在Autofac和WebAPI 2 Owin中的服务解析期间获取User.Identity

Question

What I', trying to do is have a UserContext instantiated (single instance per user ideally). The UserContext depends on the current logged-in user.

MyUser is created by calling GlobalContext.User(username)

The following snippet is called from my Startup.Configuration(IAppBuilder app) :

private static IContainer RegisterServices()
{
    var builder = new ContainerBuilder();
    builder.RegisterApiControllers(System.Reflection.Assembly.GetAssembly(typeof(MyWeb.API.Startup)));
    builder.RegisterType<GlobalContext>().As<IGlobalContext>().SingleInstance();
    builder.Register(c => c.Resolve<IGlobalContext>().User(
        HttpContext.Current.User.Identity.Name)
        ).As<MyUser>();
    builder.RegisterType<UserContext>().As<IUserContext>().InstancePerLifetimeScope();
    return builder.Build();
}

Everything seems to work fine when ran in IIS Express. When I run this in an integration test using the Owin WebApp.Start<Startup>(url: BaseAddress) HttpContext.Current is null. This is expected from all the reading that I've done so far, but what's the alternative?

I think I need to access the owinContext or the autofac lifetime scope to get the current user during resolution, but how do I do that?

Is there a better way to do this? or am I missing something trivial?

All help is appreciated.

EDITED TO ADD INFO: In case it helps I'm including my Configuration() method here:

using System.Web;
using System.Web.Http;
using Autofac;
using Autofac.Integration.WebApi;
using Owin;
using System.Reflection;

namespace SomeNameSpace
{

 public partial class Startup
    {

    public void Configuration(IAppBuilder app)
    {
        var configuration = new HttpConfiguration{ IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Always };

        WebApiConfig.Register(configuration);
        BreezeConfig.Register(configuration);
        CorsConfig.Register(configuration);

        // Autofac IoC
        var container = RegisterServices();
        app.UseAutofacMiddleware(container);

        app.UseWindowsAuthentication();

        var urt = new UserRolesTranformer(new GlobalContext());
        app.UseClaimsTranformation(urt.Transformation);

        app.UseAutofacWebApi(configuration);
        configuration.DependencyResolver = new AutofacWebApiDependencyResolver(container);

        //app.Use(typeof(TestMiddleware));
        app.UseAutofacWebApi(configuration);
        app.UseWebApi(configuration);
    }
}

Ultimate Goal: create a test that simulates multiple concurrent users logging in and ensuring that each user get's their own UserContext instance.

Answer 1

In the case of a Unit Test, you shouldn't really need access to the HttpContext or the OwinContext. As I imagine you have already discovered, a Unit Test has no concept of a HttpContext.

I am assuming that your IGlobalContext has a method User which takes a Username and returns you a User, perhaps from your database based on the Username passed in from the Current Context?

What you should do is have different Autofac registrations for your website and for your unit test so that you can have different dependencies in each environment. Then in your Unit Tests Autofac registration you could register either a completely different dependency to be resolved in your Unit Test, or you could pass into your User method, a mocked username that you know exists.

So you would keep this as your Autofac Registrations in your Website.

private static IContainer RegisterServices()
{
    var builder = new ContainerBuilder();
    builder.RegisterApiControllers(System.Reflection.Assembly.GetAssembly(typeof(MyWeb.API.Startup)));
    builder.RegisterType<GlobalContext>().As<IGlobalContext>().SingleInstance();
    builder.Register(c => c.Resolve<IGlobalContext>().User(
        HttpContext.Current.User.Identity.Name)
        ).As<MyUser>();
    builder.RegisterType<UserContext>().As<IUserContext>().InstancePerLifetimeScope();
    return builder.Build();
}

Then in your Unit Test, when you register your Autofac registrations with something like this..

private static IContainer RegisterServices()
{
    var builder = new ContainerBuilder();
    builder.RegisterApiControllers(System.Reflection.Assembly.GetAssembly(typeof(MyWeb.API.Startup)));
    builder.RegisterType<GlobalContext>().As<IGlobalContext>().SingleInstance();
    builder.Register(c => c.Resolve<IGlobalContext>().User(
        "MyTestUser")
        ).As<MyUser>();
    builder.RegisterType<UserContext>().As<IUserContext>().InstancePerLifetimeScope();
    return builder.Build();
}

This way you know in your Unit Test, exactly what User you are passing in and what User you should be getting back.

Or by using your own entirely mocked user like this ...

public class TestUser : MyUser
{
    //Known Test Scenario Properties and Methods as required
}

private static IContainer RegisterServices()
{
    var builder = new ContainerBuilder();
    builder.RegisterApiControllers(System.Reflection.Assembly.GetAssembly(typeof(MyWeb.API.Startup)));
    builder.RegisterType<GlobalContext>().As<IGlobalContext>().SingleInstance();
    builder.RegisterType<TestUser>().As<MyUser>();
    builder.RegisterType<UserContext>().As<IUserContext>().InstancePerLifetimeScope();
    return builder.Build();
}

I hope this helps?