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a protocol analog to abstract/concrete identifiers

From: Dan Connolly <connolly@w3.org>
Date: Thu, 18 Sep 2008 11:47:27 -0500
To: www-tag <www-tag@w3.org>
Message-Id: <1221756447.6800.726.camel@pav.lan>

This abstract/concrete notion...

[[
      * An abstract identifier is an identifier (arc) of a target
        resource (node) that MUST NOT resolve directly to a
        representation of that resource, but MAY resolve to a
        description of that resource (descriptor). 
        
      * A concrete identifier is an identifier of a target resource that
        MAY resolve directly to a representation of that resource, but
        MUST NOT resolve to a descriptor of that resource. 
]]
 -- http://wiki.oasis-open.org/xri/AbstractIdentifierArchitecture

... has an analog at the protocol level.

Given I1 which identifies X1,
when I do an HTTP GET on I1,
  - if I get a 200 response, the body is a representation of X1
  - if I get a 3xx or 4xx response, any body I find is closer
    to a "description" of X1.

cf the spec for 300 Multiple Choices :

"the response SHOULD include an entity containing a list of resource
characteristics and location(s) from which the user or user agent can
choose the one most appropriate."
 -- http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.1

I suspect this analog is enough to meet whatever requirements
motivate the definitions of abstract/concrete identifiers.


-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
gpg D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Thursday, 18 September 2008 16:47:38 GMT

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