Depth-first nested routing in an ASP.NET website

Question

I've been exploring the System.Web.Routing namespace, playing with constraints and such, but I can't see a way to implement this.

I'm working on an ASP.NET website (non-WAP, non-MVC) using the WebPages/Razor framework.

I'm trying to implement a form of "nested routing", where a route can contain child routes that are only attempted if the parent matches; each child attempting to match the "remainder" of the URI. A "depth-first" route match search, if you will.

routes.Add(new ParentRoute("{foo}/{*remainder}", new[] {
    new ParentRoute("{bar}/{*remainder}", new[] {
        new Route("{baz}"),
        new Route("{zip}"),
    }),
    new ParentRoute("{qux}/{*remainder}", new[] {
        new Route("{baz}"),
        new Route("{zip}"),
    }),
));

I've excluded necessary constraints/handlers (among other parameters) for brevity.

In any case, each step descending through the tree would match the {*remainder} tail of the URI. If a branch fails, it moves up and on to the next, essentially testing something like:

foo
  foo/bar
    foo/bar/baz
    foo/bar/zip
  foo/qux
    foo/qux/baz
    foo/qux/zip

Now, I'm certainly not asking "please to write teh codez", but rather a gesture in the right direction.

Where would I want to be looking in the API in order to begin implementing such a feature? I can find countless tutorials and information on writing routes, constraints, etc., but not on extending the routing engine.

---

Addendum
^{I'll just keep adding as warrants}

1. Please note, I am aware that URL generation from a "routing tree" such as this would be complicated; it is not something I intend to implement.

2. I just realized a sort of iterative route generation could suffice; so I guess I'll post that as a possible answer shortly. Nope, it wouldn't. Too many edge cases.

Answer 1

I have the following code but there is one point I am not sure how you want to handle it: do you know how many child can have a route at the maximum?

In the Global.asax:

    public static void RegisterRoutes(RouteCollection routes)
    {
        routes.Add(new Route("test/{path}", new RouteValueDictionary { { "path", string.Empty } }, new TestingRouteHandler()));
    }

The TestingRoutHandler class:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web.Routing;
using System.Web;
using System.Web.UI;
using System.Web.Compilation;

namespace WebApplication1
{
    class TestingRouteHandler : IRouteHandler
    {
        public IHttpHandler GetHttpHandler(RequestContext requestContext)
        {
            //This is where you should treat the request, test if the file exists and if not, use the parent part of the url
            string aspxFileName = string.Format("~/{0}.aspx", requestContext.HttpContext.Request.Url.PathAndQuery.Replace("/", string.Empty));

            return (IHttpHandler)BuildManager.CreateInstanceFromVirtualPath(aspxFileName, typeof(Page)) as Page;
        }
    }
}