Re: [xmpp] Barry Leiba's No Objection on draft-ietf-xmpp-posh-04: (with COMMENT)

Barry Leiba <> Fri, 31 July 2015 05:55 UTC

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Date: Fri, 31 Jul 2015 07:55:56 +0200
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From: Barry Leiba <>
To: Peter Saint-Andre - &yet <>
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Subject: Re: [xmpp] Barry Leiba's No Objection on draft-ietf-xmpp-posh-04: (with COMMENT)
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Hi, Peter, and thanks for the quick response.  Only the last issue
remains to chat further about:

>> -- Section 8 --
>> I'm not terribly happy with the mechanism of having a faux hierarchy in
>> the .well-known name (posh.servicename.json), not registering any
>> .well-known name here, and asking the .well-known registry (via the
>> designated expert) to register and evaluate each POSH service -- the
>> .well-known DE is not an expert for POSH.  Also if, using your example,
>> Victoria Beckham should want to have a .well-known URI to access her
>> tweets from anywhere, returning them in JSON wrappers, she might want to
>> register "posh.spice.json", which would then get in the way of that name
>> for POSH, entirely unintentionally.
>> I'd be much happier with using a real URI hierarchy and registering
>> "posh" as a .well-known name here, so a POSH URI might be this:
>> or this (I prefer the former, but don't really care):
>> ...and you might establish an FCFS registry of POSH service names under
>> which "spice" (or "spice.json") would be registered.  Now you're putting
>> it all under one .well-known name, and only asking the .well-known expert
>> to review this one, rather than one for every POSH service.
> We're not terribly happy with the faux hierarchy, either, and we considered
> the approach you suggest (and consulted on the matter with Mark Nottingham).
> Unfortunately, the specification for well-known URIs (RFC 5785) states:
>    Registered names MUST conform to the segment-nz production in
>    [RFC3986].
> Because the segment-nz production does not allow "/", a real hierarchy won't
> work.
> In practice, we are not expecting a large number of POSH registrations so I
> doubt that this would put a significant burden on the DE for the well-known
> URI registry. However, do you think it would be helpful to provide some
> additional guidance to the DE in this document?

The hierarchy would work fine: the point is that the registered
.well-known name would just be "posh", and would be registered once
here -- and that confirms fine to the .well-known requirements.  This
document would then specify the use of hierarchy under
.well-known/posh, and would create a (FCFS) registry for POSH service

If you like, it could even do POSH service names and POSH format
names, and specify ".well-known/posh/<servicename>/<formatname>",
define one <formatname> as "json" and say that a registry could be
created in future if necessary.

I know that changing this would affect current implementations and
make them change, but I think it's worth it.  On the other hand, if
you don't agree, I won't push it further.  I just think it'd be much
better to have just "posh" as the registered .well-known "segment-nz".