ASP.NET MVC 4 Routes - controller/id vs controller/action/id - asp.net-mvc

Question

I'm trying to add a route to the default one, so that I have both urls working:
http://www.mywebsite.com/users/create
http://www.mywebsite.com/users/1
This will make the first route work:
routes.MapRoute(
name: "Default",
url: "{controller}/{action}/{id}",
defaults: new { controller = "users", action = "Index", id = UrlParameter.Optional }
);
However, the second route won't work obviously.
This will make the second route work, but will break the first one:
routes.MapRoute(
name: "Book",
url: "books/{id}",
defaults: new { controller = "users", action = "Details" }
);
How to combine the two route configurations so that both URLs work?
I apologize if there is already a question like this on SO, I wasn't able to find anything.

Answer 1

The key is to put more specific routes first. So put the "Book" route first. Edit I guess you also need a constraint to only allow numbers to match the "id" part of this route. End edit
routes.MapRoute(
name: "Book",
url: "books/{id}",
defaults: new { controller = "users", action = "Details" },
constraints: new { id = #"\d+" }
);
routes.MapRoute(
name: "Default",
url: "{controller}/{action}/{id}",
defaults: new { controller = "users", action = "Index", id = UrlParameter.Optional }
);
And ensure that the "id" parameter in your "Details" action is an int:
// "users" controller
public ActionResult books(int id)
{
// ...
}
This way, the "Books" route will not catch a URL like /users/create (since the second parameter is reqiured to be a number), and so will fall through to the next ("Default") route.