How to properly organize two languages ​​in asp mvc site?

Question

Search Engine Optimization

Hello!
The task is this: to organize two languages, so that the user's automatic language is determined and the required version is issued, and there are no changes in the URL, everything is the same.
Here's what I did:
this is the base controller

protected override void OnActionExecuted(ActionExecutedContext filterContext)
        {
            // Is it View ?
            ViewResultBase view = filterContext.Result as ViewResultBase;
            if (view == null) // if not exit
                return;


         filterContext.HttpContext.Request.UserLanguages[0]; // needs validation return "en-us" as default            
            string cultureName = "";

            // Attempt to read the culture cookie from Request
            HttpCookie cultureCookie = Request.Cookies["_culture"];
            if (cultureCookie != null)
                cultureName = cultureCookie.Value;
            else
                cultureName = filterContext.HttpContext.Request.UserLanguages[0];
Request.UserLanguages.Length > 0 ? Request.UserLanguages[0] : null; // obtain it from HTTP header AcceptLanguages

            if (cultureName == "en") { cultureName = "en-US"; }
            if (cultureName == "ru") { cultureName = "ru-RU"; }
          

            // Are views implemented separately for this culture?  if not exit
            bool viewImplemented = CultureHelper.IsViewSeparate(cultureName);
            if (viewImplemented == false)
                return;

            string viewName = view.ViewName;

            int i = 0;

            if (string.IsNullOrEmpty(viewName))
                viewName = filterContext.RouteData.Values["action"] + "." + cultureName; // Index.en-US
            else if ((i = viewName.IndexOf('.')) > 0)
            {
                // contains . like "Index.cshtml"                
                viewName = viewName.Substring(0, i + 1) + cultureName + viewName.Substring(i);
            }
            else
                viewName += "." + cultureName; // e.g. "Index" ==> "Index.en-Us"

            view.ViewName = viewName;

            filterContext.Controller.ViewBag._culture = "." + cultureName;

            base.OnActionExecuted(filterContext);
        }


        protected override void ExecuteCore()
        {
            string cultureName = null;
            // Attempt to read the culture cookie from Request
            HttpCookie cultureCookie = Request.Cookies["_culture"];
            if (cultureCookie != null)
                cultureName = cultureCookie.Value;
            else
                cultureName = Request.UserLanguages[0]; // obtain it from HTTP header AcceptLanguages

            // Validate culture name
            cultureName = CultureHelper.GetValidCulture(cultureName); // This is safe


            // Modify current thread's culture            
            Thread.CurrentThread.CurrentCulture = System.Globalization.CultureInfo.CreateSpecificCulture(cultureName);
            Thread.CurrentThread.CurrentUICulture = System.Globalization.CultureInfo.CreateSpecificCulture(cultureName);

            base.ExecuteCore();
        }

as you can see from the code, the language in the browser is checked (is there also a setting in cookies), and a representation is formed for the corresponding language (Index.ru-ru.cshtml or Index.en-us.cshtml)
And in HomeController everything is as usual

public ActionResult Index()
        {

            ViewBag.ClassMain = "active";         
            return View();
        }

URL is always Index for both English and Russian versions. Everything works fine, except that when a site or any page is added to Google, it swears, there is an error on the site. I understand that the Google bot, like the other, does not contain a language variable .... how can this be fixed? how to define a bot and give it always ru submissions?

Answer 1

Take a little out of context

if (cultureName == "en") { cultureName = "en-US"; }
            if (cultureName == "ru") { cultureName = "ru-RU"; }

1) Here else will not hurt.
2) You say that you have 2 languages. What happens if cultureName = 'de'? Maybe make it the default?