Generating url for a resource in asp.net web api outside of ApiController

I'm not sure about the ApiController, as I haven't used it before. This may then be redundant for you, but then again, it may not be. Check out your Global.asax.cs file, specifically the RegisterRoutes function. Initially, you should see the following mapping:

  routes.MapRoute ("Default", "{controller}/{action}/{id}", new { controller = "MyController", action = "Index", id = "" });

So by default your application is set up to handle routes in the following format:

 {ControllerName}/{ActionName}/{ResourceId}

A controller class set up like the following should enable you to receive requests in that format.

 class {ControllerName}Controller : ApiController
 {
      public ActionResult {ActionName} (string id)
      {
           // fetch your resource by its unique identifier
      }
 }