[regext] RDAP and link context

[James Mitchell <[e-mail]>]

Hi all,

What is the purpose of the context URI in the links structure? From 9083:
The "value" JSON value is the context URI as described by [RFC8288]. The "value", "rel", and "href" JSON values MUST be specified.

My understanding is that the context URI is the request URI that generated the JSON response. Implementing this correctly presents problems for a valid server implementations given caching is non-trivial because one object can be located from more than one URI. For example, /domain/EXAMPLE.COM, /domain/example.com, /domain/eXaMpLe.cOm are all different context URIs even though we understand they will return the same object. For a less trivial example, consider a domain object matched by A-labels, U-labels, and any other labels that identify an object via UTS46 or variant processing.

I’ve surveyed a few registries and noted inconsistent implementations of the spec:

  *   .org – link context is identical to the target for all links
  *   .com – link context is present for a singular self link and the context and relation type are absent for links in notices
  *   .xyz – link context is absent from all links

I am not aware of any specifications where the link context is explicitly defined with the creation/definition of a link (e.g. HTTP link header, w3c HTML5 spec, Atom).

Is the link object’s context/value used at all? Is it possible for a future update the RDAP spec to remove the link context, perhaps in RDAP-X?

Thanks,
James