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Re: URI for current resources

From: Al Gilman <asgilman@iamdigex.net>
Date: Sat, 18 Nov 2000 19:45:32 -0500
Message-Id: <200011190013.TAA107039@smtp2.mail.iamworld.net>
To: roconnor@uwaterloo.ca
Cc: www-talk@w3.org, Dan Brickley <Daniel.Brickley@bristol.ac.uk>
At 06:08 PM 2000-11-18 -0500, Gerald Oskoboiny wrote:
>On Sat, Nov 18, 2000 at 12:57:27PM -0800, roconnor@uwaterloo.ca wrote:
>> I was reading through ``Cool URIs Don't Change'' to try to find a solution
>> to my problem, and it didn't really help.
>
>(for those who don't know, that's
<http://www.w3.org/Provider/Style/URI>http://www.w3.org/Provider/Style/URI )
>
>> Here is what I want to do.
>> 
>> I want to have a URL such as
<<http://www.example.com/~roconnor/Math1A/>http://www.example.com/~roconnor/
Math1A/>
>> contain data for my current index of Quiz solutions for my Math1A class.
>> 
>> These will link to things like
>>
<<http://www.example.com/~roconnor/Fall2000/Math1A/Quiz4.sol>http://www.exam
ple.com/~roconnor/Fall2000/Math1A/Quiz4.sol>
>> 
>> I also think I should put the same index resource at
>>
<<http://www.example.com/~roconnor/Fall2000/Math1A/>http://www.example.com/~
roconnor/Fall2000/Math1A/>
>
>I suggest putting it there instead of
><<http://www.example.com/~roconnor/Math1A/>http://www.example.com/~roconno
r/Math1A/>
>
>> The problem is the following:  Next year say I teach Math 1A again.  So
>> I'll have a new index at
<<http://www.example.com/~roconnor/Math1A/>http://www.example.com/~roconnor/
Math1A/>
>
>If you want a page for "the current session of Math1A taught
>by Russell O'Connor", you could either set up a redirect from
><<http://www.example.com/~roconnor/Math1A/>http://www.example.com/~roconno
r/Math1A/> to the current
>session and update the redirect each year/term, or publish
>a simple page at that URI that says something like:
>
>    I have taught a number of sessions of Math1A; the current
>    session is _Fall 2000_. Past sessions include:
>
>      - _Spring 2000_
>      - _Fall 1999_
>      - ...
>
>> I can maintain my old index at
>>
<<http://www.example.com/~roconnor/Fall2000/Math1A/>http://www.example.com/~
roconnor/Fall2000/Math1A/>, but all
>> the bookmarks and links people have made from my original page
>> will be pointing to the wrong file.
>> 
>> This seems like a problem to me.
>
>We have encountered similar problems when managing W3C's
>TR space [1]: each spec has a "latest version" URI, e.g.
>
>    <http://www.w3.org/TR/html401/>http://www.w3.org/TR/html401/
>
>and a "this version" URI, e.g.
>
>   
<http://www.w3.org/TR/1999/REC-html401-19991224/>http://www.w3.org/TR/1999/R
EC-html401-19991224/
>
>Currently, the "latest version" URIs are managed using symlinks
>in the filesystem that point to the most recent dated specs.
>But this means we need to use absolute links within the specs
>so links will still work even if followed from the latest or
>dated versions at different levels of the tree.
>

I think that the need for absolute URLs on W3.org may be a byproduct of
unfortunate decisions in the design of the pathspace above the revision
sequences. 

The placement of the year number where it is in URL path to the frozen version
is one such unfortunate choice.  In hierarchical namespaces you have to think
about the order in which things go in.

The Lynx distribution manages a logical URL prefix for the latest 'released'
subtree of URLs, as well as providing frozen URLs for specific released
versions.  The references within a subtree appear to be still by relative
URLs.  But the  logical 'latest' URL paths and their physical versioned
sometime-synonyms are siblings, fellow descendants of the same prefix in the
path space.

Wander over to http://lynx.browser.org/ and follow to the current and
latest-release distribution links, then inspect the source and you may find a
pattern that works for the curriculum evolution scenario you wish.

Al


>Another way to handle this would have been to use redirects
>instead of symlinks, but that makes the "latest version" URIs
>a bit more difficult to bookmark due to lame support of
>temporary redirects in current browsers.
>
>[1] <http://www.w3.org/TR/>http://www.w3.org/TR/
>
>-- 
>Gerald Oskoboiny       <gerald@w3.org>  +1 613 261 6630
>System Administrator  
<http://www.w3.org/People/Gerald/>http://www.w3.org/People/Gerald/
>World Wide Web Consortium (W3C)      <http://www.w3.org/>http://www.w3.org/
>  
Received on Saturday, 18 November 2000 19:13:35 GMT

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