaxValue)
{
EnsureStoreEventsNotNull(storeEvents);
return(storeEvents.OpenStreamAsync(bucketId, streamId.ToString(), minRevision, maxRevision, cancellationToken));
}