async Task <IExecutionResult> IOperationHandler <AppendToStreamAsync, IExecutionResult> .Handle(AppendToStreamAsync operation, CancellationToken cancellationToken)
{
var id = CosmosStreamNameStrategy.GetStreamIdentifier(operation.StreamId);
var streamType = CosmosStreamNameStrategy.GetStreamType(operation.StreamId);
long eventPosition = EventPosition.Start;
if (operation.ExpectedVersion == ExpectedVersion.NoStream || operation.ExpectedVersion == ExpectedVersion.Any)
{
await _operationDispatcher.Dispatch(new CreateNewStream(id, streamType, operation.Events)).ConfigureAwait(false);
eventPosition++;
}
else
{
var streamDoc = await _operationDispatcher
.Dispatch <GetStreamDocumentByIdAsync, Optional <StreamDocument> >(new GetStreamDocumentByIdAsync(id)).ConfigureAwait(false);
streamDoc.ThrowsIf(stream => !stream.HasValue, new AggregateNotFoundException(operation.StreamId));
var existingStream = streamDoc.Value.ToCosmosStream();
existingStream.ThrowsIf(stream => operation.ExpectedVersion.Value != stream.Version.Value && operation.ExpectedVersion != ExpectedVersion.SafeStream,
new WrongExpectedStreamVersionException(operation.ExpectedVersion.Value.ToString(),
existingStream.Version.Value.ToString()));
var streamEvents = await _operationDispatcher
.Dispatch <GetEventDocumentsForward, IEnumerable <EventDocument> >
(
new GetEventDocumentsForward(eDoc => eDoc.StreamId == id, Convert.ToInt32(StreamPosition.Start), _cosmosDBConfigurations.ReadBatchSize)
).ConfigureAwait(false);
existingStream = existingStream.AppendEvents(streamEvents.Select(e => e.ToCosmosEvent()));
operation.ExpectedVersion = operation.ExpectedVersion.WithVersion(operation.ExpectedVersion + operation.Events.Length);
var newVersionedStream = existingStream.ChangeVersion(operation.ExpectedVersion);
await _cosmosClient.UpdateItemAsync(id, _cosmosDBConfigurations.StreamContainerName, newVersionedStream.ToCosmosStreamDocument(),
operation.ExpectedVersion.MetaData).ConfigureAwait(false);
eventPosition = newVersionedStream.NextEventNumber;
}
foreach (var @event in operation.Events)
{
var newEvent = new EventDocument(@event.EventId, id, eventPosition, this._eventSerializer.Serialize(@event.Data),
@event.EventMetadata, @event.EventType);
await _cosmosClient.CreateItemAsync(newEvent, this._cosmosDBConfigurations.EventContainerName).ConfigureAwait(false);
eventPosition++;
}
return(ExecutionResult.Success);
}
public async Task <IExecutionResult> AppendToStreamAsync(string streamId, Version expectedVersion, params CosmosEventData[] events) => await _operationDispatcher.Dispatch(new AppendToStreamAsync(streamId, expectedVersion, events)).ConfigureAwait(false);