MVCPostall/Postall/Controllers/OtherLoginsController.cs

// AccountController.cs
using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Authentication.Facebook;
using Microsoft.AspNetCore.Mvc;

namespace Postall.Controllers
{
    public class OtherLoginsController : Controller
    {
        [HttpGet]
        public IActionResult Index()
        {
            return View();
        }

        [HttpGet]
        public IActionResult FacebookLogin()
        {
            var properties = new AuthenticationProperties { RedirectUri = Url.Action("FacebookResponse") };
            return Challenge(properties, FacebookDefaults.AuthenticationScheme);
        }

        [HttpGet]
        public async Task<IActionResult> FacebookResponse()
        {
            var result = await HttpContext.AuthenticateAsync(FacebookDefaults.AuthenticationScheme);

            if (!result.Succeeded)
                return RedirectToAction("Login");

            var claims = result.Principal.Identities.FirstOrDefault()
                .Claims.Select(claim => new
                {
                    claim.Issuer,
                    claim.OriginalIssuer,
                    claim.Type,
                    claim.Value
                });

            // Aqui você pode implementar sua lógica de login
            // Por exemplo, criar ou atualizar o usuário no banco de dados

            return RedirectToAction("Index", "Home");
        }

        [HttpPost]
        public IActionResult Logout()
        {
            return SignOut("Cookies", FacebookDefaults.AuthenticationScheme);
        }
    }
}