W3C home > Mailing lists > Public > public-vocabs@w3.org > March 2015

Re: Proposal for Schema.org extension mechanism

From: Guha <guha@google.com>
Date: Thu, 19 Mar 2015 16:36:41 -0700
Message-ID: <CAPAGhv-O1aOTZ=GYN1j7CyKm_bUhTvfYaMZu=JKR=+V=-u3a7Q@mail.gmail.com>
To: W3C Vocabularies <public-vocabs@w3.org>
Cc: Sandro Hawke <sandro@w3.org>, Tim Berners-Lee <timbl@w3.org>, Ralph Swick <swick@w3.org>
The various discussions around this extension proposal seem to have reached
quiescence. I am hoping this is more because the questions were answered
than because of boredom.

We would like to proceed with the implementation of this proposal. If there
are strong objections, now would be the right time to raise them.

guha

On Fri, Feb 13, 2015 at 1:34 PM, Guha <guha@google.com> wrote:

>
> Schema.org extension mechanism
>
>
>
> Motivation
>
>    As schema.org adoption has grown, a number groups with more
> specialized vocabularies have expressed interest in extending schema.org
> with their terms. The most prominent example of this is GS1 with product
> vocabularies. Other examples include real estate, medical and bibliographic
> information. Even in something as common as human names, there are groups
> interested creating the vocabulary for representing all the intricacies of
> names.
>
> Outline of solution
>
> There are two kinds of extensions: reviewed extensions and external
> extensions. Both kinds of extensions typically add subclasses and
> properties to the core. Properties may be added to existing and/or new
> classes. More generally, they are an overlay on top of the core, and so
> they may add domains/ranges, superclasses, etc. as well. Extensions have to
> be consistent with the core schema.org. Every item in the core (i.e.,
> www.schema.org) is also in every extension. Extensions might overlap with
> each other in concepts (e.g., two extensions defining terms for financial
> institutions, one calling it FinancialBank and other calling it
> FinancialInstitution), but we should not have the same term being reused to
> mean something completely different (e.g., we should not have two
> extensions, one using Bank to mean river bank and the other using Bank to
> mean financial institution).
>
> Reviewed Extensions
>
> Each reviewed extension (say, e1), gets its own chunk of schema.org
> namespace: e1.schema.org. The items in that extension are created and
> maintained by the creators of that extension.  Reviewed extensions are very
> different from proposals. A proposal, if accepted, with modifications could
> either go into the core or become a reviewed extension.
>
> A reviewed extension is something that has been looked at and discussed by
> the community, albeit not as much as something in the core. We also expect
> a reviewed extension to have strong community support, preferably in the
> form of a few deployments.
>
> External Extensions
>
> Sometimes there might be a need for a third party (such as an app
> developer) to create extensions specific to their application. For example,
> Pinterest might want to extend the schema.org concept of ‘Sharing’ with
> ‘Pinning’. In such a case, they can create schema.pinterest.com and put
> up their extensions, specifying how it links with core schema.org. We
> will refer to these as external extensions.
>
>
>
> How it works for webmasters
>
> All of Schema.org core and all of the reviewed extensions will be
> available from the schema.org website. Each extension will be linked to
> from each of the touch points it has with the core. So, if an extension
> (say, having to do with Legal stuff) creates legal.schema.org/LegalPerson
> which is a subclass of schema.org/Person, the Person will link to
> LegalPerson.  Typically, a webpage / email will use only a single extension
> (e.g., legal), in which case, instead of ‘schema.org’ they say ‘
> legal.schema.org’ and use all of the vocabulary in legal.schema.org and
> schema.org.
>
> As appropriate, the main schema.org site will also link to relevant
> external extensions. With external extensions, the use of multiple
> namespaces is unavoidable.
>
> What does someone creating an extension need to do
>
>  We would like extension creators to not have to worry about running a
> website for their extension. Once the extension is approved, they simply
> upload a file with their extension into a certain directory on github.
> Changes are made through the same mechanism.
>
> Since the source code for schema.org is publicly available, we encourage
> creators of external extensions to use the same application.
>
> Examples
>
> Archives example in RDFa
>
> This example uses a type that makes sense for archival and bibliographic
> applications but which is not currently in the schema.org core:
> Microform, defined as "Any form, either film or paper, containing
> microreproductions of documents for transmission, storage, reading, and
> printing. (Microfilm, microfiche, microcards, etc.)"
>
> The extension type is taken from  http://bibliograph.net/Microform,
> (which on this proposed model would move to bib.schema.org) which is a
> version of the opensource schema.org codebases that overlays
> bibliographic extras onto the core schema.org types. The example is
> adapted from http://schema.org/workExample.
>
>
> <div vocab="http://bib.schema.org/">
>
>    <p typeof="Book" resource="http://www.freebase.com/m/0h35m">
>
>        <em property="name">The Fellowship of the Rings</em> was written by
>
>        <span property="author">J.R.R Tolkien</span> and was originally
> published
>
>        in the <span property="publisher" typeof="Organization">
>
>            <span property="location">United Kingdom</span> by
>
>            <span property="name">George Allen & Unwin</span>
>
>        </span> in <time property="datePublished">1954</time>.
>
>        The book has been republished many times, including editions by
>
>        <span property="workExample" typeof="Book">
>
>            <span property="publisher" typeof="Organization">
>
>                <span property="name">HarperCollins</span>
>
>            </span> in <time property="datePublished">1974</time>
>
>            (ISBN: <span property="isbn">0007149212</span>)
>
>        </span> and by
>
>        <span property="workExample" typeof="Book Microform">
>
>            <span property="publisher" typeof="Organization">
>
>                <span property="name">Microfiche Press</span>
>
>            </span> in <time property="datePublished">2016</time>
>
>            (ISBN: <span property="isbn">12341234</span>).
>
>        </span>
>
>    </p>
>
> </div>
>
> Alternative RDFa:
>
> The example above puts all data into the extension namespace. Although
> this can be mapped back into normal schema.org it puts more work onto
> consumers. Here is how it would look using multiple vocabularies:
>
> <div vocab="http://schema.org/" prefix="bib: http://bib.schema.org/">
>
>    <p typeof="Book" resource="http://www.freebase.com/m/0h35m">
>
>        <em property="name">The Fellowship of the Rings</em> was written by
>
>        <span property="author">J.R.R Tolkien</span> and was originally
> published
>
>        in the <span property="publisher" typeof="Organization">
>
>            <span property="location">United Kingdom</span> by
>
>            <span property="name">George Allen & Unwin</span>
>
>        </span> in <time property="datePublished">1954</time>.
>
>        The book has been republished many times, including editions by
>
>        <span property="workExample" typeof="Book">
>
>            <span property="publisher" typeof="Organization">
>
>                <span property="name">HarperCollins</span>
>
>            </span> in <time property="datePublished">1974</time>
>
>            (ISBN: <span property="isbn">0007149212</span>)
>
>        </span> and by
>
>        <span property="workExample" typeof="Book bib:Microform">
>
>            <span property="publisher" typeof="Organization">
>
>                <span property="name">Microfiche Press</span>
>
>            </span> in <time property="datePublished">2016</time>
>
>            (ISBN: <span property="isbn">12341234</span>).
>
>        </span>
>
>    </p>
>
> </div>
>
> Here is that last approach written in JSON-LD (it works today, but would
> be even more concise if the schema.org JSON-LD context file was updated
> to declare the 'bib' extension):
>
> <script type="application/ld+json">
>
> {
>
>  "@context": [ "http://schema.org/",
>
>       { "bib": "http://bib.schema.org/" } ],
>
>  "@id": "http://www.freebase.com/m/0h35m",
>
>  "@type": "Book",
>
>  "name": "The Fellowship of the Rings",
>
>  "author": "J.R.R Tolkien",
>
>  "publisher": {
>
>     "@type": "Organization",
>
>  },
>
>  "location": "United Kingdom",
>
>  "name": "George Allen & Unwin",
>
> },
>
>  "datePublished": "1954",
>
>  "workExample": {
>
>    "@type": "Book",
>
>    "name": "Harper Collins",
>
>    "datePublished": "1974",
>
>    "isbn": "0007149212"
>
>  },
>
>  "workExample": {
>
>    "@type": ["Book", "bib:Microform"],
>
>    "name": "Microfiche Press",
>
>    "datePublished": "2016",
>
>    "isbn": "12341234"
>
>  }
>
> }
>
> </script>
>
>
> GS1 Example
>
> <script type="application/ld+json">
>
> {
>
>    "@context": "http://schema.org/",
>
>    "@vocab": "http://gs1.schema.org/",
>
>    "@id": "http://id.manufacturer.com/gtin/05011476100885",
>
>    "gtin13": "5011476100885",
>
>    "@type": "TradeItem",
>
>    "tradeItemDescription": "Deliciously crunchy Os, packed with 4 whole
> grains. Say Yes to Cheerios",
>
>    "healthClaimDescription": "8 Vitamins & Iron, Source of Calcium & High
> in Fibre",
>
>    "hasAllergenRelatedInformation": {
>
>        "@type": "gs1:AllergenRelatedInformation",
>
>        "allergenStatement": "May contain nut traces"
>
>    },
>
>    "hasIngredients": {
>
>        "@type": "gs1:FoodAndBeverageIngredient",
>
>        "hasIngredientDetail": [
>
>            {
>
>                "@type": "Ingredient",
>
>                "ingredientseq": "1",
>
>                "ingredientname": "Cereal Grains",
>
>                "ingredientpercentage": "77.5"
>
>            },
>
>            {
>
>                "@type": "Ingredient",
>
>                "ingredientseq": "2",
>
>                "ingredientname": "Whole Grain OATS",
>
>                "ingredientpercentage": "38.0"
>
>            }
>
>      ]
>
>    },
>
>    "nutrientBasisQuantity": {
>
>        "@type": "Measurement",
>
>        "value": "100",
>
>        "unit": "GRM"
>
>    },
>
>    "energyPerNutrientBasis": [
>
>        {
>
>            "@type": "Measurement",
>
>            "value": "1615",
>
>            "unit": "KJO"
>
>        },
>
>        {
>
>            "@type": "Measurement",
>
>            "value": "382",
>
>            "unit": "E14"
>
>        }
>
>    ],
>
>    "proteinPerNutrientBasis": {
>
>        "@type": "Measurement",
>
>        "value": "8.6",
>
>        "unit": "GRM"
>
>    }
>
> }
>
> </script>
>
> This example shows a possible encoding of the GS1 schemas overlaid onto
> schema.org. It uses JSON-LD syntax, which would support several
> variations on this approach. It is based on examples from GS1's proposal
> circulated to the schema.org community recently.
>
> (https://lists.w3.org/Archives/Public/public-vocabs/2015Jan/0069.html).
> Instead of writing
>
>    "@context": "http://schema.org/",   "@vocab": "http://gs1.schema.org/",
> it would be possible to simply write "@context": "http://gs1.schema.org/".
>
>
>
>
>
>
>
>
Received on Thursday, 19 March 2015 23:37:10 UTC

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