Localization via an ActionFilterAttribute in ASP.NET MVC 3 web applications

Global.asax.cs

using System.Web.Mvc;
using System.Web.Routing;
using LocalizationSample.Globalization;

namespace LocalizationSample
{
    public class MvcApplication : System.Web.HttpApplication
    {
        public static void RegisterGlobalFilters(GlobalFilterCollection filters)
        {
            filters.Add(new HandleErrorAttribute());
            filters.Add(new LocalizationAttribute());
        }

        public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

            routes.MapRoute(
                "LocalizationIndex",
                "{lang}",
                new { controller = "Home", action = "Index", lang = "" },
                new { lang = @"([^0-9]+)" }
            );

            routes.MapRoute(
                "Default", // Route name
                "{controller}/{action}/{id}", // URL with parameters
                new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
            );

        }

        protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();

            RegisterGlobalFilters(GlobalFilters.Filters);
            RegisterRoutes(RouteTable.Routes);
        }
    }
}

HomeController.cs

using System.Web.Mvc;

namespace LocalizationSample.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            return View();
        }
    }
}

Index.cshtml

@using LocalizationSample.Globalization;
@{
    ViewBag.Title = "Index";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<h2>@LocalizedResourceManager.GetResource("TitleLabel")</h2>
<div>@LocalizedResourceManager.GetResource("DescriptionLabel")</div>

LocalizationAttribute.cs

using System.Linq;
using System.Globalization;
using System.Threading;
using System.Web;
using System.Web.Mvc;

namespace LocalizationSample.Globalization
{
    public class LocalizationAttribute : ActionFilterAttribute
    {
        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            // Resolve and set the current culture
            var culture = ResolveCulture(filterContext);
            Thread.CurrentThread.CurrentUICulture = Thread.CurrentThread.CurrentCulture = culture;

            // Resolve the current site and setup the LocalizedResourceManager
            var siteName = ResolveSite();            
            LocalizedResourceManager.CurrentSiteName = siteName;

            // Continue processing the action
            base.OnActionExecuting(filterContext);
        }

        private static CultureInfo ResolveCulture(ControllerContext filterContext)
        {
            // Priority 1: from a lang parameter in the query string
            var culture = CreateCulture(GetLanguageFromRouteData(filterContext));
            if (culture != null)
                return culture;

            // Priority 2: Get culture from user's browser
            culture = CreateCulture(GetRequestLanguage(filterContext));
            if (culture != null)
                return culture;

            return Thread.CurrentThread.CurrentCulture;
        }

        private static string GetLanguageFromRouteData(ControllerContext filterContext)
        {
            return filterContext.RouteData.Values["lang"] != null ?
                filterContext.RouteData.Values["lang"].ToString() : string.Empty;
        }

        private static string GetRequestLanguage(ControllerContext filterContext)
        {
            if (filterContext.HttpContext.Request.UserLanguages != null 
                && filterContext.HttpContext.Request.UserLanguages.Count() > 0)
            {
                return filterContext.HttpContext.Request.UserLanguages[0];
            }

            return string.Empty;
        }

        private static CultureInfo CreateCulture(string name)
        {
            try
            {
                return CultureInfo.CreateSpecificCulture(name);
            }
            catch
            {
                return null;
            }
        }

        private static string ResolveSite()
        {
            var hostUrl = HttpContext.Current.Request.Url.Host;

            if (hostUrl.Contains("sitea"))
                return "SiteA";

            if (hostUrl.Contains("siteb"))
                return "SiteB";

            if (hostUrl.Contains("sitec"))
                return "SiteC";

            // Default to "SiteA"
            return "SiteA";
        }
    }
}

LocalizedResourceManager.cs

using System.Web;

namespace LocalizationSample.Globalization
{
    public class LocalizedResourceManager
    {
        public static string CurrentSiteName { get; set; }
        public static string GetResource(string property)
        {
            try
            {                
                var resourceValue = HttpContext.GetGlobalResourceObject(CurrentSiteName, property);                
                return resourceValue != null ? resourceValue.ToString() : string.Empty;
            }
            catch
            {
                return string.Empty;
            }
        }
    }
}