MassTransit Sub-Class when published is not consumed - masstransit

Question

I am trying to create Generic Implementation to publish messages with MassTransit.
BasePublisher
public abstract class BasePublisher
{
private readonly IPublishEndpoint publishEndpoint;
public BasePublisher(IPublishEndpoint publishEndpoint)
{
this.publishEndpoint = publishEndpoint;
}
public Task Publish(IntegrationBaseEvent message)
{
return publishEndpoint.Publish(message);
}
}
IntegrationBaseEvent
public class IntegrationBaseEvent
{
public IntegrationBaseEvent(Guid id, string name, DateTime createdDate)
{
Id = id;
Name = name;
CreationDate = createdDate;
}
public IntegrationBaseEvent()
{
Id = Guid.NewGuid();
CreationDate = DateTime.UtcNow;
}
public Guid Id { get; private set; }
public string Name { get; set; }
public DateTime CreationDate { get; private set; }
}
And I've created events using the abstraction IntegrationBaseEvent.
public class BusinessCreatedEvent : IntegrationBaseEvent
{
public Guid BusinessId { get; set; }
public string BusinessName { get; set; }
}
With the interface below, I am trying to publish the message but it not at all consumed
public interface IPublisher
{
Task Publish(IntegrationBaseEvent message);
}
It is consumed only when I create a separate publisher for the inherited event BusinessCreatedEvent something like below
public interface ISubscriptionPublisher
{
Task Publish(BusinessCreatedEvent message);
}
I don't want to create a different publisher and just want to use the abstract publisher like below.
public class BusinessCreatedEventHandler
{
private readonly IPublisher _publisher;
public BusinessCreatedEventHandler(IPublisher publisher)
{
_publisher = publisher;
}
public Task Handle(string id, string name)
{
var message = new BusinessCreatedEvent
{
BusinessId = id,
BusinessName = name
};
_publisher.Publish(message);
return Task.CompletedTask;
}
}
Any ideas to make it generic, please?

Answer 1

MassTransit leverages generics extensively, and limits types to the generic type specified. Since you're specifying the base interface as the generic type in the call to Publish, that base interface type is all that is published.
Your question is similar to the this one, and my answer – and the solution is the same. Convert it to object and use the Publish(object message) overload instead. That way, MassTransit will use the object type (MassTransit will call message.GetType() and properly dispatch the message type.
Or, you could make your interface include a generic method as well:
public interface IPublisher
{
Task Publish<T>(T message)
where T : class, IntegrationBaseEvent;
}