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Context Independent URI

From: Williams, Stuart <skw@hplb.hpl.hp.com>
Date: Sun, 21 Jul 2002 22:18:42 +0100
Message-ID: <5E13A1874524D411A876006008CD059F04A06F74@0-mail-1.hpl.hp.com>
To: "'www-tag@w3.org'" <www-tag@w3.org>

At the TAG telcon on 15th July [1] I was assigned the action to draft a
principle on context independent/globally scoped URI. 

Here's my first draft:

<principle>
ContextIndependentURI: 
A URI SHOULD denote the same resource or concept independent of the
context(s) in which the URI is used. i.e. when used on different occasions
or by different users or in different locations, a given URI SHOULD denote
the same resource or concept.
</principle>

<rationale>
Some URI schemes, such as file:, and some URI authority, such as localhost
eg: http://localhost/, can give rise to URI which, although syntactically
absolute URI, denote different resources or concepts dependent on the
context in which they are used. If a given URI denotes multiple different
resources or concepts depending on context, then further information in
addition to the given URI is required to distinguish between resources
denoted by the same URI. This is a long standing principle of Web
Architecture [2].

[2] http://www.w3.org/DesignIssues/Axioms.html#unique
</rationale>

<furtherDiscussion>
All identifiers are in some sense relative to a namespace. On the Web the
outermost namespace is the set of all URI. A given URI is relative to some
URI scheme, and depending on that scheme the URI assigned under that scheme
may be relative to some authority or subordinate namespace (eg. URN
namespaces).

So... I have tried to avoid using the term absolute to avoid confusion with
absolute and relative URI and tried to focus the principle on the scope of
the mapping from URI to resource/concept.

It might be useful to discuss whether there are any situations that locally
scoped absolute URI are positively useful (eg:
http://autoproxy/autoproxy/autoproxy) - or maybe one would argue that this
identifies the concept/resource of the "local proxy configuration".

</furtherDiscussion>

Comments, feedback?

Regards

Stuart Williams.
[1] http://www.w3.org/2002/07/15-tag-summary
Received on Sunday, 21 July 2002 17:19:06 GMT

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