Enable User Interface Requirements

To enable a user to sign in and sign out of your web application, you must add a user interface that provides that functionality. To do this, you will add an MVC controller to the project, and then update the _Layout.cshtml file.

Add a new MVC controller to your project

1. In the project solution in Visual Studio, right-click the Controllers folder, click Add, and then click Controller. The following dialog opens.

   

2. Click MVC Controller - Empty, and then click Add.

3. Name the new controller "AccountController.cs."

4. Replace the contents of this controller with the following code.

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   using Microsoft.AspNetCore.Authentication;
   using Microsoft.AspNetCore.Authentication.Cookies;
   using Microsoft.AspNetCore.Authorization;
   using Microsoft.AspNetCore.Mvc;
   using Microsoft.Extensions.Configuration;
   using System.Threading.Tasks;
   
   namespace LibrarianWebApp
   {
      public class AccountController : Controller
      {
         private const string AccessTokenName = "access_token";
   
         public AccountController(IConfiguration configuration)
         {
         }
   
         public async Task Login(string returnUrl = "/")
         {
            await HttpContext.ChallengeAsync("BarTenderCloud", new AuthenticationProperties() { RedirectUri = returnUrl });
         }
   
         [Authorize]
         public async Task Logout()
         {
            await HttpContext.SignOutAsync("BarTenderCloud", new AuthenticationProperties
            {
               // Indicate here where the identity provider should redirect the user after signing out.
               // Note that the resulting absolute URI must be added to the allowlist in the 
               // **Allowed Logout URLs** settings for the client.
               RedirectUri = Url.Action("Index", "Home")
            });
            await HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
         }
      }
   }
   

The Login() method requests an access token for the current user, while the Logout() method invalidates that access token.

Next, update the application user interface so that the sign-in and sign-out options can be displayed to the user. To do this, update the _Layout.cshtml file.

Update the _Layout.cshtml file

1. In the project, expand the Views folder, and then expand the Shared folder.

2. Right-click the _Layout.cshtml file, and then click Open.

3. Paste the following lines of code into the file as shown.

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             <div class="navbar-collapse collapse">
               <ul class="nav navbar-nav navbar-right">
                     @if (User.Identity.IsAuthenticated)
                     {
                        <li><a id="qsLogoutBtn" asp-controller="Account" asp-action="Logout">Logout</a></li>
                     }
                     else
                     {
                        <li><a id="qsLoginBtn" asp-controller="Account" asp-action="Login">Login</a></li>
                     }
               </ul>
             </div>
   

   

After you complete these steps and then compile and run the application, a "Login" link is displayed at the top of the web page. When you click this link, a sign-in dialog is displayed. By entering your BarTender Cloud user name and password, you can sign in, and the browser can use your access token for making BarTender Cloud API calls.