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Datatypes R2 Issue 76

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Data Types Issue 76: ED.reference URI not just URL

Introduction

The XML ITS says that, if you want to reference something from the Act.text attribute, the valid address needs to conform to http://www.ietf.org/rfc/rfc1738.txt, which are URL and not URIs. Abstract Data Types on the other hand says otherwise (http://www.ietf.org/rfc/rfc2396.txt), which are URIs.

The use of URIs in places that would have been restricted to URLs has increased and been endorsed by W3C, so the rationale for this restriction in the ITS does not make sense -- I suspect that it is an error, and should have been relaxed to reflect the abstract datatypes anyway Charliemccay 08:24, 5 April 2007 (CDT)

? backward compatible.

observed by Miroslav in an email today Charliemccay 08:24, 5 April 2007 (CDT)

Discussion

Comment from Gunther (from ISO datatypes ballot)

Disagree to the move to generally replace URL with URI. The original specification says: "A telecommunications address specified according to Internet standard RFC 2396 [1]. …" and only at the end: "By agreement, it is permissable to use a URI in place of a URL. In these cases, it is still expected that the resources identified is accessible by some agreed method. A common use of URI's is to refer to SOAP attachments." So, it is very clear that this is to be a resolvable address to some data. URL is not an alternative entity identifier scheme.

The original specification that Gunther refers to is the abstract specification. Actually the abstract datatypes have their own problems. it refers to 2396 (URI's), but the text is confusing on this matter:

A telecommunications address specified according to Internet standard RFC 2396
[2]. The URI specifies the protocol and the
contact point defined by that protocol for the resource. Notable uses of the
telecommunication address data type are for telephone and telefax numbers,
e-mail addresses, Hypertext references, FTP references, etc.

It seems that the words "telecommunications address" are confusing. I don't think that a http:// or a cid: scheme address can rightfully be called a telecommunication address. So I'd like to replace those words with Uniform Resource Identifier.

The Internet standard RFC 2396 [3] defines a URI as follows:
Just as there are many different methods of access to resources, there are several
schemes for describing the location of such resources. The generic syntax for URLs
provides a framework for new schemes to be established using protocols other than
those defined in this document.

This bit is certainly not a quote from RFC 2396 - bits of it are, but they do not come from the definition. (I know that this is my fault [GG})

URLs are used to "locate" resources, by providing an abstract identification of
the resource location. Having located a resource, a system may perform a variety of
operations on the resource, as might be characterized by such words as "access",
"update", "replace", "find attributes". In general, only the "access" method needs
to be specified for any URL scheme.

fair eoungh, though I don't know why anything after the first sentence is present - does it do anything for us?

By agreement, it is permissable to use a URI in place of a URL. In these cases, it is
still expected that the resources identified is accessible by some agreed method. A
common use of URI's is to refer to SOAP attachments

Cool, and this makes sense, except that we haven't properly defined URI - I guess that's an issue from above.


Anyhow, We all agree that the resource must actually be visible. But the problem is whether to call it a URI and impose a restriction that it must be resolvable, or whether to call it a URL and note that non-URLs may be used. It seems obvious to me that the second is facially invalid.

Certainly the abstract datatypes and implementations should refer to the same rfc

So I recommend that we standardise on URI and note clearly in all specifications that a locatable resource must be identified, and that we note in the abstract spec why we call it URL, but specify URI, and then specify that it must be locatable.--GrahameGrieve 06:50, 1 May 2007 (CDT)

Disposition

Motion in INM 3rd May 2007:

The base reference for the datatype URL is rfc 2396 (URI), in both abstract and XML ITS (and ISO datatypes). When used in the context of a TEL, and elsewhere when appropriate, we constrain this datatype to be an actual URL using rfc 1738 (as defined in rfc 2806). Paul / Charlie 5-0-6


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