- From: Jayson Lorenzen <Jayson.Lorenzen@businesswire.com>
- Date: Fri, 21 Oct 2011 10:48:45 -0700
- To: <public-html-data-tf@w3.org>
I would like to point out something that may afflict web developers, who are new to RDF and are annotating HTML with Microdata, that may be good to have some best practice outlined for, in the guidelines Jeni pointed out that the group will produce. (Jeni mentioned on 10/19 *Guidelines for publishers and consumers about how to publish and consume data embedded in HTML*) This may be old hat to seasoned RDF developers but it is bothering me, and maybe others, and at least I would like to have some help. The issue is with adding *itemprop* to the elements <link> <a> and <img> and using the *href* or *src* for a property that should be a URL, when the same URL might be used as an *itemid* of another object on the page, or even the object the *itemprop* is part of. I came across this while trying not to add too much hidden content, as Google recommend, and was trying to use the value that was already on the page, in the <a>'s href attribute. When using the *src* or *href*, RDF distillers create a relation, and the resulting RDF (at least in Turtle) can look like an endless loop waiting to happen, or just an odd relation. Here is an endless loop example: A Schema.org/NewsArticle has a copyrightHolder which is a Schema.org/Orgaization and that org has an *itemid* which is a URL (as per the Microdata spec), pointing to the Business Wire home page in this case, an *image* and then a *url* which is coming from the <a> . <span itemprop="provider publisher copyrightHolder" itemscope="itemscope" itemtype="http://schema.org/Organization" itemid="http://businesswire.com"> <meta itemprop="name" content="Business Wire"/> <a itemprop="url" href="http://www.businesswire.com"> <img itemprop="image" src="http://www.businesswire.com/images/Powered-by-Business-Wire.gif" title="Business Wire is the leading source for full-text breaking news and press releases, multimedia and regulatory filings for companies and groups throughout the world" alt="Powered by Business Wire"/> </a> </span> In an RDF extract we get a copyrightHolder for the article identified as: schema:copyrightHolder <http://www.businesswire.com>; but then for the Organization, there is a URL property which is a reference back to Business Wire, the Organization. <http://businesswire.com> a schema:Organization; schema:image <http://www.businesswire.com/images/Powered-by-Business-Wire.gif>; schema:name "Business Wire"; schema:url <http://www.businesswire.com> . Changing from using <a> , to a hidden <meta> tag <span itemprop="provider publisher copyrightHolder" itemscope="itemscope" itemtype="http://schema.org/Organization" itemid="http://businesswire.com"> <meta itemprop="name" content="Business Wire"/> <meta itemprop="url" content="http://www.businesswire.com"/> <a href="http://www.businesswire.com"> <img itemprop="image" src="http://www.businesswire.com/images/Powered-by-Business-Wire.gif" title="Business Wire is the leading source for full-text breaking news and press releases, multimedia and regulatory filings for companies and groups throughout the world" alt="Powered by Business Wire"/> </a> </span> produces a URL property that is just a text string. <http://businesswire.com> a schema:Organization; schema:image <http://www.businesswire.com/images/Powered-by-Business-Wire.gif>; schema:name "Business Wire"; schema:url "http://www.businesswire.com" . For properties that require a URL (like the contentURL from Schema.org), which is correct? Other examples of this are with Schem.org/ImageObject s where the *itemid* is the same as the contentURL (interestingly URL is upper case for this property but camel case for thumbnailUrl :) I imagine I, or other new to RDF implementors of Microdata, just use the *itemid* and or *href*/*src* wrongly for these cases, but if a guide is produced to help them/me/us, and it had an explanation of how to do this correctly, it would be a big help. Thanks for listening. Jayson Jayson Lorenzen Senior Software Engineer ____________________________ B U S I N E S S W I R E A Berkshire Hathaway Company +1.415.986.4422, ext. 766 +1.415.956.2609 (fax) www.BusinessWire.com Business Wire/San Francisco 44 Montgomery St. 39th Floor San Francisco, CA 94104 Please Note: The information in this Business Wire e-mail message, and any files transmitted with it, is confidential and may be legally privileged. It is intended only for the use of the individual(s) named above. If you are the intended recipient, be aware that your use of any confidential or personal information may be restricted by state and federal privacy laws. If you, the reader of this message, are not the intended recipient, you are hereby notified that you should not further disseminate, distribute, or forward this e-mail message. If you have received this e-mail in error, please notify the sender and delete the material from any computer.
Received on Friday, 21 October 2011 17:51:52 UTC