How to properly detect user browser culture in asp.net mvc

Question

I see that there are similar questions to this one but I haven't found an answer to my question there and therefore, I decided to ask a question to my own.

The situation: I want to get the user's browser language so that I can set his session culture key or store the localization in the database if the user has an account in order to show this user my website on his language until he changes his lang preference manually.

My issue is: Everything seems to work pretty fine in theory but...

These are my browser language preferences I know that they are set on particular order

That order is sent to the server exactly as it is no matter that my browser display language is set to Bulgarian my preference still remain en-US

This is a sample code snippet to show what my dev tools console says about my browser display language

And in my code I cannot know what is the browser language I can only get the preferred language to the user then I get the Languages[0]

Is there a way to get this display language. I cannot use JS to send it because I have a problem that my first request is always displaying the page in English than when the session is set it displays it localized. Probably there is a workaround to check and set a particular header from JS but I am thinking of a more gallant way to do it only with C#.

I am not sure it is the proper way. I have overridden on OnActionExecuting in my BaseController and I am setting the current thread's localizations based on the user's locale and he may change by drop down his preferred language also that overrides and reset the session language key. I know also that there is an auto locale option but I am not sure if it is good enough and also I don't know how it works and how can a user simply change his language while the auto globalization is turned on.

For now, I just want to get the proper browser display's language and I need some help from someone that has dealt with localizations.

Answer 1

you can use CultureHelper :

public static class CultureHelper
{

// Valid cultures
    private static readonly List<string> _validCultures = new List<string> {         "af", "af-ZA", "sq", "sq-AL", "gsw-FR", "am-ET", "ar", "ar-DZ", "ar-BH", "ar-   EG", "ar-IQ", "ar-JO", "ar-KW", "ar-LB", "ar-LY", "ar-MA", "ar-OM", "ar-QA", "ar-SA", "ar-SY", "ar-TN", "ar-AE", "ar-YE", "hy", "hy-AM", "as-IN", "az", "az-Cyrl-AZ", "az-Latn-AZ", "ba-RU", "eu", "eu-ES", "be", "be-BY", "bn-BD", "bn-IN", "bs-Cyrl-BA", "bs-Latn-BA", "br-FR", "bg", "bg-BG", "ca", "ca-ES", "zh-HK", "zh-MO", "zh-CN", "zh-Hans", "zh-SG", "zh-TW", "zh-Hant", "co-FR", "hr", "hr-HR", "hr-BA", "cs", "cs-CZ", "da", "da-DK", "prs-AF", "div", "div-MV", "nl", "nl-BE", "nl-NL", "en", "en-AU", "en-BZ", "en-CA", "en-029", "en-IN", "en-IE", "en-JM", "en-MY", "en-NZ", "en-PH", "en-SG", "en-ZA", "en-TT", "en-GB", "en-US", "en-ZW", "et", "et-EE", "fo", "fo-FO", "fil-PH", "fi", "fi-FI", "fr", "fr-BE", "fr-CA", "fr-FR", "fr-LU", "fr-MC", "fr-CH", "fy-NL", "gl", "gl-ES", "ka", "ka-GE", "de", "de-AT", "de-DE", "de-LI", "de-LU", "de-CH", "el", "el-GR", "kl-GL", "gu", "gu-IN", "ha-Latn-NG", "he", "he-IL", "hi", "hi-IN", "hu", "hu-HU", "is", "is-IS", "ig-NG", "id", "id-ID", "iu-Latn-CA", "iu-Cans-CA", "ga-IE", "xh-ZA", "zu-ZA", "it", "it-IT", "it-CH", "ja", "ja-JP", "kn", "kn-IN", "kk", "kk-KZ", "km-KH", "qut-GT", "rw-RW", "sw", "sw-KE", "kok", "kok-IN", "ko", "ko-KR", "ky", "ky-KG", "lo-LA", "lv", "lv-LV", "lt", "lt-LT", "wee-DE", "lb-LU", "mk", "mk-MK", "ms", "ms-BN", "ms-MY", "ml-IN", "mt-MT", "mi-NZ", "arn-CL", "mr", "mr-IN", "moh-CA", "mn", "mn-MN", "mn-Mong-CN", "ne-NP", "no", "nb-NO", "nn-NO", "oc-FR", "or-IN", "ps-AF", "fa", "fa-IR", "pl", "pl-PL", "pt", "pt-BR", "pt-PT", "pa", "pa-IN", "quz-BO", "quz-EC", "quz-PE", "ro", "ro-RO", "rm-CH", "ru", "ru-RU", "smn-FI", "smj-NO", "smj-SE", "se-FI", "se-NO", "se-SE", "sms-FI", "sma-NO", "sma-SE", "sa", "sa-IN", "sr", "sr-Cyrl-BA", "sr-Cyrl-SP", "sr-Latn-BA", "sr-Latn-SP", "nso-ZA", "tn-ZA", "si-LK", "sk", "sk-SK", "sl", "sl-SI", "es", "es-AR", "es-BO", "es-CL", "es-CO", "es-CR", "es-DO", "es-EC", "es-SV", "es-GT", "es-HN", "es-MX", "es-NI", "es-PA", "es-PY", "es-PE", "es-PR", "es-ES", "es-US", "es-UY", "es-VE", "sv", "sv-FI", "sv-SE", "syr", "syr-SY", "tg-Cyrl-TJ", "tzm-Latn-DZ", "ta", "ta-IN", "tt", "tt-RU", "te", "te-IN", "th", "th-TH", "bo-CN", "tr", "tr-TR", "tk-TM", "ug-CN", "uk", "uk-UA", "wen-DE", "ur", "ur-PK", "uz", "uz-Cyrl-    UZ", "uz-Latn-UZ", "vi", "vi-VN", "cy-GB", "wo-SN", "sah-RU", "ii-CN", "yo-NG"    };
    // Include ONLY cultures you are implementing
    private static readonly List<string> _cultures = new List<string> {
    "fr",// first culture is the DEFAULT
    "ar",  
    "en"

    };
    /// <summary>
    /// Returns true if the language is a right-to-left language. Otherwise, false.
    /// </summary>
    public static bool IsRighToLeft()
    {
        return System.Threading.Thread.CurrentThread.CurrentCulture.TextInfo.IsRightToLeft;

    }
    /// <summary>
    /// Returns a valid culture name based on "name" parameter. If "name" is not valid, it returns the default culture "en-US"
    /// </summary>
    /// <param name="name" />Culture's name (e.g. en-US)</param>
    public static string GetImplementedCulture(string name)
    {
        // make sure it's not null
        if (string.IsNullOrEmpty(name))
            return GetDefaultCulture(); // return Default culture
        // make sure it is a valid culture first
        if (_validCultures.Where(c => c.Equals(name, StringComparison.InvariantCultureIgnoreCase)).Count() == 0)
            return GetDefaultCulture(); // return Default culture if it is invalid
        // if it is implemented, accept it
        if (_cultures.Where(c => c.Equals(name, StringComparison.InvariantCultureIgnoreCase)).Count() > 0)
            return name; // accept it
        // Find a close match. For example, if you have "en-US" defined and the user requests "en-GB", 
        // the function will return closes match that is "en-US" because at least the language is the same (ie English)  
        var n = GetNeutralCulture(name);
        foreach (var c in _cultures)
            if (c.StartsWith(n))
                return c;
        // else 
        // It is not implemented
        return GetDefaultCulture(); // return Default culture as no match found
    }
    /// <summary>
    /// Returns default culture name which is the first name decalared (e.g. en-US)
    /// </summary>
    /// <returns></returns>
    public static string GetDefaultCulture()
    {
        return _cultures[0]; // return Default culture
    }
    public static List<string> GetCultures()
    {
        return _cultures;
    }
    public static string GetCurrentCulture()
    {
        return Thread.CurrentThread.CurrentCulture.Name;
    }
    public static string GetCurrentNeutralCulture()
    {
        return GetNeutralCulture(Thread.CurrentThread.CurrentCulture.Name);
    }
    public static string GetNeutralCulture(string name)
    {
        if (!name.Contains("-")) return name;

        return name.Split('-')[0]; // Read first part only. E.g. "en", "es"
    }
}

then in your view use :

  <script>
  var currentLang = '@CultureHelper.GetCurrentCulture()';
 </script>

Answer 2

Display language is not something that you need to know on the server, since it is only the implementation in Chrome that works this way, it does not have to be any display language in any other browser at all (though it might be). All you get is a list of languages in a preferred order (if you want bulgarian to be first, you just have to drag & drop in Chrome it to the top).

Most users will have display language = topmost language and that will also be the only language anyway.