public async IAsyncEnumerable <IEvent> ReadAsync(
StreamId streamId,
StreamVersion fromVersion,
StreamReadFilter?filter,
[EnumeratorCancellation] CancellationToken cancellationToken)
{
var metadata = await metadataReader
.GetAsync(streamId, cancellationToken)
.ConfigureAwait(false);
readValidator.Validate(
metadata,
filter?.RequiredVersion ?? StreamVersion.Any);
// If we don't have any events in the stream, then skip reading from stream.
if (metadata.Version == 0)
{
yield break;
}
await foreach (var evt in streamIterator
.ReadAsync(streamId, fromVersion, filter, cancellationToken)
.ConfigureAwait(false))
{
yield return(evt);
}
}
public async ValueTask <IStreamState> ProjectAsync(
TCommand command,
ICommandHandler <TCommand> handler,
CancellationToken cancellationToken)
{
var state = new StreamState
{
Id = command.GetEventStreamId().Value,
Version = 0L,
};
if (handlerMetadata.IsNotConsumingEvents())
{
var metadata = await eventStore
.GetStreamInfoAsync(
state.Id,
cancellationToken)
.ConfigureAwait(false);
readValidator.Validate(
metadata,
(StreamVersion?)command.RequiredVersion ?? StreamVersion.Any);
state.Version = metadata.Version;
return(state);
}
await foreach (var evt in eventStore
.ReadFromStreamAsync(
state.Id,
(StreamVersion?)command.RequiredVersion ?? StreamVersion.Any,
cancellationToken: cancellationToken)
.ConfigureAwait(false))
{
await handlerMetadata
.ConsumeAsync(
evt,
handler,
cancellationToken)
.ConfigureAwait(false);
state.Version = evt.Metadata.Version;
}
return(state);
}