public override async Task Start(CancellationToken cancellationToken)
{
if (_nextVersion == StreamVersion.End)
{
// Get the last stream version and subscribe from there.
var eventsPage = await ReadOnlyEventStore.ReadStreamBackwards(
_streamId,
StreamVersion.End,
1,
cancellationToken).NotOnCapturedContext();
//Only new events, i.e. the one after the current last one
_nextVersion = eventsPage.LastStreamVersion + 1;
}
await base.Start(cancellationToken);
}
public override async Task Start(CancellationToken cancellationToken)
{
if (FromCheckpoint == Checkpoint.End)
{
// Get the last stream version and subscribe from there.
var eventsPage = await ReadOnlyEventStore.ReadAllBackwards(
Checkpoint.End,
1,
cancellationToken).NotOnCapturedContext();
// If fromCheckpoint = 0, we have empty store, so start from zero, otherwise, the next checkpoint is
// one after the FromCheckpoint.
_nextCheckpoint = eventsPage.FromCheckpoint == 0 ? 0 : eventsPage.FromCheckpoint + 1;
}
await base.Start(cancellationToken).NotOnCapturedContext();
}
protected override async Task <bool> DoFetch()
{
var allEventsPage = await ReadOnlyEventStore
.ReadAllForwards(
_nextCheckpoint,
PageSize,
IsDisposed)
.NotOnCapturedContext();
bool isEnd = allEventsPage.IsEnd;
foreach (var streamEvent in allEventsPage.StreamEvents)
{
if (IsDisposed.IsCancellationRequested)
{
return(true);
}
try
{
await StreamEventReceived(streamEvent).NotOnCapturedContext();
LastCheckpoint = streamEvent.Checkpoint;
_nextCheckpoint = streamEvent.Checkpoint + 1;
}
catch (Exception ex)
{
try
{
SubscriptionDropped.Invoke(ex.Message, ex);
}
catch
{
//TODO logging
}
finally
{
Dispose();
}
}
}
return(isEnd);
}
protected override async Task <bool> DoFetch()
{
var streamEventsPage = await ReadOnlyEventStore
.ReadStreamForwards(
_streamId,
_nextVersion,
PageSize,
IsDisposed)
.NotOnCapturedContext();
bool isEnd = streamEventsPage.IsEndOfStream;
foreach (var streamEvent in streamEventsPage.Events)
{
if (IsDisposed.IsCancellationRequested)
{
return(true);
}
_nextVersion = streamEvent.StreamVersion + 1;
_lastVersion = streamEvent.StreamVersion;
try
{
await StreamEventReceived(streamEvent).NotOnCapturedContext();
}
catch (Exception ex)
{
try
{
SubscriptionDropped.Invoke(ex.Message, ex);
}
catch (Exception ex2)
{
// Need to log this
}
finally
{
Dispose();
}
}
}
return(isEnd);
}
