private ClientMessage.ReadStreamEventsBackwardCompleted ReadStreamEventsBackward(ClientMessage.ReadStreamEventsBackward msg)
{
var lastCommitPosition = _readIndex.LastCommitPosition;
try
{
if (msg.ValidationStreamVersion.HasValue && _readIndex.GetLastStreamEventNumber(msg.EventStreamId) == msg.ValidationStreamVersion)
{
return(NoData(msg, ReadStreamResult.NotModified, lastCommitPosition));
}
var access = _readIndex.CheckStreamAccess(msg.EventStreamId, StreamAccessType.Read, msg.User);
if (!access.Granted)
{
return(NoData(msg, ReadStreamResult.AccessDenied, lastCommitPosition));
}
var result = _readIndex.ReadStreamEventsBackward(msg.EventStreamId, msg.FromEventNumber, msg.MaxCount);
CheckEventsOrder(msg, result);
var resolvedPairs = ResolveLinkToEvents(result.Records, msg.ResolveLinkTos, msg.User);
if (resolvedPairs == null)
{
return(NoData(msg, ReadStreamResult.AccessDenied, lastCommitPosition));
}
return(new ClientMessage.ReadStreamEventsBackwardCompleted(
msg.CorrelationId, msg.EventStreamId, result.FromEventNumber, result.MaxCount,
(ReadStreamResult)result.Result, resolvedPairs, result.Metadata, access.Public, string.Empty,
result.NextEventNumber, result.LastEventNumber, result.IsEndOfStream, lastCommitPosition));
}
catch (Exception exc)
{
Log.ErrorException(exc, "Error during processing ReadStreamEventsBackward request.");
return(NoData(msg, ReadStreamResult.Error, lastCommitPosition, exc.Message));
}
}
void IHandle <ClientMessage.ReadStreamEventsBackward> .Handle(ClientMessage.ReadStreamEventsBackward message)
{
var lastCommitPosition = _readIndex.LastCommitPosition;
EventRecord[] records;
var result = _readIndex.ReadStreamEventsBackward(message.EventStreamId, message.FromEventNumber, message.MaxCount, out records);
var nextEventNumber = result == RangeReadResult.Success & records.Length > 0
? records[records.Length - 1].EventNumber - 1
: -1;
if (result == RangeReadResult.Success && records.Length > 1)
{
for (var index = 1; index < records.Length; index++)
{
if (records[index].EventNumber != records[index - 1].EventNumber - 1)
{
throw new Exception(string.Format(
"Invalid order of events has been detected in read index for the event stream '{0}'. "
+ "The event {1} at position {2} goes after the event {3} at position {4}",
message.EventStreamId,
records[index].EventNumber,
records[index].LogPosition,
records[index - 1].EventNumber,
records[index - 1].LogPosition));
}
}
}
EventLinkPair[] resolvedPairs;
if (result == RangeReadResult.Success && message.ResolveLinks)
{
resolvedPairs = ResolveLinkToEvents(records);
}
else
{
resolvedPairs = new EventLinkPair[records.Length];
for (int i = 0; i < records.Length; ++i)
{
resolvedPairs[i] = new EventLinkPair(records[i], null);
}
}
message.Envelope.ReplyWith(
new ClientMessage.ReadStreamEventsBackwardCompleted(message.CorrelationId,
message.EventStreamId,
resolvedPairs,
result,
nextEventNumber,
records.Length == 0 ? lastCommitPosition : (long?)null));
}
private ClientMessage.ReadStreamEventsBackwardCompleted ReadStreamEventsBackward(ClientMessage.ReadStreamEventsBackward msg)
{
using (HistogramService.Measure(_readerStreamRangeHistogram))
{
var lastCommitPosition = _readIndex.LastReplicatedPosition;
try
{
if (msg.MaxCount > MaxPageSize)
{
throw new ArgumentException(string.Format("Read size too big, should be less than {0} items",
MaxPageSize));
}
if (msg.ValidationStreamVersion.HasValue &&
_readIndex.GetStreamLastEventNumber(msg.EventStreamId) == msg.ValidationStreamVersion)
{
return(NoData(msg, ReadStreamResult.NotModified, lastCommitPosition,
msg.ValidationStreamVersion.Value));
}
var access = _readIndex.CheckStreamAccess(msg.EventStreamId, StreamAccessType.Read, msg.User);
if (!access.Granted)
{
return(NoData(msg, ReadStreamResult.AccessDenied, lastCommitPosition));
}
var result = _readIndex.ReadStreamEventsBackward(msg.EventStreamId, msg.FromEventNumber,
msg.MaxCount);
CheckEventsOrder(msg, result);
var resolvedPairs = ResolveLinkToEvents(result.Records, msg.ResolveLinkTos, msg.User);
if (resolvedPairs == null)
{
return(NoData(msg, ReadStreamResult.AccessDenied, lastCommitPosition));
}
return(new ClientMessage.ReadStreamEventsBackwardCompleted(
msg.CorrelationId, msg.EventStreamId, result.FromEventNumber, result.MaxCount,
(ReadStreamResult)result.Result, resolvedPairs, result.Metadata, access.Public, string.Empty,
result.NextEventNumber, result.LastEventNumber, result.IsEndOfStream, lastCommitPosition));
}
catch (Exception exc)
{
Log.ErrorException(exc, "Error during processing ReadStreamEventsBackward request.");
return(NoData(msg, ReadStreamResult.Error, lastCommitPosition, error: exc.Message));
}
}
}
void IHandle <ClientMessage.ReadStreamEventsBackward> .Handle(ClientMessage.ReadStreamEventsBackward message)
{
var lastCommitPosition = _readIndex.LastCommitPosition;
var result = _readIndex.ReadStreamEventsBackward(message.EventStreamId, message.FromEventNumber, message.MaxCount);
if (result.Result == RangeReadResult.Success && result.Records.Length > 1)
{
var records = result.Records;
for (var index = 1; index < records.Length; index++)
{
if (records[index].EventNumber != records[index - 1].EventNumber - 1)
{
throw new Exception(string.Format(
"Invalid order of events has been detected in read index for the event stream '{0}'. "
+ "The event {1} at position {2} goes after the event {3} at position {4}",
message.EventStreamId,
records[index].EventNumber,
records[index].LogPosition,
records[index - 1].EventNumber,
records[index - 1].LogPosition));
}
}
}
var resolvedPairs = ResolveLinkToEvents(result.Records, message.ResolveLinks);
message.Envelope.ReplyWith(
new ClientMessage.ReadStreamEventsBackwardCompleted(message.CorrelationId,
message.EventStreamId,
resolvedPairs,
result.Result,
result.NextEventNumber,
result.LastEventNumber,
result.IsEndOfStream,
result.IsEndOfStream ? lastCommitPosition : (long?)null));
}
public IndexReadStreamResult ReadStreamEventsBackward(string streamName, TStreamId streamId, long fromEventNumber, int maxCount) => _readIndex.ReadStreamEventsBackward(streamName, streamId, fromEventNumber, maxCount);
public static IndexReadStreamResult ReadStreamEventsBackward <TStreamId>(this IReadIndex <TStreamId> self, string streamName, long fromEventNumber, int maxCount)
{
var streamId = self.GetStreamId(streamName);
return(self.ReadStreamEventsBackward(streamName, streamId, fromEventNumber, maxCount));
}
public static IndexReadStreamResult ReadStreamEventsBackward(this IReadIndex <string> index, string streamName, long fromEventNumber, int maxCount) => index.ReadStreamEventsBackward(streamName, streamName, fromEventNumber, maxCount);
