public async Task <StreamReadResults> ReadFrom(string streamId, Func <IAmAStoredEvent, bool> predicate = null, StreamReadDirection direction = StreamReadDirection.Backwards, CancellationToken cancellationToken = default)
{
var readResult = client.ReadStreamAsync(
direction == StreamReadDirection.Backwards ? Direction.Backwards : Direction.Forwards,
streamId,
direction == StreamReadDirection.Backwards ? StreamPosition.End : StreamPosition.Start,
resolveLinkTos: true,
configureOperationOptions: options => options.TimeoutAfter = TimeSpan.FromSeconds(30),
cancellationToken: cancellationToken);
bool streamExists = false;
try
{
var readState = await readResult.ReadState;
streamExists = readState == ReadState.Ok;
}
#pragma warning disable 168
catch (StreamDeletedException ex)
// This happens when the stream is hard-deleted. We don't want to throw in that case
#pragma warning restore 168
{
streamExists = false;
}
if (!streamExists)
{
return(new StreamReadResults(EmptyReadResult, false, StoredEventPosition.FromInt64(-1)));
}
predicate ??= _ => true;
var lastIndex = (await client.ReadStreamAsync(Direction.Backwards, streamId,
StreamPosition.End,
1,
resolveLinkTos: false).FirstAsync(cancellationToken)).OriginalEventNumber;
IAsyncEnumerable <StoredEvent> storedEvents;
if (direction == StreamReadDirection.Backwards)
{
storedEvents = readResult
// Trust me, resharper is wrong in this one. Event can be null
// ReSharper disable once ConditionIsAlwaysTrueOrFalse
.Where(e => e.Event != null)
.Select(e => e.Event.ToStoredEvent(stateFactory))
.TakeWhile(e => e.DeserializedEvent is not EntitySoftDeleted)
.Where(e => predicate(e));
}
else
{
storedEvents = readResult
// Trust me, resharper is wrong in this one. Event can be null
// ReSharper disable once ConditionIsAlwaysTrueOrFalse
.Where(e => e.Event != null)
.Select(e => e.Event.ToStoredEvent(stateFactory))
.Where(e => predicate(e));
}
return(new StreamReadResults(storedEvents, true, StoredEventPosition.FromInt64(lastIndex.ToInt64())));
}
public async Task <StreamReadResults> ReadFrom(string streamId, Func <IAmAStoredEvent, bool> predicate = null, StreamReadDirection direction = StreamReadDirection.Backwards, CancellationToken cancellationToken = default)
{
predicate ??= _ => true;
IAsyncEnumerable <StoredEvent> storedEvents;
if (direction == StreamReadDirection.Backwards)
{
var readResult = await connection.ReadStreamEventsBackwardAsync(streamId, StreamPosition.End, pageSize, true);
if (!StreamExists(readResult))
{
return(new StreamReadResults(EmptyReadResult, false, StoredEventPosition.FromInt64(-1)));
}
storedEvents = readResult.Events
// Trust me, resharper is wrong in this one. Event can be null
// ReSharper disable once ConditionIsAlwaysTrueOrFalse
.Where(e => e.Event != null)
.Select((e, _) => e.Event.ToStoredEvent(stateFactory))
.TakeWhile(e => e.DeserializedEvent is not EntitySoftDeleted)
.Where(e => predicate(e))
.ToAsyncEnumerable();
}
else
{
var readResult = await connection.ReadStreamEventsForwardAsync(streamId, StreamPosition.Start, pageSize, true);
if (!StreamExists(readResult))
{
return(new StreamReadResults(EmptyReadResult, false, StoredEventPosition.FromInt64(-1)));
}
storedEvents = readResult.Events
// Trust me, resharper is wrong in this one. Event can be null
// ReSharper disable once ConditionIsAlwaysTrueOrFalse
.Where(e => e.Event != null)
.Select((e, c) => e.Event.ToStoredEvent(stateFactory))
.Where(e => predicate(e))
.ToAsyncEnumerable();
}
var result = await connection.ReadEventAsync(streamId, StreamPosition.End, false);
var idx = result.Event?.OriginalEventNumber ?? -1;
return(new StreamReadResults(storedEvents, true, StoredEventPosition.FromInt64(idx)));
}
public StreamReadResults(IAsyncEnumerable <StoredEvent> events, bool streamExists, StoredEventPosition storedEventPosition)
{
Events = events ?? throw new ArgumentNullException(nameof(events));
StreamExists = streamExists;
StoredEventPosition = storedEventPosition;
}
