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Re: Feed Validation Service: Dublin Core Terms extent does not accept units

From: Phil Ringnalda <philringnalda@gmail.com>
Date: Sun, 06 Jul 2008 21:07:08 -0700
Message-ID: <4871966C.3050005@gmail.com>
To: Heather McCartney <Heather.McCartney@ioko.com>
CC: www-validator@w3.org, rubys@intertwingly.net

Heather McCartney wrote:
> I have a question about the validation of Dublin Core Terms extent tag.
> Dublin Core guidance at
> http://dublincore.org/documents/usageguide/qualifiers.shtml#extent says
> that "it generally consists of both a numeric value and a caption that
> is needed to interpret the numeric value". One of the valid examples
> given is "21 minutes". However, if I use this example in my rss feed,
> validation fails with the message
>
> "dcterms:extent must be a positive integer: 21 minutes".

The feedvalidator's knowledge of Dublin Core is based on the RSS 1.0 
modules at http://purl.org/rss/1.0/modules/dc/ and 
http://purl.org/rss/1.0/modules/dcterms/ - in part because that's likely 
to be what someone writing a consumer of them in RSS will expect, and in 
part because they are at least something which can be validated. Dublin 
Core's own description of elements is more like diffident advice to 
people who are writing profiles of it, or who are specifying elements 
which subset it. Probably the strongest advice about actual content is 
dc:date, where "Recommended best practice is to use an encoding scheme, 
such as the W3CDTF profile of ISO 8601 [W3CDTF]." Not to use *that* 
encoding scheme, but to use an encoding scheme; not the thing to do, but 
recommended best practice; not even an actual scheme, since W3CDTF is 
only intended to be used by other specs which are required to specify 
granularities and the meaning of different granularities if more than 
one is allowed (sadly, RSS 1.0 also failed to do so, but we sort of 
pretend it did, since that's the one Dublin Core element which is very 
widely used by RSS consumers).

So, while it's sort of frustrating that we have to use a dead "Proposed" 
spec for RSS 1.0 to validate use of Dublin Core in RSS 2.0 or Atom so 
that we have any hope of promoting interop, it's the only alternative 
besides just doing absolutely no validation: <dcterms:extent>Oh, about 
the time it takes me to eat two slices of toast</dcterms:extent> is 
completely and utterly valid according to Dublin Core themselves.
Received on Wednesday, 9 July 2008 01:48:20 GMT

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