How to do open generic decorator chaining with unity + UnityAutoRegistration

Question

Went off on an interesting tangent today after reading this article on command handler decoration. I wanted to see if I could implement the pattern using Unity instead of Si

Answer 1

This would be the equivalent in Unity:

// Go look in all assemblies and register all implementa-
// tions of ICommandHandler by their closed interface:
var container = new UnityContainer();

var handlerRegistrations =
    from assembly in AppDomain.CurrentDomain.GetAssemblies()
    from implementation in assembly.GetExportedTypes()
    where !implementation.IsAbstract
    where !implementation.ContainsGenericParameters
    let services =
        from iface in implementation.GetInterfaces()
        where iface.IsGenericType
        where iface.GetGenericTypeDefinition() == 
            typeof(ICommandHandler<>)
        select iface
    from service in services
    select new { service, implementation };

foreach (var registration in handlerRegistrations)
{
    container.RegisterType(registration.service, 
        registration.implementation, "Inner1");
}

// Decorate each returned ICommandHandler object with an
// TransactionCommandHandlerDecorator.
container.RegisterType(typeof(ICommandHandler<>), 
    typeof(TransactionCommandHandlerDecorator<>),
    "Inner2",
    InjectionConstructor(new ResolvedParameter(
        typeof(ICommandHandler<>), "Inner1")));

// Decorate each returned ICommandHandler object with an
// DeadlockRetryCommandHandlerDecorator.
container.RegisterType(typeof(ICommandHandler<>), 
    typeof(DeadlockRetryCommandHandlerDecorator<>), 
    InjectionConstructor(new ResolvedParameter(
        typeof(ICommandHandler<>), "Inner2")));