/// <summary>
/// Fetches raw events along with their deserialized EventDocument-derived instances when possible, returning an enumerable of
/// (raw, doc, error) tuples
/// </summary>
/// <param name="consumer">Event consumer implementation</param>
/// <param name="route">Queue designator</param>
/// <param name="partition">Logical partition to fetch from <see cref="IEventConsumer.PartitionCount"/></param>
/// <param name="checkpoint">A point in time as of which to fetch</param>
/// <param name="skip">Number of events to skip in the beginning</param>
/// <param name="count">Number of events to fetch</param>
/// <param name="lossMode">Data loss tolerance</param>
/// <returns>
/// A tuple of `raw` event representation, its converted EventDocument-derived instance `doc`, and an error (if any) which surfaced
/// during event doc deserialization attempt, thus `doc` and `err` are mutually exclusive
/// </returns>
public static async Task <IEnumerable <(Event raw, EventDocument doc, Exception err)> > FetchEventDocsAsync(this IEventConsumer consumer,
Route route,
int partition,
ulong checkpoint,
int skip,
int count,
DataLossMode lossMode = DataLossMode.Default)
{
var got = await consumer.NonNull(nameof(consumer))
.FetchAsync(route, partition, checkpoint, skip, count, lossMode);
using (var ms = new IO.BufferSegmentReadingStream())
{
return(got.Select(e => {
EventDocument doc = null;
Exception error = null;
try
{
if (e.ContentType == CONTENT_TYPE_JSON_DOC && e.Content != null)
{
ms.UnsafeBindBuffer(e.Content, 0, e.Content.Length);
var map = JsonReader.DeserializeDataObject(ms, EVENT_JSON_ENCODING, true) as JsonDataMap;
doc = JsonReader.ToDoc <EventDocument>(map, fromUI: false);
}
}
catch (Exception err)
{
error = err;
}
return (raw: e, doc: doc, err: error);
}).ToArray());
}
}
