I want to place Automapper profile in my Business Layer - asp.net-core

Question

I've created a web api core 2.0 application.
I've got my main app and the Business Layer.
I want to place the automapper profile in the business layer so that all the mappings are made in the business layer. My business layer is just a class library project.
Is this possible? or do I need to place all my mapping in a Profile class in the main app?
Just a theoretical explanation can help.

Answer 1

Yes, it's possible but it depends on where the model classes reside.
You can give each layer or project a Profile where you map the appropriate model classes. Then in the project where you want to use the mapper, create the ObjectMapper class to load the Profiles.
namespace BL.Config
{
public class MapperProfile : Profile
{
public MapperProfile()
{
CreateMap<Entity, Dto>();
...
}
}
public class ObjectMapper
{
public static IMapper Mapper
{
get { return mapper.Value; }
}
public static IConfigurationProvider Configuration
{
get { return config.Value; }
}
public static Lazy<IMapper> mapper = new Lazy<IMapper>(() =>
{
var mapper = new Mapper(Configuration);
return mapper;
});
public static Lazy<IConfigurationProvider> config = new Lazy<IConfigurationProvider>(() =>
{
var config = new MapperConfiguration(cfg =>
{
cfg.AddProfile<BL.Config.MapperProfile>();
cfg.AddProfile<AppCore.Config.MapperProfile>(); // any other profiles you need to use
});
return config;
});
}
}
When I need to use AutoMapper, I use the ObjectMapper.Mapper to get my mapper instance. I like to add this to an abstract service.
public interface IAutoMapperService
{
IMapper Mapper { get; }
}
public abstract class AutoMapperService : IAutoMapperService
{
public IMapper Mapper
{
get { return BAL.Config.ObjectMapper.Mapper; }
}
}
And usage: The service has the Mapper member.
public class SomeService : AutoMapperService, ISomeService
{
public Foo GetFoo()
{
var foo = Mapper.Map<Foo>(bar);
return foo;
}
}
Or just implement the IAutoMapperService if you can't inherit another base class.
The downside is BL requires the AutoMapper dependency. But using this way I find I can hide many models from the other layers.