Get an unique session in each browser tab

I got a lot to do at work, hence the silence. I got a lot to blog about, but so little time ;/ I found an interesting question at Stackoverflow which this answer is for (also to show you that the blog is not forgotten).

A user wanted to store browser tab specific data which can be a problem since most browsers share a session between different tabs. The solution is to create a new route which generates a GUID and then use that guid to fetch and store session information. Keep in mind that you need two routes: one that works for users which just surfed into the site, and one that loads an existing guid.

Here is the route class:

public class GuidRoute : Route
{
    private readonly bool _isGuidRoute;

    public GuidRoute(string uri, object defaults)
        : base(uri, new RouteValueDictionary(defaults), new MvcRouteHandler())
    {
        _isGuidRoute = uri.Contains("guid");

        DataTokens = new RouteValueDictionary();
    }

    public override RouteData GetRouteData(HttpContextBase httpContext)
    {
        var routeData = base.GetRouteData(httpContext);
        if (routeData == null)
            return null;

        if (!routeData.Values.ContainsKey("guid") || 
        routeData.Values["guid"].ToString() == "")
            routeData.Values["guid"] = Guid.NewGuid().ToString("N");

        return routeData;
    }

    public override VirtualPathData GetVirtualPath
    (RequestContext requestContext, RouteValueDictionary values)
    {
        return !_isGuidRoute ? null : base.GetVirtualPath(requestContext, values);
    }
}

Replace the default route in global.asax with it:

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

routes.Add("Default", new GuidRoute(
    "{controller}/{action}/{id}",
    new { controller = "Home", action = "Index", 
        guid = "", id = UrlParameter.Optional }));

routes.Add("GuidRoute", new GuidRoute(
    "g/{guid}/{controller}/{action}/{id}",
    new { controller = "Home", action = "Index", 
        guid = "", id = UrlParameter.Optional }));

And finally some extension methods to make life easier in the controllers:

public static class ControllerExtensionMethods
{
    public static string GetGuid(this Controller controller)
    {
        return controller.RouteData.Values["guid"].ToString();
    }

    public static void SetGuidSession
    (this Controller controller, string name, object value)
    {
        controller.Session[controller.GetGuid() + "_" + name] = value;
    }

    public static object GetGuidSession(this Controller controller, string name)
    {
        return controller.Session[controller.GetGuid() + "_" + name];
    }
}

One thing left though: Any browser bookmarks will use an old GUID. Should not be a problem in most cases (unless the user opens the bookmark in multiple tabs = sharing the session between the tabs). Same thing goes for opening a link in a new tab = shared.