Handler

BasicAuthenticationHandler.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using System.Web;

namespace WebAPIKoans.MessageHandlers
{
    public class BasicAuthenticationHandler : DelegatingHandler
    {
        Task<HttpResponseMessage> UnauthorizedTask = Task.Factory.StartNew(() =>
        {
            // Returns the Unauthorized Message (401) which actually challenges the client to issue authentication
            return new HttpResponseMessage(HttpStatusCode.Unauthorized);
        });

        protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
        {
            //If the authorization Header is not found then challenge for the token
            if (request.Headers.Authorization == null)
            {
                return UnauthorizedTask;
            }


            //If the Scheme and the authroization is correct then send it to the next handler
            if (request.Headers.Authorization.Scheme == "Basic" && !string.IsNullOrEmpty(request.Headers.Authorization.Scheme))
                return base.SendAsync(request, cancellationToken);

            return UnauthorizedTask;
        }
    }
}