Enable Scrutor to use external DI

We had DI running for quite some time now using the standard microsoft implementation. Due to several reasons (one beeing https://github.com/aspnet/AspNetCore/issues/2737) we now move to SimpleInjector (which we used on legacy WebApi projects alot).

Now SimpleInjector does not have rich assembly scanning support and states

Although many other DI libraries contain an advanced API for doing convention based registration, we found that doing this with custom LINQ queries is easier to write, more understandable, and can often prove to be more flexible than using a predefined and restrictive API.

I can totally accept this, however we are now sitting infront of quite some Scrutor lines which did this heavy lifting for us.

Something that would now have been really cool is to still be able to use Scrutor but inject a custom RegistrationStrategy which under the hood would not do services.Add but instead a custom action like container.Register. (SimpleInjector even has some code under the hood which turns ServiceDescriptor objects into SImpleInjector registrations).

Does this make any sense or is it completely out of the scope of this project?

Thanks, Philipp

[pfeigl]

Closing - thanks for the help, everything worked out today just nicely.

[pfeigl]

This is btw. what seems to work ok for now for us. There is quite a few cases not considered here (which were not relevant to us).

• Collection registrations use the Lifestyle of the first identified collection item
• Only registrations based on ImplementationType do work (We did not use anything else like factories - atleast not via Scrutor)

var processedCollections = new List<Type>();
foreach(var descriptor in services)
{
	Lifestyle lifestyle;
	switch (descriptor.Lifetime)
	{
		case ServiceLifetime.Scoped:
			lifestyle = Lifestyle.Scoped;
			break;
		case ServiceLifetime.Singleton:
			lifestyle = Lifestyle.Singleton;
			break;
		case ServiceLifetime.Transient:
		default:
			lifestyle = Lifestyle.Transient;
			break;
	}

	if (services.Any(d => d != descriptor && d.ServiceType == descriptor.ServiceType))
	{
		if(processedCollections.Contains(descriptor.ServiceType))
		{
			continue;
		}
		Container.Collection.Register(descriptor.ServiceType, services
			.Where(d => d.ServiceType == descriptor.ServiceType)
			.Select(d => lifestyle.CreateRegistration(d.ImplementationType, Container)));
		processedCollections.Add(descriptor.ServiceType);
	}
	else
	{
		Container.Register(descriptor.ServiceType, descriptor.ImplementationType, lifestyle);
	}
}