- From: Guha <guha@google.com>
- Date: Fri, 13 Feb 2015 13:35:07 -0800
- To: W3C Vocabularies <public-vocabs@w3.org>
- Cc: Sandro Hawke <sandro@w3.org>, Tim Berners-Lee <timbl@w3.org>, Ralph Swick <swick@w3.org>
- Message-ID: <CAPAGhv-eox7VW2Q_OL4ZSEFVGxUSD2uY6wXbXRHe2aLN424Kwg@mail.gmail.com>
Google doc url for those who want to leave comments there:
https://docs.google.com/document/d/1-hq53ZtP1NxRqpjCCuhVRRwqQmEuaAzWDQ7OuG18_pg/edit?usp=sharing
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 Friday, 13 February 2015 21:35:35 UTC