Bitten by the URI Opacity Axiom


Jon Udel has a post today entitled Divergent citation-indexing paths. Funny that he wrote about this; it seems he and I are on such a parallel trajectory these days. For evidence, take a look at my post from last week I titled Lessons Learned from Delicious Praise.

In his post Jon states “, unlike Bloglines, treats the URLs that you feed to its citation counter in a case-sensitive way.” I wonder if Jon is aware of the Tim Berners-Lee’s URI Opacity Axiom?  A correct reading of the URI Opacity Axiom would reveal that in that Bloglines is in the wrong and is in the right in this case; i.e. URLs are case-sensitive and programs SHOULD NOT[1] infer that two URLs with different casing point to the same resource. (NOTE: case doesn’t matter with domain names but it DOES matter in URL paths.)

As a matter of fact the URI Opacity Axiom is such as a closely held belief among those I like to call “the Weborati” that if you even question it so as to understand it on certain W3C or related mailing lists you’ll be in for a firestorm as if you blasphemed the messiah! ;-0

All kidding aside, especially since some of those people who hold the URI Opacity Axiom dear read this blog (!), after spending the time to research it and really learn it I came to believe that it is a very good idea for people to follow the URI Opacity Axiom. And I’ll discuss why in the future when I have more time. Unfortunately, like many principled concepts some people have elevated the URI Opacity Axiom to the level of dogma, and many of those who preach it believe it means a distortion of what it really means.

So Jon identified a real-world problem that following the URI Opacity Axiom introduces yet it is somewhat of a “catch-22“; following the axiom creates real-world problems but not following it creates other real world problems. But longer term, I really don’t think it has to be this way, and I’m working on ideas to address this issue that may turn into draft proposals or recommendations or something else. Basically I think with some “layers” of technology added to the web we could have the best of both worlds.

As an aside, could update links based upon 301 redirects and then website owners could 301 redirect to a(n ideally lowercased) canonical URL whenever their server receives a request for a URL that is not in the canonical URLs format. This assumes of course that the website owner/server operator has chosen for their URLs to effectively be case-insensitive[2].

  1. I use the “SHOULD NOT” in the same way RFC 2119 defines the use of the uppercased term.  
  2. In my opinion running a website with case-sensitive URLs either means the web developer just wasn’t thinking or that they don’t have a clue about the affect case-sensitive URLs have on website usability. Ah, but that’s another subject for another day. :)
This entry was posted in Axioms, Commentary, Internet Professionals, SoapBox, URIs. Bookmark the permalink.

2 Responses to Bitten by the URI Opacity Axiom

  1. Sandi Solow says:

    Thanks for stopping by my blog – it was nice to meet you last night! See you at SoCon07!

  2. Pingback: Seeing things the way in which one wants them to be (not the way they are)

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