Autofac Extensions: It’s the Little Things

I get tired of reading, and writing, dependency registrations in Autofac. Very descriptive, but also very repetitive. Imagine a large application with a couple of dozen small, focused services each with a registration like:

builder.RegisterType<DescriptiveService>()
       .As<IDescriptiveService>()
       .InstancePerHttpRequest();

It's not a pretty sight.

To make this easy to read and, especially with syntax highlighting, relatively easy to spot errors I created a small extension method as part of my dependency configuration class.

public static class DependencyConfig
{
    private static void RegisterPerRequest<TImpl, T>(this ContainerBuilder builder)
        where TImpl : class, T
    {
         builder.RegisterType<TImpl>()
                .As<T>()
                .InstancePerHttpRequest();
    }

    public static void Configure(Action<IDependencyResolver> setResolver)
    {
         var builder = new ContainerBuilder();
         builder.RegisterPerRequest<DescriptiveService,IDescriptiveService>();

         // ...
    }
}

I'll grant you that it works better in a wide window or with shorter class names but I'm happy to not be repeating so much code.