URL Redirecting in an OWIN Self-Hosted Web Application

Perhaps this will get old quick; I don't know. Had a small research task for this. In this case I'm using a couple WebAPI controllers along with OWIN to demo.

1. Create new console application.
2. Install nuget packages Microsoft.Owin.SelfHost, Microsoft.AspNet.WebApi.Owin
3. Create RedirectMiddleware.cs like below (source)
4. Create Startup.cs like below
5. Make Program.cs (self-host starter) like below.
6. Add a couple controller classes, I added AController and BController.

---

 public class RedirectMiddleware : OwinMiddleware
 {

  public RedirectMiddleware(OwinMiddleware next) : base(next)
  {
  }

  public async override Task Invoke(IOwinContext context)
  {
   var url = context.Request.Uri;
   var shouldRedirect = ShouldRedirect(url.AbsoluteUri);
   if (shouldRedirect.Item1)
   {
    // permanent redirect
    context.Response.StatusCode = 301;
    context.Response.Headers.Set("Location", shouldRedirect.Item2);
   }
   else
   {
    await Next.Invoke(context);
   }
  }

  private Tuple<bool, string> ShouldRedirect(string uri)
  {
   if (uri.EndsWith("A"))
   {
    return Tuple.Create(true, "/B");
   }
   else
   {
    return Tuple.Create(false, "");
   }
  }

 }

---

 class Startup
 {

  public void Configuration(IAppBuilder appBuilder)
  {
   // Setup WebAPI configuration
   var configuration = new HttpConfiguration();

   configuration.Routes.Add("API Default", new HttpRoute("{Controller}"));

   /// Register our middleware
   /// Order of registration is the order the middleware will execute in.
   appBuilder.Use();

   // Register the WebAPI to the pipeline
   appBuilder.UseWebApi(configuration);

   appBuilder.Run((owinContext) =>
   {
    owinContext.Response.ContentType = "text/plain";
    return owinContext.Response.WriteAsync("Controllers are /A and /B.  http://localhost:5000/A will take you to B");
   });
  }

 }

---

 class Program
 {
  static void Main(string[] args)
  {
   const string baseUrl = "http://localhost:5000/";
   using (WebApp.Start<Startup>(baseUrl))
   {
    Console.WriteLine("Hit me up @ http://localhost:5000.  Press Enter to shut down.");
    Console.ReadKey();
   }
  }
 }