Document IGrpcService

[benmccallum]

I've been exploring the code and I'm wondering how IGrpcService works.

It seems like it's an alternative to having to use [ServiceContract], i.e. rather than:

[ServiceContract]
public interface IMyService
{
    int SomeMethod();
}

public class MyService : IMyService
{
    public int SomeMethod() => 1;
}

I can just do:

public class MyService : IGrpcService
{
    public int SomeMethod() => 1;
}

But I'm wondering how that works from the client side. Can I just do channel.CreateGrpcService<MyService>(), e.g. using the concrete type and not the interface?

That's quite nice in that you don't need to define an interface too, but doesn't this falls apart when you don't want your consumer project referencing the server project? You'd want them both referencing a separate project with just the contract stuff, e.g. request/response classes and an interface for the service, so no implementation.

Unless there's another use case I'm missing, perhaps where the contract is defined as an abstract type, inherits IGrpcService and is implemented in the server project?

[benmccallum]

More than happy to contrib a docs addition once I get my head around this.

[mgravell]

You won't be able to do it with a concrete type, no - it won't know how to connect the dots.

You're right that this hasn't been as fully fleshed out; if you want to help document it, for the client, I'd probably start by testing what happens with an interface IMyService : IGrpcService. It could also be that there is simply a gap here! (I won't rule out that possibility)

[benmccallum]

Ah I see, so in that sense it really is just an alternative to the atreibute but in both cases you need your contract interface. Cool. I have a pretty good use case for this library and will see if I have time to play around this weekend, learn some thing and contrib some docs. Cheers!

[mythz]

Looking at the GrpcServiceTests is good documentation for how to use this feature where it lets you expose every public method on a concrete type implementing IGrpcService as a gRPC Service.

It also lets you call the gRPC Service using a typed generic API using the Request/Response DTOs without needing a custom interface for the Service.