Oidc Auth Azure B2c

b2c.cs

using System;
using System.IdentityModel.Claims;
using System.IdentityModel.Tokens;
using System.Web;
using System.Web.Mvc;
using System.Web.Routing;
using System.Web.Security;
using Microsoft.IdentityModel.Protocols;
using Microsoft.IdentityModel.Protocols.OpenIdConnect;
using Microsoft.IdentityModel.Tokens;
using Microsoft.Owin;
using Microsoft.Owin.Security;
using Microsoft.Owin.Security.Cookies;
using Microsoft.Owin.Security.OpenIdConnect;
using Owin;

[assembly: OwinStartup(typeof(YourNamespace.Startup))]

namespace YourNamespace
{
    public class Startup
    {
        private static string clientId = "<Your-Client-Id>"; // Application (client) ID
        private static string tenant = "<Your-Tenant-Name>.onmicrosoft.com"; // Tenant Name
        private static string policy = "<Your-Policy-Name>"; // B2C policy, e.g., B2C_1_SignUpSignIn
        private static string redirectUri = "https://<Your-Site>/"; // Redirect URI for the app
        private static string clientSecret = "<Your-Client-Secret>"; // Optional: Use if needed for confidential clients
        private static string metadataEndpoint = $"https://{tenant}/tfp/{policy}/v2.0/.well-known/openid-configuration";

        public void Configuration(IAppBuilder app)
        {
            app.SetDefaultSignInAsAuthenticationType(CookieAuthenticationDefaults.AuthenticationType);
            
            app.UseCookieAuthentication(new CookieAuthenticationOptions());

            app.UseOpenIdConnectAuthentication(new OpenIdConnectAuthenticationOptions
            {
                ClientId = clientId,
                RedirectUri = redirectUri,
                Authority = $"https://{tenant}/{policy}",
                PostLogoutRedirectUri = redirectUri,
                Scope = "openid profile", // Add additional scopes if needed
                ResponseType = "id_token",

                TokenValidationParameters = new TokenValidationParameters
                {
                    NameClaimType = "name", // Adjust claim type mapping as necessary
                },

                Notifications = new OpenIdConnectAuthenticationNotifications
                {
                    AuthenticationFailed = context =>
                    {
                        context.HandleResponse();
                        context.Response.Redirect("/Home/Error?message=" + context.Exception.Message);
                        return System.Threading.Tasks.Task.FromResult(0);
                    },

                    RedirectToIdentityProvider = context =>
                    {
                        if (context.ProtocolMessage.RequestType == OpenIdConnectRequestType.LogoutRequest)
                        {
                            var logoutUri = $"https://{tenant}/{policy}/oauth2/v2.0/logout?post_logout_redirect_uri={redirectUri}";
                            context.ProtocolMessage.IssuerAddress = logoutUri;
                        }
                        return System.Threading.Tasks.Task.FromResult(0);
                    }
                }
            });
        }
    }

    public class HomeController : Controller
    {
        [Authorize]
        public ActionResult Index()
        {
            return View();
        }

        public ActionResult Login()
        {
            if (!Request.IsAuthenticated)
            {
                HttpContext.GetOwinContext().Authentication.Challenge(new AuthenticationProperties { RedirectUri = "/" }, OpenIdConnectAuthenticationDefaults.AuthenticationType);
                return new HttpUnauthorizedResult();
            }

            return RedirectToAction("Index");
        }

        public ActionResult Logout()
        {
            HttpContext.GetOwinContext().Authentication.SignOut(OpenIdConnectAuthenticationDefaults.AuthenticationType, CookieAuthenticationDefaults.AuthenticationType);
            return RedirectToAction("Index");
        }
    }
}