buechermarkt/BuechermarktClient/SigningService.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace BuechermarktClient
{
   class SigningService
   {
      public SigningService()
      {
         WebServer es = new WebServer(r =>
         {
            return "hi";
         }, "test");
         es.Run();
      }
   }

   public class WebServer
   {
      private readonly HttpListener _listener = new HttpListener();
      private readonly Func<HttpListenerRequest, string> _responderMethod;

      public WebServer(string[] prefixes, Func<HttpListenerRequest, string> method)
      {
         if (!HttpListener.IsSupported)
            throw new NotSupportedException(
                "Needs Windows XP SP2, Server 2003 or later.");

         // URI prefixes are required, for example 
         // "http://localhost:8080/index/".
         if (prefixes == null || prefixes.Length == 0)
            throw new ArgumentException("prefixes");

         // A responder method is required
         if (method == null)
            throw new ArgumentException("method");

         foreach (string s in prefixes)
            _listener.Prefixes.Add(s);

         _responderMethod = method;
         _listener.Start();
      }

      public WebServer(Func<HttpListenerRequest, string> method, params string[] prefixes)
          : this(prefixes, method) { }

      public void Run()
      {
         ThreadPool.QueueUserWorkItem((o) =>
         {
            Console.WriteLine("Webserver running...");
            try
            {
               while (_listener.IsListening)
               {
                  ThreadPool.QueueUserWorkItem((c) =>
                  {
                     var ctx = c as HttpListenerContext;
                     try
                     {
                        string rstr = _responderMethod(ctx.Request);
                        byte[] buf = Encoding.UTF8.GetBytes(rstr);
                        ctx.Response.ContentLength64 = buf.Length;
                        ctx.Response.OutputStream.Write(buf, 0, buf.Length);
                     }
                     catch { } // suppress any exceptions
                     finally
                     {
                        // always close the stream
                        ctx.Response.OutputStream.Close();
                     }
                  }, _listener.GetContext());
               }
            }
            catch { } // suppress any exceptions
         });
      }

      public void Stop()
      {
         _listener.Stop();
         _listener.Close();
      }
   }
}