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Re: best practice RDF in HTML

From: Ivan Herman <ivan@w3.org>
Date: Fri, 15 Jun 2012 08:47:00 +0200
Cc: David Wood <david@3roundstones.com>, Gregg Kellogg <gregg@greggkellogg.net>, public-lod <public-lod@w3.org>, semantic-web <semantic-web@w3.org>
Message-Id: <4502CB6E-ED36-46B9-8F52-1515548D491E@w3.org>
To: Sebastian Hellmann <hellmann@informatik.uni-leipzig.de>

On Jun 15, 2012, at 08:25 , Sebastian Hellmann wrote:

> Thanks all,
> that thread was really helpful. So it will be visible/invisible RDFa and Turtle in the <script> part.
> The RDF WG (or whoever is responsible) should make it clear that RDFa Parser implemention honor the script Turtle part.

Actually... I am not sure that will or indeed should happen. It is up to the tools to choose whether they are 'multi syntax' or not, and it is up to the (possibly friendly:-) competition among those tools that will dominate on this. Tools may also include an automatic inclusion of microdata parsing, too, and this is not something that an RDFa document should specify, for example. On the other hands, there may be tools that decide to extract Turtle in HTML only, and nothing else.


Ivan


> This will make it a more universal combination, which offers more transparency.
> All the best and thanks again.
> Sebastian
> 
> On 06/14/2012 04:30 PM, David Wood wrote:
>> Hi Gregg,
>> 
>> On Jun 14, 2012, at 10:07, Gregg Kellogg wrote:
>> 
>>> Sent from my iPad
>>> 
>>> On Jun 12, 2012, at 9:36 AM, "Ivan Herman"<ivan@w3.org>  wrote:
>>> 
>>>> Sebastian,
>>>> 
>>>> Stéphane Corlosquet has already commented on this, but somehow the thread went on: the upcoming Turtle standard refers to the possibility of adding Turtle into an HTML file using the<script>  element[1]. [1] refers to the editor's draft, but the RDF WG is very close to Last Call.
>>>> 
>>>> Some (essentially RDFa) tools already implement that, eg, pyRdfa[2], or (as far as I know) the Ruby based RDF Distiller[3] do it (possibly through a separate option setting).
>>> It is standard behavior in the Ruby RDFa processor (used by the distiller) it is also standard behavior to extract RDF from embedded RDF/XML. But, I think that both these mechanisms are marginal use cases (RDF/XML for legacy uses, turtle in script elements for examples, and where turtle is really the idiom).
>>> 
>>> IMO, using RDFa for describing any RDF in HTML is the best practice, whether visible or hidden. If you prefer, microdata can also be used (without going through JSON), which is essentially equivalent to RDFa Lite, but has several vocabulary caveats, so should probably be used just for publishing schema.org content.
>> 
>> That is a clear explanation of current best practice.  Thanks.  However, one should also consider what might happen to best practices once new features become available or standardized.  There is a positive feedback loop there.
>> 
>> For example, what should one do if one wishes to publish HTML about content already described by RDF?  Similarly, what if a publisher already has RDF about a resource and wishes to include it in an HTML representation?  In those cases, one might reasonably suggest that the RDF be included as Turtle in an HTML page because it is certainly easier to construct such a thing than to determine how and where to insert RDFa attributes.
>> 
>> Regards,
>> Dave
>> 
>>> Gregg
>>> 
>>>> Does this help?
>>>> 
>>>> Ivan
>>>> 
>>>> 
>>>> 
>>>> [1] http://dvcs.w3.org/hg/rdf/raw-file/default/rdf-turtle/index.html#in-html
>>>> [2] http://www.w3.org/2012/pyRdfa/
>>>> [3] http://rdf.greggkellogg.net/distiller
>>>> 
>>>> 
>>>> 
>>>> 
>>>> On Jun 12, 2012, at 18:22 , Sebastian Hellmann wrote:
>>>> 
>>>>> Dear Mark,
>>>>> my main concerns are:
>>>>> 1. What are the best practices to include invisible RDFa in an HTML document. I think Keith answered that. Maybe at the end of the body would be the most unobtrusive way.  The same question was raised here: http://answers.semanticweb.com/questions/10161/is-visually-hidden-rdfa-an-anti-pattern
>>>>> I just wanted to reassure that hidden RDFa is not contradicting the intention of RDFa.
>>>>> Are there any practical disadvantages (besides the obvious increase in byte size)?
>>>>> 
>>>>> 2. Are there any alternatives to RDFa to include RDF in HTML ?
>>>>> 
>>>>> All the best,
>>>>> Sebastian
>>>>> 
>>>>> 
>>>>> On 06/12/2012 05:52 PM, Mark Birbeck wrote:
>>>>>> Hi Sebastian,
>>>>>> 
>>>>>> It's not clear to me whether you are saying that you don't want to use
>>>>>> RDFa because:
>>>>>> 
>>>>>> * you don't like it, or;
>>>>>> 
>>>>>> * you think that it needs to have some user-oriented manifestation.
>>>>>> 
>>>>>> There is no requirement that the RDFa in a document is displayed to
>>>>>> the user in any way, or that the triples somehow 'double-up'. This
>>>>>> means that your example could also be marked up like this:
>>>>>> 
>>>>>> <div
>>>>>>   xmlns:cd="http://www.recshop.fake/cd#"
>>>>>>   about="http://www.recshop.fake/cd/Empire_Burlesque"
>>>>>>    <span property="cd:artist" content="Bob Dylan"></span>
>>>>>>   <span property="cd:dbpedia"
>>>>>> resource="http://dbpedia.org/resource/Empire_Burlesque"></span>
>>>>>> </div>
>>>>>> 
>>>>>> Regards,
>>>>>> 
>>>>>> Mark
>>>>>> 
>>>>>> 
>>>>>> On Tue, Jun 12, 2012 at 3:02 PM, Sebastian Hellmann
>>>>>> <hellmann@informatik.uni-leipzig.de>   wrote:
>>>>>>> Dear list,
>>>>>>> What are the best practice to include a set of RDF triples in HTML.
>>>>>>> *Please note*: I am not looking for the RDFa way to include triples. I just
>>>>>>> want to add a set of triples somewhere in an HTML document. They are not
>>>>>>> supposed to show up like "Wikinomics", "Don Tapscott" in  the following
>>>>>>> example:
>>>>>>> 
>>>>>>> <div  xmlns:dc="http://purl.org/dc/elements/1.1/"
>>>>>>> about="http://www.example.com/books/wikinomics">
>>>>>>> <span  property="dc:title">Wikinomics</span>
>>>>>>> <span  property="dc:creator">Don Tapscott</span>
>>>>>>> <span  property="dc:date">2006-10-01</span>
>>>>>>> </div>
>>>>>>> 
>>>>>>> I don't want to use the strings in the HTML document as objects in the
>>>>>>> triples. My use case is that I just have a large set of triples, e.g. 1000
>>>>>>> that I want to include as a bulk somewhere and ship along with the html.
>>>>>>> Which way is the best? Do the examples below work?
>>>>>>> All the best,
>>>>>>> Sebastian
>>>>>>> 
>>>>>>> *******************************************
>>>>>>> Include in head
>>>>>>> ******************************************
>>>>>>> <html>
>>>>>>> <head>
>>>>>>> <script type="application/rdf+xml">
>>>>>>> <rdf:RDF
>>>>>>> xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>>>>>>> xmlns:cd="http://www.recshop.fake/cd#">
>>>>>>> 
>>>>>>> <rdf:Description
>>>>>>> rdf:about="http://www.recshop.fake/cd/Empire Burlesque">
>>>>>>> <cd:artist>Bob Dylan</cd:artist>
>>>>>>> <cd:dbpedia rdf:resource="http://dbpedia.org/resource/Empire_Burlesque">
>>>>>>> </rdf:Description>
>>>>>>> </rdf:RDF>
>>>>>>> </script>
>>>>>>> </head>
>>>>>>> <body>
>>>>>>> </body>
>>>>>>> </html>
>>>>>>> ******************************
>>>>>>> attach after html
>>>>>>> *****************************
>>>>>>> <html>
>>>>>>> <head>
>>>>>>> </head>
>>>>>>> <body>
>>>>>>> </body>
>>>>>>> </html>
>>>>>>> <rdf:RDF
>>>>>>> xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>>>>>>> xmlns:cd="http://www.recshop.fake/cd#">
>>>>>>> 
>>>>>>> <rdf:Description
>>>>>>> rdf:about="http://www.recshop.fake/cd/Empire Burlesque">
>>>>>>> <cd:artist>Bob Dylan</cd:artist>
>>>>>>> <cd:dbpedia rdf:resource="http://dbpedia.org/resource/Empire_Burlesque">
>>>>>>> </rdf:Description>
>>>>>>> </rdf:RDF>
>>>>>>> 
>>>>>>> 
>>>>>>> --
>>>>>>> Dipl. Inf. Sebastian Hellmann
>>>>>>> Department of Computer Science, University of Leipzig
>>>>>>> Projects: http://nlp2rdf.org , http://dbpedia.org
>>>>>>> Homepage: http://bis.informatik.uni-leipzig.de/SebastianHellmann
>>>>>>> Research Group: http://aksw.org
>>>>>>> 
>>>>>>> 
>>>>> 
>>>>> -- 
>>>>> Dipl. Inf. Sebastian Hellmann
>>>>> Department of Computer Science, University of Leipzig
>>>>> Projects: http://nlp2rdf.org , http://dbpedia.org
>>>>> Homepage: http://bis.informatik.uni-leipzig.de/SebastianHellmann
>>>>> Research Group: http://aksw.org
>>>>> 
>>>>> 
>>>> 
>>>> ----
>>>> Ivan Herman, W3C Semantic Web Activity Lead
>>>> Home: http://www.w3.org/People/Ivan/
>>>> mobile: +31-641044153
>>>> FOAF: http://www.ivan-herman.net/foaf.rdf
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>> 
>> 
> 
> 
> -- 
> Dipl. Inf. Sebastian Hellmann
> Department of Computer Science, University of Leipzig
> Projects: http://nlp2rdf.org , http://dbpedia.org
> Homepage: http://bis.informatik.uni-leipzig.de/SebastianHellmann
> Research Group: http://aksw.org
> 


----
Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
FOAF: http://www.ivan-herman.net/foaf.rdf
Received on Friday, 15 June 2012 06:52:07 UTC

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