Managing AutoFac object creation for UnitOfWork

Question

I am new to architecture, I am in the process of learning and designing an application end to end. I have the below architecture and am using Autofac to manage object creation.

All businessobject contracts have been setup on webapi startup and that is the only startup which can actually startup all my autofac configurations/modules.

I use UnitOfWork/Repository pattern and it resides beyond my business layer, I do not want to refer the UnitOfWork in my WebAPi but i cannot startup UnitOfWork otherwise.

Can someone please give me some inputs on what should be my architecture/design/autofac unitofwork implementation?

Answer 1

In App_start register web project specific dependencies (controllers, etc). Have a static method in BL layer which registers unit of work, repositories, etc. Call this static method in App_start when all the web dependencies are being registered as below:

//App_Start (web project)
var builder = new ContainerBuilder();
var config = GlobalConfiguration.Configuration;
MyProject.BusinessLayer.RegisterDependancies.Register(builder); <-- Register Unit of Work here in static BL method
builder.RegisterControllers(typeof(MvcApplication).Assembly);
builder.RegisterApiControllers(typeof(MvcApplication).Assembly);
builder.RegisterModule<AutofacWebTypesModule>();
builder.RegisterWebApiFilterProvider(config);
builder.RegisterModule(new AutofacModules.AutoMapperModule());
builder.RegisterModule(new AutofacModules.Log4NetModule());

var container = builder.Build();

DependencyResolver.SetResolver(new AutofacDependencyResolver(container));
config.DependencyResolver = new AutofacWebApiDependencyResolver(container);


//Static method in BL
namespace MyProject.BusinessLayer
{
    public static class RegisterDependancies
    {
        public static void Register(ContainerBuilder builder)
        {
            builder.RegisterType<MyContext>().As<IDataContextAsync>().InstancePerLifetimeScope();
            builder.RegisterType<UnitOfWork>().As<IUnitOfWorkAsync>().InstancePerLifetimeScope();
            builder.RegisterGeneric(typeof(Repository<>)).As(typeof(IRepositoryAsync<>)).InstancePerLifetimeScope();
            builder.RegisterAssemblyTypes(typeof(BusinessService).Assembly).Where(t => t.Name.EndsWith("Service")).AsImplementedInterfaces().InstancePerLifetimeScope();
        }
    }
}