private async Task StoreEventsForInternal <T>(T entity, string entityId,
CancellationToken cancellationToken = default(CancellationToken)) where T : EventSourcedEntity
{
var entityType = EventStoreMapping.GetEntityName <T>();
if (entityType == null)
{
throw new Exception("Unknown entity");
}
var context = await _ddpContextProvider.Get();
// Verify concurrency - for now just throw on breaking
var latestEvent = await context.EventTables.Where(x => x.EntityType == entityType && x.EntityId == entityId)
.OrderByDescending(x => x.Version).Select(x => x.Version).FirstOrDefaultAsync();
if (entity.UnmutatedVersion > latestEvent)
{
throw new Exception("Tried to save an entity but someone else got here first.");
}
var next = 1;
var domainEvents = entity.GetMutatingEvents();
foreach (var domainEvent in domainEvents)
{
var eventType = EventStoreMapping.GetEventName(domainEvent.GetType());
if (eventType == null)
{
throw new Exception("Unknown event");
}
var eventData = await SerializeEventData(domainEvent);
var eventTable = new EventTable
{
EventId = domainEvent.EventId,
EntityType = entityType,
EntityId = entityId,
Version = entity.UnmutatedVersion + next,
EventData = eventData,
EventType = eventType
};
context.EventTables.Add(eventTable);
next++;
}
await context.SaveChangesAsync(cancellationToken);
}
private async Task <EventStream> GetEventsForInternal <T>(string entityId, int?version = null,
CancellationToken cancellationToken = default(CancellationToken))
where T : EventSourcedEntity
{
var entityType = EventStoreMapping.GetEntityName <T>();
if (entityType == null)
{
throw new Exception($"Unable to find event store mapping for entity type {typeof(T)}. Did you forget to add an entity binding to the event store mapping?");
}
var context = await _ddpContextProvider.Get();
var query = context.EventTables.Where(x => x.EntityType == entityType && x.EntityId == entityId);
if (version.HasValue)
{
query = query.Where(x => x.Version <= version);
}
var eventTables = await query.ToListAsync();
var allEvents = new List <IDomainEvent>();
foreach (var eventTable in eventTables)
{
var eventType = EventStoreMapping.GetEventType(eventTable.EventType);
if (eventType == null)
{
throw new Exception($"Unable to find event store mapping for event {eventTable.EventType}. Did you forget to add an event binding to the event store mapping?");
}
var materialized = (IDomainEvent)JsonConvert.DeserializeObject(eventTable.EventData, eventType);
allEvents.Add(materialized);
}
return(new EventStream(allEvents, eventTables.Max(x => x.Version)));
}
