Adding 2FA Authenticator Support (#66)

* Adding support for 2fa, more auth options

* WIP getting auth stuff working

* Added Manage views. 2FA working now for MVC app.

* Switching to using a controller for no-UI logout scenario

* Adding Razor Pages impl of 2FA auth stuff. Works.

src/WebRazorPages/Pages/Account/LoginWith2fa.cshtml.cs

@@ -0,0 +1,94 @@
+using ApplicationCore.Interfaces;
+using Infrastructure.Identity;
+using Microsoft.AspNetCore.Identity;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.RazorPages;
+using System;
+using System.ComponentModel.DataAnnotations;
+using System.Threading.Tasks;
+
+namespace Microsoft.eShopWeb.RazorPages.Pages.Account
+{
+    public class LoginWith2faModel : PageModel
+    {
+        private readonly SignInManager<ApplicationUser> _signInManager;
+        private readonly IAppLogger<LoginWith2faModel> _logger;
+
+        public LoginWith2faModel(SignInManager<ApplicationUser> signInManager, 
+            IAppLogger<LoginWith2faModel> logger)
+        {
+            _signInManager = signInManager;
+            _logger = logger;
+        }
+
+        [BindProperty]
+        public InputModel Input { get; set; }
+
+        public bool RememberMe { get; set; }
+
+        public string ReturnUrl { get; set; }
+
+        public class InputModel
+        {
+            [Required]
+            [StringLength(7, ErrorMessage = "The {0} must be at least {2} and at max {1} characters long.", MinimumLength = 6)]
+            [DataType(DataType.Text)]
+            [Display(Name = "Authenticator code")]
+            public string TwoFactorCode { get; set; }
+
+            [Display(Name = "Remember this machine")]
+            public bool RememberMachine { get; set; }
+        }
+
+        public async Task<IActionResult> OnGetAsync(bool rememberMe, string returnUrl = null)
+        {
+            // Ensure the user has gone through the username & password screen first
+            var user = await _signInManager.GetTwoFactorAuthenticationUserAsync();
+
+            if (user == null)
+            {
+                throw new ApplicationException($"Unable to load two-factor authentication user.");
+            }
+
+            ReturnUrl = returnUrl;
+            RememberMe = rememberMe;
+
+            return Page();
+        }
+
+        public async Task<IActionResult> OnPostAsync(bool rememberMe, string returnUrl = null)
+        {
+            if (!ModelState.IsValid)
+            {
+                return Page();
+            }
+
+            var user = await _signInManager.GetTwoFactorAuthenticationUserAsync();
+            if (user == null)
+            {
+                throw new ApplicationException($"Unable to load two-factor authentication user.");
+            }
+
+            var authenticatorCode = Input.TwoFactorCode.Replace(" ", string.Empty).Replace("-", string.Empty);
+
+            var result = await _signInManager.TwoFactorAuthenticatorSignInAsync(authenticatorCode, rememberMe, Input.RememberMachine);
+
+            if (result.Succeeded)
+            {
+                _logger.LogInformation("User with ID '{UserId}' logged in with 2fa.", user.Id);
+                return LocalRedirect(Url.GetLocalUrl(returnUrl));
+            }
+            else if (result.IsLockedOut)
+            {
+                _logger.LogWarning("User with ID '{UserId}' account locked out.", user.Id);
+                return RedirectToPage("./Lockout");
+            }
+            else
+            {
+                _logger.LogWarning("Invalid authenticator code entered for user with ID '{UserId}'.", user.Id);
+                ModelState.AddModelError(string.Empty, "Invalid authenticator code.");
+                return Page();
+            }
+        }  
+    }
+}