Subject: visibility/privacy extensions

From: Bill de hOra <[email-masked]>
Date: Mon, 16 Jun 2008 14:24:49 +0100

Hi,

are there any format or category extensions for stating view privacy or 
moderation levels on content or feeds? )

Bill

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From: James M Snell <[email-masked]>
Date: Mon, 16 Jun 2008 08:01:38 -0700

In Connections, we've adopted a category based "flags" mechanisms, e.g.

   <category scheme="http://.../flags" term="private" />

It is essentially a boolean flag.  If the term "private" is included in 
the entry, the entry is private, otherwise it's not.  The "flags" scheme 
contains a number of other types of flags relevant to the entry.  So 
far, this has worked reasonably well for us.

- James

---

From: Peter Keane <[email-masked]>
Date: Mon, 16 Jun 2008 10:54:08 -0500

In our project, similarly to Connections,  we use:

<category term="public" scheme="http://.../category/visibility"/>

I'd be v. interested to know what other folks do, esp. if there is an
opportunity for standardization. In fact, I could see real utility in
some semi-formal way to register category schemes and terms. As has been
noted [1][2], atom:category has the potential to be quite a powerful
exension mechanism, getting us a "description framework" without having
to use RDF (not that there's anything wrong w/ RDF ;-)).

--peter keane

[1]http://torrez.us/archives/2006/05/25/447/
[2]http://www.majordojo.com/2006/05/overloading-atomcategory.php#c12851

On Mon, Jun 16, 2008 at 08:01:38AM -0700, James M Snell wrote:
> It is essentially a boolean flag.  If the term "private" is included in the 
> entry, the entry is private, otherwise it's not.  The "flags" scheme 
> contains a number of other types of flags relevant to the entry.  So far, 
> this has worked reasonably well for us.
>
> - James
>
> Bill de hOra wrote:
>>
>> Hi,
>>

---

From: Sylvain Hellegouarch <[email-masked]>
Date: Mon, 16 Jun 2008 18:33:42 +0200

> to use RDF (not that there's anything wrong w/ RDF ;-)).

I don't know if trying to register category schemes is the right 
approach but I am too using atom:category elements for that particular 
topic. The combination of scheme+term offers a very granular way of 
specifying a context in which a resource may be processed.

- Sylvain

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From: "Erling Wegger Linde" <[email-masked]>
Date: Mon, 16 Jun 2008 23:04:39 +0200

>From an outsider, just watching this list from time to time: Why not
use RDF? Isn't RDF more general? Could these categories be used
anywhere outside of Atom?

I'm not very familiar with the atom:category(ies) so I ask: can
atom:categories be referred to / used in a meaningful way with RDF?
E.g. can you either use URIs e.g. "http://.../flags#private" or
"http://.../flags/private" to refer to them? Or could one create a
general approach for using GRDDL (
http://research.talis.com/2006/grddl-wg/primer ) ? If you cannot, then
I think this approach will be a dead end in a few years, agree?

If there is one thing I think Atom is missing is a standardized way to
combine it with RDF. Why not try to use RDF when you can, not try to
avoid it?

Thanks,
- Erling

-- 
Med vennlig hilsen
Erling Wegger Linde

---

From: Sylvain Hellegouarch <[email-masked]>
Date: Tue, 17 Jun 2008 08:10:48 +0200

> atom:categories be referred to / used in a meaningful way with RDF?

Unless I'm mistaken, they are URIs so yes I'd say a client that is built 
with such purpose could make sense of those elements.

> I think this approach will be a dead end in a few years, agree?

No I don't. Could you explain?

I actually believe atom:category elements have the basic minimum that 
someone may be looking for when adding a context to a resource.

> combine it with RDF. Why not try to use RDF when you can, not try to

I don't understand what you mean by standardizing RDF with Atom. If 
someone is interested in using RDF inside Atom can't they just do so 
already? Or do you mean mapping the Atom model to the RDF data model?

Looking at the GRRDL Primer specification it looks like it's a 
transformation mechanism of a source document to a RDF representation. 
Is there any showstopper from the RDF community to already create such 
specification for consuming Atom documents?

More fundamentally my *personal* issue here is that RDF has chosen a 
top-down approach by saying "We needed a mechanism to enable meaningful 
consuming of heterogeneous resources" so they defined RDF and gradually 
offered simpler mechanisms to allow the profane to join the RDF world 
(like GRRDL Primer). Atom on the other hand has followed a bottom-up 
path and  been about "Let's have the lowest entry barrier we can and 
gradually add more complex mechanisms if they are needed". But because 
the base format is well defined you can make an Atom document already 
meaningful on its own.

- Sylvain

---

From: Story Henry <[email-masked]>
Date: Tue, 17 Jun 2008 09:47:20 +0200

Hi Linde,

There is some work on GRDDLing atom. One of them is here

   https://sommer.dev.java.net/atom/

David Powell is working on an XSLT1 transform for another ontology.

The atom group as a whole tends not to be very interested in these  
discussions, as they open up a painful history of years of debate that  
started with very early versions of RSS, and a good deal of confusion  
and misunderstanding all over.

RDF is very powerful. So it is better to spend time working on  
solutions that reveal that aspect of things. All the rest is GRDDLable.

	Henry

On 17 Jun 2008, at 08:10, Sylvain Hellegouarch wrote:
> transformation mechanism of a source document to a RDF  
> representation. Is there any showstopper from the RDF community to  
> already create such specification for consuming Atom documents?
>
> top-down approach by saying "We needed a mechanism to enable  
> meaningful consuming of heterogeneous resources" so they defined RDF  
> and gradually offered simpler mechanisms to allow the profane to  
> join the RDF world (like GRRDL Primer). Atom on the other hand has  
> followed a bottom-up path and  been about "Let's have the lowest  
> entry barrier we can and gradually add more complex mechanisms if  
> they are needed". But because the base format is well defined you  
> can make an Atom document already meaningful on its own.

---

From: Aristotle Pagaltzis <[email-masked]>
Date: Tue, 17 Jun 2008 10:29:41 +0200

* Erling Wegger Linde <[email-masked]> [2008-06-16 23:15]:
> Why not use RDF? Isn't RDF more general?

Yes, which makes it more demanding to process properly. If Atom
was specified in terms of RDF, you can bet that the same thing
would happen as it did with RSS 1.0: aggregators would parse the
RDF as XML, instead of building a graph out of it, and would
therefore break if anyone actually used Atom as RDF, eg. changing
the precise XML serialisation or adding triples in unexpected
places.

As I found out when I changed the namespace prefix bindings in my
feed, even just using Atom as actual XML will break a whole bunch
of naïve Atom parsers!

I don’t like this reality, but reality has a way of not caring
about whether I like it or not…

> Could these categories be used anywhere outside of Atom?

Not as it’s written.

> atom:categories be referred to / used in a meaningful way with

An atom:category is basically a rudimentary shorthand for writing
an RDF triple (where the Entry is always the subject).

> Why not try to use RDF when you can, not try to avoid it?

See above.

Note that there’s nothing stopping anyone from GRDDLing Atom (or
otherwise creating a mapping), and there are community efforts
underway, eg. http://djpowell.net/blog/entries/Atom-RDF.html

Regards,
-- 
Aristotle Pagaltzis // <http://plasmasturm.org/>

---

From: "Erling Wegger Linde" <[email-masked]>
Date: Tue, 17 Jun 2008 11:48:11 +0200

> with such purpose could make sense of those elements.

Ok, could you give me an example of such a URI? (I think I have never
seen an atom:category scheme before..). What would happen if you use a
URI to an RDF or N3 file instead? ( I think one should make it
possible to use both )

>> "http://.../flags/private" to refer to them? Or could one create a# Atom to turtle xslt 2.0 generated by the really excellent xq2xsl script from the above XQuery. It retains a small dependency on Saxon. Test it out by translating Tim Bray's Atom feed using the W3C XSLT 2.0 service.

Let's say that using RDF and other Semantic Web technologies is
getting more widely used. It is my opinion that this will happen
sooner or later. If the atom:category approach isn't very compatible
with such Semantic Web technologies, then I think people will not want
to use it in the future.

I mean, what information are you trying to add with atom:category
elements? Are you trying to state the scope/domain of an Atom feed?
Where will these category schemes/URIs be stored? Does someone create
public schemes for everyone to use? Or do everyone just create their
own schemes? How can you tell if a scheme is related to another
scheme? E.g. a concept in a scheme is a subclass of another concept in
another scheme? Could you express something like that?

I think that ontologies describing all sorts of concept will be
created for many domains, independent of whether they are used with
the Atom format/protocol or not. Why should one need to create such
schemes for a specific format/protocol if they can be shared and
reused other places using RDF?

> I don't understand what you mean by standardizing RDF with Atom. If someone
> is interested in using RDF inside Atom can't they just do so already? Or do
> you mean mapping the Atom model to the RDF data model?
>
> transformation mechanism of a source document to a RDF representation. Is
> there any showstopper from the RDF community to already create such

What I mean is: it is probably easy to transform Atom elements such as
<summary>, <author> etc. to RDF as they do not change! However, I
wonder how the atom:category schemes looks like, and if it is possible
to create a general GRRDL script that will transform them into
something meaningful in RDF. But please give me an example of an
atom:category scheme.

> offered simpler mechanisms to allow the profane to join the RDF world (like
> GRRDL Primer). Atom on the other hand has followed a bottom-up path and
>  been about "Let's have the lowest entry barrier we can and gradually add
> more complex mechanisms if they are needed". But because the base format is
> well defined you can make an Atom document already meaningful on its own.

Yes, the simplicity and the RESTfullness of the Atom format/protocol
is what I love about it. I just suggest that the atom:category
approach is way out of scope! You have to draw the line somewhere I
think, and I think atom:categories is far across that line, as it
would be much easier to use RDF here. I think it is impossible to make
the atom:category approach powerful enough (as users will probably
demand more features in the future) without actually making it more
similar to RDF, and that would be a waste of time and energy, as you
could just have used RDF from the beginning. I think at least one
should be able to use both.

>>>> the

-- 
Med vennlig hilsen
Erling Wegger Linde

---

From: "Erling Wegger Linde" <[email-masked]>
Date: Tue, 17 Jun 2008 12:08:25 +0200

> the precise XML serialisation or adding triples in unexpected

But what about using RDF in the <content type="application/rdf+xml">
would this break the aggregators too? Regarding the atom:category(ies)
I would like to state that a feed contains entries about for instance
projects. Say:

<feed>
<category term="http://usefulinc.com/ns/doap#Project" />
...

Would that mess up a client too?

> I don't like this reality, but reality has a way of not caring
> Not as it's written.
> Note that there's nothing stopping anyone from GRDDLing Atom (or

Just as you don't misunderstand me, I think it is great that Atom is
kept simple, and as long as it is possible to use GRDDL or other
approaches to map it to RDF I think it is great. However I think that
the atom:category approach might not cooperate very we using GRDDL to
transform Atom to RDF is greall with the future Semantic Web. This is
just my intuition, and I think I need to see some more examples of
atom:category schemes and how they are used before I conclude on this
one. However, it should be possible to just use URIs to refer to which
categories a Feed contains. Whether these URIs refers to an RDF
document or the homepage of a company, a wikipedia site or whatever,
it should be easy to deal with for a client. However, it would still
make it possible for a client to look up that RDF document, or use a
previously known ontology to find out that the category is actually a
subClassOf another category/concept that it is already familiar with.
I just don't understand why one are inventing the atom:category
schemes?

- Erling

-- 
Med vennlig hilsen
Erling Wegger Linde

---

From: "Erling Wegger Linde" <[email-masked]>
Date: Tue, 17 Jun 2008 11:53:40 +0200

> David Powell is working on an XSLT1 transform for another ontology.

Thanks Henry. I'll have to take a closer look at that, as well as I'm
searching for an example of an atom:category scheme.

> started with very early versions of RSS, and a good deal of confusion and
> misunderstanding all over.
>
> RDF is very powerful. So it is better to spend time working on solutions
> that reveal that aspect of things. All the rest is GRDDLable.

Yes, I can sympathize with the historic reasons. However I think maybe
one has to limit the scope of Atom somewhere, and atom:category(ies)
just intuitively seems as a not so good idea to me.

- Erling

-- 
Med vennlig hilsen
Erling Wegger Linde

---

From: Story Henry <[email-masked]>
Date: Tue, 17 Jun 2008 12:18:08 +0200

> searching for an example of an atom:category scheme.

Tim Bray uses category in his feed a lot:

    http://www.tbray.org/ongoing/ongoing.atom

You can then apply the following xquery to it, and see one way to  
write this out
in N3:

https://sommer.dev.java.net/atom/2006-06-06/transform/atom2turtle.xquery

If you have time you could write a little applet that does this for  
any URI. and I'll post in on the sommer atom page.

Henry

---

From: "Brian Smith" <[email-masked]>
Date: Tue, 17 Jun 2008 08:25:38 -0500

James M Snell wrote:
> It is essentially a boolean flag.  If the term "private" is 
> included in the entry, the entry is private, otherwise it's 
> not.  The "flags" scheme contains a number of other types of 
> flags relevant to the entry.  So far, this has worked 
> reasonably well for us.

What does "private" mean in Connections? Some groups can see the entry but
others can't? Only the author can see it?

Thanks,
Brian