ASP.NET MVC3 Routing various subfolders to the same controller - asp.net-mvc

Question

I'm trying to set up my MVC project to have URLs so that I can go to:
/Groups/
/Groups/Register
/Groups/Whatever
But in my controller, I can also flag some actions as admin only, so that they are accessed at:
/Admin/Groups/Delete/{id}
I would like to keep one GroupController, and have actions so that:
public class GroupController : Controller
{
public ActionResult Index(){
return View();
}
[AdminAction]
public ActionResult Delete(int id){
...
return View();
}
}
Allows:
/Groups is a valid URL.
/Admin/Groups is a valid URL (but would call some other action besides Index - maybe)
/Admin/Groups/Delete/{id} is a valid URL (post only, whatever)
/Groups/Delete is an INVALID url.
I realize this is probably a pretty broad question, but I'm new to MVC and I'm not really sure where to start looking, so if you could just point me in the right direction that would be hugely appreciated.

Answer 1

As we discussed in the comments below, while it is possible to use my original answer below to achieve the routing solution you requested, a better solution is to use Areas, establish an Admin area, and create controllers in your Admin area to handle the administrative tasks for different objects, such as Group, User, etc. This allows you to set up restricted administrative functions more easily, and is both a better design and a better security model.
ORIGINAL ANSWER
What you want can be accomplished by using the following routes:
public static void RegisterRoutes(RouteCollection routes)
{
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
routes.MapRoute(
"Admin", // Route name
"admin/{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
routes.MapRoute(
"Default", // Route name
"{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
);
}
However, as Akos said in the comments, it is a much better design to separate the administrative functions into a different controller. While this is possible, I would recommend against using this design.
UPDATE
It is possible to use a RouteConstraint on your Default route to make it fail if Admin actions are requested. The Default route would look like this:
routes.MapRoute(
"Default", // Route name
"{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index", id = UrlParameter.Optional, // Parameter defaults
new { action = IsNotAdminAction() } // route constraint
);
The RouteConstraint would look like this:
public class IsNotAdminAction : IRouteConstraint
{
private string adminActions = "create~delete~edit";
public IsNotAdminAction()
{ }
public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection)
{
// return false if there is a match
return !adminActions.Contains(values[parameterName].ToString().ToLowerInvariant());
}
}