问仅使用ASP.NET MVC 5进行社交登录

EN

    [AllowAnonymous]
    public async Task<ActionResult> ExternalLoginCallback(string returnUrl)
    {
        ExternalLoginInfo loginInfo = await HttpContext.GetOwinContext().Authentication.GetExternalLoginInfoAsync();
        if (loginInfo == null)
        {
            return RedirectToAction("Login");
        }
        // what do I do here ?????????
    }

    app.UseCookieAuthentication(new CookieAuthenticationOptions
    {
        AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
        LoginPath = new PathString("/Account/Login")
    });

    app.UseExternalSignInCookie(DefaultAuthenticationTypes.ExternalCookie);

    // bla-bla-bla
    app.UseGoogleAuthentication(googleAuthOptions);