hello james.
thanks for the quick response!
On 2014-05-27, 11:28 , James M Snell wrote:
> On Tue, May 27, 2014 at 11:15 AM, Erik Wilde <
dr...@berkeley.edu> wrote:
>> -
http://tools.ietf.org/html/draft-snell-activitystreams-08#section-3.4
>> talks about "RFC 5988 link relations" and seems to assume mostly what RFC
>> 5988 calls "registered relation types"? i am wondering whether all AS
>> constructs work robustly when "extension relation types", i.e. URIs, are
>> used as link relation types. specifically, this could mean that the property
>> name of a link would be a URI. i think it is very important to align AS with
>> RFC5988 web linking, but maybe both the text and the examples should
>> specifically mention both kinds of link relations?
> Yes, the intention is that *any* link relation can be used as a
> property in an AS 2.0 document so long as the link relation does not
> conflict with an existing core property value. So you can use a
> URI/IRI form as a property name.
that's very good to hear. i would suggest to make that explicit in the
text and to add examples that use the URI form of relation types. also,
if there's a test suite somewhere (is there?), it should make sure to
always cover these two variations.
>> - regarding the link-related draft text, here's another thing i am wondering
>> about. the text says: 'Within an object, in the absence of a specific "rel"
>> property within the link object itself, the name of the property whose value
>> is a link serves as the "link relation".' so how would one *know* that a
>> property's value is a link? it cannot be done by just inspecting the value,
>> right? other properties might have URI values as well, and a link's URI
>> might be relative and not *look* like a URI, right?
> In general, a link value would include either a "url" or "id"
> property.
but looking at it the other way around: in order to figure out that
something indeed *is* a link, is it sufficient to look for either
property and then conclude that only links will have those?
> The "url" *should* be an absolute URI/IRI. The "id" *must*
> be an absolute URI/IRI. That said, however, Link Values are not
> strongly typed. So, in the following:
> {
> "a": "foo",
> "b": "
http://example.org/foo",
> "c": {
> "url": "
http://example.org/foo"
> },
> "d": {
> "id": "
http://example.org/foo"
> },
> "e": {
> "displayName": "foo"
> }
> }
> Any of these (properties "a" through "e") can be processed as Link
> Values but can be processed in other ways also. The property "a", for
> instance, can be processed as a Link Value if you choose to treat the
> string value as a relative reference. There's no requirement that you
> have to treat it that, way, however. You'll have to understand the
> meaning of the "a" property.
i guess this is where the bigger question then becomes how the various
a's that may float around can be distinguished. this of course brings up
the (careful, dirty word coming up!) interesting topic of: namespaces.
on some levels (verbs and object types), there is some explicit
extension/openness model. it would be interesting to discuss how this
does or does not apply to the question of figuring out if the above "a"
property is or isn't a link.
>> - at a more abstract level, i am wondering how/if complete AS resources can
>> be linked. what i am talking about is a kind of atom:feed/atom:link
>> construct, which allows to represent ways in which a resource (i.e., a
>> complete AS) is related to other web resources (as opposed to how a specific
>> activity is related to something else). in our work on feeds (which we want
>> to move to AS), this kind of information proves to be very valuable, but of
>> course it also complicates matters since then there has to be a model for
>> how to "inherit" this information. atom's way of doing this certainly is one
>> of the more byzantine parts of the atom spec:
>>
http://tools.ietf.org/html/rfc4287#section-4.2.11
> The idea has been to strike a balance between the kind of strong
> typing provided by Atom's link element and the loosely defined duck
> typing allowed by JSON in general. We can layer in stronger typing
> using JSON-LD constructs, if necessary. Overall, however, in AS 2.0,
> if it looks like a duck...
not sure this is what i was talking about. what i am looking for is the
ability for a publisher of activities to expose information about that
particular *stream*. think of it as the ability to "link a stream"
instead of just "linking an activity". we have found this to be very
helpful when using feeds, for example in spatial settings where a
particular feed can link to "zoom out" and "zoom in" feeds, allowing a
consumer to navigate related information sources. another example is to
link to a query/filter resource that allows a consumer to choose a
different set of activities. generally speaking, the goal is to link
information resources (in this case, activity streams), and i am
wondering how to best do that.
thanks and cheers,