How to handle hierarchical routes in ASP.NET Web API?

Question

Currently I have two controllers

1 - Parent Controller

2 - Child Controller

I access my Parent Controller like this

someurl\\parentc         


        

Answer 1

I wanted to handle this in a more general way, instead of wiring up a ChildController directly with controller = "Child", as Abhijit Kadam did. I have several child controllers and didn't want to have to map a specific route for each one, with controller = "ChildX" and controller = "ChildY" over and over.

My WebApiConfig looks like this:

config.Routes.MapHttpRoute(
  name: "DefaultApi",
  routeTemplate: "api/{controller}/{id}",
  defaults: new { id = RouteParameter.Optional }
);
  config.Routes.MapHttpRoute(
  name: "ChildApi",
  routeTemplate: "api/{parentController}/{parentId}/{controller}/{id}",
  defaults: new { id = RouteParameter.Optional }
);

My parent controllers are very standard, and match the default route above. A sample child controller looks like this:

public class CommentController : ApiController
{
    // GET api/product/5/comment
    public string Get(ParentController parentController, string parentId)
    {
        return "This is the comment controller with parent of "
        + parentId + ", which is a " + parentController.ToString();
    }
    // GET api/product/5/comment/122
    public string Get(ParentController parentController, string parentId,
        string id)
    {
        return "You are looking for comment " + id + " under parent "
            + parentId + ", which is a "
            + parentController.ToString();
    }
}
public enum ParentController
{
    Product
}

Some drawbacks of my implementation

• As you can see, I used an enum, so I'm still having to manage parent controllers in two separate places. It could have just as easily been a string parameter, but I wanted to prevent api/crazy-non-existent-parent/5/comment/122 from working.
• There's probably a way to use reflection or something to do this on the fly without managing it separetly, but this works for me for now.
• It doesn't support children of children.

There's probably a better solution that's even more general, but like I said, this works for me.