Subject: [urn] constraining URI resolvers (CREF10)

From: Peter Saint-Andre - &yet <[email-masked]>
Date: Wed, 11 Mar 2015 20:16:16 -0600

Section 5 states:

    A resolver that conforms to the URI specification [RFC3986] will
    extract a scheme of "urn" rather than a scheme value of "urn:<nid>".

CREF10 proposes alternate text (because, as Henry Thompson points out, 
we cannot constrain URI resolvers in general):

    In part because of the separation of semantics from syntax
    [I-D.ietf-urnbis-semantics-clarif], generic URI processors must pay
    special attention to the parsing and analysis rules of RFC 3986 and,
    in particular, must treat the URI as opaque unless the scheme and its
    requirements are recognized.  The URN resolver can either be an
    external resolver that the URI resolver knows of, or it can be
    functionality built into the URI resolver.  Note that this
    requirement MAY impose constraints on the contexts in which URNs are
    appropriately used; see the previous section.

This looks good to me.

Peter

-- 
Peter Saint-Andre
https://andyet.com/

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From: [email-masked] (Henry S. Thompson)
Date: Thu, 19 Mar 2015 11:26:33 +0000

> we cannot constrain URI resolvers in general):

Actually, what it proposes to replace is, if I read it correctly, is
not the bit quoted above, but rather the next bit, i.e.

  A URN MUST be considered an opaque URI by URI resolvers and passed
  (with the "urn" scheme) to a URN resolver for
  resolution.

>    appropriately used; see the previous section.

It's better, but there's now a disconnect here:

    generic URI processors must ... treat the URI as opaque unless the
    scheme and its requirements are recognized.  The URN resolver can
    either ...

Would something like this serve to bridge the gap:

    generic URI processors must ... treat the URI as opaque unless the
    scheme and its requirements are recognized, in which case they may
    be in a position to invoke scheme-appropriate processing, that is,
    a URN resolver.  The URN resolver can either ...

?

ht 
-- 
       Henry S. Thompson, School of Informatics, University of Edinburgh
      10 Crichton Street, Edinburgh EH8 9AB, SCOTLAND -- (44) 131 650-4440
                Fax: (44) 131 650-4587, e-mail: [email-masked]
                       URL: http://www.ltg.ed.ac.uk/~ht/
 [mail from me _always_ has a .sig like this -- mail without it is forged spam]

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From: "Svensson, Lars" <[email-masked]>
Date: Thu, 19 Mar 2015 11:51:53 +0000

>     a URN resolver.  The URN resolver can either ...

Looks good to me.

Best,

Lars

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From: Peter Saint-Andre - &yet <[email-masked]>
Date: Thu, 19 Mar 2015 07:41:15 -0600

>      a URN resolver.  The URN resolver can either ...

Good catch.

Peter

-- 
Peter Saint-Andre
https://andyet.com/