W3C home > Mailing lists > Public > public-vocabs@w3.org > September 2014

Re: ItemList proposal

From: Jarno van Driel <jarnovandriel@gmail.com>
Date: Wed, 17 Sep 2014 15:58:00 +0200
Message-ID: <CADK2AU2BsT177YXefmEz2DPsq15ASOpgYWYyqFG5swg1Tz9KOQ@mail.gmail.com>
To: Stéphane Corlosquet <scorlosquet@gmail.com>
Cc: Dan Brickley <danbri@google.com>, "martin.hepp@ebusiness-unibw.org" <martin.hepp@ebusiness-unibw.org>, Vicki Tardif Holland <vtardif@google.com>, "Jason Johnson (BING)" <jasjoh@microsoft.com>, W3C Web Schemas Task Force <public-vocabs@w3.org>
Please try the RDFa example above in
https://www.google.com/webmasters/markup-tester/events, and you will see
that @href is well understood by Google event markup parser (same applies
to @resource). Google definitely has a sharp in-house RDFa parser, it's
just a matter of using it across the board on all their products, which I'm
sure is only a matter of time before it happens. The sooner the better, of
course. We're all waiting to see this parser deployed on
http://www.google.com/webmasters/tools/richsnippets.

The Microdata markup above will not work, and that's by design because MD
doesn't honor the @href as being used as URI for data items. That said,
@itemid might work.

Steph.

2014-09-17 15:55 GMT+02:00 Stéphane Corlosquet <scorlosquet@gmail.com>:

>
>
> On Wed, Sep 17, 2014 at 3:21 AM, Jarno van Driel <jarnovandriel@gmail.com>
> wrote:
>
>> "The trick is to avoid relying on an explicit value for 'url', and
>>> instead use the href value as the URI as the Webpage. This is in fact much
>>> more in line with Linked Data best practices and it avoids blank nodes. A
>>> pet peeve of mine is that Schema.org relies too heavily on an explicit
>>> 'url' property in its examples. If the 'url' property is not provided,
>>> consumers such as Google should simply use the resource URI provided in
>>> @itemid (microdata), @href/@resource (RDFa) or @id in JSON-LD."
>>
>>
>> Kudos for this solution, it's a beauty. But...
>>
>> Unfortunately the current support for @itemid and @resource by the
>> sponsors is unreliable. Let me illustrate by giving an example:
>> (parsing these through rdfa.info/play/, Structured Data Linter,
>> Structured Data Testing Tool (=Google ) and Structured Data Validator
>> (=Yandex) will illustrate the issue). And I know, by testing it, that
>> Google's WMT doesn't handle @itemid @@resource very well either.
>>
>> Microdata:
>> <body>
>>   <a href="http://example.com/article" itemscope itemtype="
>> http://schema.org/Article">
>>     <span itemprop="name">Multiple identical @itemid's don't merge</span>
>>   </a>
>>
>>   <a href="http://example.com/article" itemscope itemtype="
>> http://schema.org/Article">
>>     <span itemprop="description">Google (WMT and SDTT) and Yandex (SDV)
>> fail to merge 2 entities with the same @href/@itemid</span>
>>   </a>
>> </body>
>>
>> RDFa:
>> <body vocab="http://schema.org/">
>>   <a href="http://example.com/article" typeof="Article">
>>     <span property="name">Multiple identical @itemid's don't merge</span>
>>   </a>
>>
>>   <a href="http://example.com/article" typeof="Article">
>>     <span property="description">Google (WMT and SDTT) and Yandex (SDV)
>> fails to merge 2 entities with the same @href, however Yandex succeeds when
>> @resource is specified where Google does not</span>
>>   </a>
>> </body>
>>
>>
> Please try the RDFa example above in
> https://www.google.com/webmasters/markup-tester/events, and you will see
> that @href is well understood by Google event markup parser (same applies
> to @resource). Google definitely has a sharp in-house RDFa parser, it's
> just a matter of using it across the board on all their products, which I'm
> sure is only a matter of time before it happens. The sooner the better, of
> course. We're all waiting to see this parser deployed on
> http://www.google.com/webmasters/tools/richsnippets.
>
> The Microdata markup above will not work, and that's by design because MD
> doesn't honor the @href as being used as URI for data items. That said,
> @itemid might work.
>
> Steph.
>
>
>> Which does lead me to say that something needs to change in the way the
>> sponsors deal with @resource (and @href) before relying on Stéphane's
>> solution (again, which I think is a beauty).
>>
>> I see it as a bit of a disgrace the Structured Data Linter is the only
>> tool that's able to parse both microdata and RDFa examples successfully. It
>> most certainly doesn't help one bit in global identifiers being deployed by
>> web developers. I for one would not expect the sponsors to be behind in
>> supporting this.
>>
>>
>> 2014-09-17 7:12 GMT+02:00 Stéphane Corlosquet <scorlosquet@gmail.com>:
>>
>>>
>>>
>>> On Tue, Sep 16, 2014 at 5:08 PM, Dan Brickley <danbri@google.com> wrote:
>>>
>>>> On 16 September 2014 21:50, Jarno van Driel <jarnovandriel@gmail.com>
>>>> wrote:
>>>> > Not much really, it's a custom I picked up because the W3 Validator
>>>> > (http://validator.w3.org/) kept complaining about not providing a
>>>> @title for
>>>> > anchors, which it stopped complaining about if one added an empty
>>>> @title. So
>>>> > I became accustomed to alway specifying a @title, even it it's empty.
>>>> >
>>>> > To be honest I don't even know if the workaround is still needed or
>>>> not, I
>>>> > haven't looked into it for ages.  :)
>>>> >
>>>> > I'll remove it from the document though.
>>>>
>>>> Ah thanks, I thought it might be some wiki markup / escaping artifact.
>>>>
>>>> It's a big document. Maybe we could settle on one single core example
>>>> that applies new Itemlist to the breadcrumbs usecase?
>>>>
>>>> A lot of people are interested in knowing how
>>>> https://support.google.com/webmasters/answer/185417?hl=en should look.
>>>>
>>>> Here's the old markup:
>>>>
>>>> <div itemscope itemtype="http://data-vocabulary.org/Breadcrumb">
>>>>   <a href="http://www.example.com/dresses" itemprop="url">
>>>>     <span itemprop="title">Dresses</span>
>>>>   </a> ›
>>>> </div>
>>>> <div itemscope itemtype="http://data-vocabulary.org/Breadcrumb">
>>>>   <a href="http://www.example.com/dresses/real" itemprop="url">
>>>>     <span itemprop="title">Real Dresses</span>
>>>>   </a> ›
>>>> </div>
>>>> <div itemscope itemtype="http://data-vocabulary.org/Breadcrumb">
>>>>   <a href="http://www.example.com/clothes/dresses/real/green"
>>>> itemprop="url">
>>>>     <span itemprop="title">Real Green Dresses</span>
>>>>   </a>
>>>> </div>
>>>>
>>>> How concisely can we do this with new ItemList? Does this look
>>>> monsterously verbose, or bearable?
>>>>
>>>> <ol itemscope="" itemtype="http://schema.org/ItemList">
>>>>   <li itemprop="itemListElement" itemscope=""
>>>> itemtype="http://schema.org/ListItem">
>>>>     <span itemprop="item" itemscope="" itemtype="
>>>> http://schema.org/WebPage">
>>>>       <a href="http://www.example.com/dresses" itemprop="url">
>>>>         <span itemprop="title">Dresses</span>
>>>>       </a>
>>>>     </span>
>>>>   </li>
>>>> ›  <li itemprop="itemListElement" itemscope=""
>>>> itemtype="http://schema.org/ListItem">
>>>>     <span itemprop="item" itemscope="" itemtype="
>>>> http://schema.org/WebPage">
>>>>       <a href="http://www.example.com/dresses/real" itemprop="url">
>>>>         <span itemprop="title">Real Dresses</span>
>>>>       </a>
>>>>     </span>
>>>>   </li>
>>>> ›  <li itemprop="itemListElement" itemscope=""
>>>> itemtype="http://schema.org/ListItem">
>>>>     <span itemprop="item" itemscope="" itemtype="
>>>> http://schema.org/WebPage">
>>>>       <a href="http://www.example.com/clothes/dresses/real/green"
>>>> itemprop="url">
>>>>         <span itemprop="title">Real Green Dresses</span>
>>>>       </a>
>>>>     </span>
>>>>   </li>
>>>> </ol>
>>>>
>>>
>>> This example can be simplified by removing one level of nesting, as
>>> shown in this example in RDFa, which I tested in Play
>>> <http://rdfa.info/play/>:
>>>
>>> <ol vocab="http://schema.org/" typeof="ItemList">
>>>   <li property="itemListElement" typeof="ListItem">
>>>       <a property="item" typeof="WebPage" href="
>>> http://www.example.com/dresses">
>>>         <span property="title">Dresses</span>
>>>       </a>
>>>       <meta property="position" content="1">
>>>   </li>
>>> ›  <li property="itemListElement" typeof="ListItem">
>>>       <a property="item" typeof="WebPage" href="
>>> http://www.example.com/dresses/real">
>>>         <span property="title">Real Dresses</span>
>>>       </a>
>>>       <meta property="position" content="2">
>>>   </li>
>>> </ol>
>>>
>>> The trick is to avoid relying on an explicit value for 'url', and
>>> instead use the href value as the URI as the Webpage. This is in fact much
>>> more in line with Linked Data best practices and it avoids blank nodes. A
>>> pet peeve of mine is that Schema.org relies too heavily on an explicit
>>> 'url' property in its examples. If the 'url' property is not provided,
>>> consumers such as Google should simply use the resource URI provided in
>>> @itemid (microdata), @href/@resource (RDFa) or @id in JSON-LD.
>>>
>>> Equivalent JSON-LD:
>>>     {
>>>       "@id": "_:g70204145541180",
>>>       "@type": "ItemList",
>>>       "itemListElement": [
>>>         "_:g70204145492480",
>>>         "_:g70204145237140"
>>>       ]
>>>     },
>>>     {
>>>       "@id": "_:g70204145492480",
>>>       "@type": "ListItem",
>>>       "item": "http://www.example.com/dresses",
>>>       "position": "1"
>>>     },
>>>     {
>>>       "@id": "_:g70204145237140",
>>>       "@type": "ListItem",
>>>       "item": "http://www.example.com/dresses/real",
>>>       "position": "2"
>>>     },
>>>     {
>>>       "@id": "http://www.example.com/dresses",
>>>       "@type": "WebPage",
>>>       "title": "Dresses"
>>>     },
>>>     {
>>>       "@id": "http://www.example.com/dresses/real",
>>>       "@type": "WebPage",
>>>       "title": "Real Dresses"
>>>     }
>>>
>>>
>>> --
>>> Steph.
>>>
>>
>>
>
>
> --
> Steph.
>
Received on Wednesday, 17 September 2014 13:58:28 UTC

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