public async Task <IActionResult> ExternalLoginCallback(string returnUrl = null, string remoteError = null)
{
returnUrl = returnUrl ?? Url.Content("~/");
LoginViewModel loginViewModel = new LoginViewModel
{
ReturnUrl = returnUrl,
ExternalLogins =
(await Signinmanager.GetExternalAuthenticationSchemesAsync()).ToList()
};
if (remoteError != null)
{
ModelState
.AddModelError(string.Empty, $"Error from external provider: {remoteError}");
return(View("Login", loginViewModel));
}
// Get the login information about the user from the external login provider
var info = await Signinmanager.GetExternalLoginInfoAsync();
if (info == null)
{
ModelState
.AddModelError(string.Empty, "Error loading external login information.");
return(View("Login", loginViewModel));
}
// If the user already has a login (i.e if there is a record in AspNetUserLogins
// table) then sign-in the user with this external login provider
var signInResult = await Signinmanager.ExternalLoginSignInAsync(info.LoginProvider,
info.ProviderKey, isPersistent : false, bypassTwoFactor : true);
if (signInResult.Succeeded)
{
return(LocalRedirect(returnUrl));
}
// If there is no record in AspNetUserLogins table, the user may not have
// a local account
else
{
// Get the email claim value
var email = info.Principal.FindFirstValue(ClaimTypes.Email);
if (email != null)
{
// Create a new user without password if we do not have a user already
var user = await Usermanager.FindByEmailAsync(email);
if (user == null)
{
user = new ApplicationUser
{
UserName = info.Principal.FindFirstValue(ClaimTypes.Email),
Email = info.Principal.FindFirstValue(ClaimTypes.Email)
};
await Usermanager.CreateAsync(user);
await Usermanager.AddToRoleAsync(user, "User");
}
// Add a login (i.e insert a row for the user in AspNetUserLogins table)
await Usermanager.AddLoginAsync(user, info);
await Signinmanager.SignInAsync(user, isPersistent : false);
return(LocalRedirect(returnUrl));
}
// If we cannot find the user email we cannot continue
ViewBag.ErrorTitle = $"Email claim not received from: {info.LoginProvider}";
ViewBag.ErrorMessage = "Please contact support on " + Configuration["Email"];
return(View("Error"));
}
}
