Handling an Unknown Message

In the case where your system receives a message with a message type that you cannot handle, Jasper gives you the ability to write your own policy about how to deal with that message with the IMissingHandler interface shown below:

public interface IMissingHandler
{
    Task Handle(Envelope envelope, IMessagingRoot root);
}

To create your own policy or fall through handler, implement your own version of that interface like this sample shown below:

public class MyMissingHandler : IMissingHandler
{
    public Task Handle(Envelope envelope, IMessagingRoot root)
    {
        return root.Acknowledgements
            .SendFailureAcknowledgement(envelope,"I don't know how to process this message");
    }
}

Lastly, to register your own policy, just add it to the application IoC container like so:

public class ConfigureMissingHandlerApp : JasperOptions
{
    public ConfigureMissingHandlerApp()
    {
        // Just add your type to the IoC container
        Services.AddSingleton<IMissingHandler, MyMissingHandler>();
    }
}

Do note that you can add multiple IMissingHandler's in a single application and all of them will be executed.