Re: W3 validator breaks W3 link checker!

From: Hugo Haas (hugo@w3.org)
Date: Fri, Mar 23 2001

  • Next message: Gerald Oskoboiny: "updated the validator with recent fixes"

    Date: Fri, 23 Mar 2001 07:19:49 -0500
    From: Hugo Haas <hugo@w3.org>
    To: rowe@excc.ex.ac.uk
    Cc: www-validator@w3.org
    Message-ID: <20010323071948.A26023@w3.org>
    Subject: Re: W3 validator breaks W3 link checker!
    
    * <rowe@excc.ex.ac.uk> [2001-03-22 21:02+0000]
    > Thanks for making the on-linevalidator available, our 'standard'
    > template includes a discrete link to http://validator.w3.org/check/referer.
    > 
    > But when I manually run checklink on such a page the validator sends
    > back a redirect to http://validator.w3.org/ (presumably because it
    > can't tell which page the request comes from) which checklink then
    > complains about!
    
    Hmmm... well, the link checker does not really complain, it just says
    that it found a permanent redirect and that the link _should_ be
    updated, which is true considering what the Validator returns.
    
    > Could the validator check the user agent for W3C-checklink and if so
    > just return something harmless?
    
    This is because the link checker does not send a referer header, which
    is in the to-do list[2].
    
    Since there is no Referer HTTP header, the Validator doesn't know what
    to validate, and redirects the client to the Validator main page.
    
    The HTTP/1.1 specification reads about 301[3] status codes:
    
       The requested resource has been assigned a new permanent URI and any
       future references to this resource SHOULD use one of the returned
       URIs.
    
    So, a permanent redirect (301) is not the right code to use here.
    I would either:
    - return a 200 explaining that because the client did not send a
      Referer header, the original page could not be checked, and having a
      link to the Validator home page.
    - return a 302 (Found) or a 303 (See Other) to redirect the client to
      the home page.
    
    Gerald, I will let you decide what you think is best.
    
    Basically, I need to add referer support to the link checker and this
    redirect feature should be modified.
    
      1. http://validator.w3.org/check/referer
      2. http://www.w3.org/2000/07/checklink#what
      3. http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.2
    -- 
    Hugo Haas - W3C
    mailto:hugo@w3.org - http://www.w3.org/People/Hugo/ - tel:+1-617-452-2092