Re: [regext] Fwd: I-D Action: draft-ietf-regext-rdap-sorting-and-paging-03.txt

[Tom Harrison <[e-mail]>]

Hi Mario,

On Wed, Jun 12, 2019 at 12:20:40PM +0200, Mario Loffredo wrote:
> in this new version "cc" has been added to the list of sorting properties
> and RFC8605 has been added to the Normative References.

Thanks for putting this together.  Some comments/feedback:

 - Is there a need to be prescriptive about the 'cursor' parameter?
   The draft could simply have text along the lines of "a server that
   implements paging will include at least a 'next' link for fetching
   the next page, and optionally 'first'/'prev'/'last' links for
   accessing other pages in the set of search results".  That way, a
   server can use whatever suits it best, whether that be limit/offset
   parameters or a more generic cursor parameter (or something else).

 - This draft takes a different approach to country/cc values than
   that taken by the reverse search draft.  Why are these values
   treated separately here?  Should servers that don't currently use the
   'cc' parameter, but which do have country name values in their
   jCards, be prevented from sorting based on the country name if a
   client requests that sorting be done by cc?

 - I think it would be useful to document explicitly what happens when
   sorting is carried out on a field for which a record can have
   multiple values.  For example, with jCard properties, the draft
   currently has text about using the value that is most preferred
   (per the 'pref' parameter), but there could be instances of
   multiple values for a property where no 'pref' parameter has been
   set.  This may be as simple as saying "the server will sort based
   on the first value for a given field that appears in the object".

 - Along similar lines, I think it would be useful to go into more
   detail about the exact logic for sorting.  For example, clients
   will typically want IP addresses to be sorted based on their
   numeric value, rather than on their string value, but the current
   text isn't prescriptive about this.

 - The ABNF for 'cursor' is:

    "cursor=" ( ALPHA / DIGIT / "/" / "=" / "-" / "_" )

   which appears to limit it to a single character.  It looks like it
   should instead be:

    "cursor=" 1*( ALPHA / DIGIT / "/" / "=" / "-" / "_" )

 - I don't understand the text in section 2.4 about the problems with
   cursor pagination.  What is a "key field" in "it needs at least one
   key field"?  Also, what is a "key" in "it does not allow to sort
   just by any field because the sorting criterion must contain a
   key"?

-Tom