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RE: Using fragment identifiers with URNs

From: Stephen Cranefield <SCranefield@infoscience.otago.ac.nz>
Date: Thu, 27 Sep 2001 14:04:36 +1200
Message-ID: <B57613845A50D211864C0000F8FA5C2804207616@mars.otago.ac.nz>
To: "'uri@w3.org'" <uri@w3.org>
Roy Fielding wrote:
> The notion of retrieval is not in any way specific to the URI 
> scheme -- there is a paragraph in RFC 2396 that says exactly
> that, regardless of whether it is a locator or a name. 

Could you identify this paragraph?  I can only find paragraphs
that contradict this, e.g.:

  This paper describes a "superset" of operations that can be applied  
  to URI.  ...  Some of the functionality described is not applicable
  to all URI schemes ...

  Not all resources are network "retrievable"; e.g., human beings,
  corporations, and bound books in a library can also be considered
  resources. ...

  A fragment identifier is only meaningful when a URI reference [sic]
  is intended for retrieval and the result of that retrieval is a document
  for which the identified fragment is consistently defined.

  [I presume this last paragraph should really say "... when a URI
  is intended for retrieval ..." as a *URI reference* is always intended
  for retrieval according to the definition in Section 4.1.]

These paragraphs clearly imply that not all URI schemes have a notion
of retrieval defined.

> The retrieval mechanism is defined by the application, in all cases,
> regardless of URI scheme.

This is not true.  The retrieval mechanism for http URLs is defined by
the HTTP protocol, not any particular application.  A client does not
need to know how a Web server is set up in order to access an http URL.
It just uses a standard protocol that is associated with that URI scheme.

> The syntax applies to names already -- I doubt that it can 
> get any broader.

It certainly seems to be considered that way in common usage.  However,
RFC 2396 implies the opposite.  I don't know if the intent of RFC2396 was
different, but as a specification, it's the wording that counts.

- Stephen
Received on Wednesday, 26 September 2001 22:02:07 UTC

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