OrchardCore.Users - a service to decide which kind of parameter use to link external login to existing account in the second check

[PiemP]

Discussed in #16023

Each module that add an extenal login provider (like GitHub or OpenID) can specify the value of ClaimTypes.NameIdentifier to link the external login information to an existing OrchardCore account.

But in this line of code, OrchardCore force another check over external login data that could redirect a user to a view that ask about link external login data to an existing account by checking the email value returned by the login provider.

OrchardCore/src/OrchardCore.Modules/OrchardCore.Users/Controllers/AccountController.cs

Lines 387 to 415 in 649b740

	var email = info.Principal.FindFirstValue(ClaimTypes.Email) ?? info.Principal.FindFirstValue("email");
	if (!string.IsNullOrWhiteSpace(email))
	{
	iUser = await _userManager.FindByEmailAsync(email);
	}
	ViewData["ReturnUrl"] = returnUrl;
	ViewData["LoginProvider"] = info.LoginProvider;
	if (iUser != null)
	{
	if (iUser is User userToLink && registrationSettings.UsersMustValidateEmail && !userToLink.EmailConfirmed)
	{
	return RedirectToAction(nameof(RegistrationController.ConfirmEmailSent),
	new
	{
	Area = "OrchardCore.Users",
	Controller = typeof(RegistrationController).ControllerName(),
	ReturnUrl = returnUrl,
	});
	}
	// Link external login to an existing user
	ViewData["UserName"] = iUser.UserName;
	ViewData["Email"] = email;
	return View(nameof(LinkExternalLogin));
	}

I would like each module that add an external login can manage this behavior by a dedicated service. If a module doesn't implement this service: the actual behavior is applied.

Probably could be useful to have a settings to disable this code.

I'm not sure if this "second check" over external login data is correct or it's nature: seems a second chance to connect external login data to user account.

[Piedone]

Would you like to venture into contributing this?

[PiemP]

Would you like to venture into contributing this?

Yes... this week I have some issue at home but next week I try to build something that, I hope, are acceptable.

[Piedone]

Thank you!

[Piedone]

See #16110 (comment) for a description of the use case of this issue in detail.