public async Task <Page> TryGetEventsAsync(long offset)
{
var results = new List <IEvent>();
using (var context = _dbContextFactory.Create())
{
var events = await context.Events
.AsNoTracking()
.OrderBy(x => x.SequenceNo)
.Skip((int)offset)
.Take(250)
.ToListAsync();
foreach (var @event in events)
{
if (!_eventTypeCache.TryGet(@event.Type, out var type))
{
continue;
}
var result = (IEvent)_eventDeserializer.Deserialize(@event.Data, type);
results.Add(result);
}
return(new Page(offset + events.Count, offset, results));
}
}
public IEventContext <IEvent> CreateContext(Entities.Event dbEvent)
{
if (dbEvent == null)
{
throw new ArgumentNullException(nameof(dbEvent));
}
if (!_eventTypeCache.TryGet(dbEvent.Type, out var type))
{
throw new ArgumentException($"Could not find event type for '{dbEvent.Type}'");
}
var @event = (IEvent)_eventDeserializer.Deserialize(dbEvent.Data, type);
if (_cache.TryGetValue(type, out var activator))
{
return(activator(dbEvent.StreamId, @event, dbEvent.CorrelationId, dbEvent.CausationId, @event.Timestamp, Actor.From(dbEvent.Actor)));
}
activator = BuildActivator(typeof(EventContext <>).MakeGenericType(type));
_cache.TryAdd(type, activator);
var correlationId = dbEvent.CorrelationId != null?CorrelationId.From(dbEvent.CorrelationId) : (CorrelationId?)null;
var causationId = dbEvent.CausationId != null?CausationId.From(dbEvent.CorrelationId) : (CausationId?)null;
return(activator(dbEvent.StreamId, @event, correlationId, causationId, @event.Timestamp, Actor.From(dbEvent.Actor)));
}
public IEventContext <IEvent> CreateContext(ReceivedMessage message)
{
if (message == null)
{
throw new ArgumentNullException(nameof(message));
}
if (!_eventTypeCache.TryGet(message.RoutingKey, out var type))
{
throw new ArgumentException($"Could not find event type for '{message.RoutingKey}'");
}
var eventData = Encoding.UTF8.GetString(message.Body);
var @event = (IEvent)_eventDeserializer.Deserialize(eventData, type);
string streamId = null;
CorrelationId?correlationId = null;
CausationId? causationId = null;
string actor = null;
if (message.BasicProperties.Headers != null)
{
if (message.BasicProperties.Headers.ContainsKey(nameof(IEventContext <IEvent> .StreamId)))
{
streamId = message.BasicProperties.Headers[nameof(IEventContext <IEvent> .StreamId)]?.ToString();
}
if (message.BasicProperties.Headers.ContainsKey(nameof(IEventContext <IEvent> .CorrelationId)))
{
var value = message.BasicProperties.Headers[nameof(IEventContext <IEvent> .CorrelationId)]?.ToString();
correlationId = value != null?CorrelationId.From(value) : (CorrelationId?)null;
}
if (message.BasicProperties.Headers.ContainsKey(nameof(IEventContext <IEvent> .CausationId)))
{
var value = message.BasicProperties.Headers[nameof(IEventContext <IEvent> .CausationId)]?.ToString();
causationId = value != null?CausationId.From(value) : (CausationId?)null;
}
if (message.BasicProperties.Headers.ContainsKey(nameof(IEventContext <IEvent> .Actor)))
{
actor = message.BasicProperties.Headers[nameof(IEventContext <IEvent> .Actor)]?.ToString();
}
}
if (_cache.TryGetValue(type, out var activator))
{
return(activator(streamId, @event, correlationId, causationId, @event.Timestamp, Actor.From(actor ?? "<Unknown>")));
}
activator = BuildActivator(typeof(EventContext <>).MakeGenericType(type));
_cache.TryAdd(type, activator);
return(activator(streamId, @event, correlationId, causationId, @event.Timestamp, Actor.From(actor ?? "<Unknown>")));
}
public async Task <Page> GetEventsAsync(long offset, CancellationToken cancellationToken = default)
{
var results = new List <IEventContext <IEvent> >();
var events = await GetAllEventsForwardsInternalAsync(offset).ConfigureAwait(false);
if (events.Count > 0 && events[0].SequenceNo != offset + 1)
{
_logger.LogInformation("Gap detected in stream. Expecting sequence no {ExpectedSequenceNo} but found sequence no {ActualSequenceNo}. Reloading events after {DefaultReloadInterval}ms.", offset + 1, events[0].SequenceNo, DefaultReloadInterval);
events = await GetAllEventsAfterDelayInternalAsync(offset).ConfigureAwait(false);
}
for (var i = 0; i < events.Count - 1; i++)
{
if (events[i].SequenceNo + 1 != events[i + 1].SequenceNo)
{
_logger.LogInformation("Gap detected in stream. Expecting sequence no {ExpectedSequenceNo} but found sequence no {ActualSequenceNo}. Reloading events after {DefaultReloadInterval}ms.", events[i].SequenceNo + 1, events[i + 1].SequenceNo, DefaultReloadInterval);
events = await GetAllEventsAfterDelayInternalAsync(offset).ConfigureAwait(false);
break;
}
}
foreach (var @event in events)
{
if (!_eventTypeCache.TryGet(@event.Type, out var type))
{
throw new InvalidOperationException($"Cannot find type for event '{@event.Name}' - '{@event.Type}'.");
}
var result = _eventContextFactory.CreateContext(@event);
//var result = (IEvent)_eventDeserializer.Deserialize(@event.Data, type);
results.Add(result);
}
return(new Page(offset + events.Count, offset, results));
}