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Re: are 'cid' URLs relative?

From: Michael Mealling <michael@bailey.dscga.com>
Date: Fri, 26 May 2000 09:32:16 -0400
To: Al Gilman <asgilman@iamdigex.net>
Cc: Jonathan Borden <jborden@mediaone.net>, xml-uri@w3.org
Message-ID: <20000526093216.C8849@bailey.dscga.com>
On Fri, May 26, 2000 at 09:36:00AM -0500, Al Gilman wrote:
> At 10:53 PM 2000-05-25 -0400, Jonathan Borden wrote:
> [sorry to have to belabor the correction of a minor red herring...]

Not really. This actually applies to several URI schemes....

> RFC-2392 which defines the IETF Proposed Standard for the 'cid' URL says
> explicitly  "The Content-ID of a MIME body part is required to be globally
> unique."
> 
> For 'globally' in this case, read "across all messages and not just within
> the current multipart."
>
> <snip>
> 
> The kind of context-dependency that you allude to is explicitly proscribed
> by the "required to be globally unique" language in the RFC.

Correct. This actually applies to several URI schemes that have
specifically proscribed the use of relative URIs by making either
invalidating the concept entirely by requiring uniqueness or by
disallowing the "/" character in the right hand side. The
URN scheme did this as well since the concept of relativeness
was considered dangerous in things that required very strong 'name'
semantics. I.e. a URN is an opaque thing, it is considered an 
error to think you understand enough of the namespace to do 
things like relative naming.

-MM




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Received on Friday, 26 May 2000 09:43:58 UTC

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