ASP.NET_Core_SPAs.Controllers.AccountController.ExternalLoginCallback C# (CSharp) Method

        public async Task<IActionResult> ExternalLoginCallback(string returnUrl = null)
        {
            var info = await _signInManager.GetExternalLoginInfoAsync();
            if (info == null)
            {
                return RedirectToAction(nameof(Login));
            }

            // Sign in the user with this external login provider if the user already has a login.
            var result = await _signInManager.ExternalLoginSignInAsync(info.LoginProvider, info.ProviderKey, isPersistent: false);
            if (result.Succeeded)
            {
                _logger.LogInformation(5, "User logged in with {Name} provider.", info.LoginProvider);
                return RedirectToLocal(returnUrl);
            }
            if (result.RequiresTwoFactor)
            {
                return RedirectToAction(nameof(SendCode), new { ReturnUrl = returnUrl });
            }
            if (result.IsLockedOut)
            {
                return View("Lockout");
            }
            else
            {
                // If the user does not have an account, then ask the user to create an account.
                ViewData["ReturnUrl"] = returnUrl;
                ViewData["LoginProvider"] = info.LoginProvider;
                var email = info.Principal.FindFirstValue(ClaimTypes.Email);
                return View("ExternalLoginConfirmation", new ExternalLoginConfirmationViewModel { Email = email });
            }
        }