Orchard/src/Orchard.Web/Modules/Orchard.Localization/Selectors/BrowserCultureSelector.cs

using System;
using System.Globalization;
using System.Linq;
using System.Web;
using Orchard.Environment.Extensions;
using Orchard.Localization.Services;

namespace Orchard.Localization.Selectors {
    [OrchardFeature("Orchard.Localization.CutlureSelector")]
    public class BrowserCultureSelector : ICultureSelector {
        private readonly Lazy<ICultureManager> _cultureManager;

        public BrowserCultureSelector(
            Lazy<ICultureManager> cultureManager) {
            _cultureManager = cultureManager;
        }

        public CultureSelectorResult GetCulture(HttpContextBase context) {
            if (context == null) return null;

            /* Fall back to Browser */
            var userLanguages = context.Request.UserLanguages;

            if (userLanguages == null || !userLanguages.Any())
                return null;

            var cultures = _cultureManager.Value.ListCultures().ToList();

            foreach (var userLanguage in userLanguages
                .Select(ul => ul.Split(';')[0].Trim())) {

                if (cultures.Contains(userLanguage, StringComparer.OrdinalIgnoreCase)) {
                    return new CultureSelectorResult { Priority = -4, CultureName = CultureInfo.CreateSpecificCulture(userLanguage).Name };
                }
            }

            return null;
        }
    }
}