[regext] Benjamin Kaduk's Discuss on draft-ietf-regext-rdap-partial-response-13: (with DISCUSS and COMMENT)

[Benjamin Kaduk via Datatracker <[e-mail]>]

Benjamin Kaduk has entered the following ballot position for
draft-ietf-regext-rdap-partial-response-13: Discuss

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DISCUSS:
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As was the case for Murray, I'm unconvinced that I have understood what
Section 3 intended to convey.  However, I am balloting Discuss because
my current best understanding is for a statement that seems inconsistent
with my understanding of how the partial response mechanism works.  In
particular, how would the topmost objects be returned according to
different field sets, if there's only a single query parameter and (I
assume) all topmost objects are the results of the same single query?


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COMMENT:
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Thanks to the shepherd for noting that the examples have been through
JSONLint!

Abstract

   The Registration Data Access Protocol (RDAP) does not include
   capabilities to request partial responses.  Servers will only return
   full responses that include all of the information that a client is
   authorized to receive.  A partial response capability that limits the

[There is perhaps some stylistic question of whether to describe the
present state in the present tense vs. saying something like "prior to
the mechanism defined in this document" or "as specified in [RFC7483".]

Section 1

   Currently, RDAP does not provide a client with any way to request a
   partial response.  Servers can only provide the client with a full

nit: will this age well?

Section 2

   The path segment defined in this section is an OPTIONAL extension of
   search path segments defined in [RFC7482].  This document defines an

It's not entirely clear to me in what sense it's accurate to say that
this section "defines" a path segment.  (Perhaps RDAP path segments
diverge from normal HTTP and generic URI path segments in this sense?)
My current understanding is that we are defining an optional query
parameter in the purest URI sense, which does not require a new path
segment in the URI sense.

   full response (Figure 1).  The field sets supported by a server are
   usually described in out-of-band documents (e.g.  RDAP profile)

nit: comma (and only one space) after "e.g.".

Section 2.1

   responses about the available field sets.  Such information is
   collected in a new data structure named "subsetting_metadata"
   containing the following properties:

I assume this is a JSON datastructure, specifically?

   o  "availableFieldSets": "AvailableFieldSet[]" (OPTIONAL) an array of
      objects, with each element describing an available field set.
      Members are:

      *  "name": "String" (REQUIRED) the field set name;
      *  "default": "Boolean" (REQUIRED) whether the field set is
         applied by default;

Is it allowed to have more than one entry in the array set
"default":true?

      *  "links": "Link[]" (OPTIONAL) an array of links as described in
         [RFC8288] containing the query string that applies the field
         set.

I suggest giving an example or a bit more detail as to exactly what
structure/format is expected here; 8288 has a fair bit of meat to it.
Ah, but this is covered in Section 2.1.2, so maybe just a
forward-reference is enough.  It would be good (either here or there) to
give some indication as to which of "value"/"rel"/"href"/"title"/"type"
are required/optional, though.

Section 4

   o  "id": the server provides only the key field: "handle" for
      entities, "ldhName" for domains and nameservers.  If a returned
      domain or nameserver is an Internationalized Domain Name (IDN)
      [RFC5890], then the "unicodeName" field MUST be included in the

nit: I suggest "also" or "additionally be included".

   The "objectClassName" field is implicitly included in each of the
   above field sets.  RDAP providers SHOULD include a "self" link in
   each field set.  RDAP providers MAY also add any property providing
   service information.

Just to check my understanding: the "property" that might also be added
here is a "field" that would be included in a given field set and
corresponding query response?  (I don't know if "property" has
RDAP-specific connotations that make it a better word to use here.)

(nit?) I'm also not entirely sure that 'include a "self" link in each
field set' is pedantically correct, as opposed to 'include a "links"
field indicating the "self" link relationship'.

Section 8

I suppose it's always possible that by using a narrow field set a client
would not get back some important piece of information, e.g., a modifier
that restricts the scope of applicability of some information.  It seems
fairly obvious that the onus for knowing what fields are possible and
avoiding this scenario falls on the client, though perhaps it is worth
also giving some guidance to the server to take this into consideration
while defining field sets.

   Servers can also define different result limits according to the
   available field sets, so a more flexible truncation strategy can be

I'm not entirely sure I am understanding this correctly -- is it just
saying (roughly) "when using the 'id' field set it's safe to use much
larger page size than for the 'full' field set"?  (I didn't find a
specific definition of "result limits" in RFCs 7482 or 7483.)

   implemented.  The new query parameter presented in this document
   provides RDAP operators with a way to implement a server that reduces
   inefficiency risks.

Perhaps it's worth mentioning that in the face of unupdated clients
these potential gains are not actually realized.

Section 9.1

The one place we cite RFC 7481 does not seem to itself be a normative
usage (though I can imagine that one does need to read it in order to
build a complete system).

Appendix A

   Looking at the implementation experiences of partial response, two
   approaches are observed:

Looking at context from later in the suggestion suggests that this
survey was not restricted to RDAP partial response, which might be worth
mentioning.

   o  The request of some fields might not match the client's access and
      authorization levels.  Clients might request unauthorized fields
      and servers should define a strategy for responding, such as
      always returning an error response or returning a response that

nit: I think this is more of "servers have to" than "servers should"
(even though this strategy might just be "do whatever the existing code
happens to do").

Appendix A.1

   o  Relevant entity object information is included in a jCard, but
      such information cannot be easily selected because it is split
      into the items of a jagged array;

nit: I didn't find "jagged array" used in either RFC 7483 or RFC 7095;
is is relationship to jCard specified somewhere else?

   The latter approach seems to facilitate RDAP interoperability.
   Servers can define basic field sets which, if known to clients, can
   increase the probability of obtaining a valid response.  The usage of

nit: the "latter approach" seems to be an artifact of some text moves,
as there isn't a recent comparison of two approaches in this section.
("Latter approach" also appears in the following paragraph.)