public async Task <int> Save(IAggregate aggregate, bool concurrencyCheck = true)
{
var streamName = StreamName($"{aggregate.GetType().Name }-{aggregate.Id}");
var pendingEvents = aggregate.GetPendingEvents();
var originalVersion = concurrencyCheck ? aggregate.Version - pendingEvents.Count : ExpectedVersion.Any;
WriteResult result;
var commitHeaders = CreateCommitHeaders(aggregate);
var eventsToSave = pendingEvents.Select(x => ToEventData(Guid.NewGuid(), x, commitHeaders));
var eventBatches = GetEventBatches(eventsToSave);
if (eventBatches.Count == 1)
{
// If just one batch write them straight to the Event Store
result = await _eventStoreConnection.AppendToStreamAsync(streamName, originalVersion, eventBatches[0]);
}
else
{
// If we have more events to save than can be done in one batch according to the WritePageSize, then we need to save them in a transaction to ensure atomicity
using (var transaction = await _eventStoreConnection.StartTransactionAsync(streamName, originalVersion))
{
foreach (var batch in eventBatches)
{
await transaction.WriteAsync(batch);
}
result = await transaction.CommitAsync();
}
}
aggregate.ClearPendingEvents();
return((int)result.NextExpectedVersion);
}