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Re: [FeedValidator] Feed Validation Service: pubDate versus lastBuildDate

From: Sam Ruby <rubys@intertwingly.net>
Date: Fri, 26 Jan 2007 09:18:54 -0500
Message-ID: <45BA0DCE.7080300@intertwingly.net>
To: Users of the FeedValidator <feedvalidator-users@lists.sourceforge.net>
CC: www-validator@w3.org

Alan Peery wrote:
> In trying to work with the an RSS feed from IBM that contains support 
> news on one of their products 
> (http://www-306.ibm.com/software/support/rss/tivoli/2366.xml?rss=s2366&ca=rsstivoli), 
> I found that all of the pubDate fields are set to the same time, 
> evidently the the feed was last output from the backend database it must 
> live in.  While the RSS 2.0 spec 
> (http://www.rssboard.org/rss-specification#requiredChannelElements) 
> isn't very precise expected values, I think the intention was for the 
> pubDate field to be when the *item* was published. 

Given the sordid history of RSS 2.0, second guessing the intention of 
the specification is problematic at best, but if you wish to pursue this 
further, I'd suggest that you start with the RSS Advisory Board.

> This would then make a feed where all the pubDate entries were identical 
> suspect, as the user had possibly misread the intention of the spec and 
> put a date appropriate for lastBuildDate into pubDate.  I think the 
> validator should emit a warning in this case, indicating possible 
> misinterpretation of the two fields...  As an example, IBM probably 
> didn't release information about Fix Packs 6,4,5 and 3 on the same 
> day...  Having the pubDate garbled this way makes it impossible to sort 
> the RSS feed by date, which is how I noticed the issue in the first 
> place as the items were out of order in the RSS file...

Atom 1.0 is much clearer on this [1]:

     Date values SHOULD be as accurate as possible. For example, it
     would be generally inappropriate for a publishing system to
     apply the same timestamp to several entries that were published
     during the course of a single day.

Accordingly, the Feed Validator implements the check that you desire, 
but only for Atom 1.0 feeds.

[1] 
http://www.atomenabled.org/developers/syndication/atom-format-spec.php#date.constructs

- Sam Ruby
Received on Friday, 26 January 2007 14:19:10 GMT

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