Resolving an API's own hypermedia links

Question

Let's say we have a RESTful API method:

POST /people
{
    "name" : "John",
    "_links" : {
        "address" : {
            "href" : "/addresses/2"
        }
    }
}

You can see that address has a link to another resource.

To resolve the address_id of that resource, should the server:

1. Break up the URL and identify the "id" part of the route

2. Even make a curl request to itself, in order to get the address_id of that linked resource?

Answer 1

I feel, as you probably do, that #2 is the way it should be done, and #1 is just a hack based on internal knowledge. What if the client sent a href that was an absolute URI, http://yoursite.com/addresses/2 would you still want to use #1, and try to detect the ID?
Lets presume your site sends address resource representations with a defined and documented MIME type. What if the client sent a href value pointing to a third-party URI, which also returned responses of that format, and presuming you'd want to support that. You'd have to implement #2 anyway. In that instance there's little reason not to use it for your own (performance being the main one).

To be honest, what I would probably do is go with #1 until the need for #2 arose.