Facebook login in asp.net core not working and return 500 - facebook

Question

I have been using facebook login for one of my asp.net core projects. However, it stopped working for Facebook login suddenly. I am getting HTTP 500 error.
The issue is, even in the debug more, asp.net core is not mentioning any error. It is just same 500 error code. Nothing else.
When I tried to set breakpoint in the first line of public async Task<IActionResult> ExternalLoginCallback(string returnUrl = null) function, I realized that it is not even hitting that and failing even before that.
I am not sure how to debug this further. Am I missing anything here? Or is there any change from FB in the login side?
The return URL being hit is by Facebook is:
https://localhost:44300/signin-facebook?code=AQBxGGw7ZCoa9xtXc3CCsVGRD9TJLL428bZ_eJpUu4CtVu3K4UrfOZuYYdwFBXzGZ6GOGXpOi2Nme_jfbewB84otVZhKZfs4i7Dhi9Y3E_rloU9ouLeIvuOsm29jr7IDCtTj_HM7rKuKjj3zmc4yz5i_fniZ9ZhMfXtSus5KyKa4EFkZTsmKrz2ngMlGQalUAob_52GJNhvSIXDlmiNSrZLJV3m7Zbkf9eXETQkqhu2L1kgXPvWkMzVP8EN00GwRCYB3xT1kQMOimDANRKhziZjoVS5QZFUJTP0Faj47tE1xNfmAzb30iuwcaRORCOTMipUrnRvOO4nGRo8JuUNdPJaO&state=CfDJ8EHIO3qHMHFClr5BAt4EC1Wj7LyAs5Pg1XOqKo4uFiJM2Jr1rNyooxLIu2fbXr6Z3X5_kqbF_7WwFfvF3L3H4xgyooo-3Y9BV8Zh1S5wXlLJDAyCT5_LwkPJ1j8Zrwx4umQJp6NOl76GwRXpi1_BHlWGRxnh_naTL35iqeGovOa8oEDC0jOQ4trRe7YG3fV_ptjWk4yOnvJnsI81O-6wfyhdc3jm-LTP7ZO7-duf_lPZXZ8mL42XyLXDTIyOJ__S2yLYdvwItdDVntsM8Hwq94goXdU-RaH7ZkDA8iAzeCl3Ke0tWAdYBKy9vooJIXmE9Q#_=_
Based on this article, it should have state_token too in the URL. But that seems to be missing here. How can I figure out here what is the actual error?
I am using asp.net core RC2 release.
My callback function is:
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.ExternalPrincipal.FindFirstValue(ClaimTypes.Email);
if (email == null)
{
return View("Error");
}
/* Determine user from external login info */
var name = info.ExternalPrincipal.FindFirstValue(ClaimTypes.Name);
string firstName;
string lastName = "";
if (!string.IsNullOrWhiteSpace(name))
{
firstName = name.Split(' ').Length > 1? name.Split(new[] { ' ' }, 2)[0] : name;
lastName = name.Split(' ').Length > 1 ? name.Split(new[] { ' ' }, 2)[1] : "";
}
else
firstName = email.Split('#')[0];
var user = await _userManager.FindByEmailAsync(email);
if (user == null)
{
/* No user with same email ID. So, create a new user.*/
var newUser = new ApplicationUser
{
UserName = email,
Email = email,
FirstName = firstName,
LastName = lastName,
PasswordLastModifiedTime = DateTime.UtcNow,
UserSignUpDate = DateTime.UtcNow
};
var userCreationResult = await _userManager.CreateAsync(newUser);
if (userCreationResult.Succeeded)
{
userCreationResult = await _userManager.AddLoginAsync(newUser, info);
if (userCreationResult.Succeeded)
{
// Add user claims TODO:// Test if the claims are added successfully.
await _userManager.AddClaimAsync(newUser, new Claim("FirstName", newUser.FirstName));
await _userManager.AddClaimAsync(newUser, new Claim("LastName", newUser.LastName));
// Set user email to confirmed. This is more of work around
var code = await _userManager.GenerateEmailConfirmationTokenAsync(newUser);
userCreationResult = await _userManager.ConfirmEmailAsync(newUser, code);
if (userCreationResult.Succeeded)
{
//Create Subscription for user
var planService = new PlanServices();
var plan = planService.Find((int)SubscriptionType.Basic);
await _subscriptionService.CreateSubscription(newUser, plan, null);
await _signInManager.SignInAsync(newUser, isPersistent: false);
_logger.LogInformation(6, "User created an account using {Name} provider.",
info.LoginProvider);
await _emailSender.SendWelcomeEmailAsync(newUser.Email, newUser.FirstName);
return RedirectToLocal(returnUrl);
}
}
}
}
else
{
/* A user with email ID exists. Associate the account with that.*/
var loginAddResult = await _userManager.AddLoginAsync(user, info);
if (loginAddResult.Succeeded)
{
await _signInManager.SignInAsync(user, isPersistent: false);
return RedirectToLocal(returnUrl);
}
}
return View("ExternalLoginConfirmation", new ExternalLoginConfirmationViewModel { Email = email, FirstName = firstName, LastName = lastName});
}
}
And ConfigureServices method is:
public void ConfigureServices(IServiceCollection services)
{
// Add framework services.
services.AddApplicationInsightsTelemetry(Configuration);
services.AddScoped<ApplicationDbContext>();
services.AddIdentity<ApplicationUser, IdentityRole>(o =>
{
o.Password.RequireDigit = false;
o.Password.RequireLowercase = false;
o.Password.RequireUppercase = false;
o.Password.RequireNonLetterOrDigit = false;
o.Password.RequiredLength = 8;
})
.AddEntityFrameworkStores<ApplicationDbContext>()
.AddDefaultTokenProviders();
services.AddCaching();
services.AddSession();
services.AddMvc();
// Add application services.
services.AddTransient<IEmailSender, AuthMessageSender>();
services.AddTransient<ISmsSender, AuthMessageSender>();
services.AddTransient<ISubscriptionService, SubscriptionService>();
services.Configure<AuthMessageSenderOptions>(Configuration);
services.Configure<RecaptchaOptions>(Configuration);
__serviceProvider = services.BuildServiceProvider();
}
The thing is, it worked well for a long time and has stopped working now. Also, it is not even hitting ExternalLoginCallback, so I am not sure where to head for debugging it further.