- From: Martynas Jusevičius <martynas@graphity.org>
- Date: Tue, 20 Oct 2015 00:19:00 +0000
- To: James M Snell <jasnell@gmail.com>
- Cc: Melvin Carvalho <melvincarvalho@gmail.com>, public-socialweb@w3c.org
- Message-ID: <CAE35VmxZBoDKHpz4X_vhH2zd3FKXyvXkGU7crV8mg5DCv8iLrQ@mail.gmail.com>
What is the problem exactly? That AS 2.0 document is "invalid"? How is that
validity defined?
In RDF interpretation, there is no valid or invalid data - anyone can
assert anything. In practice, this only becomes a problem when consuming
data - but then it can be validated using constraints.
If the specification depends on certain syntax of a certain serialization,
then maybe it's based on the wrong design assumptions? An RDF application
should be agnostic to serializations.
On Tue, 20 Oct 2015 at 01:48, James M Snell <jasnell@gmail.com> wrote:
> Doing so would not address the problem I describe.
>
> On Mon, Oct 19, 2015 at 4:42 PM, Martynas Jusevičius
> <martynas@graphity.org> wrote:
> > Why not put some constraints on the data? And make them dereferenceable?
> > There's a spec for that: https://w3c.github.io/data-shapes/shacl/
> >
> > On Tue, Oct 20, 2015 at 1:39 AM, James M Snell <jasnell@gmail.com>
> wrote:
> >> By way of example: The following is a valid expanded form JSON-LD
> >> document that uses the AS 2.0 vocabulary. It can be served using the
> >> `application/ld+json` media type. It is NOT, however, a valid AS 2.0
> >> document.
> >>
> >> ```
> >> [
> >> {
> >> "@type": [
> >> "http://www.w3.org/ns/activitystreams#Create"
> >> ],
> >> "http://www.w3.org/ns/activitystreams#actor": [
> >> {
> >> "@id": "acct:sally@example.org",
> >> "@type": [
> >> "http://www.w3.org/ns/activitystreams#Person"
> >> ],
> >> "http://www.w3.org/ns/activitystreams#displayName": [
> >> {
> >> "@value": "Sally"
> >> }
> >> ]
> >> }
> >> ],
> >> "http://www.w3.org/ns/activitystreams#object": [
> >> {
> >> "@type": [
> >> "http://www.w3.org/ns/activitystreams#Note"
> >> ],
> >> "http://www.w3.org/ns/activitystreams#content": [
> >> {
> >> "@value": "This is a simple note"
> >> }
> >> ]
> >> }
> >> ],
> >> "http://www.w3.org/ns/activitystreams#published": [
> >> {
> >> "@type": "http://www.w3.org/2001/XMLSchema#dateTime",
> >> "@value": "2015-01-25T12:34:56Z"
> >> }
> >> ]
> >> }
> >> ]
> >> ```
> >>
> >> The following is also a valid JSON-LD document that can be served
> >> using the `application/ld+json` media type. It also uses the AS 2.0
> >> vocabulary but it is also not a valid AS 2.0 document:
> >>
> >> ```
> >> {
> >> "@context": ["http://www.w3.org/ns/activitystreams", {
> >> "foo": "as:displayName",
> >> "bar": "as:content",
> >> "baz": "@id",
> >> "fuz": "@type"
> >> }],
> >> "@type": "Create",
> >> "actor": {
> >> "fuz": "Person",
> >> "baz": "acct:sally@example.org",
> >> "foo": "Sally"
> >> },
> >> "object": {
> >> "fuz": "Note",
> >> "bar": "This is a simple note"
> >> },
> >> "published": "2015-01-25T12:34:56Z"
> >> }
> >> ```
> >>
> >> In fact, both of the above examples are valid JSON-LD serializations
> >> of exactly the same data, which you can only know if you apply the
> >> JSON-LD processing APIs.
> >>
> >> A key part of the reason AS 2.0 requires a normative JSON-LD context
> >> and compact serialization is to normalize the data format and make it
> >> possible for implementers to choose not to apply full JSON-LD
> >> processing and still be able to make reasonable sense of the data.
> >>
> >> - James
> >>
> >> On Mon, Oct 19, 2015 at 4:30 PM, Martynas Jusevičius
> >> <martynas@graphity.org> wrote:
> >>> I don't see any reason for a new media type. Media types identify file
> >>> formats basically, which is orthogonal to what AS doing: creating yet
> >>> another RDF vocabulary to describe social graphs and document
> >>> hierarchies. If the serialization format is JSON-LD, then it can be
> >>> interpreted as both RDF and JSON, which is a bonus. But in general,
> >>> Linked Data applications should advertise which RDF serializations
> >>> they support, instead of creating or extending media types. By
> >>> extending the JSON media type, the interoperability would decrease.
> >>>
> >>> Martynas
> >>>
> >>> On Tue, Oct 20, 2015 at 12:58 AM, Melvin Carvalho
> >>> <melvincarvalho@gmail.com> wrote:
> >>>>
> >>>>
> >>>> On 19 October 2015 at 21:37, James M Snell <jasnell@gmail.com> wrote:
> >>>>>
> >>>>> We have had a number of open github issues. I recommend closing the
> >>>>> following:
> >>>>>
> >>>>> #52 - "New media type or application/ld+json plus profile" -
> >>>>> https://github.com/jasnell/w3c-socialwg-activitystreams/issues/52
> >>>>>
> >>>>> This one has been around for a while. There was a concern brought
> up
> >>>>> about the creation of the application/activity+json media type and
> >>>>> whether or not AS2 should use the application/ld+json media type with
> >>>>> a profile parameter. The concern is that use of the
> >>>>> application/activity+json media type could harm interoperability.
> >>>>>
> >>>>> In my opinion, the concern is largely theoretical and is not backed
> >>>>> by real implementation experience. There is nothing to be gained by
> >>>>> switching to using the application/ld+json media type. Nor is there
> >>>>> anything "broken" about using the "application/activity+json".
> >>>>
> >>>>
> >>>> Thanks for bringing this up, James.
> >>>>
> >>>> Am I right to say that you would consider the two proposals of:
> >>>>
> >>>> 1 using the application/activity+json media type
> >>>> 2 using the the application/ld+json media type plus profile mechanism
> [1]
> >>>>
> >>>> largely equivalent?
> >>>>
> >>>> Or do you strongly favor one option over the other? If so, I think
> it's
> >>>> important to understand why
> >>>>
> >>>> [1] http://www.w3.org/TR/json-ld/#iana-considerations (see Optional
> >>>> Parameters)
> >>>>
> >>>>>
> >>>>>
> >>>>> #157 - "Vocabulary item for "Blog" type" -
> >>>>> https://github.com/jasnell/w3c-socialwg-activitystreams/issues/157
> >>>>>
> >>>>> In my opinion, this is unnecessary.
> >>>>>
> >>>>> #175 - "Should we have a type for the object of an "Offer" activity?
> >>>>> " -
> https://github.com/jasnell/w3c-socialwg-activitystreams/issues/175
> >>>>>
> >>>>> In my opinion, this is unnecessary.
> >>>>>
> >>>>> #205 - "Object partOf Collection" -
> >>>>> https://github.com/jasnell/w3c-socialwg-activitystreams/issues/205
> >>>>>
> >>>>> Question raised over whether we need a reverse property on objects
> >>>>> to indicate which collection(s) they are members of. In my opinion
> >>>>> this is unnecessary.
> >>>>>
> >>>>> #208 - "owl:Class vs. rdf:Property (for verbs and roles)" -
> >>>>> https://github.com/jasnell/w3c-socialwg-activitystreams/issues/208
> >>>>>
> >>>>> Raises a concern over the fundamental design of verbs in AS2. This
> >>>>> requests revisiting a design decision that was made early within the
> >>>>> design of AS2 without presenting any new information. I see little
> >>>>> value in rehashing the prior conversation and selected design.
> >>>>>
> >>>>> - James
> >>>>>
> >>>>
>
Received on Tuesday, 20 October 2015 00:19:42 UTC