Now that we have our application configured in Azure, we need to update the Startup.Auth.cs class (in the App_Start folder) so that the application can utilize Azure Active Directory authentication for the users.  The Startup.Auth.cs class looks like this.

using System;
using System.IdentityModel.Claims;
using System.Threading.Tasks;
using System.Web;
using Microsoft.Owin.Security;
using Microsoft.Owin.Security.Cookies;
using Microsoft.Owin.Security.OpenIdConnect;
using Microsoft.IdentityModel.Clients.ActiveDirectory;
using Owin;
using BusinessApps.HelpDesk.Models;
using BusinessApps.HelpDesk.Helpers;
 
namespace BusinessApps.HelpDesk
{
    public partial class Startup
    {
        public void ConfigureAuth(IAppBuilder app)
        {
            ApplicationDbContext db = new ApplicationDbContext();
 
            app.SetDefaultSignInAsAuthenticationType(CookieAuthenticationDefaults.AuthenticationType);
 
            app.UseCookieAuthentication(new CookieAuthenticationOptions());
 
            OpenIdConnectAuthenticationOptions options = new OpenIdConnectAuthenticationOptions();
            options.ClientId = SettingsHelper.ClientId;
            options.Authority = SettingsHelper.AzureADAuthority;
            options.PostLogoutRedirectUri = SettingsHelper.LogoutAuthority;
 
            OpenIdConnectAuthenticationNotifications notifications = new OpenIdConnectAuthenticationNotifications();
            notifications.AuthorizationCodeReceived = (context) =>
            {
                string code = context.Code;
 
                AuthenticationHelper authHelper = new AuthenticationHelper();
                
                String signInUserId = context.AuthenticationTicket.Identity.FindFirst(ClaimTypes.NameIdentifier).Value;
 
                AuthenticationContext authContext = new AuthenticationContext(SettingsHelper.AzureADAuthAuthority);
                AuthenticationResult result = authContext.AcquireTokenByAuthorizationCode(code, new Uri(HttpContext.Current.Request.Url.GetLeftPart(UriPartial.Path)), authHelper.GetClientAssertionCertificate(), null);
 
                return Task.FromResult(0);
            };
 
            notifications.RedirectToIdentityProvider = (context) =>
            {
                string appBaseUrl = context.Request.Scheme + "://" + context.Request.Host + context.Request.PathBase;
                context.ProtocolMessage.RedirectUri = appBaseUrl + "/";
                context.ProtocolMessage.PostLogoutRedirectUri = appBaseUrl;
 
                return Task.FromResult(0);
            };
 
            notifications.AuthenticationFailed = (context) =>
            {
                context.HandleResponse();
                return Task.FromResult(0);
            };
 
            options.Notifications = notifications;
 
            app.UseOpenIdConnectAuthentication(options);
        }
    }
}

Next, we can add an AuthenticationHelper class to the Helpers folder.  This class will do the Azure authentication token management, and looks like this:

using Microsoft.IdentityModel.Clients.ActiveDirectory;
using System.Security.Cryptography.X509Certificates;
using System.Threading.Tasks;
 
namespace BusinessApps.HelpDesk.Helpers
{
    public class AuthenticationHelper
    {
        public ClientAssertionCertificate GetClientAssertionCertificate()
        {
            X509Store certStore = new X509Store(StoreName.My, StoreLocation.CurrentUser);
            certStore.Open(OpenFlags.ReadOnly);
 
            X509Certificate2 cert = certStore.Certificates.Find(X509FindType.FindByThumbprint, SettingsHelper.CertThumbprint, false)[0];
 
            ClientAssertionCertificate cac = new ClientAssertionCertificate(SettingsHelper.ClientId, cert);
 
            return cac;
        }
 
        public async Task<AuthenticationResult> GetToken(string resource)
        {
            ClientAssertionCertificate cac = GetClientAssertionCertificate();
 
            AuthenticationContext authContext = new AuthenticationContext(SettingsHelper.AzureADAuthority);
            AuthenticationResult authResult = await authContext.AcquireTokenAsync(resource, cac);
 
            return authResult;
        }
    }
}

Next, we’ll tell the application to define unique users by name.  This can be accomplished by adding the following line of code to the Global.asax.cs file:

AntiForgeryConfig.UniqueClaimTypeIdentifier = ClaimTypes.NameIdentifier;

The entire Global.asax.cs file now looks like this:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Helpers;
using System.Web.Mvc;
using System.Web.Optimization;
using System.Web.Routing;
 
namespace BusinessApps.HelpDesk
{
    public class MvcApplication : System.Web.HttpApplication
    {
        protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();
            FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            BundleConfig.RegisterBundles(BundleTable.Bundles);
 
            AntiForgeryConfig.UniqueClaimTypeIdentifier = ClaimTypes.NameIdentifier;
        }
    }
}

With any luck, if we run the application at this point, it will launch successfully:

Clicking Log In in the top right corner will take us to the Log In screen.  Choose OpenIdConnect to login via Azure:

This takes us to the standard Azure login screen.  Choose/Enter the organizational account, enter a password, and click Sign In (note the name of the application listed at the top of the login screen):

If all goes well, the application now knows who we are!

Pretty painless, right?

The Help Desk Demo

• The Help Desk demo, Part 1 – Creating the project
• The Help Desk demo, Part 2 – Azure Active Directory
• The Help Desk demo, Part 3 – Authentication
• The Help Desk demo, Part 4 – Microsoft Graph
• The Help Desk demo, Part 5 – SQL Azure
• The Help Desk demo, Part 6 – SharePoint
• The Help Desk demo, Part 7 – Wiring it all up
• The Help Desk demo, Part 8 – Deploying to Azure

The entire source code for the Help Desk demo can be found here https://github.com/OfficeDev/PnP/tree/dev/Solutions/BusinessApps.HelpDesk/, in the Office 365 Dev PnP GitHub repository.