Katana not finding start up method using reflection

Question

I am working through Scott Allen's MVC 5 Fundamentals course on Pluralsight

The following code should work , but when I browse to localhost:8080 I get a blank page

using System;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;
using Microsoft.Owin.Hosting;
using Owin;
namespace ConsoleApplication1
{
    using AppFunc = Func<IDictionary<string, object>, Task>;
    class Program
    {
        static void Main(string[] args)
        {
            string uri = "http://localhost:8080";
            using (WebApp.Start<Startup>(uri))   // Katana Please start, using the configuration from the Startup class and listening on the port given by the uri
            {
                Console.WriteLine("Started!");
                Console.ReadKey();
                Console.WriteLine("Stopping!");
            }
        }
    }

    public class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            app.Use<HelloWorldComponent>();
        }
    }

    public class HelloWorldComponent
    {
        AppFunc _next;
        public HelloWorldComponent(AppFunc next)
        {
            _next = next;
        }

        // Katana uses reflection to find this Invoke function that matches the AppFunc signature
        public Task Invoke(IDictionary<string, object> environment)
        { 
            var response = environment["owin.ResonseBody"] as Stream;

            using (var writer = new StreamWriter(response))
            {
                return writer.WriteAsync("Hello");
            }
        }
    }
}

How do I get it working?

I see that the Invoke Method does not actually match the AppFunc signature because it does not include Task — Kirsten, Apr 19 '15 at 00:48
IAppBuilder is deprecated in Owin... but Katana is built on it. http://jamesmckay.net/2014/08/sorting-out-the-confusion-that-is-owin-katana-and-iappbuilder/ — Kirsten, Apr 19 '15 at 00:55

score 2 · Accepted Answer · answered Apr 22 '15 at 12:11

2

Everything is setup correctly, there is just a small typo in fetching the response object:

 var response = environment["owin.ResponseBody"] as Stream;

 using (var writer = new StreamWriter(response))
 {
    return writer.WriteAsync("Hello");
 }

Notice the "p" in "ResponseBody"!

answered Apr 22 '15 at 12:11

OdeToCode

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18

I have a new problem at http://stackoverflow.com/questions/29803698/an-unhandled-exception-of-type-system-argumentexception-occurred-in-microsoft – Kirsten Apr 22 '15 at 16:33

Katana not finding start up method using reflection

1 Answers1