public async Task UpdateProductAsync(CatalogItem productToUpdate)
{
//TODO: checking for necessity of publishing event PriceChanged
//TODO: Other possibilities for state of event is not considered
//To update the price of a product and guarantee consistency,
//(that the publishing of it's related event has definitely happened after persisting in current service,
//first we need to update CatalogContext(and product)
//and we need to store details of the related event in database (IntegrationEventLogContext)
//IN THE SAME TRANSACTION
//then we will publish the event
//and if everything goes as expected, we change the state of event to published in db
//TODO don't send productToUpdate to repo. fetch the current object, change it's price then send it (if fetched in admin panel before update there is no problem
var oldPrice = _catalogContext.CatalogItems.AsNoTracking().Single(e => e.Id == productToUpdate.Id).Price;
if (oldPrice != productToUpdate.Price)
{
ProductPriceChangedIntegrationEvent evt =
new ProductPriceChangedIntegrationEvent(productToUpdate.Id, productToUpdate.Price, oldPrice);
using (var transaction = _catalogContext.Database.BeginTransaction())
{
_catalogContext.CatalogItems.Update(productToUpdate);
await _catalogIntegrationEventService.SaveEventAndCatalogContextChangesAsync(evt);
transaction.Commit();
}
_eventBus.Publish(evt);
await _integrationEventLogService.MarkEventAsPublished(evt.Id);
}
else
{
_catalogContext.CatalogItems.Update(productToUpdate);
_catalogContext.SaveChanges();
}
}
public async Task PublishThroughEventBusAsync(IntegrationEvent evt)
{
_eventBus.Publish(evt);
_eventLogService.MarkEventAsPublished(evt);
}