marechai/Marechai/Areas/Identity/Pages/Account/Manage/TwoFactorAuthentication.cshtml.cs

using System.Threading.Tasks;
using Marechai.Database.Models;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.Extensions.Logging;

namespace Marechai.Areas.Identity.Pages.Account.Manage
{
    public class TwoFactorAuthenticationModel : PageModel
    {
        const    string AuthenicatorUriFormat = "otpauth://totp/{0}:{1}?secret={2}&issuer={0}";
        readonly ILogger<TwoFactorAuthenticationModel> _logger;
        readonly SignInManager<ApplicationUser> _signInManager;

        readonly UserManager<ApplicationUser> _userManager;

        public TwoFactorAuthenticationModel(UserManager<ApplicationUser> userManager,
                                            SignInManager<ApplicationUser> signInManager,
                                            ILogger<TwoFactorAuthenticationModel> logger)
        {
            _userManager   = userManager;
            _signInManager = signInManager;
            _logger        = logger;
        }

        public bool HasAuthenticator { get; set; }

        public int RecoveryCodesLeft { get; set; }

        [BindProperty]
        public bool Is2faEnabled { get; set; }

        public bool IsMachineRemembered { get; set; }

        [TempData]
        public string StatusMessage { get; set; }

        public async Task<IActionResult> OnGet()
        {
            ApplicationUser user = await _userManager.GetUserAsync(User);

            if(user == null)
            {
                return NotFound($"Unable to load user with ID '{_userManager.GetUserId(User)}'.");
            }

            HasAuthenticator    = await _userManager.GetAuthenticatorKeyAsync(user) != null;
            Is2faEnabled        = await _userManager.GetTwoFactorEnabledAsync(user);
            IsMachineRemembered = await _signInManager.IsTwoFactorClientRememberedAsync(user);
            RecoveryCodesLeft   = await _userManager.CountRecoveryCodesAsync(user);

            return Page();
        }

        public async Task<IActionResult> OnPost()
        {
            ApplicationUser user = await _userManager.GetUserAsync(User);

            if(user == null)
            {
                return NotFound($"Unable to load user with ID '{_userManager.GetUserId(User)}'.");
            }

            await _signInManager.ForgetTwoFactorClientAsync();

            StatusMessage =
                "The current browser has been forgotten. When you login again from this browser you will be prompted for your 2fa code.";

            return RedirectToPage();
        }
    }
}