GraphQL + Autofac

Question

I'm exploring GraphQL at the moment. In one of my ObjectGraphTypes I want to inject a service implementation which queries EF about some addition data.

public class RoomType : ObjectGraphType<Room>
    {
        public RoomType(IUserRepository userRepository)
        {
            Field(x => x.Id).Description("Identifier for a room");
            Field(x => x.Name).Description("Name of the room");
            Field<ListGraphType<UserType>, IEnumerable<User>>().Name("Users").Resolve(ctx =>
            {
                var roomId = ctx.Source.Id;
                return userRepository.GetUsersInRoom(roomId);
            });
        }
    }

Where both RoomType and IUserRepository has been registed within in Autofac container. However, during execution the RoomType cannot be resolved as it's missing a parameterless constructor, which makes me think that its been construction via reflection and not via the container. Any suggestions on how to proceed?

Thanks!

score 2 · Accepted Answer · answered Apr 29 '19 at 17:13

The issue was in the Schema. You have to have an implementation of ISchema which is registered within the container. You also need to register an implementation of IDependencyResolver which is an interface in the GraphQl library (GraphQL.IDependencyResolver) like this:

 builder.Register<IDependencyResolver>(c =>
            {
                var context = c.Resolve<IComponentContext>();
                return new FuncDependencyResolver(type => context.Resolve(type));
            });

At the end, make sure that all of your schemas, queries and types are registered in autofac.

GraphQL + Autofac

1 Answers1