The following two links access the same action method (they share the same document type and access the same controller and action):

http://stage.bullydog.com/Products/accessories/podmount and http://stage.sctflash.com/Products/accessories/podmount

I use Request.Url.Host to determine the brand of products I want to return from a database. When I access http://stage.bullydog.com/Products/accessories/podmount first, Request.Url.Host contains the value stage.bullydog.com, but if I then go to http://stage.sctflash.com/Products/accessories/podmount, Request.Url.Host may contain stage.sctflash.com or it may contain stage.bullydog.com.

The action method that is called is:

public ActionResult GetAccessoriesByType(RenderModel model, string id)
    {
        Common _common = new Common();
        string brand = Request.Url != null ? _common.GetProductBrand() : BrandType.SCT;

        var productSearchResultsModel = new ProductSearchResultsModel
        {
            Accessories = _accessoryRepository.GetAccessoriesByType(id, brand)
        };

        return View("~/Views/accessories.cshtml", productSearchResultsModel);
    }

The code that gets the brand is:

public class Common
{
    public string GetProductBrand()
    {
        var host = HttpContext.Current.Request.Url.Host;

        if (host.Contains("sctflash"))
            return BrandType.SCT;

        if (host.Contains("bigrig") || host.Contains("bigrigs"))
            return BrandType.BigRig;

        if (host.Contains("bullydog"))
            return BrandType.BullyDog;

        return BrandType.SCT;
    }
}

How can I ensure the Request.Url.Host contains the proper host when the same action method is accessed from two different hosts?

You can see this in action if you go to http://stage.bullydog.com/Products/accessories/podmount and then go to http://stage.sctflash.com/Products/accessories/podmount and refresh either one, the logo should change which means that the value returned by Request.Url.Host was incorrect.

Also, can GetProductBrand be static and still be thread-safe in this case?