Overriding Application_PreRequestHandlerExecute

I have inherited an application which uses Application_PreRequestHandlerExecute to redirect to login if the session has expired.

Currently there is a list of hard-coded urls which should not invoke a redirect. Essentially, these are ajax methods which return json, so they are dealt with separately in javascript.

I would like to change the mechanism so that the default (in Application_PreRequestHandlerExecute) remains the same but alternative behaviour can be controlled by ActionFilters on the appropriate Actions (i.e. those corresponding to the hard-coded list of urls).

How do I check for the presence of the particular ActionFilter in Application_PreRequestHandlerExecute?

EDIT: Perhaps I need to replace Application_PreRequestHandlerExecute with a Global Action Filter?

The short answer is to replace with a global Action Filter.

Within that, filterContext has everything that I need.

EDIT: This is the gist of what I went for:

public enum SessionExpiredBehaviour
{
    Redirect,
    Ignore,
    JSON
}


[AttributeUsage(AttributeTargets.Method)]
public class SessionExpiredFilterAttribute : ActionFilterAttribute
{
    public SessionExpiredBehaviour Behaviour { get; set; } = SessionExpiredBehaviour.Redirect;

    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {

        if (HttpContext.Current.Session["User"] == null)
        {
            switch (this.Behaviour)
            {

                case SessionExpiredBehaviour.Redirect:
                    filterContext.Result =
                        new RedirectToRouteResult(new RouteValueDictionary
                        {
                            { "action", "RedirectToLogin" },
                            { "controller", "Account" }
                        });
                    break;

                case SessionExpiredBehaviour.JSON:
                    //TODO
                    break;
            }

        }
        base.OnActionExecuting(filterContext);

    }
}