Re: [XML-URI] HTTP extensions framework comparison

> I just skimmed RFC 2774, and I don't think it mandates the use of http
> URIs; so I take your statement to mean that, when an application is
> searching extension declarations for something it knows how to process,
it
> must use the comparison rules in RFC 2616 if it is looking for http URI
> names, and literal comparison otherwise.

Nope, there is nothing specific to HTTP URIs in this. As I have mentioned
before, it just so happens that HTTP URIs use all aspects of the URI
syntax defined by RFC 2396 and so there is a 1:1 mapping between the
equality rules defined for HTTP URIs and URIs and RFC 2396. It is more for
historic reasons that anything else that those rules are explained in the
HTTP spec and not in the URI spec.

There is also no "must" for an application consuming a URI used to
identify an extension to use any of these equality rules - the rules are

* An application *generating* a name must follow the rules
  from the space the name belongs to.

* An application *consuming* a must at a minimum use case-sensitive
  comparison but may apply specific URI scheme equality rules if it wants
  to/knows about them.

> Are you advocating this as a general rule for saying whether two URIs
name
> the same resource, or just for comparison for the purposes of RFC
> 2774?  Either way, it seems odd to require processors to have special
> knowledge of the http scheme in this way.

If every single spec using URIs would have to define their own equality
rules then we would be in a big mess and would likely end up with little
interoperability - the exact reason for the XML NS discussion. This is why
RFC 2774 is silent on the subject as it relies on RFC 2616 and RFC 2396 to
provide the rules.

Henrik Frystyk Nielsen
mailto:frystyk@microsoft.com

Received on Wednesday, 19 July 2000 12:26:04 UTC