Calling ASP.NET Web API protected by Azure AD from a console app

Program.cs

using System;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;
using Microsoft.IdentityModel.Clients.ActiveDirectory;

namespace ConsoleApplication2
{
    class Program
    {
        private const string Authority = "https://login.microsoftonline.com/testazuread.onmicrosoft.com";
        private const string Resource = "https://testazuread.onmicrosoft.com/WebApplication3";
        private const string ClientId = "11111111-a00b-4131-8233-292e0403c7ba";
        private static readonly Uri RedirectUri = new Uri("https://localhost");

        //private const string ApiUri = "https://localhost:44303/api/values";
        private const string ApiUri = "https://testapiapp.azurewebsites.net/api/values";

        static void Main(string[] args)
        {
            RunTestAsync().Wait();
        }

        private static async Task RunTestAsync()
        {
            string accessToken = await GetAccessTokenAsync();

            using (var client = new HttpClient())
            {
                var req = new HttpRequestMessage(HttpMethod.Get, ApiUri);
                req.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
                req.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

                HttpResponseMessage res = await client.SendAsync(req);

                string json = await res.Content.ReadAsStringAsync();
                Console.WriteLine(json);
            }
        }

        private static async Task<string> GetAccessTokenAsync()
        {
            var authenticationContext = new AuthenticationContext(Authority);
            var result =
                await authenticationContext.AcquireTokenAsync(Resource, ClientId, RedirectUri, new PlatformParameters(PromptBehavior.RefreshSession));
            string accessToken = result.AccessToken;
            return accessToken;
        }
    }
}

Startup.Auth.cs

using System.Configuration;
using System.IdentityModel.Tokens;
using Microsoft.Owin.Security.ActiveDirectory;
using Owin;

namespace WebApplication3
{
    public partial class Startup
    {
        // For more information on configuring authentication, please visit http://go.microsoft.com/fwlink/?LinkId=301864
        public void ConfigureAuth(IAppBuilder app)
        {
            app.UseWindowsAzureActiveDirectoryBearerAuthentication(
                new WindowsAzureActiveDirectoryBearerAuthenticationOptions
                {
                    Tenant = ConfigurationManager.AppSettings["ida:Tenant"],
                    TokenValidationParameters = new TokenValidationParameters {
                         ValidAudience = ConfigurationManager.AppSettings["ida:Audience"]
                    },
                });
        }
    }
}

Startup.cs

using Owin;

namespace WebApplication3
{
    public partial class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            ConfigureAuth(app);
        }
    }
}

ValuesController.cs

using System.Collections.Generic;
using System.Web.Http;

namespace WebApplication3.Controllers
{
    [Authorize]
    public class ValuesController : ApiController
    {
        // GET api/values
        public IEnumerable<string> Get()
        {
            return new [] { User.Identity.Name };
        }
    }
}

Web.config

<?xml version="1.0" encoding="utf-8"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=301879
  -->
<configuration>
  <appSettings>
    <add key="webpages:Version" value="3.0.0.0" />
    <add key="webpages:Enabled" value="false" />
    <add key="ClientValidationEnabled" value="true" />
    <add key="UnobtrusiveJavaScriptEnabled" value="true" />
    <add key="ida:Tenant" value="testazuread.onmicrosoft.com" />
    <add key="ida:Audience" value="https://testazuread.onmicrosoft.com/WebApplication3" />
    <add key="ida:ClientID" value="1111111-2a48-4ed3-a5e8-9fa9f72daa79" />
  </appSettings>
  <system.web>
    <compilation debug="true" targetFramework="4.5.2" />
    <httpRuntime targetFramework="4.5.2" />
  </system.web>
  <system.webServer>
    <handlers>
      <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
      <remove name="OPTIONSVerbHandler" />
      <remove name="TRACEVerbHandler" />
      <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
    </handlers>
  </system.webServer>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Newtonsoft.Json" culture="neutral" publicKeyToken="30ad4fe6b2a6aeed" />
        <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Optimization" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="1.1.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-1.5.2.14234" newVersion="1.5.2.14234" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-5.2.3.0" newVersion="5.2.3.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
  <system.codedom>
    <compilers>
      <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:6 /nowarn:1659;1699;1701" />
      <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:14 /nowarn:41008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+" />
    </compilers>
  </system.codedom>
</configuration>