Provide API for easy service/repo registration

[jaredcnance]

Description

services.AddResourceService<FooService>();

should register any applicable forms:

services.Add<IResourceService<Foo>, FooService>();
services.Add<IResourceService<Foo, int>, FooService>();
services.Add<IGetAllService<Foo>, FooService>();
services.Add<IGetAllService<Foo, int>, FooService>();
// ... 

It should also handle services with mappings:

services.Add<IResourceService<Foo, Bar, int>, FooService>();

This API may be usable by the service discovery pipeline

[btecu]

I should mention that having services.Add<IResourceService<Foo>, FooService>(); instead of services.Add<IResourceService<Foo, int>, FooService>(); doesn't error out, which might be confusing.

[jaredcnance]

Why should it error out? You're simply registering a dependency. The fact that the former doesn't work, should be entirely dependent upon how you're requesting the dependency in your controller/service. For example, if in your controller you request IResourceService<Foo> it should just work:

public class FooController : JsonApiController<Foo>
{
    public PeopleController(
        IJsonApiContext jsonApiContext,
        IResourceService<Foo> resourceService, // <-- id type not specified
        ILoggerFactory loggerFactory) 
        : base(jsonApiContext, resourceService, loggerFactory)
    { }
}

// requires 
services.Add<IResourceService<Foo>, FooService>();

but, if your controller requests the id specific type IResourceService<Foo, int>, then it will fail to activate unless that type has been registered:

public class FooController : JsonApiController<Foo, int>
{
    public PeopleController(
        IJsonApiContext jsonApiContext,
        IResourceService<Foo, int> resourceService, // <-- id type specified
        ILoggerFactory loggerFactory) 
        : base(jsonApiContext, resourceService, loggerFactory)
    { }
}

// requires
services.Add<IResourceService<Foo, int>, FooService>();

That said, we might be able to do something with Roslyn analyzers that would produce a warning if you've registered a dependency that is not used in any constructor arguments 🤷‍♂️

[btecu]

That makes sense.