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Re: updating RFC 2718 (Guidelines for new URL schemes)

From: Martin Duerst <duerst@w3.org>
Date: Wed, 01 Sep 2004 23:34:58 +0900
Message-Id: <>
To: Larry Masinter <LMM@acm.org>, uri@w3.org
Cc: djz@corp.webtv.net, rpetke@wcom.net, "'Harald Tveit Alvestrand'" <harald@alvestrand.no>, Tony Hansen <tony@att.com>, "'Paul Hoffman / IMC'" <phoffman@imc.org>

At 16:48 04/08/29 -0700, Larry Masinter wrote:

>* Syntactic compatibility
>I think the sentiments in this section are good; I'm uneasy
>about the lengthy 'motivation for syntactic compatibility',
>since it's really not just a motivation, but also an explanation
>for what is meant by 'syntactic compatibility'. I think
>some of the Motivations are confused (e.g., the discussion
>about fragment syntax, but URI schemes don't define
>fragment syntax!)
>So I think this section can be reduced to asking that
>URI schemes use RFC2396bis generic syntax, because of
>compatibility with relative references.

I think this has two aspects:
- We have to clearly state that every URI scheme syntax has
   to follow the (generic) URI syntax in that it cannot allow
   URIs that don't fit into the URI syntax. As a very simple
   example, if a foo: scheme would allow "#" as part of the
   URI syntax, it would be out. Similar for misusing "%", and
   a few other things.
- We also should recommend that any components of the generic
   syntax (e.g. // for top level, / for hierarchy,...) are used
   with the semantics defined in RFC 2396bis.

>* 2.2 Is the scheme well defined?
>This should be turned into a guideline rather than
>a question, with the suggestion that there are
>resource locator schemes and non-locator schemes.
>I think it's useful if schemes are clear about whether
>(or under what circumstance) the 'resource' might be
>something that returns a (body/entity/...?) which has
>a Media Type, and can be used with fragment identifiers
>in their conventional definition.
>* 2.2.5 Character encodings
>I think this turns into a requirement for compatibility
>with IRI guidelines.

"IRI guidelines" or the IRI spec?

>Maybe there is a place here to
>note that there is only one namespace, a "URI scheme"
>is also an "IRI scheme".

Yes. The considerations that Stuart Williams brought into
IRIs, and that are listed as issue @@@,
Some of this will probably end up in the IRI spec, but
it actually belongs here.

There are quite a few points that came up in my recent review
of the xxmp

>2.3 Demonstrated utility
>I'd like to suggest that we require something stronger: that new
>URI schemes have demonstratable, new, long-lived
>   Because URI schemes are a single, global namespace, the
>   unrestricted registration of many new URI schemes can
>   clutter implementation space, and possibly lead to
>   contention for "short names". For this reason, new
>   URI schemes should have a clear utility to the broad
>   Internet community, and provide some means of identifying
>   resources that is not already available with previously
>   registered URI schemes.
>Perhaps this is controversial :)

It seems to go into the opposite direction of what was discussed
at the BOF, namely to relax the rules. But I guess this could
work out by saying that the above is desirable, and there should
be potential for it, rather than having it as a hard-and-fast rule.

Regards,    Martin.
Received on Wednesday, 1 September 2004 14:35:06 UTC

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