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Re: htmldata-ISSUE-4 (Property as subject): Should the registry allow a property name or URI to be used as an alias for @itemid [Microdata to RDF]

From: Jeni Tennison <jeni@jenitennison.com>
Date: Mon, 7 Nov 2011 17:41:26 +0000
Message-Id: <2561E1CF-43C4-49AC-9E21-9B7304011148@jenitennison.com>
To: HTML Data Task Force WG <public-html-data-tf@w3.org>
On 5 Nov 2011, at 18:21, HTML Data Task Force Issue Tracker wrote:
> htmldata-ISSUE-4 (Property as subject): Should the registry allow a property name or URI to be used as an alias for @itemid [Microdata to RDF]
> http://www.w3.org/2011/htmldata/track/issues/4
> Raised by: Gregg Kellogg
> On product: Microdata to RDF
> Schema.org provides a 'url' property which, in practice, is used to set the subject for an item. Moreover, in many examples, the property is used with a literal content model, rather than a URI content model.
> For example, the following use case is common in schema.org examples:
> <div itemprop="tracks" itemscope itemtype="http://schema.org/MusicRecording">
>   <span itemprop="name">Rope</span>
>   <meta itemprop="url" content="foo-fighters-rope.html">
>   ...
> </div>
> In this case the @content attribute is used where the value is expected to be a URI. And, it is clear that this URI is intended as the subject of the item.

I think that is a bug in the schema.org examples. It is certainly non-compliant with microdata (which states that URLs must be specified within URL property elements). We should not bend over backwards to support this anti-pattern.

> A registry entry could be created which would affect processing of a microdata processor by specifying a content model for the property (URI reference) and that it is to be used as the subject of an item. Note, that there is a special case where the item already has an @itemid attribute, or there are more than one 'url' property values. This could be resolved by using the first property value only if the item has no @itemid.

I'm more and more leaning towards not treating the 'url' property as an identifier of the thing-the-item-is-talking-about at all. In good web architecture, there should be a distinction between the thing and the page-about-the-thing, and I think it's likely that the 'url' property will be used for the page-about-the-thing whereas the @itemid will be used for the thing itself.

So my vote would be for not doing anything special with the 'url' property.


Jeni Tennison
Received on Monday, 7 November 2011 17:42:04 UTC

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