OWIN (Open Web Interface for .NET) is a simpler model for composing web-based applications without tying the application to the web server.

Due to the differences in the way OWIN handles the application pipeline (detecting when a request starts/ends, etc.) integrating Autofac into an OWIN application is slightly different than the way it gets integrated into more “standard” ASP.NET apps. You can read about OWIN and how it works on this overview.

The important thing to remember is that order of OWIN middleware registration matters. Middleware gets processed in order of registration, like a chain, so you need to register foundational things (like Autofac middleware) first.

To take advantage of Autofac in your OWIN pipeline:

  • Reference the Autofac.Owin package from NuGet.
  • Build your Autofac container.
  • Register the Autofac middleware with OWIN and pass it the container.
public class Startup
  public void Configuration(IAppBuilder app)
    var builder = new ContainerBuilder();
    // Register dependencies, then...
    var container = builder.Build();

    // Register the Autofac middleware FIRST.

    // ...then register your other middleware.

Check out the individual ASP.NET integration library pages for specific details on different app types and how they handle OWIN support.