Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Olivier Rossel]

DNS trickery is the ultimate step for a fully flexible architecture.
Unfortunately it requires to have some admin rights over your own
domain. Something uber difficult in companies.

A workaround would be to create a top domain name, something like
..uris (or more realistically cooluris.net), with an automatic
delegation of  its subdomains to official owners
of an existing domain name.
For example the owner of datao.net would be able to get full access to
the subdomain datao.net.uris (or datao.net.cooluris.net) for its URIs.
And all the URIs of his or her RDF data would be in that domain.
Then he would either CNAME it so it resolves to t-d-b.org or his/her
own 303 system.
And that service would then 303 to the real web servers of datao.net

This would make a clean separation of contexts between URIs and URLs.

I advocate the creation of a .uri top domain name. That would be the
domain of semantic data. But because a top domain name is not
something easy to get, we could consider something more classical.
Maybe .cooluris.net

The crucial point is that this domain name will delegate its
subdomains to official owners of a real domain name (i.e datao.net can
claim full control of datao.net.cooluris.net, for example).

Given the fact that these services (CNAME to 303 + 303 to web data)
have default behaviour that make things simple for beginners, we would
have an efficient infrastructure.

On Thursday, July 9, 2009, Christopher St John  wrote:
> On Thu, Jul 9, 2009 at 10:46 AM, Pierre-Antoine
> Champin wrote:
>>
>> However, some people will still be concerned about naming their resources
>> under a domain that is not theirs. That is not only a matter of
>> URI-prettiness, but also of relying on an external service, which may cease
>> to exist tomorrow.
>>
>
> I'm switching uridirector.praxisbridge.org[1] to optionally
> include accept headers in choosing a template. That should
> give people a quick low-effort[2] way to get up and running
> without having to warp their URIs to match a third party
> service (and without having to commit to using the
> service once another option is available)
>
> It seems pretty clear that people should (a) only mint URLs
> in domains the control and (b) maybe think about including a
> sub-domain in the URIs for specific data sets (and thereby
> get the power of the domain name system on their side
> when they need to move the data later on)
>
> Note that following (a) doesn't mean you need to run your
> own server, it's sufficient to just register the domain.
> Smart-ish redirectors (third party or local) will then allow
> you a lot of flexibility in choosing exactly where the data
> is located.
>
> -cks
>
>
> [1] Like purl o t-b-g, only with host name header
> recognition so you can CNAME your own domains over and
> maintain complete control over your URI, see previous email:
> http://lists.w3.org/Archives/Public/public-lod/2009Jul/0072.html
> It's not quite fully baked, but it's getting there.
>
> [2] You need to know what a CNAME is, and have access to
> your DNS configuration. But you're not minting URLs in domains
> you don't have administrative control over, are you?
>
> --
> Christopher St. John
> c...@praxisbridge.com
> http://praxisbridge.com
> http://artofsystems.blogspot.com
>
>

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Olivier Rossel]

Externalizing the 303 feature is the good idea, imo.

But such a service should also handle the content negociation feature.
So the 303 may redirect to different URLs depending on the content
negociated. This makes the service more complex internally but
provides a very relevant service for RDF publishers (i.e they just
have to take care of one config on their server : mime-types).
Plus managing the redirect  is as easy as changing the xml:base of
their RDF/XML.



On Wednesday, July 8, 2009, David Booth  wrote:
>  On Wed 08/07/09  5:08 PM , Olivier Rossel olivier.ros...@gmail.com sent:
>> Do you mean that all deferencable URIs of a RDF document should have
>> their domain name to end with t-d-b.org, so their resolution leads to
>> the TDB server which redirects to the final location?
>
> No, I'm not suggesting that *all* deferenceable RDF URIs should use 
> t-d-b..org.  I'm just pointing out that it is an alternative if you cannot 
> configure your own server to do 303 redirects.  Using it does require putting 
> "http://t-d-b.org?"; at the beginning of your URI, so if you do not want to do 
> that then you should use a different approach.  To be clear, if you use this 
> approach, then instead of writing a URI such as
>
>           http://example/mydata.rdf
>
> you would write it as
>
>          http://t-d-b.org?http://example/mydata.rdf
>
> and if that URI is dereferenced, the 303-redirect service will automatically 
> return a 303 redirect to
>
>         http://example/mydata.rdf
>
> David Booth
>
>>
>> On Wednesday, July 8, 2009, David Booth > .org> wrote:> On Wed, 2009-07-08 at 15:50 +0100,
>> Pierre-Antoine Champin wrote:> [ . . . ]
>> >> ok, the solutions proposed here (by myself
>> and others) still involve>> editing the .htaccess.
>> >
>> > Once again, use of a 303-redirect service such
>> as> http://thing-described-by.org/ or
>> http://t-d-b.org/> does not require *any* configuration or
>> .htaccess editing.  It does not> address the problem of setting the content 
>> type
>> correctly, but it *does*> provide an easy way to generate 303 redirects,
>> in conformance with "Cool> URIs for the Semantic Web":
>> > http://www.w3.org/TR/cooluris/#r303gendocument>
>> > Hmm, I thought the use of a 303-redirect service
>> was mentioned in "Cool> URIs for the Semantic Web", but in looking
>> back, I see it was in "Best> Practice Recipes for Publishing RDF
>> Vocabularies":> http://www.w3.org/TR/swbp-vocab-pub/#redirect
>> > Maybe it should be mentioned in a future version
>> of the Cool URIs> document as well.
>> >
>> >
>> > --
>> > David Booth, Ph.D.
>> > Cleveland Clinic (contractor)
>> >
>> > Opinions expressed herein are those of the
>> author and do not necessarily> reflect those of Cleveland Clinic.
>> >
>> >
>> >
>>
>>
>>
>>
>>
>>
>

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Christopher St John]

On Thu, Jul 9, 2009 at 10:46 AM, Pierre-Antoine
Champin wrote:
>
> However, some people will still be concerned about naming their resources
> under a domain that is not theirs. That is not only a matter of
> URI-prettiness, but also of relying on an external service, which may cease
> to exist tomorrow.
>

I'm switching uridirector.praxisbridge.org[1] to optionally
include accept headers in choosing a template. That should
give people a quick low-effort[2] way to get up and running
without having to warp their URIs to match a third party
service (and without having to commit to using the
service once another option is available)

It seems pretty clear that people should (a) only mint URLs
in domains the control and (b) maybe think about including a
sub-domain in the URIs for specific data sets (and thereby
get the power of the domain name system on their side
when they need to move the data later on)

Note that following (a) doesn't mean you need to run your
own server, it's sufficient to just register the domain.
Smart-ish redirectors (third party or local) will then allow
you a lot of flexibility in choosing exactly where the data
is located.

-cks


[1] Like purl o t-b-g, only with host name header
recognition so you can CNAME your own domains over and
maintain complete control over your URI, see previous email:
http://lists.w3.org/Archives/Public/public-lod/2009Jul/0072.html
It's not quite fully baked, but it's getting there.

[2] You need to know what a CNAME is, and have access to
your DNS configuration. But you're not minting URLs in domains
you don't have administrative control over, are you?

-- 
Christopher St. John
c...@praxisbridge.com
http://praxisbridge.com
http://artofsystems.blogspot.com

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Pierre-Antoine Champin]

I like this! :)

However, some people will still be concerned about naming their 
resources under a domain that is not theirs. That is not only a matter 
of URI-prettiness, but also of relying on an external service, which may 
cease to exist tomorrow.


However, this could easily be solved. All we would need is a PHP script 
that would behave just like t-d-b.org -- PHP having the advantage of 
working without any .htaccess fiddling, at least in most cases.


So I could basically achieve the same thing with a URI like
  http://example.com/tdb.php?mydata.rdf
or
  http://example.com/a_path/tdb.php?/another_path/mydata.rdf

Of course, this would not prevent the use of specific recipies, like
  http://example.com/tdb1.php?mydata
or
  http://example.com/tdb2.php?/{}/mydata


  pa

Le 09/07/2009 14:43, David Booth a écrit :

(Discussing 303-redirect services, such as  http://t-d-b.org/ or 
http://thing-described-by.org/ )

  On Thu 09/07/09  6:12 AM , Olivier Rossel olivier.ros...@gmail.com sent:

Externalizing the 303 feature is the good idea, imo.

But such a service should also handle the content negociation feature.
So the 303 may redirect to different URLs depending on the content
negociated. This makes the service more complex internally but
provides a very relevant service for RDF publishers (i.e they just
have to take care of one config on their server : mime-types).


That sounds like an interesting idea.  It would require that URIs be registered 
in advance with the t-d-b.org server, so that it would know where to forward, 
depending on the Accept header (content negotiation), in a similar way that 
URIs are registered in advance with the purl.org server.   Correction:  come to 
think of it, that would not be necessary.  Instead the t-d-b.org server could 
be configured to have one or more standard recipes available for converting a 
generic URI to a specific URI depending on the content type requested.

For example t-d-b.org might have a recipe called conneg1 such that, given a GET 
request for URI
 http://t-d-b.org/conneg1?http://example/mydata
if the Accept header indicates that RDF is preferred, then the server could 
303-redirect to
 http://example/mydata.rdf
(Note that the owner of that URI would still have to ensure that the MIME type 
is served correctly.)  But if the Accept header indicates that HTML is 
preferred, then the server could 303-redirect to
 http://example/mydata.html

Annother recipe, conneg2, might use a URI pattern, such that {} in the target 
URI is replaced by rdf or html.  So for example, given a GET request for URI
 http://t-d-b.org/conneg1?http://example/{}/mydata
if the Accept header indicates that RDF is preferred, then the server could 
303-redirect to
 http://example/rdf/mydata
But if the Accept header indicates that HTML is preferred, then the server 
could 303-redirect to
 http://example/html/mydata

Note that a key advantage of this recipe-based approach is that it does not 
require the target URIs to be registered with the server.  This is beneficial 
in three ways:

  - Easier to implement the server.
  - Easier for URI owners to use.
  - The initial HTTP request can be safely optimized away by smart clients, as 
described here:
http://thing-described-by.org/#optimizing

What kinds of recipes would be most useful to foks?


Plus managing the redirect  is as easy as changing the xml:base of
their RDF/XML.


That sounds like a somewhat different design than I sketched above.  Can you 
describe in more detail what you mean, with an example?  What would the 
t-d-b.org server do, and how would it know to do it?

David Booth

Re: Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[David Booth]

(Discussing 303-redirect services, such as  http://t-d-b.org/ or 
http://thing-described-by.org/ )

 On Thu 09/07/09  6:12 AM , Olivier Rossel olivier.ros...@gmail.com sent:
> Externalizing the 303 feature is the good idea, imo.
> 
> But such a service should also handle the content negociation feature.
> So the 303 may redirect to different URLs depending on the content
> negociated. This makes the service more complex internally but
> provides a very relevant service for RDF publishers (i.e they just
> have to take care of one config on their server : mime-types).

That sounds like an interesting idea.  It would require that URIs be registered 
in advance with the t-d-b.org server, so that it would know where to forward, 
depending on the Accept header (content negotiation), in a similar way that 
URIs are registered in advance with the purl.org server.   Correction:  come to 
think of it, that would not be necessary.  Instead the t-d-b.org server could 
be configured to have one or more standard recipes available for converting a 
generic URI to a specific URI depending on the content type requested.

For example t-d-b.org might have a recipe called conneg1 such that, given a GET 
request for URI
http://t-d-b.org/conneg1?http://example/mydata
if the Accept header indicates that RDF is preferred, then the server could 
303-redirect to
http://example/mydata.rdf
(Note that the owner of that URI would still have to ensure that the MIME type 
is served correctly.)  But if the Accept header indicates that HTML is 
preferred, then the server could 303-redirect to
http://example/mydata.html

Annother recipe, conneg2, might use a URI pattern, such that {} in the target 
URI is replaced by rdf or html.  So for example, given a GET request for URI
http://t-d-b.org/conneg1?http://example/{}/mydata
if the Accept header indicates that RDF is preferred, then the server could 
303-redirect to
http://example/rdf/mydata
But if the Accept header indicates that HTML is preferred, then the server 
could 303-redirect to
http://example/html/mydata

Note that a key advantage of this recipe-based approach is that it does not 
require the target URIs to be registered with the server.  This is beneficial 
in three ways:

 - Easier to implement the server.
 - Easier for URI owners to use.
 - The initial HTTP request can be safely optimized away by smart clients, as 
described here:
http://thing-described-by.org/#optimizing 

What kinds of recipes would be most useful to foks?

> Plus managing the redirect  is as easy as changing the xml:base of
> their RDF/XML.

That sounds like a somewhat different design than I sketched above.  Can you 
describe in more detail what you mean, with an example?  What would the 
t-d-b.org server do, and how would it know to do it?

David Booth

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Hugh Glaser]

On 09/07/2009 07:56, "Peter Ansell"  wrote:

> 2009/7/9 Juan Sequeda :
>> On Jul 9, 2009, at 2:25 AM, Hugh Glaser  wrote:

>>> Mind you, it does mean that you should make sure that you don't put too
>>> many
>>> LD URIs in one document.
>>> If dbpedia decided to represent all the RDF in one document, and then use
>>> hash URIs, it would be somewhat problematic.
>> 
>> Could you explain why???
> 
> Does it seem reasonable to have to trawl through millions (or
> billions) of RDF triples resolved from a large database that only used
> one base URI with fragment identifiers for everything else if you
> don't need to considering that 100 specific RDF triples in a compact
> document might have been all you needed to see?
> 
> Peter
> 
> 
As a concrete example:
For dblp we split the data into year models, before asserting into the
triplestore, so we can serve RDF for each URI, by sort of DESCRIBing.
Paper:
http://dblp.rkbexplorer.com/id/journals/expert/ShadboltGGHS04
comes from a model file:
http://dblp.rkbexplorer.com/models/dblp-publications-2004.rdf
which is 155MB.
using hash URIs would require files of that size to be served for every
access, although if we were actually doing it that way we would of course
change our model file granularity size to avoid it.
So there is both possible network and processing overhead, which can be got
wrong.
In fact large foaf files give you quite a lot of extra stuff, if all you
wanted was some personal details.
When you want to know about timbl, if you only wanted his blog address you
don't necessarily want to download and process 30-odd KB of RDF, much of it
details of the people he knows (such as Tom Ilube's URI).
Just something to be aware of when serving linked data as hash.

And to add something else to the mix.
This is another reason semantic sitemaps are so important for search engines
like Sindice.
Sindice can index our model file, but on receiving a request for a URI in
it, without the sitemap, all it could easily be able to do would be point
the requester at the 155MB model file. Because of the sitemap, it can much
more easily work out for itself what it needs to know about the URI to point
the user at the linked data URI - all without spidering our whole
triplestore, which would be unacceptable.

Ah, the rich tapestry of life that is linked data!

Best
Hugh

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Roderic Page]

Hashed URIs can bring other problems.

For example, if I have a service http://mydata.org/uri that takes a  
URI and returns what it knows about the thing identified by that URI  
and I pass it a hash URI, e.g. http://ci.nii.ac.jp/naid/110006281382#article 
, my browser will trim #article and send http://ci.nii.ac.jp/naid/110006281382 
 to my client.


But, http://ci.nii.ac.jp/naid/110006281382 is NOT the URI of interest  
(it's a web page, http://ci.nii.ac.jp/naid/110006281382#article  
identifies the article itself). So, I have to fuss with URL encoding  
and Apache mod_rewrite to get http://ci.nii.ac.jp/naid/110006281382#article 
 past the browser and web server and to my client.


It's little things like this that make like *cough* interesting.

Regards

Rod

-
Roderic Page
Professor of Taxonomy
DEEB, FBLS
Graham Kerr Building
University of Glasgow
Glasgow G12 8QQ, UK

Email: r.p...@bio.gla.ac.uk
Tel: +44 141 330 4778
Fax: +44 141 330 2792
AIM: rodpage1...@aim.com
Facebook: http://www.facebook.com/profile.php?id=1112517192
Twitter: http://twitter.com/rdmpage
Blog: http://iphylo.blogspot.com
Home page: http://taxonomy.zoology.gla.ac.uk/rod/rod.html

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Richard Light]

In message 

@ecs.soton.ac.uk>, Hugh Glaser  writes


Hash URIs are very valuable in linked data, precisely *because* they
can't be directly requested from a server - they allow us to bypass
the whole HTTP 303 issue.

Mind you, it does mean that you should make sure that you don't put too many
LD URIs in one document.
If dbpedia decided to represent all the RDF in one document, and then use
hash URIs, it would be somewhat problematic.


One aspect of this that puzzles me is how you do the "deliver a 
human-readable or machine-processible version depending on the Accept 
header" trick when the actual resource is a single RDF document 
containing hash-referenced assertions.


Richard
--
Richard Light

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Toby A Inkster]

On 9 Jul 2009, at 07:44, Juan Sequeda wrote:

On Jul 9, 2009, at 2:25 AM, Hugh Glaser  wrote:


Mind you, it does mean that you should make sure that you don't  
put too many

LD URIs in one document.
If dbpedia decided to represent all the RDF in one document, and  
then use

hash URIs, it would be somewhat problematic.


Could you explain why???


The very practical problem of file sizes.

Your hash URIs can of course be distributed across a collection of  
files. e.g.


http://example.com/~alice/foaf.rdf#me
http://example.com/~bob/foaf.rdf#me
http://example.com/~carol/foaf.rdf#me

--
Toby A Inkster

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Peter Ansell]

2009/7/9 Juan Sequeda :
> On Jul 9, 2009, at 2:25 AM, Hugh Glaser  wrote:
>> On 09/07/2009 00:38, "Toby A Inkster"  wrote:
>>
>>> On 8 Jul 2009, at 19:58, Seth Russell wrote:
>>>
 Is it not true that everything past the hash (#alice) is not
 transmitted back to the server when a browser clicks on a
 hyperlink ?   If that is true, then the server would not be able to
 serve anything different if a browser clicked upon http://
 example.com/foaf.rdf or if they clicked upon http://example.com/
 foaf.rdf#alice .
>>>
>>> Indeed - the server doesn't see the fragment.
>>>
 If that is true, and it probably isn't, then is not the Semantic
 Web crippled from using that techniqe to distinguish between
 resources and at the same time hyper linking between those
 different resources?
>>>
>>>
>>> Not at all.
>>>
>>> Is the web of documents crippled because the server can't distinguish
>>> between requests for http://example.com/document.html and http://
>>> example.com/document.html#part2 ? Of course it isn't - the server
>>> doesn't need to distinguish between them - it serves up the same web
>>> page either way and lets the user agent distinguish.
>>>
>>> Hash URIs are very valuable in linked data, precisely *because* they
>>> can't be directly requested from a server - they allow us to bypass
>>> the whole HTTP 303 issue.
>>
>> Mind you, it does mean that you should make sure that you don't put too
>> many
>> LD URIs in one document.
>> If dbpedia decided to represent all the RDF in one document, and then use
>> hash URIs, it would be somewhat problematic.
>
> Could you explain why???

Does it seem reasonable to have to trawl through millions (or
billions) of RDF triples resolved from a large database that only used
one base URI with fragment identifiers for everything else if you
don't need to considering that 100 specific RDF triples in a compact
document might have been all you needed to see?

Peter

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Juan Sequeda]

On Jul 9, 2009, at 2:25 AM, Hugh Glaser  wrote:


On 09/07/2009 00:38, "Toby A Inkster"  wrote:


On 8 Jul 2009, at 19:58, Seth Russell wrote:


Is it not true that everything past the hash (#alice) is not
transmitted back to the server when a browser clicks on a
hyperlink ?   If that is true, then the server would not be able to
serve anything different if a browser clicked upon http://
example.com/foaf.rdf or if they clicked upon http://example.com/
foaf.rdf#alice .


Indeed - the server doesn't see the fragment.


If that is true, and it probably isn't, then is not the Semantic
Web crippled from using that techniqe to distinguish between
resources and at the same time hyper linking between those
different resources?



Not at all.

Is the web of documents crippled because the server can't distinguish
between requests for http://example.com/document.html and http://
example.com/document.html#part2 ? Of course it isn't - the server
doesn't need to distinguish between them - it serves up the same web
page either way and lets the user agent distinguish.

Hash URIs are very valuable in linked data, precisely *because* they
can't be directly requested from a server - they allow us to bypass
the whole HTTP 303 issue.
Mind you, it does mean that you should make sure that you don't put  
too many

LD URIs in one document.
If dbpedia decided to represent all the RDF in one document, and  
then use

hash URIs, it would be somewhat problematic.


Could you explain why???



--
Toby A Inkster

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Roberto García]

Hi Martin, all,

I would like to point to something that might be useful for RDF data
publishing. The ReDeFer RDF2HTML service
(http://rhizomik.net/redefer/) renders input RDF/XML data as HTML for
user interaction (e.g. as used in http://rhizomik.net/rhizomer/). Now,
it also embeds RDFa that facilitates retrieving the source RDF back.

I've tested it with a pair of GoodRelations examples:
http://rhizomik.net/redefer-services/rdf2html?rdf=http://www.heppnetz.de/projects/goodrelations/minimalExampleGoodRelations.owl
http://rhizomik.net/redefer-services/rdf2html?rdf=http://www.heppnetz.de/projects/goodrelations/goodrelationsExamplesPrimerFinalOWL.owl

I've been able to check that it works for these examples by comparing
the triples generated by RDFa Distiller and RDFa Bookmarklet from the
previous HTML+RDFa pages to those generated by any23 and Triplr from
the original OWL files.

The generated HTML+RDFa can be then used in order to publish RDF just
by Cut&Paste, e.g. using an online editor like FCKEditor. This has
been the procedure followed in order to publish the RDF in
http://rhizomik.net/redefer/rdf2html/minimalExampleGoodRelations/

The HTML+RDFa view might be customised using CSS and made more usable
if the source RDF contains rdfs:labels for the involved resources,
which are used instead of the last part of the URIs if available.

In any case, if it is no to be shown to the user, it is easier to just
model triples using hidden  instead of using this service...

Best regards,


Roberto García
http://rhizomik.net/~roberto

PD: Caution, this is work in progress. Feedback appreciated :-)



On Wed, Jul 8, 2009 at 12:59 PM, Martin Hepp
(UniBW) wrote:
> Google has just changed the wording of the documentation:
>
> http://knol.google.com/k/google-rich-snippets/google-rich-snippets/32la2chf8l79m/1#
>
> The mentioning of cloaking risk is removed. While this is not final
> clearance,
> it is a nice sign that our concerns are heard.
>
> Best
> Martin
>
>
> Martin Hepp (UniBW) wrote:
>>
>> Dear all:
>> Fyi - I am in contact with Google as for the clarification of what kind of
>> empty div/span elements are considered acceptable in the context of RDFa. It
>> may take a few days to get an official statement. Just so that you know it
>> is being taken care of...
>>
>> Martin
>>
>>
>>
>> Mark Birbeck wrote:
>>>
>>> Hi Martin,
>>>
>>>

 b) download RDFa snippet that just represents the RDF/XML content (i.e.
 such
 that it does not have to be consolidated with the "presentation level"
 part
 of the Web page.

>>>
>>> By coincidence, I just read this:
>>>
>>>  Hidden div's -- don't do it!
>>>  It can be tempting to add all the content relevant for a rich snippet
>>>  in one place on the page, mark it up, and then hide the entire block
>>>  of text using CSS or other techniques. Don't do this! Mark up the
>>>  content where it already exists. Google will not show content from
>>>  hidden div's in Rich Snippets, and worse, this can be considered
>>>  cloaking by Google's spam detection systems. [1]
>>>
>>> Regards,
>>>
>>> Mark
>>>
>>> [1]
>>> 
>>>
>>>
>>
>
> --
> --
> martin hepp
> e-business & web science research group
> universitaet der bundeswehr muenchen
>
> e-mail:  mh...@computer.org
> phone:   +49-(0)89-6004-4217
> fax:     +49-(0)89-6004-4620
> www:     http://www.unibw.de/ebusiness/ (group)
>        http://www.heppnetz.de/ (personal)
> skype:   mfhepp twitter: mfhepp
>
> Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!
> 
>
> Webcast:
> http://www.heppnetz.de/projects/goodrelations/webcast/
>
> Talk at the Semantic Technology Conference 2009: "Semantic Web-based
> E-Commerce: The GoodRelations Ontology"
> http://tinyurl.com/semtech-hepp
>
> Tool for registering your business:
> http://www.ebusiness-unibw.org/tools/goodrelations-annotator/
>
> Overview article on Semantic Universe:
> http://tinyurl.com/goodrelations-universe
>
> Project page and resources for developers:
> http://purl.org/goodrelations/
>
> Tutorial materials:
> Tutorial at ESWC 2009: The Web of Data for E-Commerce in One Day: A Hands-on
> Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey
>
> http://www.ebusiness-unibw.org/wiki/GoodRelations_Tutorial_ESWC2009
>
>
>
>
>

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Hugh Glaser]

On 09/07/2009 00:38, "Toby A Inkster"  wrote:

> On 8 Jul 2009, at 19:58, Seth Russell wrote:
> 
>> Is it not true that everything past the hash (#alice) is not
>> transmitted back to the server when a browser clicks on a
>> hyperlink ?   If that is true, then the server would not be able to
>> serve anything different if a browser clicked upon http://
>> example.com/foaf.rdf or if they clicked upon http://example.com/
>> foaf.rdf#alice .
> 
> Indeed - the server doesn't see the fragment.
> 
>> If that is true, and it probably isn't, then is not the Semantic
>> Web crippled from using that techniqe to distinguish between
>> resources and at the same time hyper linking between those
>> different resources?
> 
> 
> Not at all.
> 
> Is the web of documents crippled because the server can't distinguish
> between requests for http://example.com/document.html and http://
> example.com/document.html#part2 ? Of course it isn't - the server
> doesn't need to distinguish between them - it serves up the same web
> page either way and lets the user agent distinguish.
> 
> Hash URIs are very valuable in linked data, precisely *because* they
> can't be directly requested from a server - they allow us to bypass
> the whole HTTP 303 issue.
Mind you, it does mean that you should make sure that you don't put too many
LD URIs in one document.
If dbpedia decided to represent all the RDF in one document, and then use
hash URIs, it would be somewhat problematic.
> 
> --
> Toby A Inkster
> 
> 
> 
> 
> 

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Toby A Inkster]

On 8 Jul 2009, at 19:58, Seth Russell wrote:

Is it not true that everything past the hash (#alice) is not  
transmitted back to the server when a browser clicks on a  
hyperlink ?   If that is true, then the server would not be able to  
serve anything different if a browser clicked upon http:// 
example.com/foaf.rdf or if they clicked upon http://example.com/ 
foaf.rdf#alice .


Indeed - the server doesn't see the fragment.

If that is true, and it probably isn't, then is not the Semantic  
Web crippled from using that techniqe to distinguish between  
resources and at the same time hyper linking between those  
different resources?



Not at all.

Is the web of documents crippled because the server can't distinguish  
between requests for http://example.com/document.html and http:// 
example.com/document.html#part2 ? Of course it isn't - the server  
doesn't need to distinguish between them - it serves up the same web  
page either way and lets the user agent distinguish.


Hash URIs are very valuable in linked data, precisely *because* they  
can't be directly requested from a server - they allow us to bypass  
the whole HTTP 303 issue.


--
Toby A Inkster

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

Martin Hepp (UniBW) wrote:

Google has just changed the wording of the documentation:

http://knol.google.com/k/google-rich-snippets/google-rich-snippets/32la2chf8l79m/1# 



The mentioning of cloaking risk is removed. While this is not final 
clearance,

it is a nice sign that our concerns are heard.


Great work!

Doing the right thing is what matters, and I do believe that Google (as 
they've just demonstrated), Yahoo! etc. all want to make the Web a 
better and smarter place etc. :-)


Kingsley


Best
Martin


Martin Hepp (UniBW) wrote:

Dear all:
Fyi - I am in contact with Google as for the clarification of what 
kind of empty div/span elements are considered acceptable in the 
context of RDFa. It may take a few days to get an official statement. 
Just so that you know it is being taken care of...


Martin



Mark Birbeck wrote:

Hi Martin,

 
b) download RDFa snippet that just represents the RDF/XML content 
(i.e. such
that it does not have to be consolidated with the "presentation 
level" part

of the Web page.



By coincidence, I just read this:

  Hidden div's -- don't do it!
  It can be tempting to add all the content relevant for a rich snippet
  in one place on the page, mark it up, and then hide the entire block
  of text using CSS or other techniques. Don't do this! Mark up the
  content where it already exists. Google will not show content from
  hidden div's in Rich Snippets, and worse, this can be considered
  cloaking by Google's spam detection systems. [1]

Regards,

Mark

[1] 
 



  







--


Regards,

Kingsley Idehen   Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software Web: http://www.openlinksw.com

Re: Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[David Booth]

 On Wed 08/07/09  5:08 PM , Olivier Rossel olivier.ros...@gmail.com sent:
> Do you mean that all deferencable URIs of a RDF document should have
> their domain name to end with t-d-b.org, so their resolution leads to
> the TDB server which redirects to the final location?

No, I'm not suggesting that *all* deferenceable RDF URIs should use t-d-b.org.  
I'm just pointing out that it is an alternative if you cannot configure your 
own server to do 303 redirects.  Using it does require putting 
"http://t-d-b.org?"; at the beginning of your URI, so if you do not want to do 
that then you should use a different approach.  To be clear, if you use this 
approach, then instead of writing a URI such as

  http://example/mydata.rdf

you would write it as

 http://t-d-b.org?http://example/mydata.rdf

and if that URI is dereferenced, the 303-redirect service will automatically 
return a 303 redirect to

http://example/mydata.rdf

David Booth

> 
> On Wednesday, July 8, 2009, David Booth  .org> wrote:> On Wed, 2009-07-08 at 15:50 +0100,
> Pierre-Antoine Champin wrote:> [ . . . ]
> >> ok, the solutions proposed here (by myself
> and others) still involve>> editing the .htaccess.
> >
> > Once again, use of a 303-redirect service such
> as> http://thing-described-by.org/ or
> http://t-d-b.org/> does not require *any* configuration or
> .htaccess editing.  It does not> address the problem of setting the content 
> type
> correctly, but it *does*> provide an easy way to generate 303 redirects,
> in conformance with "Cool> URIs for the Semantic Web":
> > http://www.w3.org/TR/cooluris/#r303gendocument>
> > Hmm, I thought the use of a 303-redirect service
> was mentioned in "Cool> URIs for the Semantic Web", but in looking
> back, I see it was in "Best> Practice Recipes for Publishing RDF
> Vocabularies":> http://www.w3.org/TR/swbp-vocab-pub/#redirect
> > Maybe it should be mentioned in a future version
> of the Cool URIs> document as well.
> >
> >
> > --
> > David Booth, Ph.D.
> > Cleveland Clinic (contractor)
> >
> > Opinions expressed herein are those of the
> author and do not necessarily> reflect those of Cleveland Clinic.
> >
> >
> >
> 
> 
> 
> 
> 
> 

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Hugh Glaser]

Sorry to hear that, Pat.

On 08/07/2009 14:51, "Pat Hayes"  wrote:

> 
> 
> On Jul 5, 2009, at 10:16 AM, Hugh Glaser wrote:
> 
>> OK, I'll have a go :-)
>> Why did I think this would be fun to do on a sunny Sunday morning
>> that has turned into afternoon?
>> Here are the instructions:
>> 
> 
> And here is why I cannot follow them.
> 
>> 
>> 1.  Create a web-accessible directory, let's say foobar, with all
>> your .rdf, .ttl, .ntriples and .html files in it.
>> 2.  Copy lodpub.php and path.php into it.
> 
> OK so far...
> 
>> 3.  Access path.php from your web server.
> 
> I can see this file, but I cannot access it. Attempting to do so gives
> me the message
> 
> Can not open file .htaccess
> Reason: Could not download file (403:HTTP/1.1
> 403 forbidden)
Just a clarification, which probably doesn't help you, but just might.
When you try to access path.php, you should either get some text in which
the string htaccess appears (success), or some indication that you cannot
access path.php or run php.
I see no reason why you would get the message above trying to access
path.php.
(Unless somehow the attempt to run php has resulted in an attempt to access
.htaccess because of a local issue, in which case the system is badly
configured in its error reporting.)
I guess that what you have seen is the result of creating a file called
.htaccess on your local machine, and then trying to upload it to the server,
using some sort of web-based upload facility?
Best
Hugh
> 
> I have checked with my system admin, and they tell me, Yes that is
> correct. You cannot access your .htaccess file. You cannot modify it
> or paste anything into it. Only we have access to it. No, we will not
> change this policy for you, no matter how important you think you are.
> Although they do not say it openly, the implicit message is, we don't
> give a damn what the W3C thinks you ought to be able to do on our
> website.
> 
> Now, has anyone got any OTHER ideas?  An idea that does not involve
> changing any actual code, and so can be done using a text editor on an
> HTML text file, would be a very good option.
> 
> Pat Hayes
> 
> 

>> 4.  Follow the instruction to paste that text into .htaccess
>> 5.  You can remove path.php if you like, it was only there to help
>> you get the .htaccess right.
>> 
>> That should be it.
>> The above text and files are at
>> http://www.rkbexplorer.com/blog/?p=11
>> 
>> Of course, I expect that you can tell me all sorts of problems/
>> better ways, but I am hoping it works for many.
>> 
>> Some explanation:
>> We use a different method, and I have tried to extract the essence,
>> and keep the code very simple.
>> We trap all 404 (File not Found) in the directory, and then any
>> requests coming in for non-existent files will generate a 303 with
>> an extension added, depending on the Accept header.
>> Note that you probably need the leading "/" followed by the full
>> path from the domain root, otherwise it will just print out the text
>> "lodpub.php";
>> (That is not what the apache specs seem to say, but it is what seems
>> to happen).
>> If you get "Additionally, a 404 Not Found error was encountered
>> while trying to use an ErrorDocument to handle the request.", then
>> it means that web server is not finding your ErrorDocument .
>> Put the file path.php in the same directory and point your browser
>> at it - this will tell you what the path should be.
>> 
>> Note that the httpd.conf (in /etc/httpd/conf) may not let your
>> override, if your admins have tied things down really tight.
>> Mine says:
>>AllowOverride All
>> 
>> Finally, at the moment, note that I think that apache default does
>> not put the correct MIME type on rdf files, but that is a separate
>> issue, and it makes no difference that the 303 happened.
>> 
>> Best
>> Hugh
>> 
>> On 05/07/2009 01:52, "Pierre-Antoine Champin" >> wrote:
>> 
>>> Le 03/07/2009 15:14, Danny Ayers a écrit :
 2009/7/2 Bill Roberts:
> I thought I'd give the .htaccess approach a try, to see what's
> involved in
> actually setting it up.  I'm no expert on Apache, but I know the
> basics of
> how it works, I've got full access to a web server and I can read
> the online
> Apache documentation as well as the next person.
 
 I've tried similar, even stuff using PURLs - incredibly difficult to
 get right. (My downtime overrides all, so I'm not even sure if I got
 it right in the end)
 
 I really think we need a (copy&  paste) cheat sheet.
 
 Volunteers?
>>> 
>>> (raising my hand) :)*
>>> 
>>> Here is a quick python script that makes it easier (if not completely
>>> immediate). It may still requires a one-liner .htaccess, but one
>>> that (I
>>> think) is authorized by most webmasters.
>>> 
>>> I guess a PHP version would not even require that .htaccess, but
>>> sorry,
>>> I'm not fluent in PHP ;)
>>> 
>>> So, assuming you want to publish a vocabulary with an RDF and an HTML
>>> description at http://example

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[David Booth]

On Wed, 2009-07-08 at 15:50 +0100, Pierre-Antoine Champin wrote:
[ . . . ]
> ok, the solutions proposed here (by myself and others) still involve 
> editing the .htaccess. 

Once again, use of a 303-redirect service such as
http://thing-described-by.org/ or http://t-d-b.org/ 
does not require *any* configuration or .htaccess editing.  It does not
address the problem of setting the content type correctly, but it *does*
provide an easy way to generate 303 redirects, in conformance with "Cool
URIs for the Semantic Web":
http://www.w3.org/TR/cooluris/#r303gendocument 

Hmm, I thought the use of a 303-redirect service was mentioned in "Cool
URIs for the Semantic Web", but in looking back, I see it was in "Best
Practice Recipes for Publishing RDF Vocabularies":
http://www.w3.org/TR/swbp-vocab-pub/#redirect
Maybe it should be mentioned in a future version of the Cool URIs
document as well.


-- 
David Booth, Ph.D.
Cleveland Clinic (contractor)

Opinions expressed herein are those of the author and do not necessarily
reflect those of Cleveland Clinic.

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Ian Davis]

On Wednesday, July 8, 2009, Toby Inkster  wrote:
> On Wed, 2009-07-08 at 15:13 +0100, Mark Birbeck wrote:
>> The original point of this thread seemed to me to be saying that if
>> .htaccess is the key to the semantic web, then it's never going to
>> happen.
>
> It simply isn't the key to the semantic web though.
>
> .htaccess is a simple way to configure Apache to do interesting things.
> It happens to give you a lot of power in deciding how requests for URLs
> should be translated into responses of data. If you have hosting which
> allows you such advanced control over your settings, and you can create
> nicer URLs, then by all means do so - and not just for RDF, but for all
> your URLs. It's a Good Thing to do, and in my opinion, worth switching
> hosts to achieve.
>
> But all that isn't necessary to publish linked data. If you own
> example.com, you can upload foaf.rdf and give yourself a URI like:
>
>         
>
> (Or foaf.ttl, foaf.xhtml, whatever.)

This just works and is how the html web grew. Write a document and
save it into a publuc spaxe. Fancy stuff like pretty URIs need more
work but are not at all necessary for linked data or the semantic web.


>
> Let's not blow this all out of proportion.

Hear hear!

> --
> Toby A Inkster
> 
> 

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Seth Russell]

>
>
> But all that isn't necessary to publish linked data. If you own
> example.com, you can upload foaf.rdf and give yourself a URI like:
>
>
>
>
I'm going to ask a stupid question ... don't everybody laugh at once.

Is it not true that everything past the hash (#alice) is not transmitted
back to the server when a browser clicks on a hyperlink ?   If that is true,
then the server would not be able to serve anything different if a browser
clicked upon http://example.com/foaf.rd
or if they clicked upon
http://example.com/foaf.rd #alice .   If
that is true, and it probably isn't, then is not the Semantic Web crippled
from using that techniqe to distinguish between resources and at the same
time hyper linking between those different resources?

Ok, you can stop laughfing now.

-- 
Seth Russell
Thoughts about The New Semantic Web http://fastblogit.com/seth/
www.speaktomecatalog.com

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Toby Inkster]

On Wed, 2009-07-08 at 15:13 +0100, Mark Birbeck wrote:
> The original point of this thread seemed to me to be saying that if
> .htaccess is the key to the semantic web, then it's never going to
> happen.

It simply isn't the key to the semantic web though.

.htaccess is a simple way to configure Apache to do interesting things.
It happens to give you a lot of power in deciding how requests for URLs
should be translated into responses of data. If you have hosting which
allows you such advanced control over your settings, and you can create
nicer URLs, then by all means do so - and not just for RDF, but for all
your URLs. It's a Good Thing to do, and in my opinion, worth switching
hosts to achieve.

But all that isn't necessary to publish linked data. If you own
example.com, you can upload foaf.rdf and give yourself a URI like:



(Or foaf.ttl, foaf.xhtml, whatever.)

No, that's not as elegant as <http://example.com/alice> with a
connection negotiated 303 redirect to representations in various
formats, but it does work, and it won't break anything. 

Let's not blow this all out of proportion.

-- 
Toby A Inkster

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Pierre-Antoine Champin]

Mark,

disclaimer: I have nothing against the RDFa solution; I just don't think 
that one size fits all :)


ok, the solutions proposed here (by myself and others) still involve 
editing the .htaccess. However, compared to configuring HTTP 
redirections using mod_rewrite, they have two advantages:


- they are shorter and hopefully easier to adapt
- they are more likely to be allowed for end users

So I think it is a progress.

Furthermore, some of the recipes may work without even touching the 
.htaccess file, providing that


- executable files are automatically considered as CGI scripts
- index.php is automatically considered as a directory index

One size does not fit all, that is why we should provide several simple 
recipes in which people may find the one that works for them.


This is why I'm asking (again) to IIS-users and (other httpd)-users to 
provide non apache recipes as well.


Of course, the "publish it in RDFa" recipe is a perfectly legal one !

  pa

Le 08/07/2009 15:13, Mark Birbeck a écrit :

Hi Pat,


I have checked with my system admin, and they tell me, Yes that is correct.
You cannot access your .htaccess file. You cannot modify it or paste
anything into it. Only we have access to it. No, we will not change this
policy for you, no matter how important you think you are. Although they do
not say it openly, the implicit message is, we don't give a damn what the
W3C thinks you ought to be able to do on our website.


I agree that this seems to be getting like Groundhog Day. :)

The original point of this thread seemed to me to be saying that if
.htaccess is the key to the semantic web, then it's never going to
happen.

I.e., ".htaccess is a major bottleneck".

The initial discussion around that theme was then followed by all
sorts of discussions about how people could create scripts that would
choose between different files, and deliver the correct one to the
user. But the fact remained -- as you rightly point out here -- that
you still need to modify .htaccess.



Now, has anyone got any OTHER ideas?  An idea that does not involve changing
any actual code, and so can be done using a text editor on an HTML text
file, would be a very good option.


:)

Did I mention RDFa?

Regards,

Mark

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Mark Birbeck]

Hi Pat,

> I have checked with my system admin, and they tell me, Yes that is correct.
> You cannot access your .htaccess file. You cannot modify it or paste
> anything into it. Only we have access to it. No, we will not change this
> policy for you, no matter how important you think you are. Although they do
> not say it openly, the implicit message is, we don't give a damn what the
> W3C thinks you ought to be able to do on our website.

I agree that this seems to be getting like Groundhog Day. :)

The original point of this thread seemed to me to be saying that if
.htaccess is the key to the semantic web, then it's never going to
happen.

I.e., ".htaccess is a major bottleneck".

The initial discussion around that theme was then followed by all
sorts of discussions about how people could create scripts that would
choose between different files, and deliver the correct one to the
user. But the fact remained -- as you rightly point out here -- that
you still need to modify .htaccess.


> Now, has anyone got any OTHER ideas?  An idea that does not involve changing
> any actual code, and so can be done using a text editor on an HTML text
> file, would be a very good option.

:)

Did I mention RDFa?

Regards,

Mark

-- 
Mark Birbeck, webBackplane

mark.birb...@webbackplane.com

http://webBackplane.com/mark-birbeck

webBackplane is a trading name of Backplane Ltd. (company number
05972288, registered office: 2nd Floor, 69/85 Tabernacle Street,
London, EC2A 4RR)

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Pat Hayes]

On Jul 5, 2009, at 10:16 AM, Hugh Glaser wrote:


OK, I'll have a go :-)
Why did I think this would be fun to do on a sunny Sunday morning  
that has turned into afternoon?

Here are the instructions:



And here is why I cannot follow them.



1.  Create a web-accessible directory, let's say foobar, with all  
your .rdf, .ttl, .ntriples and .html files in it.

2.  Copy lodpub.php and path.php into it.


OK so far...


3.  Access path.php from your web server.


I can see this file, but I cannot access it. Attempting to do so gives  
me the message


Can not open file .htaccess
Reason: Could not download file (403:HTTP/1.1
403 forbidden)

I have checked with my system admin, and they tell me, Yes that is  
correct. You cannot access your .htaccess file. You cannot modify it  
or paste anything into it. Only we have access to it. No, we will not  
change this policy for you, no matter how important you think you are.  
Although they do not say it openly, the implicit message is, we don't  
give a damn what the W3C thinks you ought to be able to do on our  
website.


Now, has anyone got any OTHER ideas?  An idea that does not involve  
changing any actual code, and so can be done using a text editor on an  
HTML text file, would be a very good option.


Pat Hayes



4.  Follow the instruction to paste that text into .htaccess
5.  You can remove path.php if you like, it was only there to help  
you get the .htaccess right.


That should be it.
The above text and files are at
http://www.rkbexplorer.com/blog/?p=11

Of course, I expect that you can tell me all sorts of problems/ 
better ways, but I am hoping it works for many.


Some explanation:
We use a different method, and I have tried to extract the essence,  
and keep the code very simple.
We trap all 404 (File not Found) in the directory, and then any  
requests coming in for non-existent files will generate a 303 with  
an extension added, depending on the Accept header.
Note that you probably need the leading "/" followed by the full  
path from the domain root, otherwise it will just print out the text  
"lodpub.php";
(That is not what the apache specs seem to say, but it is what seems  
to happen).
If you get "Additionally, a 404 Not Found error was encountered  
while trying to use an ErrorDocument to handle the request.", then  
it means that web server is not finding your ErrorDocument .
Put the file path.php in the same directory and point your browser  
at it - this will tell you what the path should be.


Note that the httpd.conf (in /etc/httpd/conf) may not let your  
override, if your admins have tied things down really tight.

Mine says:
   AllowOverride All

Finally, at the moment, note that I think that apache default does  
not put the correct MIME type on rdf files, but that is a separate  
issue, and it makes no difference that the 303 happened.


Best
Hugh

On 05/07/2009 01:52, "Pierre-Antoine Champin" > wrote:



Le 03/07/2009 15:14, Danny Ayers a écrit :

2009/7/2 Bill Roberts:
I thought I'd give the .htaccess approach a try, to see what's  
involved in
actually setting it up.  I'm no expert on Apache, but I know the  
basics of
how it works, I've got full access to a web server and I can read  
the online

Apache documentation as well as the next person.


I've tried similar, even stuff using PURLs - incredibly difficult to
get right. (My downtime overrides all, so I'm not even sure if I got
it right in the end)

I really think we need a (copy&  paste) cheat sheet.

Volunteers?


(raising my hand) :)*

Here is a quick python script that makes it easier (if not completely
immediate). It may still requires a one-liner .htaccess, but one  
that (I

think) is authorized by most webmasters.

I guess a PHP version would not even require that .htaccess, but  
sorry,

I'm not fluent in PHP ;)

So, assuming you want to publish a vocabulary with an RDF and an HTML
description at http://example.com/mydir/myvoc, you need to:

1. Make `myvoc` a directory at the place where your HTTP server will
   serve it at the desired URI.
2. Copy the script in this directory as 'index.cgi' (or  
'index.wsgi' if

   your server as WSGI support).
3. In the same directory, put two files named 'index.html' and
   'index.rdf'

If it does not work now (it didn't for me),you have to tell your HTTP
server that the directory index is index.wsgi. In apache, this is  
done

by creating (if not present) a `.htaccess` file in the `myvoc`
diractory, and adding the following line::

DirectoryIndex index.cgi

(or `index.wsgi`, accordingly)

There is more docs in the script itself. I think the more recipes
(including for other httpds) we can provide with the script, the more
useful it will be. So feel free to propose other ones.

 enjoy

  pa






IHMC (850)434 8903 or (650)494 3973
40 South Alcaniz St.   (850)202 4416   office
Pensacola(

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Martin Hepp (UniBW)]

Google has just changed the wording of the documentation:

http://knol.google.com/k/google-rich-snippets/google-rich-snippets/32la2chf8l79m/1#

The mentioning of cloaking risk is removed. While this is not final 
clearance,

it is a nice sign that our concerns are heard.

Best
Martin


Martin Hepp (UniBW) wrote:

Dear all:
Fyi - I am in contact with Google as for the clarification of what 
kind of empty div/span elements are considered acceptable in the 
context of RDFa. It may take a few days to get an official statement. 
Just so that you know it is being taken care of...


Martin



Mark Birbeck wrote:

Hi Martin,

 
b) download RDFa snippet that just represents the RDF/XML content 
(i.e. such
that it does not have to be consolidated with the "presentation 
level" part

of the Web page.



By coincidence, I just read this:

  Hidden div's -- don't do it!
  It can be tempting to add all the content relevant for a rich snippet
  in one place on the page, mark it up, and then hide the entire block
  of text using CSS or other techniques. Don't do this! Mark up the
  content where it already exists. Google will not show content from
  hidden div's in Rich Snippets, and worse, this can be considered
  cloaking by Google's spam detection systems. [1]

Regards,

Mark

[1] 
 



  




--
--
martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen

e-mail:  mh...@computer.org
phone:   +49-(0)89-6004-4217
fax: +49-(0)89-6004-4620
www: http://www.unibw.de/ebusiness/ (group)
http://www.heppnetz.de/ (personal)
skype:   mfhepp 
twitter: mfhepp


Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!


Webcast:
http://www.heppnetz.de/projects/goodrelations/webcast/

Talk at the Semantic Technology Conference 2009: 
"Semantic Web-based E-Commerce: The GoodRelations Ontology"

http://tinyurl.com/semtech-hepp

Tool for registering your business:
http://www.ebusiness-unibw.org/tools/goodrelations-annotator/

Overview article on Semantic Universe:
http://tinyurl.com/goodrelations-universe

Project page and resources for developers:
http://purl.org/goodrelations/

Tutorial materials:
Tutorial at ESWC 2009: The Web of Data for E-Commerce in One Day: A Hands-on 
Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey

http://www.ebusiness-unibw.org/wiki/GoodRelations_Tutorial_ESWC2009




begin:vcard
fn:Martin Hepp
n:Hepp;Martin
org:Bundeswehr University Munich;E-Business and Web Science Research Group
adr:;;Werner-Heisenberg-Web 39;Neubiberg;;D-85577;Germany
email;internet:mh...@computer.org
tel;work:+49 89 6004 4217
tel;pager:skype: mfhepp
url:http://www.heppnetz.de
version:2.1
end:vcard

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

Richard Light wrote:
In message <4a50ad9f.9030...@champin.net>, Pierre-Antoine Champin 
 writes


PS: any IIS user volunteering to translate those recipies to IIS 
configuration?


I have implemented the 303 redirection strategy in IIS, but using a 
custom 404 "page not found" error handler.  Is that relevant to this 
discussion?


Richard

Absolutely!

Again, Linked Data isn't about Apache or any other product, programming 
language, operating system etc., its about the Web :-)



--


Regards,

Kingsley Idehen   Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software Web: http://www.openlinksw.com

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Richard Light]

In message <4a50ad9f.9030...@champin.net>, Pierre-Antoine Champin 
 writes


PS: any IIS user volunteering to translate those recipies to IIS 
configuration?


I have implemented the 303 redirection strategy in IIS, but using a 
custom 404 "page not found" error handler.  Is that relevant to this 
discussion?


Richard
--
Richard Light

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

Toby A Inkster wrote:

On 5 Jul 2009, at 01:52, Pierre-Antoine Champin wrote:

I guess a PHP version would not even require that .htaccess, but 
sorry, I'm not fluent in PHP ;)



The situation with PHP should be much the same, though I suppose web 
hosts might be more likely to set index.php in the DirectoryIndex as a 
default.


Anyway, I've done a quick port of your code to PHP. (I stripped out 
your connection negotiation code and replaced it with my own, as I 
figured out it would be faster to paste in the ConNeg class I'm 
familiar with rather than do line-by-line porting of the Python to 
PHP.) Here it is, same license - LGPL 3.


We should start a repository somewhere of useful code for serving 
linked data.

Toby,

Sure!

First step should be to use "del.icio.us" (or similar services) to 
bookmark you page using tag: linked_data_deployment or lod_deployment or 
something along those lines. Once in place there is  beached for 
RDFization into other Linked Data Spaces that ultimately will be 
discoverable via the burgeoning "Web of Linked Data".


Basically, just as Kurt's done with his music data space related effort, 
we do the same re. Linked Data deployment.


Also, we can then have Tom link to the del.ico.us bookmark from 
 .


Kingsley












  



--


Regards,

Kingsley Idehen   Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software Web: http://www.openlinksw.com

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Juan Sequeda]

yay!! more "easy-lod" goodness! more incentive to get this up on
linkeddata.org this week!

do we have any volunteers for ruby?

Juan Sequeda, Ph.D Student
Dept. of Computer Sciences
The University of Texas at Austin
www.juansequeda.com
www.semanticwebaustin.org


On Sun, Jul 5, 2009 at 5:16 PM, Hugh Glaser  wrote:

> OK, I'll have a go :-)
> Why did I think this would be fun to do on a sunny Sunday morning that has
> turned into afternoon?
> Here are the instructions:
>
>
>  1.  Create a web-accessible directory, let's say foobar, with all your
> .rdf, .ttl, .ntriples and .html files in it.
>  2.  Copy lodpub.php and path.php into it.
>  3.  Access path.php from your web server.
>  4.  Follow the instruction to paste that text into .htaccess
>  5.  You can remove path.php if you like, it was only there to help you get
> the .htaccess right.
>
> That should be it.
> The above text and files are at
> http://www.rkbexplorer.com/blog/?p=11
>
> Of course, I expect that you can tell me all sorts of problems/better ways,
> but I am hoping it works for many.
>
> Some explanation:
> We use a different method, and I have tried to extract the essence, and
> keep the code very simple.
> We trap all 404 (File not Found) in the directory, and then any requests
> coming in for non-existent files will generate a 303 with an extension
> added, depending on the Accept header.
> Note that you probably need the leading "/" followed by the full path from
> the domain root, otherwise it will just print out the text "lodpub.php";
> (That is not what the apache specs seem to say, but it is what seems to
> happen).
> If you get "Additionally, a 404 Not Found error was encountered while
> trying to use an ErrorDocument to handle the request.", then it means that
> web server is not finding your ErrorDocument .
> Put the file path.php in the same directory and point your browser at it -
> this will tell you what the path should be.
>
> Note that the httpd.conf (in /etc/httpd/conf) may not let your override, if
> your admins have tied things down really tight.
> Mine says:
>AllowOverride All
>
> Finally, at the moment, note that I think that apache default does not put
> the correct MIME type on rdf files, but that is a separate issue, and it
> makes no difference that the 303 happened.
>
> Best
> Hugh
>
> On 05/07/2009 01:52, "Pierre-Antoine Champin" 
> wrote:
>
> > Le 03/07/2009 15:14, Danny Ayers a écrit :
> >> 2009/7/2 Bill Roberts:
> >>> I thought I'd give the .htaccess approach a try, to see what's involved
> in
> >>> actually setting it up.  I'm no expert on Apache, but I know the basics
> of
> >>> how it works, I've got full access to a web server and I can read the
> online
> >>> Apache documentation as well as the next person.
> >>
> >> I've tried similar, even stuff using PURLs - incredibly difficult to
> >> get right. (My downtime overrides all, so I'm not even sure if I got
> >> it right in the end)
> >>
> >> I really think we need a (copy&  paste) cheat sheet.
> >>
> >> Volunteers?
> >
> > (raising my hand) :)*
> >
> > Here is a quick python script that makes it easier (if not completely
> > immediate). It may still requires a one-liner .htaccess, but one that (I
> > think) is authorized by most webmasters.
> >
> > I guess a PHP version would not even require that .htaccess, but sorry,
> > I'm not fluent in PHP ;)
> >
> > So, assuming you want to publish a vocabulary with an RDF and an HTML
> > description at http://example.com/mydir/myvoc, you need to:
> >
> > 1. Make `myvoc` a directory at the place where your HTTP server will
> > serve it at the desired URI.
> > 2. Copy the script in this directory as 'index.cgi' (or 'index.wsgi' if
> > your server as WSGI support).
> > 3. In the same directory, put two files named 'index.html' and
> > 'index.rdf'
> >
> > If it does not work now (it didn't for me),you have to tell your HTTP
> > server that the directory index is index.wsgi. In apache, this is done
> > by creating (if not present) a `.htaccess` file in the `myvoc`
> > diractory, and adding the following line::
> >
> >  DirectoryIndex index.cgi
> >
> > (or `index.wsgi`, accordingly)
> >
> > There is more docs in the script itself. I think the more recipes
> > (including for other httpds) we can provide with the script, the more
> > useful it will be. So feel free to propose other ones.
> >
> >   enjoy
> >
> >pa
> >
>

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Hugh Glaser]

OK, I'll have a go :-)
Why did I think this would be fun to do on a sunny Sunday morning that has 
turned into afternoon?
Here are the instructions:


 1.  Create a web-accessible directory, let's say foobar, with all your .rdf, 
.ttl, .ntriples and .html files in it.
 2.  Copy lodpub.php and path.php into it.
 3.  Access path.php from your web server.
 4.  Follow the instruction to paste that text into .htaccess
 5.  You can remove path.php if you like, it was only there to help you get the 
.htaccess right.

That should be it.
The above text and files are at
http://www.rkbexplorer.com/blog/?p=11

Of course, I expect that you can tell me all sorts of problems/better ways, but 
I am hoping it works for many.

Some explanation:
We use a different method, and I have tried to extract the essence, and keep 
the code very simple.
We trap all 404 (File not Found) in the directory, and then any requests coming 
in for non-existent files will generate a 303 with an extension added, 
depending on the Accept header.
Note that you probably need the leading "/" followed by the full path from the 
domain root, otherwise it will just print out the text "lodpub.php";
(That is not what the apache specs seem to say, but it is what seems to happen).
If you get "Additionally, a 404 Not Found error was encountered while trying to 
use an ErrorDocument to handle the request.", then it means that web server is 
not finding your ErrorDocument .
Put the file path.php in the same directory and point your browser at it - this 
will tell you what the path should be.

Note that the httpd.conf (in /etc/httpd/conf) may not let your override, if 
your admins have tied things down really tight.
Mine says:
AllowOverride All

Finally, at the moment, note that I think that apache default does not put the 
correct MIME type on rdf files, but that is a separate issue, and it makes no 
difference that the 303 happened.

Best
Hugh

On 05/07/2009 01:52, "Pierre-Antoine Champin"  
wrote:

> Le 03/07/2009 15:14, Danny Ayers a écrit :
>> 2009/7/2 Bill Roberts:
>>> I thought I'd give the .htaccess approach a try, to see what's involved in
>>> actually setting it up.  I'm no expert on Apache, but I know the basics of
>>> how it works, I've got full access to a web server and I can read the online
>>> Apache documentation as well as the next person.
>>
>> I've tried similar, even stuff using PURLs - incredibly difficult to
>> get right. (My downtime overrides all, so I'm not even sure if I got
>> it right in the end)
>>
>> I really think we need a (copy&  paste) cheat sheet.
>>
>> Volunteers?
>
> (raising my hand) :)*
>
> Here is a quick python script that makes it easier (if not completely
> immediate). It may still requires a one-liner .htaccess, but one that (I
> think) is authorized by most webmasters.
>
> I guess a PHP version would not even require that .htaccess, but sorry,
> I'm not fluent in PHP ;)
>
> So, assuming you want to publish a vocabulary with an RDF and an HTML
> description at http://example.com/mydir/myvoc, you need to:
>
> 1. Make `myvoc` a directory at the place where your HTTP server will
> serve it at the desired URI.
> 2. Copy the script in this directory as 'index.cgi' (or 'index.wsgi' if
> your server as WSGI support).
> 3. In the same directory, put two files named 'index.html' and
> 'index.rdf'
>
> If it does not work now (it didn't for me),you have to tell your HTTP
> server that the directory index is index.wsgi. In apache, this is done
> by creating (if not present) a `.htaccess` file in the `myvoc`
> diractory, and adding the following line::
>
>  DirectoryIndex index.cgi
>
> (or `index.wsgi`, accordingly)
>
> There is more docs in the script itself. I think the more recipes
> (including for other httpds) we can provide with the script, the more
> useful it will be. So feel free to propose other ones.
>
>   enjoy
>
>pa
>
<>
<>

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Pierre-Antoine Champin]

Note that I managed to have extension-less script run.

Recipe 2


(advantage over the 'index.php' recipe: works with slash based 
namespaces; disadvantage: 2 more lines in the .htaccess ;)


what you need is the following directive in .htaccess
(which is allowed by my webmaster)

  
SetHandler application/x-httpd-php
  

(where myvoc is the name of your PHP file)

For CGI (resp. WSGI) scripts, replace "application/x-httpd-php" by 
"cgi-script" (resp. "wsgi-script").


so with the following layout

  .../mydir/.htaccess
  .../mydir/myvoc (Toby's php script)
  .../mydir/myvoc.html
  .../mydir/myvoc.rdf

you would have the URI http://example.com/mydir/myvoc correctly 
redirecting to the appropriate representation.


Of course, you can have several vocabularies living in the same 
directory, all you need to do is add several  directives to the 
.htaccess.


  pa

PS: any IIS user volunteering to translate those recipies to IIS 
configuration?


Le 05/07/2009 13:54, Toby A Inkster a écrit :

On 5 Jul 2009, at 01:52, Pierre-Antoine Champin wrote:


I guess a PHP version would not even require that .htaccess, but
sorry, I'm not fluent in PHP ;)



The situation with PHP should be much the same, though I suppose web
hosts might be more likely to set index.php in the DirectoryIndex as a
default.

Anyway, I've done a quick port of your code to PHP. (I stripped out your
connection negotiation code and replaced it with my own, as I figured
out it would be faster to paste in the ConNeg class I'm familiar with
rather than do line-by-line porting of the Python to PHP.) Here it is,
same license - LGPL 3.

We should start a repository somewhere of useful code for serving linked
data.

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Juan Sequeda]

> We should start a repository somewhere of useful code for serving linked
>> data.
>>
>
> I agree.


(I raise my hand)

If I am not wrong, this thread has given out 4 different implementations for
serving linked data. I mentioned before that I wanted to post this on
linkeddata.org

I will work out the logistics with Tom Heath, so we can put upload the code
examples hopefully this week!


>
Juan Sequeda

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Pierre-Antoine Champin]

Le 05/07/2009 13:54, Toby A Inkster a écrit :

On 5 Jul 2009, at 01:52, Pierre-Antoine Champin wrote:


I guess a PHP version would not even require that .htaccess, but
sorry, I'm not fluent in PHP ;)



The situation with PHP should be much the same, though I suppose web
hosts might be more likely to set index.php in the DirectoryIndex as a
default.


this was my intuition as well.
However, I actually have to add the DirectoryIndex directive to have 
index.php taken into account on my server.


PHP has another advantage over CGI (and WSGI): you can usually run a PHP 
script from any directory of your hosted space, while CGI are usually 
confined in a special directory.



Anyway, I've done a quick port of your code to PHP. (I stripped out your
connection negotiation code and replaced it with my own, as I figured
out it would be faster to paste in the ConNeg class I'm familiar with
rather than do line-by-line porting of the Python to PHP.) Here it is,
same license - LGPL 3.


great :)


We should start a repository somewhere of useful code for serving linked
data.


I agree.

I note that your implementation uses absolute URIs for redirection. This 
has two main advantages over mine:

- this complies with the RFC (I had missed that part ;)
- this still works when you append path elements after the script name
  (which messes the relative URI in my script)

  pa

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Toby A Inkster]

On 5 Jul 2009, at 01:52, Pierre-Antoine Champin wrote:

I guess a PHP version would not even require that .htaccess, but  
sorry, I'm not fluent in PHP ;)



The situation with PHP should be much the same, though I suppose web  
hosts might be more likely to set index.php in the DirectoryIndex as  
a default.


Anyway, I've done a quick port of your code to PHP. (I stripped out  
your connection negotiation code and replaced it with my own, as I  
figured out it would be faster to paste in the ConNeg class I'm  
familiar with rather than do line-by-line porting of the Python to  
PHP.) Here it is, same license - LGPL 3.


We should start a repository somewhere of useful code for serving  
linked data.


--
Toby A Inkster




#Authors: Pierre-Antoine Champin 
# Toby Inkster 
#
#EasyPub is free software: you can redistribute it and/or modify
#it under the terms of the GNU Lesser General Public License as published
#by the Free Software Foundation, either version 3 of the License, or
#(at your option) any later version.
#
#EasyPub is distributed in the hope that it will be useful,
#but WITHOUT ANY WARRANTY; without even the implied warranty of
#MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#GNU Lesser General Public License for more details.
#
#You should have received a copy of the GNU Lesser General Public License
#along with EasyPub.  If not, see .

/*
This is a drop-in PHP script for publishing RDF vocabulary.

Quick start
===

Assuming you want to publish the vocabulary http://example.com/mydir/myvoc, the
reciepe with the most chances to work is the following:

1. Make `myvoc` a directory at a place where your HTTP server will serve it at
   the desired URI.
2. Copy the script in this directory as 'index.php'.
3. In the same directory, put two files named 'index.html' and 'index.rdf'

At this point, it may work (if you are lucky), or may have to tell your HTTP
server that the directory index (i.e. the file to serve for the bare directory)
is index.php.

In apache, this is done by creating (if not present) a `.htaccess` file in the
`myvoc` diractory, and adding the following line::
DirectoryIndex index.php

Fortunately, this option is allowed to end-users by most webmasters.

More generaly
=

The script will redirect, according to the Accept HTTP header, to a file with
the same name but a different extension. The file may have no extension at all,
so the following layout would work as well::

  mydir/myvoc (the script)
  mydir/myvoc.html
  mydir/myvoc.rdf

However, the tricky part is to convince the HTTP server to consider `myvoc` (an
extension-less file) as a PHP script (a thing in which I didn't succeed for the
moment...). The interesting feature of such a config is that it would support
"slash-based" vocabulary. For example, http://example.com/mydir/myvoc/MyTerm
would still redirect to the html or rdf file. This would not work with the reciep.
This would not work with the `index.php` recipe.

The script is can be configured to serve different files or support other mime
types by altering the `MAPPING` constant below.
*/

# the list below maps mime-types to redirection URL; %s is to be replaced by
# the script name (without its extension); note that the order may be
# significant (when matching */*)
$MAPPING = array(
	"text/html" => "%s.html",
	"application/rdf+xml" => "%s.rdf",
	## uncomment the following if applicable
	# "application/xhtml+xml" => "%s.html",
	# "application/turtle" => "%s.ttl",
	# "text/n3" => "%s.n3",
);

$HTML_REDIRECT = <<
Non-Information Resource

Non-Information Resource
You should be redirected to %1\$s.


CHUNK
;

$HTML_NOT_ACCEPTABLE = <<
No acceptable representation

No acceptable representation
This server has no representation of the required resource that is acceptable
by your web agent. Available representations are:
%s



CHUNK
;

$HTML_REPRESENTATION = '%1$s (%2$s)'."\n";

main($MAPPING, $HTML_REDIRECT, $HTML_NOT_ACCEPTABLE, $HTML_REPRESENTATION);

function main ($map, $h_redir, $h_unaccept, $h_rep)
{
	# Convert list of available MIME types into a string suitable for ConNeg class.
	$offers = array();
	foreach ($map as $mime => $file)
		$offers[] = $mime;
	$offers = implode(',' , $offers);
	
	$chosen = ConNeg::negotiate($offers);
	
	if (empty($chosen) || empty($map[$chosen]))
	{
		$representations = '';
		foreach ($map as $mime => $file)
			$representations .= sprintf($h_rep, $file, $mime);
		$msg = sprintf($h_unaccept, $representations);
		header("HTTP/1.1 406 Not Acceptable");
		header("Content-Type: text/html; charset=us-ascii");
		header("Content-Length: " . strlen($msg));
		print $msg;
		exit;
	}
	
	else
	{
		$filename = sprintf($map[$chosen], basename($_SERVER['SCRIPT_NAME'], '.php'));

		$goto = sprintf('%s://%s%s/%s',
			(empty($_SERVER['HTTPS']) ? 'http' : 'https'),  # prot

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Pierre-Antoine Champin]

Le 03/07/2009 15:14, Danny Ayers a écrit :

2009/7/2 Bill Roberts:

I thought I'd give the .htaccess approach a try, to see what's involved in
actually setting it up.  I'm no expert on Apache, but I know the basics of
how it works, I've got full access to a web server and I can read the online
Apache documentation as well as the next person.


I've tried similar, even stuff using PURLs - incredibly difficult to
get right. (My downtime overrides all, so I'm not even sure if I got
it right in the end)

I really think we need a (copy&  paste) cheat sheet.

Volunteers?


(raising my hand) :)*

Here is a quick python script that makes it easier (if not completely 
immediate). It may still requires a one-liner .htaccess, but one that (I 
think) is authorized by most webmasters.


I guess a PHP version would not even require that .htaccess, but sorry, 
I'm not fluent in PHP ;)


So, assuming you want to publish a vocabulary with an RDF and an HTML 
description at http://example.com/mydir/myvoc, you need to:


1. Make `myvoc` a directory at the place where your HTTP server will
   serve it at the desired URI.
2. Copy the script in this directory as 'index.cgi' (or 'index.wsgi' if
   your server as WSGI support).
3. In the same directory, put two files named 'index.html' and
   'index.rdf'

If it does not work now (it didn't for me),you have to tell your HTTP 
server that the directory index is index.wsgi. In apache, this is done 
by creating (if not present) a `.htaccess` file in the `myvoc` 
diractory, and adding the following line::


DirectoryIndex index.cgi

(or `index.wsgi`, accordingly)

There is more docs in the script itself. I think the more recipes 
(including for other httpds) we can provide with the script, the more 
useful it will be. So feel free to propose other ones.


 enjoy

  pa
#!/usr/bin/env python
#EasyPub: easy publication of RDF vocabulary
#Copyright (C) 2009 Pierre-Antoine Champin 
#
#EasyPub is free software: you can redistribute it and/or modify
#it under the terms of the GNU Lesser General Public License as published
#by the Free Software Foundation, either version 3 of the License, or
#(at your option) any later version.
#
#KTBS is distributed in the hope that it will be useful,
#but WITHOUT ANY WARRANTY; without even the implied warranty of
#MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#GNU Lesser General Public License for more details.
#
#You should have received a copy of the GNU Lesser General Public License
#along with KTBS.  If not, see .
"""
This is a drop-in CGI/WSGI script for publishing RDF vocabulary.

Quick start
===

Assuming you want to publish the vocabulary http://example.com/mydir/myvoc, the
reciepe with the most chances to work is the following:

1. Make `myvoc` a directory at a place where your HTTP server will serve it at
   the desired URI.
2. Copy the script in this directory as 'index.cgi' (or 'index.wsgi' if your
   server as WSGI support).
3. In the same directory, put two files named 'index.html' and 'index.rdf'

At this point, it may work (if you are lucky), or may have to tell your HTTP
server that the directory index (i.e. the file to serve for the bare directory)
is index.wsgi.

In apache, this is done by creating (if not present) a `.htaccess` file in the
`myvoc` diractory, and adding the following line::
DirectoryIndex index.cgi
(or `index.wsgi`, accordingly)

Fortunately, this option is allowed to end-users by most webmasters.

More generaly
=

The script will redirect, according to the Accept HTTP header, to a file with
the same name but a different extension. The file may have no extension at all, so the following layout would work as well::

  mydir/myvoc (the script)
  mydir/myvoc.html
  mydir/myvoc.rdf

However, the tricky part is to convince the HTTP server to consider `myvoc` (an
extension-less file) as a CGI script (a thing in which I didn't succeed for the
moment...). The interesting feature of such a config is that it would support
"slash-based" vocabulary. For example, http://example.com/mydir/myvoc/MyTerm
would still redirect to the html or rdf file. This would not work with the reciep. This would not work with the `index.cgi` recipe.

The script is can be configured to serve different files or support other mime
types by altering the `MAPPING` constant below.
"""

# the list below maps mime-types to redirection URL; %s is to be replaced by
# the script name (without its extension); note that the order may be
# significant (when matching */*)
MAPPING = [
("text/html", "%s.html"),
("application/rdf+xml", "%s.rdf"),
## uncomment the following if applicable
#("application/turtle", "%s.ttl"),
#("text/n3", "%s.n3"),
]

HTML_REDIRECT = """
Non-Information Resource

Non-Information Resource
You should be redirected to %s.

"""

HTML_NOT_ACCEPTABLE = """
No acceptable representation

No acceptable represent

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Danny Ayers]

2009/7/2 Bill Roberts :
> I thought I'd give the .htaccess approach a try, to see what's involved in
> actually setting it up.  I'm no expert on Apache, but I know the basics of
> how it works, I've got full access to a web server and I can read the online
> Apache documentation as well as the next person.

I've tried similar, even stuff using PURLs - incredibly difficult to
get right. (My downtime overrides all, so I'm not even sure if I got
it right in the end)

I really think we need a (copy & paste) cheat sheet.

Volunteers?

Cheers,
Danny.


-- 
http://danny.ayers.name

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

Peter Mika wrote:

Hi guys,

Have you looked at "Best Practice Recipes for Publishing RDF 
Vocabularies":


http://www.w3.org/2001/sw/BestPractices/VM/http-examples/2006-01-18/

Peter


Ivan (as W3C rep.),

We have a W3C article titled:
Best Practice Recipes for Publishing RDF Vocabularies

Abstract reads:
This document describes best practice recipes for publishing an RDFS or 
OWL vocabulary or ontology on the Web. The features of each recipe are 
clearly described, so that vocabulary or ontology creators may choose 
the recipe best suited to the needs of their particular situations. Each 
recipe contains an example configuration for use with an Apache HTTP 
server, although the principles involved may be adapted to other 
environments. The recipes are all designed to be consistent with the 
architecture of the Web as currently specified.



I think the W3C really have to decide if this is an Apache Guide or a 
general Web guide. Right now its an Apache guide, so why not correct the 
title so it reads:


Best Practice Recipes for Publishing RDF Vocabularies *using Apache*.

The "Web of Linked Data" is simply not about Apache, and I believe you 
all know that. Thus, what's the value in producing collateral that - by 
title and abstract -- implies inextricable binding of the Web and Apache.


Lets make things clearer, the clearer things are the better for the "Web 
of Linked Data" or "Linked Data Web" as a whole.


Kingsley


Juan Sequeda wrote:

Hi Bill,

Is your code to do the content negotation in RoR available somewhere?

I'm trying to come up with example code to put up (sometime soon) on 
the linkeddata.org  site.


Juan Sequeda, Ph.D Student
Dept. of Computer Sciences
The University of Texas at Austin
www.juansequeda.com 
www.semanticwebaustin.org 


On Thu, Jul 2, 2009 at 8:19 PM, Bill Roberts > wrote:


I thought I'd give the .htaccess approach a try, to see what's
involved in actually setting it up.  I'm no expert on Apache, but
I know the basics of how it works, I've got full access to a web
server and I can read the online Apache documentation as well as
the next person.

So... after an hour or so of messing around, I still couldn't get
Apache based linked data content negotiation to work properly.
 (Something to do with turning off MultiViews which in turn meant
fiddling with AllowOverride).  I had more pressing things to do so
I gave up.

Anyway, I conclude that I agree with Martin that this is not in
general an easy way to set up content negotiation!  And I had full
access to all the Apache conf files - without that I wouldn't have
got anywhere.  In contrast, last year I wrote some code to do
linked data content negotiation in a Ruby on Rails app, which was
pretty easy.

Regards

Bill













--


Regards,

Kingsley Idehen   Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software Web: http://www.openlinksw.com

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Aldo Bucchi]

Hi,

One solution for this is for someone to create and distribute a simple
to deploy Linked Data server with integrated CN that can cover common
personal ( introductory ) use cases and eventually scale to enterprise
demands.

And maybe it could even be opensource and already packaged to be
deployed via Amazon EC2.

Oh wait...!

Regards,
A

PS. And then, someone else could build an alternative, validate the
market, etc. The same old story ;)

-- 
Aldo Bucchi
skype:aldo.bucchi
http://www.univrz.com/
http://aldobucchi.com/

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Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Peter Mika]

Hi guys,

Have you looked at "Best Practice Recipes for Publishing RDF Vocabularies":

http://www.w3.org/2001/sw/BestPractices/VM/http-examples/2006-01-18/

Peter

Juan Sequeda wrote:

Hi Bill,

Is your code to do the content negotation in RoR available somewhere?

I'm trying to come up with example code to put up (sometime soon) on 
the linkeddata.org  site.


Juan Sequeda, Ph.D Student
Dept. of Computer Sciences
The University of Texas at Austin
www.juansequeda.com 
www.semanticwebaustin.org 


On Thu, Jul 2, 2009 at 8:19 PM, Bill Roberts > wrote:


I thought I'd give the .htaccess approach a try, to see what's
involved in actually setting it up.  I'm no expert on Apache, but
I know the basics of how it works, I've got full access to a web
server and I can read the online Apache documentation as well as
the next person.

So... after an hour or so of messing around, I still couldn't get
Apache based linked data content negotiation to work properly.
 (Something to do with turning off MultiViews which in turn meant
fiddling with AllowOverride).  I had more pressing things to do so
I gave up.

Anyway, I conclude that I agree with Martin that this is not in
general an easy way to set up content negotiation!  And I had full
access to all the Apache conf files - without that I wouldn't have
got anywhere.  In contrast, last year I wrote some code to do
linked data content negotiation in a Ruby on Rails app, which was
pretty easy.

Regards

Bill

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Juan Sequeda]

Hi Bill,

Is your code to do the content negotation in RoR available somewhere?

I'm trying to come up with example code to put up (sometime soon) on the
linkeddata.org site.

Juan Sequeda, Ph.D Student
Dept. of Computer Sciences
The University of Texas at Austin
www.juansequeda.com
www.semanticwebaustin.org


On Thu, Jul 2, 2009 at 8:19 PM, Bill Roberts  wrote:

> I thought I'd give the .htaccess approach a try, to see what's involved in
> actually setting it up.  I'm no expert on Apache, but I know the basics of
> how it works, I've got full access to a web server and I can read the online
> Apache documentation as well as the next person.
>
> So... after an hour or so of messing around, I still couldn't get Apache
> based linked data content negotiation to work properly.  (Something to do
> with turning off MultiViews which in turn meant fiddling with
> AllowOverride).  I had more pressing things to do so I gave up.
>
> Anyway, I conclude that I agree with Martin that this is not in general an
> easy way to set up content negotiation!  And I had full access to all the
> Apache conf files - without that I wouldn't have got anywhere.  In contrast,
> last year I wrote some code to do linked data content negotiation in a Ruby
> on Rails app, which was pretty easy.
>
> Regards
>
> Bill
>
>
>
>
>
>

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Bill Roberts]

I thought I'd give the .htaccess approach a try, to see what's  
involved in actually setting it up.  I'm no expert on Apache, but I  
know the basics of how it works, I've got full access to a web server  
and I can read the online Apache documentation as well as the next  
person.


So... after an hour or so of messing around, I still couldn't get  
Apache based linked data content negotiation to work properly.   
(Something to do with turning off MultiViews which in turn meant  
fiddling with AllowOverride).  I had more pressing things to do so I  
gave up.


Anyway, I conclude that I agree with Martin that this is not in  
general an easy way to set up content negotiation!  And I had full  
access to all the Apache conf files - without that I wouldn't have got  
anywhere.  In contrast, last year I wrote some code to do linked data  
content negotiation in a Ruby on Rails app, which was pretty easy.


Regards

Bill

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Danny Ayers]

2009/7/2 Linde, A.E. :

> Could someone summarise this thread in a single (unbiased?) post, please?

I'll try to answer the questions, even though I've only skimmed the thread...

> a) what is/are the blocks on LOD via RDF

The vast majority of publication tools and supporting services are
geared towards publishing HTML. While a key piece of Web architecture
is the the ability to publish multiple representations of a given
resource (e.g. both HTML and RDF/XML format documents with a single
URI through content negotiation), the mechanisms needed to do this are
often unavailable from regular hosting services. Similarly the
redirect handling needed to provide a description of a resource that
cannot appear directly on the Web - things, people etc - is also not
possible.
Typically these would be done through using .htaccess files on Apache.

> b) how does RDFa help and what are its own failings;

RDFa allows the RDF to be published in a HTML document, so content
negotiation isn't needed. You get two representations in one.

Again tool support is a problem, although with RDFa being a new spec
the situation is bound to improve.

GRDDL may also be a useful alternative if the source data is available
in an XML format.

> c) what are the recipes for making data discoverable, linkable and usable

there are recipes at:
http://www4.wiwiss.fu-berlin.de/bizer/pub/LinkedDataTutorial/
though perhaps a cheat sheet would be a good idea?

 > if i) one has full access to a server;

this is pretty well documented, e.g. as above

> ii) one has only user directory acccess to a server;

while this may often be the same as i) generally I'd suggest it's a
case-by-case thing, depending on the web server configuration

iii) one does not know or care what a server is.

Depending on the nature of the data, it may be possible to use one of
the semweb-enabled document-first publishing tools (a semantic wiki or
CMS). Alternately a relational DB to RDF mapping tool may help.

But best bet right now though would be to have a word with someone
offering linked data publishing services - Talis or OpenLink, may be
others.

I've no doubt missed a lot of points and alternate approaches, but I
these were top of my own mental heap :)

Cheers,
Danny.

-- 
http://danny.ayers.name

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Linde, A.E.]

Discussion on this seems to have died down. I've tried to follow this thread 
but do not have enough SW and RDF knowledge to understand all that was said. 
But I'd like to learn by being able to publish RDF versions of knowledge in a 
way that is discoverable and usable by others in LOD fashion.

Could someone summarise this thread in a single (unbiased?) post, please? With 
the main points being: a) what is/are the blocks on LOD via RDF; b) how does 
RDFa help and what are its own failings; c) what are the recipes for making 
data discoverable, linkable and usable if i) one has full access to a server; 
ii) one has only user directory acccess to a server; iii) one does not know or 
care what a server is.

Many thanks, from me and I'm sure many others, to anyone who can satisfy these 
requests.

Cheers,
Tony.

--
Tony Linde
Project Manager
Department of Physics & Astronomy
University of Leicester



From: "Martin Hepp (UniBW)" 
Reply-To: 
Date: Wed, 1 Jul 2009 16:51:15 +0100
To: Mark Birbeck 
Cc: , semantic-web at W3C 
Subject: Re: .htaccess a major bottleneck to Semantic Web adoption / Was:  Re:  
 RDFa vs RDF/XML and content negotiation

Dear all:
Fyi - I am in contact with Google as for the clarification of what kind of 
empty div/span elements are considered acceptable in the context of RDFa. It 
may take a few days to get an official statement. Just so that you know it is 
being taken care of...

Martin



Mark Birbeck wrote:

Hi Martin,




b) download RDFa snippet that just represents the RDF/XML content (i.e. such
that it does not have to be consolidated with the "presentation level" part
of the Web page.




By coincidence, I just read this:

  Hidden div's -- don't do it!
  It can be tempting to add all the content relevant for a rich snippet
  in one place on the page, mark it up, and then hide the entire block
  of text using CSS or other techniques. Don't do this! Mark up the
  content where it already exists. Google will not show content from
  hidden div's in Rich Snippets, and worse, this can be considered
  cloaking by Google's spam detection systems. [1]

Regards,

Mark

[1] 
<http://knol.google.com/k/google-rich-snippets/google-rich-snippets/32la2chf8l79m/1#>



--
--
martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen

e-mail:  mh...@computer.org
phone:   +49-(0)89-6004-4217
fax: +49-(0)89-6004-4620
www: http://www.unibw.de/ebusiness/ (group)
 http://www.heppnetz.de/ (personal)
skype:   mfhepp
twitter: mfhepp

Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!


Webcast:
http://www.heppnetz.de/projects/goodrelations/webcast/

Talk at the Semantic Technology Conference 2009:
"Semantic Web-based E-Commerce: The GoodRelations Ontology"
http://tinyurl.com/semtech-hepp

Tool for registering your business:
http://www.ebusiness-unibw.org/tools/goodrelations-annotator/

Overview article on Semantic Universe:
http://tinyurl.com/goodrelations-universe

Project page and resources for developers:
http://purl.org/goodrelations/

Tutorial materials:
Tutorial at ESWC 2009: The Web of Data for E-Commerce in One Day: A Hands-on 
Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey

http://www.ebusiness-unibw.org/wiki/GoodRelations_Tutorial_ESWC2009

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Martin Hepp (UniBW)]

Dear all:
Fyi - I am in contact with Google as for the clarification of what kind 
of empty div/span elements are considered acceptable in the context of 
RDFa. It may take a few days to get an official statement. Just so that 
you know it is being taken care of...


Martin



Mark Birbeck wrote:

Hi Martin,

  

b) download RDFa snippet that just represents the RDF/XML content (i.e. such
that it does not have to be consolidated with the "presentation level" part
of the Web page.



By coincidence, I just read this:

  Hidden div's -- don't do it!
  It can be tempting to add all the content relevant for a rich snippet
  in one place on the page, mark it up, and then hide the entire block
  of text using CSS or other techniques. Don't do this! Mark up the
  content where it already exists. Google will not show content from
  hidden div's in Rich Snippets, and worse, this can be considered
  cloaking by Google's spam detection systems. [1]

Regards,

Mark

[1] 


  


--
--
martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen

e-mail:  mh...@computer.org
phone:   +49-(0)89-6004-4217
fax: +49-(0)89-6004-4620
www: http://www.unibw.de/ebusiness/ (group)
http://www.heppnetz.de/ (personal)
skype:   mfhepp 
twitter: mfhepp


Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!


Webcast:
http://www.heppnetz.de/projects/goodrelations/webcast/

Talk at the Semantic Technology Conference 2009: 
"Semantic Web-based E-Commerce: The GoodRelations Ontology"

http://tinyurl.com/semtech-hepp

Tool for registering your business:
http://www.ebusiness-unibw.org/tools/goodrelations-annotator/

Overview article on Semantic Universe:
http://tinyurl.com/goodrelations-universe

Project page and resources for developers:
http://purl.org/goodrelations/

Tutorial materials:
Tutorial at ESWC 2009: The Web of Data for E-Commerce in One Day: A Hands-on 
Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey

http://www.ebusiness-unibw.org/wiki/GoodRelations_Tutorial_ESWC2009




begin:vcard
fn:Martin Hepp
n:Hepp;Martin
org:Bundeswehr University Munich;E-Business and Web Science Research Group
adr:;;Werner-Heisenberg-Web 39;Neubiberg;;D-85577;Germany
email;internet:mh...@computer.org
tel;work:+49 89 6004 4217
tel;pager:skype: mfhepp
url:http://www.heppnetz.de
version:2.1
end:vcard

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Tom Heath]

Hi Pat,

OK, yelling heard loud and clear :)

By way of concrete actions, I gave Ivan Herman a (probably unfairly)
hard time today here at Dagstuhl to 'encourage' the authors of the
Vocabs Best Practices to press on with the revision of that document
that addresses the current issues. An update of the "How to Publish
Linked Data on the Web" tutorial is also on the cards; perhaps one of
the outcomes of this revision could be a greater emphasis on the hash
URI pattern (and maybe also the 'health warning' you describe ;).

Cheers,

Tom.


2009/6/29 Pat Hayes :
>
> On Jun 28, 2009, at 6:20 PM, Tom Heath wrote:
>
>> Hi Pat,
>>
>> 2009/6/25 Pat Hayes :
>>>
>>> With the sincerest respect, Tom, your attitude here is part of the
>>> problem.
>>> Maybe, along with many other people, I am indeed still stuck in the
>>> mid-1990s. You have permission to be as condescending as you like. But
>>> still, here I am, stuck. Thoroughly stuck. So no amount of condescending
>>> "sooo-20th-century, my dear" chatter is going to actually enable me to
>>> get
>>> to a place where I can do what you think I should be doing.
>>
>> Condescension was never my intention here. My goal was to draw a
>> comparison that might enable us to learn a lesson from the history of
>> the Web and use that to help us move forward. As Mark described, over
>> the course of time more and more tools became available that made it
>> easier to publish HTML. Presumably these only arose because publishing
>> HTML was to some degree hard. The Web community has gone through this
>> process once already; let's learn the lessons from last time and apply
>> them to publishing RDF so people don't have to be stuck any more.
>
> Um.. I thought that was MY point :-)
>
>> Dan
>> outlined some technical approaches to doing this sort of thing. Some
>> domain-specific apps already exist that (hopefully) reduce the pain;
>> it was one of the goals of Revyu.com for example.
>>
>>> I cannot use a
>>> rewrite rule to catch incoming requests, or do whatever you are talking
>>> about here. I live in an environment where I simply do not have access at
>>> all to the workings of my server at a level that close to the metal,
>>> because
>>> it is already woven into a clever maze of PHP machinery which is too
>>> fragile
>>> to allow erks like me to mess with it. Some of the best W3C techies have
>>> taken a look, and they can't find a way through it, either. Maybe Im in a
>>> special position, but I bet a whole lot of people, especially in the
>>> corporate world, are in a similar bind.
>>
>> You're talking about two very different groups here. If the right
>> tools are created then individuals will presumably adopt some
>> specialised SaaS analogous to say wordpress.com. Corporations are a
>> different kettle of fish
>
> I work for a small research company which happens to have an ambitious
> Webmaster and a Director who is sensitive to visual graphics and Web image
> issues. The result is a maze of complex PHP giving users a very nice
> experience, but not conducive to transparent use by its inhabitants. Just
> from casual Web browsing, I cannot believe that I am in a very small
> minority. There are a lot of 'sexy' sites out there that must be in a
> similar state. I know that several 'web authoring' systems produce similar
> PHP mazes, because Ive tried using them and then editing the output they
> produce, an experience rather like debugging BCPL.
>
>> , but just as many built their own Web-serving
>> infrastructure in the 90s, so they will invest in publishing data to
>> the Semantic Web if they perceive adequate value (demonstrating that
>> value is where we need to be working even harder!).
>>
>>> System level access to a server is
>>> quite a different beast than being allowed to publish HTML on a website
>>> somewhere. I can, and do, publish HTML, or indeed just about any file I
>>> like, but I don't get to insert code. So 6 lines or 600, it makes no
>>> difference.
>>>
>>> But in any case, this is ridiculous. RDF is just XML text, for goodness
>>> sake.  I need to insert lines of code into a server file,  and write PHP
>>> scripts, in order to publish some RDF or HTML?  That is insane. It would
>>> have been insane in the mid-1990s and its even more insane now.
>>
>> No. This is incorrect. This discussion only applies to the
>> 303-redirect/slash URI pattern. You can avoid this completely by using
>> the hash URI pattern as someone mentioned (sorry for not crediting
>> directly, getting hard to navigate this thread).
>
> Yes, of course, and I apologize for overstating the case. Still, the
> slash-URI seems to be much more acceptable to many unsemantic Webbies, who
> are used to thinking of URIs as being stripped of their post-hash content at
> the slightest internet shiver, so don't regard a name including a hash as
> something 'real'; and it is the case about which all the fuss is being made.
> If the published advice was: always use hash URI patterns, I would be happy

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[David Booth]

On Mon, 2009-06-29 at 01:20 +0200, Tom Heath wrote:
> [ . . . ] This discussion only applies to the
> 303-redirect/slash URI pattern. You can avoid this completely by using
> the hash URI pattern . . . . 

And as a reminder, you can also use a 303-redirect service if you cannot
configure your server, such as:
http://thing-described-by.org/ 

For example,
http://thing-described-by.org?http://dbooth.org/2005/dbooth/
does a 303 redirect to
http://dbooth.org/2005/dbooth/
That last one doesn't happen to serve RDF, but it certainly could.


-- 
David Booth, Ph.D.
Cleveland Clinic (contractor)

Opinions expressed herein are those of the author and do not necessarily
reflect those of Cleveland Clinic.

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Pat Hayes]

On Jun 28, 2009, at 6:20 PM, Tom Heath wrote:


Hi Pat,

2009/6/25 Pat Hayes :
With the sincerest respect, Tom, your attitude here is part of the  
problem.

Maybe, along with many other people, I am indeed still stuck in the
mid-1990s. You have permission to be as condescending as you like.  
But
still, here I am, stuck. Thoroughly stuck. So no amount of  
condescending
"sooo-20th-century, my dear" chatter is going to actually enable me  
to get

to a place where I can do what you think I should be doing.


Condescension was never my intention here. My goal was to draw a
comparison that might enable us to learn a lesson from the history of
the Web and use that to help us move forward. As Mark described, over
the course of time more and more tools became available that made it
easier to publish HTML. Presumably these only arose because publishing
HTML was to some degree hard. The Web community has gone through this
process once already; let's learn the lessons from last time and apply
them to publishing RDF so people don't have to be stuck any more.


Um.. I thought that was MY point :-)


Dan
outlined some technical approaches to doing this sort of thing. Some
domain-specific apps already exist that (hopefully) reduce the pain;
it was one of the goals of Revyu.com for example.


I cannot use a
rewrite rule to catch incoming requests, or do whatever you are  
talking
about here. I live in an environment where I simply do not have  
access at
all to the workings of my server at a level that close to the  
metal, because
it is already woven into a clever maze of PHP machinery which is  
too fragile
to allow erks like me to mess with it. Some of the best W3C techies  
have
taken a look, and they can't find a way through it, either. Maybe  
Im in a

special position, but I bet a whole lot of people, especially in the
corporate world, are in a similar bind.


You're talking about two very different groups here. If the right
tools are created then individuals will presumably adopt some
specialised SaaS analogous to say wordpress.com. Corporations are a
different kettle of fish


I work for a small research company which happens to have an ambitious  
Webmaster and a Director who is sensitive to visual graphics and Web  
image issues. The result is a maze of complex PHP giving users a very  
nice experience, but not conducive to transparent use by its  
inhabitants. Just from casual Web browsing, I cannot believe that I am  
in a very small minority. There are a lot of 'sexy' sites out there  
that must be in a similar state. I know that several 'web authoring'  
systems produce similar PHP mazes, because Ive tried using them and  
then editing the output they produce, an experience rather like  
debugging BCPL.



, but just as many built their own Web-serving
infrastructure in the 90s, so they will invest in publishing data to
the Semantic Web if they perceive adequate value (demonstrating that
value is where we need to be working even harder!).


System level access to a server is
quite a different beast than being allowed to publish HTML on a  
website
somewhere. I can, and do, publish HTML, or indeed just about any  
file I

like, but I don't get to insert code. So 6 lines or 600, it makes no
difference.

But in any case, this is ridiculous. RDF is just XML text, for  
goodness
sake.  I need to insert lines of code into a server file,  and  
write PHP
scripts, in order to publish some RDF or HTML?  That is insane. It  
would

have been insane in the mid-1990s and its even more insane now.


No. This is incorrect. This discussion only applies to the
303-redirect/slash URI pattern. You can avoid this completely by using
the hash URI pattern as someone mentioned (sorry for not crediting
directly, getting hard to navigate this thread).


Yes, of course, and I apologize for overstating the case. Still, the  
slash-URI seems to be much more acceptable to many unsemantic Webbies,  
who are used to thinking of URIs as being stripped of their post-hash  
content at the slightest internet shiver, so don't regard a name  
including a hash as something 'real'; and it is the case about which  
all the fuss is being made. If the published advice was: always use  
hash URI patterns, I would be happy. But the published advice *starts*  
with 303 redirects and .htaccess file modifications.





IMO, it is
you (and Tim and the rest of the W3C) who are stuck in the past  
here.  Most
Web users do not, and will not, write code. They will be publishing  
content
in a cloud somewhere, even further away from the gritty world of  
scripts and
lines of code than people - most people - are now. Most actual  
content
providers are never going to want to even know that PHP scripts  
exist, let

alone be obliged to write or copy one.


You've over-interpreted my words here. See above.


If so, I apologise. But think of what Im saying as a cry for help.  
There are a lot of people like me, I suspect, who would really like to  
help wit

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Pat Hayes]

On Jun 28, 2009, at 6:39 PM, Tim Berners-Lee wrote:



On 2009-06 -25, at 13:29, Pat Hayes wrote:



On Jun 25, 2009, at 11:44 AM, Martin Hepp (UniBW) wrote:


Hi all:

After about two months of helping people generate RDF/XML metadata  
for their businesses using the GoodRelations annotator [1],
I have quite some evidence that the current best practices of  
using .htaccess are a MAJOR bottleneck for the adoption of  
Semantic Web technology.


I agree, and raised this issue with the W3C TAG some time ago. It  
was apparently not taken seriously. The general consensus seemed to  
be that any normal adult should be competent to manipulate an  
Apache server.


(Was yours a deliberate sarcastic misrepresentation of the TAG's  
consensus, or a genuine misunderstanding?


A genuine misunderstanding, based on the personal feedback I got, I  
admit, rather than a careful perusal of the TAG published decisions,  
my bad.


)   The TAG has expressed that the fact that Apache needs root  
intervention when it doesn't have the right mime type set up is a  
serious bug.


Well, Im glad to hear that, and apologize for not knowing it. But as I  
said in my reply to Tom, that doesn't help me actually use the SWeb  
from out here in the one-way side roads off the information  
superhighway.




My own company, however, refuses to allow its employees to have  
access to .htaccess files, and I am therefore quite unable to  
conform to the current best practice from my own work situation. I  
believe that this situation is not uncommon.


So you mean you can't set up content negotiation and redirection.


Right. As I discovered when I was trying to follow the http-range-14  
decision and experiment with my notorious 'PatHayes' self-referential  
page, in order to bring it into line with the recommendations. Talk  
about eating dog food...



But you can use foo#bar URIs like I do.


True.



Will the company allow a mime.types file to include application/rdf 
+xml?


No problem there, AFAIK.

Pat



Tim






IHMC (850)434 8903 or (650)494 3973
40 South Alcaniz St.   (850)202 4416   office
Pensacola(850)202 4440   fax
FL 32502  (850)291 0667   mobile
phayesAT-SIGNihmc.us   http://www.ihmc.us/users/phayes

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Tom Heath]

Hi Mark,

2009/6/29 Mark Birbeck :
> Hi Tom,
>
> On Sun, Jun 28, 2009 at 11:46 PM, Tom Heath wrote:
>> Martin,
>>
>> 2009/6/27 Martin Hepp (UniBW) :
>>> So if this "hidden div / span" approach is not feasible, we got a problem.
>>>
>>> The reason is that, as beautiful the idea is of using RDFa to make a) the
>>> human-readable presentation and b) the machine-readable meta-data link to
>>> the same literals, the problematic is it in reality once the structure of a)
>>> and b) are very different.
>>>
>>> For very simple property-value pairs, embedding RDFa markup is no problem.
>>> But if you have a bit more complexity at the conceptual level and in
>>> particular if there are significant differences to the structure of the
>>> presentation (e.g. in terms of granularity, ordering of elements, etc.), it
>>> gets very, very messy and hard to maintain.
>>
>> Amen. Thank you for writing this. I completely agree. RDFa has some
>> great use cases but (like any technology) has its limitations. Let's
>> not oversell it.
>
> Mmm...you put me in a difficult position here. :)

;)

> If I leap to RDFa's defence then it looks like I think it solves all
> the world's problems.
>
> But if I remain silent, then it looks like the problem being raised is
> some kind of fundamental flaw.

Just in case there's any doubt, let me clarify that this isn't an
anti-RDFa position from me, just trying to unpack the issue.

> Ah well, let's dive in...
>
> First I should say that I'd be the first to agree that RDFa has
> limitations. But the issue here is that I don't think the problem
> raised by Martin can be classed as a limitation in the way you're
> implying, Tom.
>
> If we go back a step, RDFa was carefully designed so that it could
> carry any combination of the RDF concepts in an HTML document. In the
> end we dropped reification and lists, because it didn't seem that the
> RDF community itself was clear on the future of those, but they are
> both easily added back if the issues were to be resolved.
>
> In short, it is possible to use HTML+RDFa to create complete RDF
> documents, such as RDF Schemas, OWL ontologies, and so on, and the
> resulting documents would be no more complex than their equivalent
> RDF/XML or N3 versions, with the benefit that they can be delivered
> using any of the many HTML publishing techniques currently available.

Absolutely agreed. I don't dispute this at all. Though it's not really
my point. See below...

> But most of the discussion around RDFa relates to its other use, where
> it's possible to use it to 'sprinkle' metadata into HTML documents
> that are primarily aimed at human readers. By being alongside the
> human-readable output, it makes the metadata easier to maintain.

In some cases. It depends on the publishing architecture. What effect
does it have on the maintenance cost of the layout/structural markup
of the page?

> And
> in addition it gives the user agent the opportunity to enhance the
> view of the data, by making use of the 'local' metadata.
>
> However, the point that Martin was getting at, is that sometimes there
> is just way more data in the 'RDF view' than in the 'human view', and
> that makes it very difficult to make the two align.

Yes, this is exactly how I understood his point. It's also exactly why
I keep banging on about us not saying that x is better than y. It's
not about a limitation of RDFa as a technology (apologies if it came
across that way), simply a reflection of the fact that it can be
challenging to deploy in some circumstances. Again, this is context
dependent, and the best solution can only be determined by examining
that context.

> I don't think that this is a flaw in RDFa itself,

Agreed.

> and I'm not convinced that there is an easy solution in the form of another
> technology that would solve this.

Well, such cases may justify the 303/conneg pattern.

> Martin's solution seems a reasonable
> one to me.
>
> (Although I wonder if part of the problem might be that too much
> information is being provided in the RDF view, rather than using links
> to other data that can be retrieved. Perhaps Michael could give an
> example.)

Completely agreed on this point. You'll see this approach manifested
in Revyu.com, where there is redundancy in data between HTML pages for
the sake of presenting human users with a more complete view (without
requiring them to visit multiple pages); the same is not true of the
(broadly) equivalent RDF documents, where I tried to avoid redundancy,
on the basis that any SW agent worth it's salt should be able to
dereference the referenced URIs to retrieve the data it needs. IIRC
others disagree with my approach here (TimBL? Richard C?), but this
speaks completely to the question of what is the appropriate
interaction paradigm for apps built on the Web of Data. If we can
understand the answers to this question then it may help guide our
deployment strategies for RDFa.

Cheers,

Tom.

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Yihong Ding]

Thank you, Toby.  The EASE is an interesting proposal. As I have said, we at
Fuji are now actively looking for a convenient and efficiently way of
displaying semantic data. I need to study more of this EASE project. If
possible, I would like to have more discussion with you of the topic in the
future.

best,

yihong


On Mon, Jun 29, 2009 at 10:11 AM, Toby Inkster wrote:

> On Mon, 2009-06-29 at 09:46 -0400, Yihong Ding wrote:
> > I envision an innovation of semantic data display combining the
> > strengthes of Microformat and RDFa/RDF. But it is surely not easy.
>
> It's not easy, it's EASE. ;-)
>
> http://buzzword.org.uk/2008/rdf-ease/spec
>
> Note to myself: chapter 1 needs fleshing out with some examples.
>
> --
> Toby A Inkster
> 
> 
>



-- 
===
Yihong Ding

http://yihongs-research.blogspot.com/

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Mark Birbeck]

Hi Martin,

> Beyond that, RDFa can create code that is very
> hard to maintain. In fact, I know that a large software company
> dismissed the use of RDFa in their products because of the unmanageable
> mix of conceptual and presentation layer.

Now I'm going to sound like I don't believe there are any problems with RDFa.

But... :)

The issue here is not that RDFa forces a mix of conceptual and
presentation layers -- it would be more correct to say that RDFa
_allows_ for a mix of conceptual and presentation layers. But there is
nothing to force that mixing, and RDFa can also be used for different
points along the spectrum.

For example, I could create an RDF schema or OWL ontology using RDFa,
which would be much the same, in terms of verbosity, as an RDF/XML
version. It might never be used in web browser, and so occupy a
position on the spectrum well away from the presentation end.

In this scenario the RDFa document is simply playing the role of an
equivalent RDF/XML document, with the only difference being that it
can be deployed using HTML infrastructure.

Another scenario would be to have one HTML+RDFa document for humans,
and another for machines, in just the same way that most deployment
scenarios currently involve two different documents (one HTML and one
RDF/XML).

The main thing is that you now have a choice, and the key point I'm
trying to make is that if the company you were dealing with mixes up
the conceptual and presentation layers, that's nothing to do with
RDFa, since it's perfectly possible to separate them as much or as
little as you like.

In fact it's a little like blaming HTML's @style attribute for causing
you to 'mix up presentation and content', when HTML actually has a
very powerful mechanism for keeping them apart, in CSS stylesheets.

Regards,

Mark

-- 
Mark Birbeck, webBackplane

mark.birb...@webbackplane.com

http://webBackplane.com/mark-birbeck

webBackplane is a trading name of Backplane Ltd. (company number
05972288, registered office: 2nd Floor, 69/85 Tabernacle Street,
London, EC2A 4RR)

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Mark Birbeck]

Hi Toby,

Yes...of course...you are right. :)

I would say too, that reification is even more long-winded than the
example you have given! You don't have the actual statement "the sky
is blue" in your mark-up, so you need even more RDFa. (You only have
the statement "Mark says 'the sky is blue'".)

But either way, you are right that the whole thing can be spelt out
longhand (as can lists).

The only reason I mentioned it was because for a long time in RDFa we
had a much simpler construct based on occurrences of *nested* 
and  properties. However, some browsers thought they were doing
us a favour by moving the  and  elements out of the 
and into the , which meant it was not possible to implement this
feature in JavaScript. (Obviously server-side RDFa parsers would have
had no problem with it.)

As for lists, the obvious shorthand would be , , and , but
it was not obvious what triples should be generated, so we left it.
I.e., your example uses the first/next/nil technique for collections,
but of course there is also the rdf:_1 technique for a list. It wasn't
immediately clear which would be the more useful -- or conformant --
one to generate.

Regards,

Mark

On Mon, Jun 29, 2009 at 2:05 PM, Toby Inkster wrote:
> On Mon, 2009-06-29 at 13:30 +0100, Mark Birbeck wrote:
>> If we go back a step, RDFa was carefully designed so that it could
>> carry any combination of the RDF concepts in an HTML document. In the
>> end we dropped reification and lists, because it didn't seem that the
>> RDF community itself was clear on the future of those, but they are
>> both easily added back if the issues were to be resolved.
>
> RDF reification and lists do *work* in RDFa, they're just a bit of a
> pain to mark up.
>
> e.g. here's a reification:
>
> http://purl.org/dc/elements/1.1/";
>    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#";
>    xmlns:db="http://dbpedia.org/resource/";
>    typeof="rdf:Statement">
>  Mark Birkbeck says that
>  the sky
>  http://dbpedia.org/property/color";
>      >is
>   blue.
> 
>
> And an example of a list can be found here:
>
> http://ontologi.es/rail/routes/gb/VTB1.xhtml
>
> --
> Toby A Inkster
> 
> 
>
>



-- 
Mark Birbeck, webBackplane

mark.birb...@webbackplane.com

http://webBackplane.com/mark-birbeck

webBackplane is a trading name of Backplane Ltd. (company number
05972288, registered office: 2nd Floor, 69/85 Tabernacle Street,
London, EC2A 4RR)

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Yihong Ding]

Hi Martin,

I agree to most of your opinions, especially the architecture of data
representation you suggest. The only point I would like to emphasize is to
figure out a way that eliminates the demand of storing a fact multiple
times. Even though you think that it might be inevitable, personally I still
believe the possibility.

A typical analogical example is the CSS. CSS is a great example for data
displaying. By using CSS, we do not have to store the same data multiple
times but simultaneously reach the goal of flexible data display. Well,
certainly CSS is not directly applicable in the semantic realm. But I
believe it is the right way of thinking we need to approach.

Actually, the philosophy of Microformat is closer to CSS though Microformat
is much more limited a mechanism. I envision an innovation of semantic data
display combining the strengthes of Microformat and RDFa/RDF. But it is
surely not easy.

BTW: I like your work on GoodRelations. I am now working on the radiological
medicine domain and trying to develop something like it. (And indeed data
display is a critical issue for me to solve in the project.) Hopefully we
may have some chances to cooperate in the future again.

cheers,

yihong


On Mon, Jun 29, 2009 at 9:01 AM, Martin Hepp (UniBW) <
martin.h...@ebusiness-unibw.org> wrote:

> Hi Yihong:
> I am a big fan of Codd's "one fact in one place" credo. However, in this
> particular case, that principle is violated anyway, since the literal
> values are often duplicated for presentation and meta-data prupolses
> anyway (think of "2009-06-29" vs. "June 29, 2009"). Second, for dynamic
> Web apps, it does not really matter whether the same fact is exposed
> once or twice, since the central location is one place in the database
> anyway. Third, this is the only way how a tool like the GoodRelations
> annotator [1] can create RDFa snippets for simple copy-and-paste into
> existing pages.
>
> Also note that in the particular case of RDFa, the principle of "one
> fact in one place" clashes with the "separation of concerns" principle,
> in particular, that of keeping data and presentation separate.
>
> The textbook-style "beauty of simplicity" of RDFa holds for adding a
> dc:creator property to a string value that is the same for presentation
> and at the data level. Beyond that, RDFa can create code that is very
> hard to maintain. In fact, I know that a large software company
> dismissed the use of RDFa in their products because of the unmanageable
> mix of conceptual and presentation layer.
>
> As far as security is concerned: I there is no real difference in my
> proposal, as the "content" attribute of RDFa allows serving different data
> to human and to machines, and this is a needed feature anyway. Digital
> signatures at the document or element level and / or data provenance
> approached will likely cater for that.
>
> Best
>
> Martin
>
> Yihong Ding wrote:
>
>> Hi Kingley and Martin,
>>
>> A potential problem of the model Martin suggested is that the same data
>> has
>> to be presented at least TWICE in one document. Although the RDFa portion
>> of
>> the data is supposed to be automatically generated, it, however, does not
>> prohibit anybody from manually revising it. Therefore, it leaves a huge
>> hole
>> for the hackers (or anybody who want to do some deceptive job). In our
>> imperfect world, this problem is severe.
>>
>> Adding an extra layer of data mapping always causes additional work on
>> data
>> maintenance. This time, the extra work could be a nightmare though the
>> architecture is neat.
>>
>> yihong
>>
>>
>> On Mon, Jun 29, 2009 at 8:03 AM, Kingsley Idehen > >wrote:
>>
>>
>>
>>> Martin Hepp (UniBW) wrote:
>>>
>>>
>>>
 Hi Tom:



> Amen. Thank you for writing this. I completely agree. RDFa has some
> great use cases but (like any technology) has its limitations. Let's
> not oversell it.
>
>
 We seem to agree on the observation, but not on the conclusion. What I
 want and suggest is using RDFa also for exchanging a bit more complex
 RDF
 models / data by simply using a lot of div / span or whatever elements
 that
 represent the RDF part in the SAME document BUT NOT too closely linked
 with
 the presentation level.

 
 This is the car I want to sell
 Actually, a pretty cool car, for only $1.000. Offer valid through July
 31,
 2009

 
 ... my whole RDF in RDFa
  
 

 The advantage of that would be that

 - you just have to maintain ONE file,
 - data and metadata are close by, so the likelihood of being up to date
 increases, and
 - at the same time, the code does not get too messy.
 - Also - no problems setting up the server (*).
 - Easy to create on-line tools that generate RDFa snippets for simple
 pasting.
 - Yahoo and Google will most likely honor RDFa meta-data only.

 Also note that often the literal values will be

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Toby Inkster]

On Mon, 2009-06-29 at 13:30 +0100, Mark Birbeck wrote:
> If we go back a step, RDFa was carefully designed so that it could
> carry any combination of the RDF concepts in an HTML document. In the
> end we dropped reification and lists, because it didn't seem that the
> RDF community itself was clear on the future of those, but they are
> both easily added back if the issues were to be resolved.

RDF reification and lists do *work* in RDFa, they're just a bit of a
pain to mark up.

e.g. here's a reification:

http://purl.org/dc/elements/1.1/";
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#";
xmlns:db="http://dbpedia.org/resource/";
typeof="rdf:Statement">
  Mark Birkbeck says that
  the sky
  http://dbpedia.org/property/color";
  >is
  blue.


And an example of a list can be found here:

http://ontologi.es/rail/routes/gb/VTB1.xhtml

-- 
Toby A Inkster

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Martin Hepp (UniBW)]

Hi Yihong:
I am a big fan of Codd's "one fact in one place" credo. However, in this
particular case, that principle is violated anyway, since the literal
values are often duplicated for presentation and meta-data prupolses
anyway (think of "2009-06-29" vs. "June 29, 2009"). Second, for dynamic
Web apps, it does not really matter whether the same fact is exposed
once or twice, since the central location is one place in the database
anyway. Third, this is the only way how a tool like the GoodRelations
annotator [1] can create RDFa snippets for simple copy-and-paste into
existing pages.

Also note that in the particular case of RDFa, the principle of "one
fact in one place" clashes with the "separation of concerns" principle,
in particular, that of keeping data and presentation separate.

The textbook-style "beauty of simplicity" of RDFa holds for adding a
dc:creator property to a string value that is the same for presentation
and at the data level. Beyond that, RDFa can create code that is very
hard to maintain. In fact, I know that a large software company
dismissed the use of RDFa in their products because of the unmanageable
mix of conceptual and presentation layer.

As far as security is concerned: I there is no real difference in my 
proposal, as the "content" attribute of RDFa allows serving different 
data to human and to machines, and this is a needed feature anyway. 
Digital signatures at the document or element level and / or data 
provenance approached will likely cater for that.


Best

Martin

Yihong Ding wrote:

Hi Kingley and Martin,

A potential problem of the model Martin suggested is that the same data has
to be presented at least TWICE in one document. Although the RDFa portion of
the data is supposed to be automatically generated, it, however, does not
prohibit anybody from manually revising it. Therefore, it leaves a huge hole
for the hackers (or anybody who want to do some deceptive job). In our
imperfect world, this problem is severe.

Adding an extra layer of data mapping always causes additional work on data
maintenance. This time, the extra work could be a nightmare though the
architecture is neat.

yihong


On Mon, Jun 29, 2009 at 8:03 AM, Kingsley Idehen wrote:

  

Martin Hepp (UniBW) wrote:



Hi Tom:

  

Amen. Thank you for writing this. I completely agree. RDFa has some
great use cases but (like any technology) has its limitations. Let's
not oversell it.


We seem to agree on the observation, but not on the conclusion. What I
want and suggest is using RDFa also for exchanging a bit more complex RDF
models / data by simply using a lot of div / span or whatever elements that
represent the RDF part in the SAME document BUT NOT too closely linked with
the presentation level.


This is the car I want to sell
Actually, a pretty cool car, for only $1.000. Offer valid through July 31,
2009


... my whole RDF in RDFa
 


The advantage of that would be that

- you just have to maintain ONE file,
- data and metadata are close by, so the likelihood of being up to date
increases, and
- at the same time, the code does not get too messy.
- Also - no problems setting up the server (*).
- Easy to create on-line tools that generate RDFa snippets for simple
pasting.
- Yahoo and Google will most likely honor RDFa meta-data only.

Also note that often the literal values will be in content attributes
anyway, because the string for the presentation is not suitable as meta-data
content anyway (e.g.  dates, country codes,...)

I think the approach sketched above would be a cheap and useful way of
publishing RDF meta-data. It could work with CMS / blogging software etc.
 Imaging if we were able to allow eBay sellers to put GoodRelations
meta-data directly into the open XHTML part of their product description.

The main problem with my proposal is that there is the risk that Google
considers this "cloaking" and may remove respective resources from their
index (Mark raised that issue). If that risk was confirmed, we would really
have a problem. Imagine me selling Semantic Web markup as a step beyond SEO
... and the first consequence of following my advice is being removed from
the Google index.

A second problem is that if the document contains nodes that have no
counterpart on the presentation level (e.g. intermediate nodes for holding
n-ary relations), then they will also not be dereferencable. The same holds
for URIs or  nodes that are outside the scope of the actual RDFa / XHTML
document - I see no simple way of serving neither XHTML nor RDF content for
those.

  

Martin,

If Google doesn't see invisible DIVs as cloaking, the issue vaporizes.

Also, if people take the SEO + SDQ (Linked Data Expressed in RDFa) approach
they will at least remain in the Google index via usual SEO oriented keyword
gimmickry, albeit generally suboptimal.

If we make a recipe doc showcasing these issues, we will more than likely
get Google to recalibrate back to the Web; especially if we can demonstr

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Mark Birbeck]

Hi Tom,

On Sun, Jun 28, 2009 at 11:46 PM, Tom Heath wrote:
> Martin,
>
> 2009/6/27 Martin Hepp (UniBW) :
>> So if this "hidden div / span" approach is not feasible, we got a problem.
>>
>> The reason is that, as beautiful the idea is of using RDFa to make a) the
>> human-readable presentation and b) the machine-readable meta-data link to
>> the same literals, the problematic is it in reality once the structure of a)
>> and b) are very different.
>>
>> For very simple property-value pairs, embedding RDFa markup is no problem.
>> But if you have a bit more complexity at the conceptual level and in
>> particular if there are significant differences to the structure of the
>> presentation (e.g. in terms of granularity, ordering of elements, etc.), it
>> gets very, very messy and hard to maintain.
>
> Amen. Thank you for writing this. I completely agree. RDFa has some
> great use cases but (like any technology) has its limitations. Let's
> not oversell it.

Mmm...you put me in a difficult position here. :)

If I leap to RDFa's defence then it looks like I think it solves all
the world's problems.

But if I remain silent, then it looks like the problem being raised is
some kind of fundamental flaw.

Ah well, let's dive in...

First I should say that I'd be the first to agree that RDFa has
limitations. But the issue here is that I don't think the problem
raised by Martin can be classed as a limitation in the way you're
implying, Tom.

If we go back a step, RDFa was carefully designed so that it could
carry any combination of the RDF concepts in an HTML document. In the
end we dropped reification and lists, because it didn't seem that the
RDF community itself was clear on the future of those, but they are
both easily added back if the issues were to be resolved.

In short, it is possible to use HTML+RDFa to create complete RDF
documents, such as RDF Schemas, OWL ontologies, and so on, and the
resulting documents would be no more complex than their equivalent
RDF/XML or N3 versions, with the benefit that they can be delivered
using any of the many HTML publishing techniques currently available.

But most of the discussion around RDFa relates to its other use, where
it's possible to use it to 'sprinkle' metadata into HTML documents
that are primarily aimed at human readers. By being alongside the
human-readable output, it makes the metadata easier to maintain. And
in addition it gives the user agent the opportunity to enhance the
view of the data, by making use of the 'local' metadata.

However, the point that Martin was getting at, is that sometimes there
is just way more data in the 'RDF view' than in the 'human view', and
that makes it very difficult to make the two align.

I don't think that this is a flaw in RDFa itself, and I'm not
convinced that there is an easy solution in the form of another
technology that would solve this. Martin's solution seems a reasonable
one to me.

(Although I wonder if part of the problem might be that too much
information is being provided in the RDF view, rather than using links
to other data that can be retrieved. Perhaps Michael could give an
example.)

Regards,

Mark

-- 
Mark Birbeck, webBackplane

mark.birb...@webbackplane.com

http://webBackplane.com/mark-birbeck

webBackplane is a trading name of Backplane Ltd. (company number
05972288, registered office: 2nd Floor, 69/85 Tabernacle Street,
London, EC2A 4RR)

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Yihong Ding]

Hi Kingley and Martin,

A potential problem of the model Martin suggested is that the same data has
to be presented at least TWICE in one document. Although the RDFa portion of
the data is supposed to be automatically generated, it, however, does not
prohibit anybody from manually revising it. Therefore, it leaves a huge hole
for the hackers (or anybody who want to do some deceptive job). In our
imperfect world, this problem is severe.

Adding an extra layer of data mapping always causes additional work on data
maintenance. This time, the extra work could be a nightmare though the
architecture is neat.

yihong


On Mon, Jun 29, 2009 at 8:03 AM, Kingsley Idehen wrote:

> Martin Hepp (UniBW) wrote:
>
>> Hi Tom:
>>
>> >Amen. Thank you for writing this. I completely agree. RDFa has some
>> >great use cases but (like any technology) has its limitations. Let's
>> >not oversell it.
>> We seem to agree on the observation, but not on the conclusion. What I
>> want and suggest is using RDFa also for exchanging a bit more complex RDF
>> models / data by simply using a lot of div / span or whatever elements that
>> represent the RDF part in the SAME document BUT NOT too closely linked with
>> the presentation level.
>>
>> 
>> This is the car I want to sell
>> Actually, a pretty cool car, for only $1.000. Offer valid through July 31,
>> 2009
>>
>> 
>> ... my whole RDF in RDFa
>>  
>> 
>>
>> The advantage of that would be that
>>
>> - you just have to maintain ONE file,
>> - data and metadata are close by, so the likelihood of being up to date
>> increases, and
>> - at the same time, the code does not get too messy.
>> - Also - no problems setting up the server (*).
>> - Easy to create on-line tools that generate RDFa snippets for simple
>> pasting.
>> - Yahoo and Google will most likely honor RDFa meta-data only.
>>
>> Also note that often the literal values will be in content attributes
>> anyway, because the string for the presentation is not suitable as meta-data
>> content anyway (e.g.  dates, country codes,...)
>>
>> I think the approach sketched above would be a cheap and useful way of
>> publishing RDF meta-data. It could work with CMS / blogging software etc.
>>  Imaging if we were able to allow eBay sellers to put GoodRelations
>> meta-data directly into the open XHTML part of their product description.
>>
>> The main problem with my proposal is that there is the risk that Google
>> considers this "cloaking" and may remove respective resources from their
>> index (Mark raised that issue). If that risk was confirmed, we would really
>> have a problem. Imagine me selling Semantic Web markup as a step beyond SEO
>> ... and the first consequence of following my advice is being removed from
>> the Google index.
>>
>> A second problem is that if the document contains nodes that have no
>> counterpart on the presentation level (e.g. intermediate nodes for holding
>> n-ary relations), then they will also not be dereferencable. The same holds
>> for URIs or  nodes that are outside the scope of the actual RDFa / XHTML
>> document - I see no simple way of serving neither XHTML nor RDF content for
>> those.
>>
> Martin,
>
> If Google doesn't see invisible DIVs as cloaking, the issue vaporizes.
>
> Also, if people take the SEO + SDQ (Linked Data Expressed in RDFa) approach
> they will at least remain in the Google index via usual SEO oriented keyword
> gimmickry, albeit generally suboptimal.
>
> If we make a recipe doc showcasing these issues, we will more than likely
> get Google to recalibrate back to the Web; especially if we can demonstrate
> that other search engine players --that have support RDFa -- not being
> afflicted with the same cloaking myopia.
>
> Kingsley
>
>>
>> Best
>>
>> Martin
>>
>>
>>
>> Tom Heath wrote:
>>
>>> Martin,
>>>
>>> 2009/6/27 Martin Hepp (UniBW) :
>>>
>>>
 So if this "hidden div / span" approach is not feasible, we got a
 problem.

 The reason is that, as beautiful the idea is of using RDFa to make a)
 the
 human-readable presentation and b) the machine-readable meta-data link
 to
 the same literals, the problematic is it in reality once the structure
 of a)
 and b) are very different.

 For very simple property-value pairs, embedding RDFa markup is no
 problem.
 But if you have a bit more complexity at the conceptual level and in
 particular if there are significant differences to the structure of the
 presentation (e.g. in terms of granularity, ordering of elements, etc.),
 it
 gets very, very messy and hard to maintain.


>>>
>>> Amen. Thank you for writing this. I completely agree. RDFa has some
>>> great use cases but (like any technology) has its limitations. Let's
>>> not oversell it.
>>>
>>> Tom.
>>>
>>>
>>>
>>
>> --
>> --
>> martin hepp
>> e-business & web science research group
>> universitaet der bundeswehr muenchen
>>
>> e-mail:  mh...@comput

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

Martin Hepp (UniBW) wrote:

Hi Tom:

>Amen. Thank you for writing this. I completely agree. RDFa has some
>great use cases but (like any technology) has its limitations. Let's
>not oversell it.
We seem to agree on the observation, but not on the conclusion. What I 
want and suggest is using RDFa also for exchanging a bit more complex 
RDF models / data by simply using a lot of div / span or whatever 
elements that represent the RDF part in the SAME document BUT NOT too 
closely linked with the presentation level.



This is the car I want to sell
Actually, a pretty cool car, for only $1.000. Offer valid through July 
31, 2009



... my whole RDF in RDFa
 


The advantage of that would be that

- you just have to maintain ONE file,
- data and metadata are close by, so the likelihood of being up to 
date increases, and

- at the same time, the code does not get too messy.
- Also - no problems setting up the server (*).
- Easy to create on-line tools that generate RDFa snippets for simple 
pasting.

- Yahoo and Google will most likely honor RDFa meta-data only.

Also note that often the literal values will be in content attributes 
anyway, because the string for the presentation is not suitable as 
meta-data content anyway (e.g.  dates, country codes,...)


I think the approach sketched above would be a cheap and useful way of 
publishing RDF meta-data. It could work with CMS / blogging software 
etc.  Imaging if we were able to allow eBay sellers to put 
GoodRelations meta-data directly into the open XHTML part of their 
product description.


The main problem with my proposal is that there is the risk that 
Google considers this "cloaking" and may remove respective resources 
from their index (Mark raised that issue). If that risk was confirmed, 
we would really have a problem. Imagine me selling Semantic Web markup 
as a step beyond SEO ... and the first consequence of following my 
advice is being removed from the Google index.


A second problem is that if the document contains nodes that have no 
counterpart on the presentation level (e.g. intermediate nodes for 
holding n-ary relations), then they will also not be dereferencable. 
The same holds for URIs or  nodes that are outside the scope of the 
actual RDFa / XHTML document - I see no simple way of serving neither 
XHTML nor RDF content for those.

Martin,

If Google doesn't see invisible DIVs as cloaking, the issue vaporizes.

Also, if people take the SEO + SDQ (Linked Data Expressed in RDFa) 
approach they will at least remain in the Google index via usual SEO 
oriented keyword gimmickry, albeit generally suboptimal.


If we make a recipe doc showcasing these issues, we will more than 
likely get Google to recalibrate back to the Web; especially if we can 
demonstrate that other search engine players --that have support RDFa -- 
not being afflicted with the same cloaking myopia.


Kingsley


Best

Martin



Tom Heath wrote:

Martin,

2009/6/27 Martin Hepp (UniBW) :
  

So if this "hidden div / span" approach is not feasible, we got a problem.

The reason is that, as beautiful the idea is of using RDFa to make a) the
human-readable presentation and b) the machine-readable meta-data link to
the same literals, the problematic is it in reality once the structure of a)
and b) are very different.

For very simple property-value pairs, embedding RDFa markup is no problem.
But if you have a bit more complexity at the conceptual level and in
particular if there are significant differences to the structure of the
presentation (e.g. in terms of granularity, ordering of elements, etc.), it
gets very, very messy and hard to maintain.



Amen. Thank you for writing this. I completely agree. RDFa has some
great use cases but (like any technology) has its limitations. Let's
not oversell it.

Tom.

  


--
--
martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen

e-mail:  mh...@computer.org
phone:   +49-(0)89-6004-4217
fax: +49-(0)89-6004-4620
www: http://www.unibw.de/ebusiness/ (group)
 http://www.heppnetz.de/ (personal)
skype:   mfhepp 
twitter: mfhepp


Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!


Webcast:
http://www.heppnetz.de/projects/goodrelations/webcast/

Talk at the Semantic Technology Conference 2009: 
"Semantic Web-based E-Commerce: The GoodRelations Ontology"

http://tinyurl.com/semtech-hepp

Tool for registering your business:
http://www.ebusiness-unibw.org/tools/goodrelations-annotator/

Overview article on Semantic Universe:
http://tinyurl.com/goodrelations-universe

Project page and resources for developers:
http://purl.org/goodrelations/

Tutorial materials:
Tutorial at ESWC 2009: The Web of Data for E-Commerce in One Day: A Hands-on 
Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey

http://www.ebusiness-un

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Tom Heath]

Hi Martin,

2009/6/29 Martin Hepp (UniBW) :
> Hi Tom:
>
>>Amen. Thank you for writing this. I completely agree. RDFa has some
>>great use cases but (like any technology) has its limitations. Let's
>>not oversell it.
>
> We seem to agree on the observation, but not on the conclusion. What I want
> and suggest is using RDFa also for exchanging a bit more complex RDF models
> / data by simply using a lot of div / span or whatever elements that
> represent the RDF part in the SAME document BUT NOT too closely linked with
> the presentation level.
>
> 
> This is the car I want to sell
> Actually, a pretty cool car, for only $1.000. Offer valid through July 31,
> 2009
>
> 
> ... my whole RDF in RDFa
>  
> 
>
> The advantage of that would be that
>
> - you just have to maintain ONE file,
> - data and metadata are close by, so the likelihood of being up to date
> increases, and
> - at the same time, the code does not get too messy.
> - Also - no problems setting up the server (*).
> - Easy to create on-line tools that generate RDFa snippets for simple
> pasting.
> - Yahoo and Google will most likely honor RDFa meta-data only.
>
> Also note that often the literal values will be in content attributes
> anyway, because the string for the presentation is not suitable as meta-data
> content anyway (e.g.  dates, country codes,...)
>
> I think the approach sketched above would be a cheap and useful way of
> publishing RDF meta-data. It could work with CMS / blogging software etc.
> Imaging if we were able to allow eBay sellers to put GoodRelations meta-data
> directly into the open XHTML part of their product description.
>
> The main problem with my proposal is that there is the risk that Google
> considers this "cloaking" and may remove respective resources from their
> index (Mark raised that issue). If that risk was confirmed, we would really
> have a problem. Imagine me selling Semantic Web markup as a step beyond SEO
> ... and the first consequence of following my advice is being removed from
> the Google index.
>
> A second problem is that if the document contains nodes that have no
> counterpart on the presentation level (e.g. intermediate nodes for holding
> n-ary relations), then they will also not be dereferencable. The same holds
> for URIs or  nodes that are outside the scope of the actual RDFa / XHTML
> document - I see no simple way of serving neither XHTML nor RDF content for
> those.

These are exactly the reasons why I emphasise the limitations and ask
that we don't oversell the capabilities of any technology, RDFa
included.

Tom.

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Martin Hepp (UniBW)]

Hi Tom:


Amen. Thank you for writing this. I completely agree. RDFa has some
great use cases but (like any technology) has its limitations. Let's
not oversell it.


We seem to agree on the observation, but not on the conclusion. What I 
want and suggest is using RDFa also for exchanging a bit more complex 
RDF models / data by simply using a lot of div / span or whatever 
elements that represent the RDF part in the SAME document BUT NOT too 
closely linked with the presentation level.



This is the car I want to sell
Actually, a pretty cool car, for only $1.000. Offer valid through July 
31, 2009



... my whole RDF in RDFa



The advantage of that would be that

- you just have to maintain ONE file,
- data and metadata are close by, so the likelihood of being up to date 
increases, and

- at the same time, the code does not get too messy.
- Also - no problems setting up the server (*).
- Easy to create on-line tools that generate RDFa snippets for simple 
pasting.

- Yahoo and Google will most likely honor RDFa meta-data only.

Also note that often the literal values will be in content attributes 
anyway, because the string for the presentation is not suitable as 
meta-data content anyway (e.g.  dates, country codes,...)


I think the approach sketched above would be a cheap and useful way of 
publishing RDF meta-data. It could work with CMS / blogging software 
etc.  Imaging if we were able to allow eBay sellers to put GoodRelations 
meta-data directly into the open XHTML part of their product description.


The main problem with my proposal is that there is the risk that Google 
considers this "cloaking" and may remove respective resources from their 
index (Mark raised that issue). If that risk was confirmed, we would 
really have a problem. Imagine me selling Semantic Web markup as a step 
beyond SEO ... and the first consequence of following my advice is being 
removed from the Google index.


A second problem is that if the document contains nodes that have no 
counterpart on the presentation level (e.g. intermediate nodes for 
holding n-ary relations), then they will also not be dereferencable. The 
same holds for URIs or  nodes that are outside the scope of the actual 
RDFa / XHTML document - I see no simple way of serving neither XHTML nor 
RDF content for those.


Best

Martin



Tom Heath wrote:

Martin,

2009/6/27 Martin Hepp (UniBW) :
  

So if this "hidden div / span" approach is not feasible, we got a problem.

The reason is that, as beautiful the idea is of using RDFa to make a) the
human-readable presentation and b) the machine-readable meta-data link to
the same literals, the problematic is it in reality once the structure of a)
and b) are very different.

For very simple property-value pairs, embedding RDFa markup is no problem.
But if you have a bit more complexity at the conceptual level and in
particular if there are significant differences to the structure of the
presentation (e.g. in terms of granularity, ordering of elements, etc.), it
gets very, very messy and hard to maintain.



Amen. Thank you for writing this. I completely agree. RDFa has some
great use cases but (like any technology) has its limitations. Let's
not oversell it.

Tom.

  


--
--
martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen

e-mail:  mh...@computer.org
phone:   +49-(0)89-6004-4217
fax: +49-(0)89-6004-4620
www: http://www.unibw.de/ebusiness/ (group)
http://www.heppnetz.de/ (personal)
skype:   mfhepp 
twitter: mfhepp


Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!


Webcast:
http://www.heppnetz.de/projects/goodrelations/webcast/

Talk at the Semantic Technology Conference 2009: 
"Semantic Web-based E-Commerce: The GoodRelations Ontology"

http://tinyurl.com/semtech-hepp

Tool for registering your business:
http://www.ebusiness-unibw.org/tools/goodrelations-annotator/

Overview article on Semantic Universe:
http://tinyurl.com/goodrelations-universe

Project page and resources for developers:
http://purl.org/goodrelations/

Tutorial materials:
Tutorial at ESWC 2009: The Web of Data for E-Commerce in One Day: A Hands-on 
Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey

http://www.ebusiness-unibw.org/wiki/GoodRelations_Tutorial_ESWC2009




begin:vcard
fn:Martin Hepp
n:Hepp;Martin
org:Bundeswehr University Munich;E-Business and Web Science Research Group
adr:;;Werner-Heisenberg-Web 39;Neubiberg;;D-85577;Germany
email;internet:mh...@computer.org
tel;work:+49 89 6004 4217
tel;pager:skype: mfhepp
url:http://www.heppnetz.de
version:2.1
end:vcard

Contd. .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

Kingsley Idehen wrote:


On 6/28/09 6:33 PM, "Tom Heath"  wrote:

  

Hi Richard,

2009/6/25 Richard Cyganiak :





(On the value of content negotiation in general: I think the key point is
that any linked data URI intended for re-use, when put into a browser by the
average person interested in linked data publishing, MUST return something
human-readable. That's a hard requirement, otherwise people will never be
confident about what a particular URI means and hence they won't re-use.
That was the thinking behind the Cool URIs note when Leo and I wrote it a
few years ago. In the past, the only way to get that effect was with content
negotiation, so even though content negotiation is a pain, it's what we had
to do. In the present, we have an alternative thanks to RDFa.
  

Not disagreeing at all about the human readable requirement, but just
a question... in this scenario you describe, is there not a risk that
Joe User will enter that URI and come to the conclusion that it
identifies the document (or section thereof), rather than a thing
described in the document?

Interested in your thoughts :)

Tom.




Tom,

Of course not, if dealing with an HTTP URI deployed in line with the Linked
Data meme's deployment guidelines. In short, the user will encounter a
document describing the Thing identified by the URI.

The issue is not the document, but what it represents (metadata) and how it
comes to be associated (implicitly) with the entity (resource) it describes
via the entities URI.

When all is said and done, the Linked Data meme has simply used HTTP to fix
an age old problem: implicit association of an Entity with its Metadata
within the context of distributed computing without any platform lock-in.

Rewind back to pre. Web, then ask yourself: how did programmers refer to
data objects and de-reference their representations (typically a proprietary
language and platform specific data structure).

Again, Linked Data is just about making what was platform specific, platform
independent, via HTTP i.e., "data access by reference" and "data
manipulation by values exposed by de-dereferenced data structures".

We really need to keep this quite simple. There are zillions of people that
understand "data access by reference" etc.. They also understand Metadata
etc.. What they don't understand is how we sometimes *inadvertently* make
this whole Linekd Data meme thing complex by not connecting the meme to what
existed before the Web (which was actually created on a computer that
already had a fully functional distributed object based OS etc..).



Kingsley





  

Tom,

Much short version.

If a user "Joe Web User" becomes fixated on the metadata document URI we 
don't have a problem. I say this because the aforementioned document 
will always act as a conduit to the URI of the entity it describes. 
Thus, Linked Data aware user agents will always be able to figure this 
out and get what they want.


The most important thing is that we add the metadata document to the 
general mix on the Web. By this I mean: in addition to the basic HTML 
document (which has no specificity re. metadata) and the standard 
ability to lookup markup (via browsers for instance), we now have the 
ability to lookup a metadata bearing document via a URI.


Keeping the URIs within scope of user agents is the single most 
important thing, since doing this is what really makes the Linked Data 
meme tick :-)


--


Regards,

Kingsley Idehen   Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software Web: http://www.openlinksw.com

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

On 6/28/09 6:33 PM, "Tom Heath"  wrote:

> Hi Richard,
> 
> 2009/6/25 Richard Cyganiak :
> 
> 
> 
>> (On the value of content negotiation in general: I think the key point is
>> that any linked data URI intended for re-use, when put into a browser by the
>> average person interested in linked data publishing, MUST return something
>> human-readable. That's a hard requirement, otherwise people will never be
>> confident about what a particular URI means and hence they won't re-use.
>> That was the thinking behind the Cool URIs note when Leo and I wrote it a
>> few years ago. In the past, the only way to get that effect was with content
>> negotiation, so even though content negotiation is a pain, it's what we had
>> to do. In the present, we have an alternative thanks to RDFa.
> 
> Not disagreeing at all about the human readable requirement, but just
> a question... in this scenario you describe, is there not a risk that
> Joe User will enter that URI and come to the conclusion that it
> identifies the document (or section thereof), rather than a thing
> described in the document?
> 
> Interested in your thoughts :)
> 
> Tom.
> 

Tom,

Of course not, if dealing with an HTTP URI deployed in line with the Linked
Data meme's deployment guidelines. In short, the user will encounter a
document describing the Thing identified by the URI.

The issue is not the document, but what it represents (metadata) and how it
comes to be associated (implicitly) with the entity (resource) it describes
via the entities URI.

When all is said and done, the Linked Data meme has simply used HTTP to fix
an age old problem: implicit association of an Entity with its Metadata
within the context of distributed computing without any platform lock-in.

Rewind back to pre. Web, then ask yourself: how did programmers refer to
data objects and de-reference their representations (typically a proprietary
language and platform specific data structure).

Again, Linked Data is just about making what was platform specific, platform
independent, via HTTP i.e., "data access by reference" and "data
manipulation by values exposed by de-dereferenced data structures".

We really need to keep this quite simple. There are zillions of people that
understand "data access by reference" etc.. They also understand Metadata
etc.. What they don't understand is how we sometimes *inadvertently* make
this whole Linekd Data meme thing complex by not connecting the meme to what
existed before the Web (which was actually created on a computer that
already had a fully functional distributed object based OS etc..).



Kingsley

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Tim Berners-Lee]

On 2009-06 -25, at 13:29, Pat Hayes wrote:



On Jun 25, 2009, at 11:44 AM, Martin Hepp (UniBW) wrote:


Hi all:

After about two months of helping people generate RDF/XML metadata  
for their businesses using the GoodRelations annotator [1],
I have quite some evidence that the current best practices of  
using .htaccess are a MAJOR bottleneck for the adoption of Semantic  
Web technology.


I agree, and raised this issue with the W3C TAG some time ago. It  
was apparently not taken seriously. The general consensus seemed to  
be that any normal adult should be competent to manipulate an Apache  
server.


(Was yours a deliberate sarcastic misrepresentation of the TAG's  
consensus, or a genuine misunderstanding?)   The TAG has expressed  
that the fact that Apache needs root intervention when it doesn't have  
the right mime type set up is a serious bug.


My own company, however, refuses to allow its employees to have  
access to .htaccess files, and I am therefore quite unable to  
conform to the current best practice from my own work situation. I  
believe that this situation is not uncommon.


So you mean you can't set up content negotiation and redirection.
But you can use foo#bar URIs like I do.

Will the company allow a mime.types file to include application/rdf+xml?

Tim

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Tom Heath]

Hi Pat,

2009/6/25 Pat Hayes :
> With the sincerest respect, Tom, your attitude here is part of the problem.
> Maybe, along with many other people, I am indeed still stuck in the
> mid-1990s. You have permission to be as condescending as you like. But
> still, here I am, stuck. Thoroughly stuck. So no amount of condescending
> "sooo-20th-century, my dear" chatter is going to actually enable me to get
> to a place where I can do what you think I should be doing.

Condescension was never my intention here. My goal was to draw a
comparison that might enable us to learn a lesson from the history of
the Web and use that to help us move forward. As Mark described, over
the course of time more and more tools became available that made it
easier to publish HTML. Presumably these only arose because publishing
HTML was to some degree hard. The Web community has gone through this
process once already; let's learn the lessons from last time and apply
them to publishing RDF so people don't have to be stuck any more. Dan
outlined some technical approaches to doing this sort of thing. Some
domain-specific apps already exist that (hopefully) reduce the pain;
it was one of the goals of Revyu.com for example.

> I cannot use a
> rewrite rule to catch incoming requests, or do whatever you are talking
> about here. I live in an environment where I simply do not have access at
> all to the workings of my server at a level that close to the metal, because
> it is already woven into a clever maze of PHP machinery which is too fragile
> to allow erks like me to mess with it. Some of the best W3C techies have
> taken a look, and they can't find a way through it, either. Maybe Im in a
> special position, but I bet a whole lot of people, especially in the
> corporate world, are in a similar bind.

You're talking about two very different groups here. If the right
tools are created then individuals will presumably adopt some
specialised SaaS analogous to say wordpress.com. Corporations are a
different kettle of fish, but just as many built their own Web-serving
infrastructure in the 90s, so they will invest in publishing data to
the Semantic Web if they perceive adequate value (demonstrating that
value is where we need to be working even harder!).

> System level access to a server is
> quite a different beast than being allowed to publish HTML on a website
> somewhere. I can, and do, publish HTML, or indeed just about any file I
> like, but I don't get to insert code. So 6 lines or 600, it makes no
> difference.
>
> But in any case, this is ridiculous. RDF is just XML text, for goodness
> sake.  I need to insert lines of code into a server file,  and write PHP
> scripts, in order to publish some RDF or HTML?  That is insane. It would
> have been insane in the mid-1990s and its even more insane now.

No. This is incorrect. This discussion only applies to the
303-redirect/slash URI pattern. You can avoid this completely by using
the hash URI pattern as someone mentioned (sorry for not crediting
directly, getting hard to navigate this thread).

> IMO, it is
> you (and Tim and the rest of the W3C) who are stuck in the past here.  Most
> Web users do not, and will not, write code. They will be publishing content
> in a cloud somewhere, even further away from the gritty world of scripts and
> lines of code than people - most people - are now. Most actual content
> providers are never going to want to even know that PHP scripts exist, let
> alone be obliged to write or copy one.

You've over-interpreted my words here. See above.

> Martin is exactly right: this is a
> MAJOR bottleneck to SWeb adoption. Its up to the people in the TAG to listen
> to this fact and do something about it, not to keep issuing useless  'best
> practice' advice that cannot be followed by 99% of the world.

I think that's overplaying things. It's like saying "stop issuing best
practices for cardiac surgeons because Average Joe can't use those to
help improve his cardiac health".

> RDF should be text, in documents. One should be able to use it without
> knowing about anything more than the RDF spec and the XML spec. If it
> requires people to tinker with files with names starting with a dot, or
> write code, or deploy scripts, then the entire SWeb architecture is
> fundamentally broken.

The architecture of the Semantic Web is the architecture of Web. And
just as in the Web we have varied publishing patterns/workflows
(ranging from simple to hard), so we will in the Semantic Web.

Cheers,

Tom.

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Tom Heath]

Martin,

2009/6/27 Martin Hepp (UniBW) :
> So if this "hidden div / span" approach is not feasible, we got a problem.
>
> The reason is that, as beautiful the idea is of using RDFa to make a) the
> human-readable presentation and b) the machine-readable meta-data link to
> the same literals, the problematic is it in reality once the structure of a)
> and b) are very different.
>
> For very simple property-value pairs, embedding RDFa markup is no problem.
> But if you have a bit more complexity at the conceptual level and in
> particular if there are significant differences to the structure of the
> presentation (e.g. in terms of granularity, ordering of elements, etc.), it
> gets very, very messy and hard to maintain.

Amen. Thank you for writing this. I completely agree. RDFa has some
great use cases but (like any technology) has its limitations. Let's
not oversell it.

Tom.

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Tom Heath]

Hi Richard,

2009/6/25 Richard Cyganiak :



> (On the value of content negotiation in general: I think the key point is
> that any linked data URI intended for re-use, when put into a browser by the
> average person interested in linked data publishing, MUST return something
> human-readable. That's a hard requirement, otherwise people will never be
> confident about what a particular URI means and hence they won't re-use.
> That was the thinking behind the Cool URIs note when Leo and I wrote it a
> few years ago. In the past, the only way to get that effect was with content
> negotiation, so even though content negotiation is a pain, it's what we had
> to do. In the present, we have an alternative thanks to RDFa.

Not disagreeing at all about the human readable requirement, but just
a question... in this scenario you describe, is there not a risk that
Joe User will enter that URI and come to the conclusion that it
identifies the document (or section thereof), rather than a thing
described in the document?

Interested in your thoughts :)

Tom.

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Toby A Inkster]

On 27 Jun 2009, at 11:25, Melvin Carvalho wrote:


What happens if you put them in one big  tree and use the
@content attribute?


view-source:http://ontologi.es/rail/routes/gb/VTB1.xhtml

--
Toby A Inkster

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

Martin Hepp (UniBW) wrote:
So if this "hidden div / span" approach is not feasible, we got a 
problem.


The reason is that, as beautiful the idea is of using RDFa to make a) 
the human-readable presentation and b) the machine-readable meta-data 
link to the same literals, the problematic is it in reality once the 
structure of a) and b) are very different.


For very simple property-value pairs, embedding RDFa markup is no 
problem. But if you have a bit more complexity at the conceptual level 
and in particular if there are significant differences to the 
structure of the presentation (e.g. in terms of granularity, ordering 
of elements, etc.), it gets very, very messy and hard to maintain.


And you give up the clear separation of concerns between the 
conceptual level and the presentation level that XML brought about.


Maybe one should tell Google that this is not cloaking if SW meta-data 
is embedded...

Yes.

Ideally, they should figure that out from the self-describing nature of 
the RDF based metadata exposed by the embedded RDFa -- assuming they are 
doing real RDFa processing :-)



Kingsley


But the snippet basically indicates that we should not recommend this 
practice.





Martin


Kingsley Idehen wrote:

Mark Birbeck wrote:

Hi Martin,

 
b) download RDFa snippet that just represents the RDF/XML content 
(i.e. such
that it does not have to be consolidated with the "presentation 
level" part

of the Web page.



By coincidence, I just read this:

  Hidden div's -- don't do it!
  It can be tempting to add all the content relevant for a rich snippet
  in one place on the page, mark it up, and then hide the entire block
  of text using CSS or other techniques. Don't do this! Mark up the
  content where it already exists. Google will not show content from
  hidden div's in Rich Snippets, and worse, this can be considered
  cloaking by Google's spam detection systems. [1]

Regards,

Mark

[1] 
 



  

Martin/Mark,

Time to make a sample RDFa doc that includes very detailed GR based 
metadata.


Mark: Should we be describing our docs for Google, fundamentally? I 
really think Google should actually recalibrate back to the Web etc..








--


Regards,

Kingsley Idehen   Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software Web: http://www.openlinksw.com

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Melvin Carvalho]

On Sat, Jun 27, 2009 at 9:21 AM, Martin Hepp
(UniBW) wrote:
> So if this "hidden div / span" approach is not feasible, we got a problem.
>
> The reason is that, as beautiful the idea is of using RDFa to make a) the
> human-readable presentation and b) the machine-readable meta-data link to
> the same literals, the problematic is it in reality once the structure of a)
> and b) are very different.
>
> For very simple property-value pairs, embedding RDFa markup is no problem.
> But if you have a bit more complexity at the conceptual level and in
> particular if there are significant differences to the structure of the
> presentation (e.g. in terms of granularity, ordering of elements, etc.), it
> gets very, very messy and hard to maintain.
>
> And you give up the clear separation of concerns between the conceptual
> level and the presentation level that XML brought about.
>
> Maybe one should tell Google that this is not cloaking if SW meta-data is
> embedded...
>
> But the snippet basically indicates that we should not recommend this
> practice.

What happens if you put them in one big  tree and use the
@content attribute?

>
> Martin
>
>
> Kingsley Idehen wrote:
>>
>> Mark Birbeck wrote:
>>>
>>> Hi Martin,
>>>
>>>

 b) download RDFa snippet that just represents the RDF/XML content (i.e.
 such
 that it does not have to be consolidated with the "presentation level"
 part
 of the Web page.

>>>
>>> By coincidence, I just read this:
>>>
>>>  Hidden div's -- don't do it!
>>>  It can be tempting to add all the content relevant for a rich snippet
>>>  in one place on the page, mark it up, and then hide the entire block
>>>  of text using CSS or other techniques. Don't do this! Mark up the
>>>  content where it already exists. Google will not show content from
>>>  hidden div's in Rich Snippets, and worse, this can be considered
>>>  cloaking by Google's spam detection systems. [1]
>>>
>>> Regards,
>>>
>>> Mark
>>>
>>> [1]
>>> 
>>>
>>>
>>
>> Martin/Mark,
>>
>> Time to make a sample RDFa doc that includes very detailed GR based
>> metadata.
>>
>> Mark: Should we be describing our docs for Google, fundamentally? I really
>> think Google should actually recalibrate back to the Web etc..
>>
>>
>
> --
> --
> martin hepp
> e-business & web science research group
> universitaet der bundeswehr muenchen
>
> e-mail:  mh...@computer.org
> phone:   +49-(0)89-6004-4217
> fax:     +49-(0)89-6004-4620
> www:     http://www.unibw.de/ebusiness/ (group)
>        http://www.heppnetz.de/ (personal)
> skype:   mfhepp twitter: mfhepp
>
> Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!
> 
>
> Webcast:
> http://www.heppnetz.de/projects/goodrelations/webcast/
>
> Talk at the Semantic Technology Conference 2009: "Semantic Web-based
> E-Commerce: The GoodRelations Ontology"
> http://tinyurl.com/semtech-hepp
>
> Tool for registering your business:
> http://www.ebusiness-unibw.org/tools/goodrelations-annotator/
>
> Overview article on Semantic Universe:
> http://tinyurl.com/goodrelations-universe
>
> Project page and resources for developers:
> http://purl.org/goodrelations/
>
> Tutorial materials:
> Tutorial at ESWC 2009: The Web of Data for E-Commerce in One Day: A Hands-on
> Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey
>
> http://www.ebusiness-unibw.org/wiki/GoodRelations_Tutorial_ESWC2009
>
>
>
>
>

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Martin Hepp (UniBW)]

So if this "hidden div / span" approach is not feasible, we got a problem.

The reason is that, as beautiful the idea is of using RDFa to make a) 
the human-readable presentation and b) the machine-readable meta-data 
link to the same literals, the problematic is it in reality once the 
structure of a) and b) are very different.


For very simple property-value pairs, embedding RDFa markup is no 
problem. But if you have a bit more complexity at the conceptual level 
and in particular if there are significant differences to the structure 
of the presentation (e.g. in terms of granularity, ordering of elements, 
etc.), it gets very, very messy and hard to maintain.


And you give up the clear separation of concerns between the conceptual 
level and the presentation level that XML brought about.


Maybe one should tell Google that this is not cloaking if SW meta-data 
is embedded...


But the snippet basically indicates that we should not recommend this 
practice.


Martin


Kingsley Idehen wrote:

Mark Birbeck wrote:

Hi Martin,

 
b) download RDFa snippet that just represents the RDF/XML content 
(i.e. such
that it does not have to be consolidated with the "presentation 
level" part

of the Web page.



By coincidence, I just read this:

  Hidden div's -- don't do it!
  It can be tempting to add all the content relevant for a rich snippet
  in one place on the page, mark it up, and then hide the entire block
  of text using CSS or other techniques. Don't do this! Mark up the
  content where it already exists. Google will not show content from
  hidden div's in Rich Snippets, and worse, this can be considered
  cloaking by Google's spam detection systems. [1]

Regards,

Mark

[1] 
 



  

Martin/Mark,

Time to make a sample RDFa doc that includes very detailed GR based 
metadata.


Mark: Should we be describing our docs for Google, fundamentally? I 
really think Google should actually recalibrate back to the Web etc..





--
--
martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen

e-mail:  mh...@computer.org
phone:   +49-(0)89-6004-4217
fax: +49-(0)89-6004-4620
www: http://www.unibw.de/ebusiness/ (group)
http://www.heppnetz.de/ (personal)
skype:   mfhepp 
twitter: mfhepp


Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!


Webcast:
http://www.heppnetz.de/projects/goodrelations/webcast/

Talk at the Semantic Technology Conference 2009: 
"Semantic Web-based E-Commerce: The GoodRelations Ontology"

http://tinyurl.com/semtech-hepp

Tool for registering your business:
http://www.ebusiness-unibw.org/tools/goodrelations-annotator/

Overview article on Semantic Universe:
http://tinyurl.com/goodrelations-universe

Project page and resources for developers:
http://purl.org/goodrelations/

Tutorial materials:
Tutorial at ESWC 2009: The Web of Data for E-Commerce in One Day: A Hands-on 
Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey

http://www.ebusiness-unibw.org/wiki/GoodRelations_Tutorial_ESWC2009




begin:vcard
fn:Martin Hepp
n:Hepp;Martin
org:Bundeswehr University Munich;E-Business and Web Science Research Group
adr:;;Werner-Heisenberg-Web 39;Neubiberg;;D-85577;Germany
email;internet:mh...@computer.org
tel;work:+49 89 6004 4217
tel;pager:skype: mfhepp
url:http://www.heppnetz.de
version:2.1
end:vcard

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

Bradley Allen wrote:

Kingsley-

On Fri, Jun 26, 2009 at 11:40 AM, Kingsley Idehen wrote:
  

Mark: Should we be describing our docs for Google, fundamentally? I really 
think Google should actually recalibrate back to the Web etc..



The correct question to ask, and the one that I believe Mark is
addressing, is should we be asking people to describe their content in
a way that may be at cross-purposes to their efforts to monetize it?

Bradley P. Allen
http://bradleypallen.org
+1 310 951 4300

  

Bradley,

Who is the monetizer? And what is being monetized?

I think people should simply describe themselves, their wants, their 
friends, their offerrings etc. as clearly as possible. The Web will take 
care of the REST, not joking :-)


Links:

1. 
http://www.seangolliher.com/2009/linked-data/serendipitous-discovery-quotient-sdq-the-future-of-seo-or-an-abstract-concept 
- SDQ vs SEO .


--


Regards,

Kingsley Idehen   Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software Web: http://www.openlinksw.com

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

Martin Hepp (UniBW) wrote:

Kingsley:
So basically you think that RDF hosting will ne a new market segment 
with services like small RDF hosting services (same as private Web 
space packages), free hosting (maybe with ads included in the RDF), etc.?

Absolutely!!

There's nothing like overtly or covertly unveiling "opportunity cost" 
palpability, when trying to unveil the virtues of any concept, to people 
charged with running a business :-)


This is the very thinking behind the "owl:shameAs" scheme we use in the 
Linked Data compliant proxy URIs generated by our Sponger's  RDFizer 
cartridges i.e., show people the impressions they are missing out on by 
providing them with a hint URI, that exposes a suggested data slot, 
within their respective data spaces.



Kingsley

Martin


Kingsley Idehen wrote:
>Martin:
>I think having a third party relay inaccurate opening and closing 
hours is a feature re. the GoodRelations, RDFa, Linked Data, and 
pinger services combo; it makes the "opportunity cost" of not putting 
the >RDFa embellished HTML doc  (from #3) on the server, palpable :-)  
Thus,  we end up with a closed loop, that simply lets the Web do the 
REST (including social and political cajoling re. doc publishing).


--
martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen

e-mail:  mh...@computer.org
phone:   +49-(0)89-6004-4217
fax: +49-(0)89-6004-4620
www: http://www.unibw.de/ebusiness/ (group)
http://www.heppnetz.de/ (personal)
skype:   mfhepp twitter: mfhepp

Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!


Webcast:
http://www.heppnetz.de/projects/goodrelations/webcast/

Talk at the Semantic Technology Conference 2009: "Semantic Web-based 
E-Commerce: The GoodRelations Ontology"

http://tinyurl.com/semtech-hepp

Tool for registering your business:
http://www.ebusiness-unibw.org/tools/goodrelations-annotator/

Overview article on Semantic Universe:
http://tinyurl.com/goodrelations-universe

Project page and resources for developers:
http://purl.org/goodrelations/

Tutorial materials:
Tutorial at ESWC 2009: The Web of Data for E-Commerce in One Day: A 
Hands-on Introduction to the GoodRelations Ontology, RDFa, and Yahoo! 
SearchMonkey


http://www.ebusiness-unibw.org/wiki/GoodRelations_Tutorial_ESWC2009







--


Regards,

Kingsley Idehen   Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software Web: http://www.openlinksw.com

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Bradley Allen]

Kingsley-

On Fri, Jun 26, 2009 at 11:40 AM, Kingsley Idehen wrote:
> Mark: Should we be describing our docs for Google, fundamentally? I really 
> think Google should actually recalibrate back to the Web etc..

The correct question to ask, and the one that I believe Mark is
addressing, is should we be asking people to describe their content in
a way that may be at cross-purposes to their efforts to monetize it?

Bradley P. Allen
http://bradleypallen.org
+1 310 951 4300

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

Mark Birbeck wrote:

Hi Martin,

  

b) download RDFa snippet that just represents the RDF/XML content (i.e. such
that it does not have to be consolidated with the "presentation level" part
of the Web page.



By coincidence, I just read this:

  Hidden div's -- don't do it!
  It can be tempting to add all the content relevant for a rich snippet
  in one place on the page, mark it up, and then hide the entire block
  of text using CSS or other techniques. Don't do this! Mark up the
  content where it already exists. Google will not show content from
  hidden div's in Rich Snippets, and worse, this can be considered
  cloaking by Google's spam detection systems. [1]

Regards,

Mark

[1] 


  

Martin/Mark,

Time to make a sample RDFa doc that includes very detailed GR based 
metadata.


Mark: Should we be describing our docs for Google, fundamentally? I 
really think Google should actually recalibrate back to the Web etc..



--


Regards,

Kingsley Idehen   Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software Web: http://www.openlinksw.com

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Martin Hepp (UniBW)]

Kingsley:
So basically you think that RDF hosting will ne a new market segment 
with services like small RDF hosting services (same as private Web space 
packages), free hosting (maybe with ads included in the RDF), etc.?

Martin


Kingsley Idehen wrote:
>Martin:
>I think having a third party relay inaccurate opening and closing 
hours is a feature re. the GoodRelations, RDFa, Linked Data, and pinger 
services combo; it makes the "opportunity cost" of not putting the >RDFa 
embellished HTML doc  (from #3) on the server, palpable :-)  Thus,  we 
end up with a closed loop, that simply lets the Web do the REST 
(including social and political cajoling re. doc publishing).


--
martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen

e-mail:  mh...@computer.org
phone:   +49-(0)89-6004-4217
fax: +49-(0)89-6004-4620
www: http://www.unibw.de/ebusiness/ (group)
http://www.heppnetz.de/ (personal)
skype:   mfhepp 
twitter: mfhepp


Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!


Webcast:
http://www.heppnetz.de/projects/goodrelations/webcast/

Talk at the Semantic Technology Conference 2009: 
"Semantic Web-based E-Commerce: The GoodRelations Ontology"

http://tinyurl.com/semtech-hepp

Tool for registering your business:
http://www.ebusiness-unibw.org/tools/goodrelations-annotator/

Overview article on Semantic Universe:
http://tinyurl.com/goodrelations-universe

Project page and resources for developers:
http://purl.org/goodrelations/

Tutorial materials:
Tutorial at ESWC 2009: The Web of Data for E-Commerce in One Day: A Hands-on 
Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey

http://www.ebusiness-unibw.org/wiki/GoodRelations_Tutorial_ESWC2009




begin:vcard
fn:Martin Hepp
n:Hepp;Martin
org:Bundeswehr University Munich;E-Business and Web Science Research Group
adr:;;Werner-Heisenberg-Web 39;Neubiberg;;D-85577;Germany
email;internet:mh...@computer.org
tel;work:+49 89 6004 4217
tel;pager:skype: mfhepp
url:http://www.heppnetz.de
version:2.1
end:vcard

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Mark Birbeck]

Hi Martin,

> b) download RDFa snippet that just represents the RDF/XML content (i.e. such
> that it does not have to be consolidated with the "presentation level" part
> of the Web page.

By coincidence, I just read this:

  Hidden div's -- don't do it!
  It can be tempting to add all the content relevant for a rich snippet
  in one place on the page, mark it up, and then hide the entire block
  of text using CSS or other techniques. Don't do this! Mark up the
  content where it already exists. Google will not show content from
  hidden div's in Rich Snippets, and worse, this can be considered
  cloaking by Google's spam detection systems. [1]

Regards,

Mark

[1] 


-- 
Mark Birbeck, webBackplane

mark.birb...@webbackplane.com

http://webBackplane.com/mark-birbeck

webBackplane is a trading name of Backplane Ltd. (company number
05972288, registered office: 2nd Floor, 69/85 Tabernacle Street,
London, EC2A 4RR)

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

Melvin Carvalho wrote:

On Thu, Jun 25, 2009 at 6:44 PM, Martin Hepp
(UniBW) wrote:
  

Hi all:

After about two months of helping people generate RDF/XML metadata for their
businesses using the GoodRelations annotator [1],
I have quite some evidence that the current best practices of using
.htaccess are a MAJOR bottleneck for the adoption of Semantic Web
technology.

Just some data:
- We have several hundred entries in the annotator log - most people spend
10 or more minutes to create a reasonable description of themselves.
- Even though they all operate some sort of Web sites, less than 30 % of
them manage to upload/publish a single *.rdf file in their root directory.
- Of those 30%, only a fraction manage to set up content negotiation
properly, even though we provide a step-by-step recipe.

The effects are
- URIs that are not dereferencable,
- incorrect media types and
and other problems.

When investigating the causes and trying to help people, we encountered a
variety of configurations and causes that we did not expect. It turned out
that helping people just managing this tiny step of publishing  Semantic Web
data would turn into a full-time job for 1 - 2 administrators.

Typical causes of problems are
- Lack of privileges for .htaccess (many cheap hosting packages give limited
or no access to .htaccess)
- Users without Unix background had trouble name a file so that it begins
with a dot
- Microsoft IIS require completely different recipes
- Many users have access just at a CMS level

Bottomline:
- For researchers in the field, it is a doable task to set up an Apache
server so that it serves RDF content according to current best practices.
- For most people out there in reality, this is regularly a prohibitively
difficult task, both because of a lack of skills and a variety in the
technical environments that turns into an engineering challenge what is easy
on the textbook-level.

As a consequence, we will modify our tool so that it generates "dummy" RDFa
code with span/div that *just* represents the meta-data without interfering
with the presentation layer.
That can then be inserted as code snippets via copy-and-paste to any XHTML
document.

Any opinions?



Been thinking about this issue for the last 6 months, and ive changed
my mind a few times.

Inclined to agree that RDFa is probably the ideal entry point for
bringing existing businesses onto Good Relations.

For a read/write web (which is the goal of commerce, right?), you're
probably back to .htaccess, though, with, say, a controller that will
manage POSTed SPARUL inserts.

I think taking it "one step at a time", in this way, seems a sensible
approach, though as a community, we'll need to put a bit of wieght
behind getting the RDFa tool set up to the state of the art.
  


.htaccess is a sad and unnecessary technical detail that assumes we have 
an Apache mono-culture, and that said mono-culture is immutable.


For GoodRelations based product, services, and offerings descriptions, 
the workflow should be as follows:


1. Describe you products and services using terms from GR (ontology 
bound annotators help here irrespective of source and location);
2. Get an HTML as output from #1 (with embedded RDFa for the product and 
services description data);

3. Optionally, publish doc from #2 to your public Web Server;
4. Optionally, notify the broader Web via pinger services (PTSW, 
Sindice, etc..).


If you couldn't publish docs to your Web Server before you encountered 
GoodRelations, RDFa, and Linked Data, then we are dealing with a totally 
different matter, one that isn't specific to Linked Data deployment.


Martin:
I think having a third party relay inaccurate opening and closing hours 
is a feature re. the GoodRelations, RDFa, Linked Data, and pinger 
services combo; it makes the "opportunity cost" of not putting the RDFa 
embellished HTML doc  (from #3) on the server, palpable :-)  Thus,  we 
end up with a closed loop, that simply lets the Web do the REST 
(including social and political cajoling re. doc publishing).




Kingsley
  

Best
Martin

[1]  http://www.ebusiness-unibw.org/tools/goodrelations-annotator/

Danny Ayers wrote:


Thank you for the excellent questions, Bill.

Right now IMHO the best bet is probably just to pick whichever format
you are most comfortable with (yup "it depends") and use that as the
single source, transforming perhaps with scripts to generate the
alternate representations for conneg.

As far as I'm aware we don't yet have an easy templating engine for
RDFa, so I suspect having that as the source is probably a good choice
for typical Web applications.

As mentioned already GRDDL is available for transforming on the fly,
though I'm not sure of the level of client engine support at present.
Ditto providing a SPARQL endpoint is another way of maximising the
surface area of the data.

But the key step has clearly been taken, that decision to publish data
directly without needing the human element to interpr

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Pat Hayes]

On Jun 26, 2009, at 3:03 AM, Toby A Inkster wrote:


On 25 Jun 2009, at 21:18, Pat Hayes wrote:

If [RDF] requires people to tinker with files with names starting  
with a dot [...] then the entire SWeb architecture is fundamentally  
broken.


RDF doesn't. Apache does.


I should have said, if the process of getting RDF published requires  
people...


Pat



Many hosts do have front ends for configuring Apache, allowing  
redirects to be set up and content-types configured by filling in  
simple web forms. But there are such a variety of these tools with  
different capabilities and different interfaces that it would be  
difficult to produce advice suitable for them all, so instead  
".htaccess" recipes are provided instead.


That said, there are a couple of steps that Martin could remove from  
his recipe and still be promoting reasonably good practice:


Step 5a - this rewrites  to . Other than aesthetics, there's no real reason to do this. Yes,  
I've read timbl's old Cool URIs document, and understand about not  
wanting to include hints of file format in a URI. But realistically,  
this file is going to always include some RDF - perhaps in a non-RDF/ 
XML serialisation, but I don't see anything inappropriate about  
serving other RDF serialisations using a ".rdf" URL, provided the  
correct MIME type is used.


Step 5b - the default Apache mime.types file knows about application/ 
rdf+xml, so this should be unnecessary. Perhaps instead have a  
GoodRelations "validator" which checks that the content type is  
correct, and only suggests this when it is found to be otherwise.


Steps 3 and 4 could be amalgamated into a single "validate your RDF  
file" step using the aforementioned validator. The validator would  
be written so that, upon a successful validation, it offers single- 
click options to ping semweb search engines, and Yahoo (via a RDF/ 
XML->DataRSS converter).


With those adjustments, the recipe would just be:

1. Upload your RDF file.
2. Add a rel="meta" link to it.
3. Validate using our helpful tool.

--
Toby A Inkster










IHMC (850)434 8903 or (650)494 3973
40 South Alcaniz St.   (850)202 4416   office
Pensacola(850)202 4440   fax
FL 32502  (850)291 0667   mobile
phayesAT-SIGNihmc.us   http://www.ihmc.us/users/phayes

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Martin Hepp (UniBW)]

Hi Toby,

Toby A Inkster wrote:

On 25 Jun 2009, at 21:18, Pat Hayes wrote:

If [RDF] requires people to tinker with files with names starting 
with a dot [...] then the entire SWeb architecture is fundamentally 
broken.


RDF doesn't. Apache does.

Many hosts do have front ends for configuring Apache, allowing 
redirects to be set up and content-types configured by filling in 
simple web forms. But there are such a variety of these tools with 
different capabilities and different interfaces that it would be 
difficult to produce advice suitable for them all, so instead 
".htaccess" recipes are provided instead.


That said, there are a couple of steps that Martin could remove from 
his recipe and still be promoting reasonably good practice:


Step 5a - this rewrites  to 
. Other than aesthetics, there's 
no real reason to do this. Yes, I've read timbl's old Cool URIs 
document, and understand about not wanting to include hints of file 
format in a URI. But realistically, this file is going to always 
include some RDF - perhaps in a non-RDF/XML serialisation, but I don't 
see anything inappropriate about serving other RDF serialisations 
using a ".rdf" URL, provided the correct MIME type is used.


Yes - while it breaks my heart, we will uses URIs including the .rdf 
extension in the future. Comparing benefits and trouble caused, it is 
not worth pushing it.
Step 5b - the default Apache mime.types file knows about 
application/rdf+xml, so this should be unnecessary. Perhaps instead 
have a GoodRelations "validator" which checks that the content type is 
correct, and only suggests this when it is found to be otherwise.
Well, our experience is that about 30% of the servers don't use the 
proper mime type by default, which causes trouble with many semweb 
applications


Steps 3 and 4 could be amalgamated into a single "validate your RDF 
file" step using the aforementioned validator. The validator would be 
written so that, upon a successful validation, it offers single-click 
options to ping semweb search engines, and Yahoo (via a 
RDF/XML->DataRSS converter).


With those adjustments, the recipe would just be:

1. Upload your RDF file.
2. Add a rel="meta" link to it.
3. Validate using our helpful tool.

Yes, that would be a good option. But actually I am prone to go for a 
more radical shift, which is offering just three alternative publication 
mechanisms:


a) download RDF/XML or N3 file (for expert users)
b) download RDFa snippet that just represents the RDF/XML content (i.e. 
such that it does not have to be consolidated with the "presentation 
level" part of the Web page.
c) have us publish it on our servers (this will require some techniques 
of validating users, update / refresh - requires some more thoughts.


Best

Martin

--
--
martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen

e-mail:  mh...@computer.org
phone:   +49-(0)89-6004-4217
fax: +49-(0)89-6004-4620
www: http://www.unibw.de/ebusiness/ (group)
http://www.heppnetz.de/ (personal)
skype:   mfhepp 
twitter: mfhepp


Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!


Webcast:
http://www.heppnetz.de/projects/goodrelations/webcast/

Talk at the Semantic Technology Conference 2009: 
"Semantic Web-based E-Commerce: The GoodRelations Ontology"

http://tinyurl.com/semtech-hepp

Tool for registering your business:
http://www.ebusiness-unibw.org/tools/goodrelations-annotator/

Overview article on Semantic Universe:
http://tinyurl.com/goodrelations-universe

Project page and resources for developers:
http://purl.org/goodrelations/

Tutorial materials:
Tutorial at ESWC 2009: The Web of Data for E-Commerce in One Day: A Hands-on 
Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey

http://www.ebusiness-unibw.org/wiki/GoodRelations_Tutorial_ESWC2009




begin:vcard
fn:Martin Hepp
n:Hepp;Martin
org:Bundeswehr University Munich;E-Business and Web Science Research Group
adr:;;Werner-Heisenberg-Web 39;Neubiberg;;D-85577;Germany
email;internet:mh...@computer.org
tel;work:+49 89 6004 4217
tel;pager:skype: mfhepp
url:http://www.heppnetz.de
version:2.1
end:vcard

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Melvin Carvalho]

On Thu, Jun 25, 2009 at 6:44 PM, Martin Hepp
(UniBW) wrote:
> Hi all:
>
> After about two months of helping people generate RDF/XML metadata for their
> businesses using the GoodRelations annotator [1],
> I have quite some evidence that the current best practices of using
> .htaccess are a MAJOR bottleneck for the adoption of Semantic Web
> technology.
>
> Just some data:
> - We have several hundred entries in the annotator log - most people spend
> 10 or more minutes to create a reasonable description of themselves.
> - Even though they all operate some sort of Web sites, less than 30 % of
> them manage to upload/publish a single *.rdf file in their root directory.
> - Of those 30%, only a fraction manage to set up content negotiation
> properly, even though we provide a step-by-step recipe.
>
> The effects are
> - URIs that are not dereferencable,
> - incorrect media types and
> and other problems.
>
> When investigating the causes and trying to help people, we encountered a
> variety of configurations and causes that we did not expect. It turned out
> that helping people just managing this tiny step of publishing  Semantic Web
> data would turn into a full-time job for 1 - 2 administrators.
>
> Typical causes of problems are
> - Lack of privileges for .htaccess (many cheap hosting packages give limited
> or no access to .htaccess)
> - Users without Unix background had trouble name a file so that it begins
> with a dot
> - Microsoft IIS require completely different recipes
> - Many users have access just at a CMS level
>
> Bottomline:
> - For researchers in the field, it is a doable task to set up an Apache
> server so that it serves RDF content according to current best practices.
> - For most people out there in reality, this is regularly a prohibitively
> difficult task, both because of a lack of skills and a variety in the
> technical environments that turns into an engineering challenge what is easy
> on the textbook-level.
>
> As a consequence, we will modify our tool so that it generates "dummy" RDFa
> code with span/div that *just* represents the meta-data without interfering
> with the presentation layer.
> That can then be inserted as code snippets via copy-and-paste to any XHTML
> document.
>
> Any opinions?

Been thinking about this issue for the last 6 months, and ive changed
my mind a few times.

Inclined to agree that RDFa is probably the ideal entry point for
bringing existing businesses onto Good Relations.

For a read/write web (which is the goal of commerce, right?), you're
probably back to .htaccess, though, with, say, a controller that will
manage POSTed SPARUL inserts.

I think taking it "one step at a time", in this way, seems a sensible
approach, though as a community, we'll need to put a bit of wieght
behind getting the RDFa tool set up to the state of the art.

>
> Best
> Martin
>
> [1]  http://www.ebusiness-unibw.org/tools/goodrelations-annotator/
>
> Danny Ayers wrote:
>>
>> Thank you for the excellent questions, Bill.
>>
>> Right now IMHO the best bet is probably just to pick whichever format
>> you are most comfortable with (yup "it depends") and use that as the
>> single source, transforming perhaps with scripts to generate the
>> alternate representations for conneg.
>>
>> As far as I'm aware we don't yet have an easy templating engine for
>> RDFa, so I suspect having that as the source is probably a good choice
>> for typical Web applications.
>>
>> As mentioned already GRDDL is available for transforming on the fly,
>> though I'm not sure of the level of client engine support at present.
>> Ditto providing a SPARQL endpoint is another way of maximising the
>> surface area of the data.
>>
>> But the key step has clearly been taken, that decision to publish data
>> directly without needing the human element to interpret it.
>>
>> I claim *win* for the Semantic Web, even if it'll still be a few years
>> before we see applications exploiting it in a way that provides real
>> benefit for the end user.
>>
>> my 2 cents.
>>
>> Cheers,
>> Danny.
>>
>>
>>
>
> --
> --
> martin hepp
> e-business & web science research group
> universitaet der bundeswehr muenchen
>
> e-mail:  mh...@computer.org
> phone:   +49-(0)89-6004-4217
> fax:     +49-(0)89-6004-4620
> www:     http://www.unibw.de/ebusiness/ (group)
>        http://www.heppnetz.de/ (personal)
> skype:   mfhepp twitter: mfhepp
>
> Check out the GoodRelations vocabulary for E-Commerce on the Web of Data!
> 
>
> Webcast:
> http://www.heppnetz.de/projects/goodrelations/webcast/
>
> Talk at the Semantic Technology Conference 2009: "Semantic Web-based
> E-Commerce: The GoodRelations Ontology"
> http://tinyurl.com/semtech-hepp
>
> Tool for registering your business:
> http://www.ebusiness-unibw.org/tools/goodrelations-annotator/
>
> Overview article on Semantic Universe:
> http://tinyurl.com/goodrelations

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

Dan Brickley wrote:

+cc: Norm Walsh

On 25/6/09 19:39, Juan Sequeda wrote:

So... then from what I understand.. why bother with content negotiation,
right?

Just do everything in RDFa, right?

We are planning to deploy soon the linked data version of Turn2Live.com.
And we are in the discussion of doing the content negotiation (a la
BBC). But if we can KISS, then all we should do is RDFa, right?


Does every major RDF toolkit have an integrated RDFa parser already?

And yep the conneg idiom isn't mandatory. You can use # URIs, at least 
if the .rdf application/rdf+xml mime type is set. I believe that's in 
the Apache defaults now. At least checking here, a fresh Ubuntu 
installation has "application/rdf+xml rdf" 
in /etc/mime.types (a file which I think comes via Apache but not 100% 
sure).


But yes - this is a major problem and headache. Not just around the 
conneg piece, but in general. I've seen similar results to those 
reported here with "write yourself a FOAF file" exercises. Even if 
people use Leigh Dodd's handy foaf-a-matic webforms to author a file 
... at the end of the session they are left with a piece of RDF/XML in 
their hands, and an instruction to "upload it to their sites". Even 
people with blogs and facebook profiles and twitter accounts etc. can 
find this daunting. And not many people know what FTP is (or was).


My suggestion here is that we look into something like OAuth for 
delegating permission tokens for uploading files. OAuth is a protocol 
that uses a Web/HTML for site A to request that some user of site B 
allow it to perform certain constrained tasks on site B. Canonical 
example being "site A (a printing company) wants to see non-public 
photos on site B (a photo-sharing site)". I believe this model works 
well for writing/publishing, as well as for mediating information access.


If site A is an RDF-generating site, and site B is a generic hosting 
site, then the idea is that we write or find a generic OAuth-enabled 
utility that B could use, such that the users of site B could give 
sites like A permission to publish documents automatically. At a 
protocol level, I would expect this to use AtomPub but it could also 
be WebDAV or another mechanism.


But how to get all those sites to implement such a thing? Well 
firstly, this isn't limited to FOAF. Or to any flavour of RDF. I think 
there is a strong story for why this will happen eventually. Strong 
because there are clear benefits for many of the actors:


* a data-portability and user control story: I don't want all my music 
profile info to be on last.fm; I want last.fm to maintain 
http://danbri.org/music for me.
* a benefits-the-data source story: I'm sure the marketing teams of 
various startups would be very happy at the ability to directly push 
content into 1000s of end-user sites. For the Google/Link karma, 
traffic etc.
* benefits the hosts story: rather than having users share their FTP 
passwords, they share task-specific tokens that can be managed and 
rolled back on finer-grained basis


So a sample flow might be:

1. User Alice is logged into her blog, which is now AtomPub+OAuth 
enabled.
2. She clicks on a link somewhere for "generate a FOAF file from your 
music interests", which takes her to a site that asks some basic 
information (name, homepage) and about some music-related sites she uses.
3. That site's FOAF generator site scans her public last.fm profile 
(after asking her username), and then does the same for her Myspace 
and YouTube profiles.
4. It then says "OK, generated music profile! May we publish this to 
your site? It then scans her homesite, blog etc via some 
auto-discovery protocol(s), to see which of them have a writable 
AtomPub + OAuth endpoint. It finds her wordpress blog supports this.
5. Alice is bounced to an OAuth permissioning page on her blog, which 
says something like:

"The Music Profile site at example.com  would like to
have read and write permission for an area of your site: 
once/always/never or for 6 months?"
6. Alice gives permission for 6 months. Some computer stuff happens in 
the background, and the Music site is given a token it can use to post 
data to Alice's site.
7. http://alice.example.com/blog/musicprofile then becomes a page (or 
mini-blog or activity stream) maintained entirely, or partially, by 
the remote site using RDFa markup sent as AtomPub blog entries, or 
maybe as AtomPub attachments.


OK I'm glossing over some details here, such as configuration, choice 
of URIs etc. I may be over-simplifying some OAuth aspects, and 
forgetting detail of what's possible. But I think there is real 
potential in this sort of model, and would like a sanity check on that!


Also the detail of whether different sites could/would write to the 
same space or feed or not. And how we can use this as a 
page-publishing model instead of a blog entry publishing model.


I've written about this before, see 
http://markmail.org/message/gp

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Damian Steer]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1

Toby Inkster wrote:

> Jena (just testing on sparql.org) doesn't seem to handle RDFa at all.

The jena GRDDL reader handles RDFa. [1]

I've started toying with writing a (direct) RDFa parser, too.

Damian

[1]

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Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Dan Brickley]

On 26/6/09 10:51, Toby Inkster wrote:

On Fri, 2009-06-26 at 09:35 +0200, Dan Brickley wrote:


Does every major RDF toolkit have an integrated RDFa parser already?


No - and even for those that do, it's often rather flaky.

Seseme/Rio doesn't have one in its stable release, though I believe one
is in development for 3.0.

Redland/Raptor often (for me at least) seems to crash on RDFa. It also
complains a lot when named entities are used (e.g. ) even though
the XHTML+RDFa 1.0 DTD does allow them.

Jena (just testing on sparql.org) doesn't seem to handle RDFa at all.

Not really "toolkits" per se, but cwm and the current release of
Tabulator don't seem to have RDFa support. (Though I think support for
the latter is being worked on.)

For application developers who are specifically trying to support RDFa,
none of this is a major problem - it's pretty easy to include a little
content-type detection and pass the XHTML through an RDFa->XML converter
prior to the rest of your code getting its hands on it - but this does
require specific handling, which must be an obstacle to adoption.


Yep, pretty much as I feared. Also the Google SGAPI currently only reads 
FOAF in RDF/XML form, not yet updated to use the rdfa support in Rapper.


Re app developers, it depends a lot. If your app is built inside some 
framework - eg. Protege - RDFa might be quite hard to integrate. Some 
apps also store to local disk rather than HTTP space, and so using 
content-negotiation is tricky. RDFa files don't have any well known 
file-suffix patterns either.


cheers,

Dan

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Toby Inkster]

On Fri, 2009-06-26 at 09:35 +0200, Dan Brickley wrote:

> Does every major RDF toolkit have an integrated RDFa parser already?

No - and even for those that do, it's often rather flaky.

Seseme/Rio doesn't have one in its stable release, though I believe one
is in development for 3.0.

Redland/Raptor often (for me at least) seems to crash on RDFa. It also
complains a lot when named entities are used (e.g.  ) even though
the XHTML+RDFa 1.0 DTD does allow them.

Jena (just testing on sparql.org) doesn't seem to handle RDFa at all.

Not really "toolkits" per se, but cwm and the current release of
Tabulator don't seem to have RDFa support. (Though I think support for
the latter is being worked on.)

For application developers who are specifically trying to support RDFa,
none of this is a major problem - it's pretty easy to include a little
content-type detection and pass the XHTML through an RDFa->XML converter
prior to the rest of your code getting its hands on it - but this does
require specific handling, which must be an obstacle to adoption.

-- 
Toby A Inkster

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Toby A Inkster]

On 25 Jun 2009, at 21:18, Pat Hayes wrote:

If [RDF] requires people to tinker with files with names starting  
with a dot [...] then the entire SWeb architecture is fundamentally  
broken.


RDF doesn't. Apache does.

Many hosts do have front ends for configuring Apache, allowing  
redirects to be set up and content-types configured by filling in  
simple web forms. But there are such a variety of these tools with  
different capabilities and different interfaces that it would be  
difficult to produce advice suitable for them all, so instead  
".htaccess" recipes are provided instead.


That said, there are a couple of steps that Martin could remove from  
his recipe and still be promoting reasonably good practice:


Step 5a - this rewrites  to example.org/semanticweb.rdf>. Other than aesthetics, there's no real  
reason to do this. Yes, I've read timbl's old Cool URIs document, and  
understand about not wanting to include hints of file format in a  
URI. But realistically, this file is going to always include some RDF  
- perhaps in a non-RDF/XML serialisation, but I don't see anything  
inappropriate about serving other RDF serialisations using a ".rdf"  
URL, provided the correct MIME type is used.


Step 5b - the default Apache mime.types file knows about application/ 
rdf+xml, so this should be unnecessary. Perhaps instead have a  
GoodRelations "validator" which checks that the content type is  
correct, and only suggests this when it is found to be otherwise.


Steps 3 and 4 could be amalgamated into a single "validate your RDF  
file" step using the aforementioned validator. The validator would be  
written so that, upon a successful validation, it offers single-click  
options to ping semweb search engines, and Yahoo (via a RDF/XML- 
>DataRSS converter).


With those adjustments, the recipe would just be:

1. Upload your RDF file.
2. Add a rel="meta" link to it.
3. Validate using our helpful tool.

--
Toby A Inkster

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Dan Brickley]

On 25/6/09 19:06, Jeff Finkelstein, Customer Paradigm wrote:

Martin-

I agree that the .htaccess file is a big stumbling block for many people
with low-cost hosting.  Would a lightweight php-based application that could
write to the .htaccess  / create the RDF file work to solve this easily?


I'd suggest exploring a lightweight but standards-based PHP app that 
could be dropped into a site, given a configuration and top-level 
directory, such that external sites could use a OAuth interface to 
negotiate write access, and then use AtomPub to post all kinds of data 
into that Web space.


(per my previous post)

Actually I forgot another benefit of this model: external sites could 
re-post data automatically, with no further user interaction. This 
solves a lot of "my foaf file ... i generated it once but didn't keep it 
up to date" problems...


Dan

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Dan Brickley]

+cc: Norm Walsh

On 25/6/09 19:39, Juan Sequeda wrote:

So... then from what I understand.. why bother with content negotiation,
right?

Just do everything in RDFa, right?

We are planning to deploy soon the linked data version of Turn2Live.com.
And we are in the discussion of doing the content negotiation (a la
BBC). But if we can KISS, then all we should do is RDFa, right?


Does every major RDF toolkit have an integrated RDFa parser already?

And yep the conneg idiom isn't mandatory. You can use # URIs, at least 
if the .rdf application/rdf+xml mime type is set. I believe that's in 
the Apache defaults now. At least checking here, a fresh Ubuntu 
installation has "application/rdf+xml rdf" 
in /etc/mime.types (a file which I think comes via Apache but not 100% 
sure).


But yes - this is a major problem and headache. Not just around the 
conneg piece, but in general. I've seen similar results to those 
reported here with "write yourself a FOAF file" exercises. Even if 
people use Leigh Dodd's handy foaf-a-matic webforms to author a file ... 
at the end of the session they are left with a piece of RDF/XML in their 
hands, and an instruction to "upload it to their sites". Even people 
with blogs and facebook profiles and twitter accounts etc. can find this 
daunting. And not many people know what FTP is (or was).


My suggestion here is that we look into something like OAuth for 
delegating permission tokens for uploading files. OAuth is a protocol 
that uses a Web/HTML for site A to request that some user of site B 
allow it to perform certain constrained tasks on site B. Canonical 
example being "site A (a printing company) wants to see non-public 
photos on site B (a photo-sharing site)". I believe this model works 
well for writing/publishing, as well as for mediating information access.


If site A is an RDF-generating site, and site B is a generic hosting 
site, then the idea is that we write or find a generic OAuth-enabled 
utility that B could use, such that the users of site B could give sites 
like A permission to publish documents automatically. At a protocol 
level, I would expect this to use AtomPub but it could also be WebDAV or 
another mechanism.


But how to get all those sites to implement such a thing? Well firstly, 
this isn't limited to FOAF. Or to any flavour of RDF. I think there is a 
strong story for why this will happen eventually. Strong because there 
are clear benefits for many of the actors:


* a data-portability and user control story: I don't want all my music 
profile info to be on last.fm; I want last.fm to maintain 
http://danbri.org/music for me.
* a benefits-the-data source story: I'm sure the marketing teams of 
various startups would be very happy at the ability to directly push 
content into 1000s of end-user sites. For the Google/Link karma, traffic 
etc.
* benefits the hosts story: rather than having users share their FTP 
passwords, they share task-specific tokens that can be managed and 
rolled back on finer-grained basis


So a sample flow might be:

1. User Alice is logged into her blog, which is now AtomPub+OAuth enabled.
2. She clicks on a link somewhere for "generate a FOAF file from your 
music interests", which takes her to a site that asks some basic 
information (name, homepage) and about some music-related sites she uses.
3. That site's FOAF generator site scans her public last.fm profile 
(after asking her username), and then does the same for her Myspace and 
YouTube profiles.
4. It then says "OK, generated music profile! May we publish this to 
your site? It then scans her homesite, blog etc via some auto-discovery 
protocol(s), to see which of them have a writable AtomPub + OAuth 
endpoint. It finds her wordpress blog supports this.
5. Alice is bounced to an OAuth permissioning page on her blog, which 
says something like:

"The Music Profile site at example.com  would like to
	have read and write permission for an area of your site: 
once/always/never or for 6 months?"
6. Alice gives permission for 6 months. Some computer stuff happens in 
the background, and the Music site is given a token it can use to post 
data to Alice's site.
7. http://alice.example.com/blog/musicprofile then becomes a page (or 
mini-blog or activity stream) maintained entirely, or partially, by the 
remote site using RDFa markup sent as AtomPub blog entries, or maybe as 
AtomPub attachments.


OK I'm glossing over some details here, such as configuration, choice of 
URIs etc. I may be over-simplifying some OAuth aspects, and forgetting 
detail of what's possible. But I think there is real potential in this 
sort of model, and would like a sanity check on that!


Also the detail of whether different sites could/would write to the same 
space or feed or not. And how we can use this as a page-publishing model 
instead of a blog entry publishing model.


I've written about this before, see 
http://markmail.org/message/gplslpe2k2zjuliq


Re p

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[John Graybeal]

Just because it's on your server doesn't mean the visitor to the  
restaurant's web page has to know that.  (Does it?)  Hmm, maybe that  
takes us back to the .htaccess argument


I agree the shop owner has to feel ownership.  So whatever solution  
you choose, the shop owner has to have access to the tool which  
enables its easy use, in their language and context.   I mention this  
because I don't know if the snippet solution will pass that test. It  
will be cool if it does.  (Please let us know how it turns out, you  
are the cutting edge research here! I find what you are doing very  
exciting.)


John

On Jun 25, 2009, at 12:26 PM, Martin Hepp (UniBW) wrote:


Hi John:
We also thought of hosting meta-data for the users, but I don't like  
that because I want the shop operators to feel ownership for the data:
If the opening hours expressed in RDF are wrong but on the personal  
Web page of that restaurant, anybody facing closed doors will blame  
the restaurant.
If the outdated opening hours in RDF are on my SW server, the  
unlucky customer will blame the Semantic Web for having crappy data.


So maybe the snippet solution in RDFa is the best.

Best
Martin


John Graybeal wrote:
This is a principal reason MMI decided to offer a vocabulary server  
for its community. The idea that 1000 different providers would all  
develop a level of web competency (for which there is evidence at  
only a minority of providers) for serving their RDF and OWL content  
-- let alone the capability to do versioning, adopt best practices,  
learn SKOS, and whatever other nuances are called for -- seemed  
like a non-starter.


This is not exactly the same problem you're facing, but something  
to consider (if the model allows it) is creating a way to serve the  
annotations from another place than the host institution.  The  
institution can refer to those served files from their own sites,  
and even update them remotely, but not have to incur all the  
management overhead as standards improve, files change, authorship  
changes, etc.


(Which is not to disagree with your plan either. That sounds fine.)

One other delivery model could be for them to give you an existing  
HTML, you give them back the modified HTML (saves them cutting and  
pasting steps?).


I'm a little ignorant on your tools and processes, so apologies if  
these are non-starters.


John


On Jun 25, 2009, at 9:44 AM, Martin Hepp (UniBW) wrote:


Hi all:

After about two months of helping people generate RDF/XML metadata  
for their businesses using the GoodRelations annotator [1],
I have quite some evidence that the current best practices of  
using .htaccess are a MAJOR bottleneck for the adoption of  
Semantic Web technology.


Just some data:
- We have several hundred entries in the annotator log - most  
people spend 10 or more minutes to create a reasonable description  
of themselves.
- Even though they all operate some sort of Web sites, less than  
30 % of them manage to upload/publish a single *.rdf file in their  
root directory.
- Of those 30%, only a fraction manage to set up content  
negotiation properly, even though we provide a step-by-step recipe.


The effects are
- URIs that are not dereferencable,
- incorrect media types and
and other problems.

When investigating the causes and trying to help people, we  
encountered a variety of configurations and causes that we did not  
expect. It turned out that helping people just managing this tiny  
step of publishing  Semantic Web data would turn into a full-time  
job for 1 - 2 administrators.


Typical causes of problems are
- Lack of privileges for .htaccess (many cheap hosting packages  
give limited or no access to .htaccess)
- Users without Unix background had trouble name a file so that it  
begins with a dot

- Microsoft IIS require completely different recipes
- Many users have access just at a CMS level

Bottomline:
- For researchers in the field, it is a doable task to set up an  
Apache server so that it serves RDF content according to current  
best practices.
- For most people out there in reality, this is regularly a  
prohibitively difficult task, both because of a lack of skills and  
a variety in the technical environments that turns into an  
engineering challenge what is easy on the textbook-level.


As a consequence, we will modify our tool so that it generates  
"dummy" RDFa code with span/div that *just* represents the meta- 
data without interfering with the presentation layer.
That can then be inserted as code snippets via copy-and-paste to  
any XHTML document.


Any opinions?

Best
Martin

[1]  http://www.ebusiness-unibw.org/tools/goodrelations-annotator/

Danny Ayers wrote:

Thank you for the excellent questions, Bill.

Right now IMHO the best bet is probably just to pick whichever  
format
you are most comfortable with (yup "it depends") and use that as  
the

single source, transforming perhaps with scripts to generate the
alternate representations for c

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

Mark Birbeck wrote:

Hi Kingsley,

  

If you are comfortable producing (X)HTML documents, then simply use RDFa and
terms from relevant vocabularies to describe yourself, your needs, your
offerings, and other things, clearly. Once you've done that, simply leave
the Web to do the REST :-)

Everything else is a technical detail (imho).



  

Mark,

But that isn't the discussion we're having, IMHO.

We're not talking about how you or I might do it -- people comfortable
with .htaccess files, server configuration, and so on.
  


I don't see how my comments implies anything to do with people capable 
of, or with privileged access to, .htaccess.


I am echoing the sentiment that concluded our conversation last week at 
dinner: let people capable of writing HTML (dropped the X) also be

capable of describing things using the RDF data model courtesy of RDFa.

When you get the structured data into the Web it will actually do the 
REST i.e. it's architecture kicks in and does all of the other wonderful 
things such as:
enabling you to find the nearest *open* BestBuy store that carries an 
esoteric MP3 model within 2 km of your current location etc..

My understanding of the discussion that was going on, is that whilst
we all want to see the semantic web succeed (even if we all have a
different view of what the semantic web is), we're asking how exactly
it is that we can achieve it.
  
And my point is we should have a simple value proposition that is 
aligned with a set of scenarios, and manifestation solutions.


To reiterate: we want people to be able add granularity to the documents 
they publish to the Web. A lot of this granularity takes the form of
metadata which can be expressed using the RDF data model by embedding 
RDFa into HTML.



And for years, the solutions proposed have been somewhat mysterious;
RDF/XML, SPARQL end-points, N3, content negotiation, 303s, and so on.
  
No, over the years the messaging has been mangled in a myriad of ways. 
Again, my goal is to focus on a simple message and from that distill
implementation scenarios. Again, there's no silver bullet for the Linked 
Data deployment matter per se. Just scenarios to which deployment 
recipes may be aligned.

You have to ask yourself at some point, do we want the data, or don't
we -- do we want people to publish stuff that we 'semwebbers' can use?
And if we do want it, then let's help them publish it.
  


We just need to politely tell the world: the granularity of markup has 
evolved from presentation oriented semantics (HTML) through document 
structure semantics (XML) to

metadata semantics (RDF).

I may be biased because I've had my nose pressed up against it for too
many years, but I believe that in this regards, RDFa is a
game-changer.
  
It's not GRDDL, which says 'publish whatever the hell you like and

we'll convert it'. It's not microformats, which says, 'here are a
handful of centralised vocabularies, for use on a decentralised web'.
And it's not RDF/XML, which requires you to take apart your server and
put it back together again.

It's HTML.
  

Dare I agree ?

:-)

And everyone knows at least one way to publish HTML, don't they?

In the years that I've been involved with the RDFa work, the mental
model I have always had, is of someone using Blogger or Drupal or
something just as simple, to publish RDF. That's now possible with
RDFa, and what's even more exciting, Yahoo! and Google will pick it
up.
  


I've had a simple mental model: the desire to express myself clearly, 
via markup :-) 

I realise I'm sounding like an evangelist (no doubt because I am one). :)

But my suggestion would be that we have a window of opportunity here,
to create a semantic infrastructure that is indistinguishable from the
web itself; the more metadata we can get into HTML-space, the more
likely we are to bring about a more 'semantic' web...before anyone
notices. ;)
  

Again, dare I agree :-)


Kingsley

Regards,

Mark

  



--


Regards,

Kingsley Idehen   Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software Web: http://www.openlinksw.com

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Giovanni Tummarello]

On Fri, Jun 26, 2009 at 12:18 AM, Pat Hayes wrote:
> With the sincerest respect, Tom, your attitude here is part of the problem.
> But in any case, this is ridiculous. RDF is just XML text, for goodness
> sake.  I need to insert lines of code into a server file,  and write PHP
> scripts, in order to publish some RDF or HTML?  That is insane. It would
> have been insane in the mid-1990s and its even more insane now. IMO, it is
> you (and Tim and the rest of the W3C) who are stuck in the past here.

Cheers for Pat \o/ ,

with all the due respect for all involved and the amount of great work
so far, lets just move ahead.

 If there is a single better simpler way to do things it should be
reccomended at once and the rest be dropped.

"celebrate diversity" and keeping more compelx specs alive while there
is no legacy "use" of it is just  a way to further lose credibilty and
ultimately relevance.

It is not a case that you find a lot of universities talking in here
but no google or yahoo or msn or whoeever else..

just sharing:

I was at last week at SemTech and had a change to have some very
interesting discussions. The big search engine guys i was talking to
were all perfectly aware of all but just decided to stay clear becouse
light years distant from what they know they can (and will) ask people
publish HTML to do in terms of metadata .

"and when we do propose something, any big web site will simply follow
it.. why should they not. ". :-)

a report, not a speculation.

Giovanni

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Bradley Allen]

Mark- Beautifully put. +1 on a hopefully accelerating trend towards
simplicity and ease of adoption. - BPA

Bradley P. Allen
http://bradleypallen.org
+1 310 951 4300



On Thu, Jun 25, 2009 at 3:34 PM, Mark
Birbeck wrote:
> Hi Kingsley,
>
>> If you are comfortable producing (X)HTML documents, then simply use RDFa and
>> terms from relevant vocabularies to describe yourself, your needs, your
>> offerings, and other things, clearly. Once you've done that, simply leave
>> the Web to do the REST :-)
>>
>> Everything else is a technical detail (imho).
>
> But that isn't the discussion we're having, IMHO.
>
> We're not talking about how you or I might do it -- people comfortable
> with .htaccess files, server configuration, and so on.
>
> My understanding of the discussion that was going on, is that whilst
> we all want to see the semantic web succeed (even if we all have a
> different view of what the semantic web is), we're asking how exactly
> it is that we can achieve it.
>
> And for years, the solutions proposed have been somewhat mysterious;
> RDF/XML, SPARQL end-points, N3, content negotiation, 303s, and so on.
>
> You have to ask yourself at some point, do we want the data, or don't
> we -- do we want people to publish stuff that we 'semwebbers' can use?
> And if we do want it, then let's help them publish it.
>
> I may be biased because I've had my nose pressed up against it for too
> many years, but I believe that in this regards, RDFa is a
> game-changer.
>
> It's not GRDDL, which says 'publish whatever the hell you like and
> we'll convert it'. It's not microformats, which says, 'here are a
> handful of centralised vocabularies, for use on a decentralised web'.
> And it's not RDF/XML, which requires you to take apart your server and
> put it back together again.
>
> It's HTML.
>
> And everyone knows at least one way to publish HTML, don't they?
>
> In the years that I've been involved with the RDFa work, the mental
> model I have always had, is of someone using Blogger or Drupal or
> something just as simple, to publish RDF. That's now possible with
> RDFa, and what's even more exciting, Yahoo! and Google will pick it
> up.
>
> I realise I'm sounding like an evangelist (no doubt because I am one). :)
>
> But my suggestion would be that we have a window of opportunity here,
> to create a semantic infrastructure that is indistinguishable from the
> web itself; the more metadata we can get into HTML-space, the more
> likely we are to bring about a more 'semantic' web...before anyone
> notices. ;)
>
> Regards,
>
> Mark
>
> --
> Mark Birbeck, webBackplane
>
> mark.birb...@webbackplane.com
>
> http://webBackplane.com/mark-birbeck
>
> webBackplane is a trading name of Backplane Ltd. (company number
> 05972288, registered office: 2nd Floor, 69/85 Tabernacle Street,
> London, EC2A 4RR)
>
>

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Mark Birbeck]

Hi Kingsley,

> If you are comfortable producing (X)HTML documents, then simply use RDFa and
> terms from relevant vocabularies to describe yourself, your needs, your
> offerings, and other things, clearly. Once you've done that, simply leave
> the Web to do the REST :-)
>
> Everything else is a technical detail (imho).

But that isn't the discussion we're having, IMHO.

We're not talking about how you or I might do it -- people comfortable
with .htaccess files, server configuration, and so on.

My understanding of the discussion that was going on, is that whilst
we all want to see the semantic web succeed (even if we all have a
different view of what the semantic web is), we're asking how exactly
it is that we can achieve it.

And for years, the solutions proposed have been somewhat mysterious;
RDF/XML, SPARQL end-points, N3, content negotiation, 303s, and so on.

You have to ask yourself at some point, do we want the data, or don't
we -- do we want people to publish stuff that we 'semwebbers' can use?
And if we do want it, then let's help them publish it.

I may be biased because I've had my nose pressed up against it for too
many years, but I believe that in this regards, RDFa is a
game-changer.

It's not GRDDL, which says 'publish whatever the hell you like and
we'll convert it'. It's not microformats, which says, 'here are a
handful of centralised vocabularies, for use on a decentralised web'.
And it's not RDF/XML, which requires you to take apart your server and
put it back together again.

It's HTML.

And everyone knows at least one way to publish HTML, don't they?

In the years that I've been involved with the RDFa work, the mental
model I have always had, is of someone using Blogger or Drupal or
something just as simple, to publish RDF. That's now possible with
RDFa, and what's even more exciting, Yahoo! and Google will pick it
up.

I realise I'm sounding like an evangelist (no doubt because I am one). :)

But my suggestion would be that we have a window of opportunity here,
to create a semantic infrastructure that is indistinguishable from the
web itself; the more metadata we can get into HTML-space, the more
likely we are to bring about a more 'semantic' web...before anyone
notices. ;)

Regards,

Mark

-- 
Mark Birbeck, webBackplane

mark.birb...@webbackplane.com

http://webBackplane.com/mark-birbeck

webBackplane is a trading name of Backplane Ltd. (company number
05972288, registered office: 2nd Floor, 69/85 Tabernacle Street,
London, EC2A 4RR)

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Richard Cyganiak]

Martin,

On 25 Jun 2009, at 18:44, Martin Hepp (UniBW) wrote:
As a consequence, we will modify our tool so that it generates  
"dummy" RDFa code with span/div that *just* represents the meta-data  
without interfering with the presentation layer.
That can then be inserted as code snippets via copy-and-paste to any  
XHTML document.


By "dummy" RDFa markup, do you mean something that is completely  
invisible, so the data wouldn't actually appear on the page, e.g. by  
using style="display:hidden"? That would worry me a bit, because the  
content is invisible without a special RDFa or GoodRelations  
processor, and hence will probably not be kept up-to-date as well as  
information that's plainly visible in a web browser. For evidence,  
have a look at the average SemWeb geek's FOAF profile. Hence, I would  
suggest to keep the information visible. Sorry if I misunderstood and  
that was your intention all along!


Just an idea: How about creating a nicely styled static HTML page that  
sort of looks like an official certificate, with a nice big  
GoodRelations logo etc, and all the data is on the page, annotated  
with RDFa? Might be cleaner than hidden RDFa markup, and a static HTML  
page is hopefully easier to deploy than content-negotiated RDF/XML.


Re .htaccess, you are completely right, it's not an option. For  
average users, the only way they will get content negotiation right is  
if their server (e.g. Virtuoso) or installable web application (e.g.  
Neologism) supports it out of the box.


(On the value of content negotiation in general: I think the key point  
is that any linked data URI intended for re-use, when put into a  
browser by the average person interested in linked data publishing,  
MUST return something human-readable. That's a hard requirement,  
otherwise people will never be confident about what a particular URI  
means and hence they won't re-use. That was the thinking behind the  
Cool URIs note when Leo and I wrote it a few years ago. In the past,  
the only way to get that effect was with content negotiation, so even  
though content negotiation is a pain, it's what we had to do. In the  
present, we have an alternative thanks to RDFa. In the future, maybe  
there'll be a day when the average linked data user will have a  
browser that supports linked data out of the box.)


Best,
Richard







Any opinions?

Best
Martin

[1]  http://www.ebusiness-unibw.org/tools/goodrelations-annotator/

Danny Ayers wrote:

Thank you for the excellent questions, Bill.

Right now IMHO the best bet is probably just to pick whichever format
you are most comfortable with (yup "it depends") and use that as the
single source, transforming perhaps with scripts to generate the
alternate representations for conneg.

As far as I'm aware we don't yet have an easy templating engine for
RDFa, so I suspect having that as the source is probably a good  
choice

for typical Web applications.

As mentioned already GRDDL is available for transforming on the fly,
though I'm not sure of the level of client engine support at present.
Ditto providing a SPARQL endpoint is another way of maximising the
surface area of the data.

But the key step has clearly been taken, that decision to publish  
data

directly without needing the human element to interpret it.

I claim *win* for the Semantic Web, even if it'll still be a few  
years

before we see applications exploiting it in a way that provides real
benefit for the end user.

my 2 cents.

Cheers,
Danny.





--
--
martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen

e-mail:  mh...@computer.org
phone:   +49-(0)89-6004-4217
fax: +49-(0)89-6004-4620
www: http://www.unibw.de/ebusiness/ (group)
   http://www.heppnetz.de/ (personal)
skype:   mfhepp twitter: mfhepp

Check out the GoodRelations vocabulary for E-Commerce on the Web of  
Data!
= 
= 
==


Webcast:
http://www.heppnetz.de/projects/goodrelations/webcast/

Talk at the Semantic Technology Conference 2009: "Semantic Web-based  
E-Commerce: The GoodRelations Ontology"

http://tinyurl.com/semtech-hepp

Tool for registering your business:
http://www.ebusiness-unibw.org/tools/goodrelations-annotator/

Overview article on Semantic Universe:
http://tinyurl.com/goodrelations-universe

Project page and resources for developers:
http://purl.org/goodrelations/

Tutorial materials:
Tutorial at ESWC 2009: The Web of Data for E-Commerce in One Day: A  
Hands-on Introduction to the GoodRelations Ontology, RDFa, and  
Yahoo! SearchMonkey


http://www.ebusiness-unibw.org/wiki/GoodRelations_Tutorial_ESWC2009

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

Jeremy Carroll wrote:

Pat Hayes wrote:


RDF should be text, in documents. One should be able to use it 
without knowing about anything more than the RDF spec and the XML 
spec. If it requires people to tinker with files with names starting 
with a dot, or write code, or deploy scripts, then the entire SWeb 
architecture is fundamentally broken.




Largely agreeing with you Pat, I think I would want to go a step 
further and say that you should be able to use RDF without knowing 
anything about the RDF spec or the XML spec, or any other spec. Web 
users are not required to read the specs.


Using RDF includes publishing it. The "infrastructure" whatever that 
is should achieve the ability to publish my data in an appropriate way.


Jeremy



Thanks to Twitter (which forces brevity), getting out to Semtech 2009, 
and hours of discussion with Martin Hepp and Aldo Bucchi, we summarize 
the current phenomena as follows:


If you are comfortable producing (X)HTML documents, then simply use RDFa 
and terms from relevant vocabularies to describe yourself, your needs, 
your offerings, and other things, clearly. Once you've done that, simply 
leave the Web to do the REST :-)


Everything else is a technical detail (imho).

--


Regards,

Kingsley Idehen   Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software Web: http://www.openlinksw.com

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Mark Birbeck]

Hi Jeremy/Pat,

On Thu, Jun 25, 2009 at 10:16 PM, Jeremy Carroll wrote:
> Pat Hayes wrote:
>>
>> RDF should be text, in documents. One should be able to use it without
>> knowing about anything more than the RDF spec and the XML spec. If it
>> requires people to tinker with files with names starting with a dot, or
>> write code, or deploy scripts, then the entire SWeb architecture is
>> fundamentally broken.
>>
>
> Largely agreeing with you Pat, I think I would want to go a step further and
> say that you should be able to use RDF without knowing anything about the
> RDF spec or the XML spec, or any other spec. Web users are not required to
> read the specs.
>
> Using RDF includes publishing it. The "infrastructure" whatever that is
> should achieve the ability to publish my data in an appropriate way.

I guess what you're getting at here is the more general point about
tools hiding RDF, but I'd like to add some comments on HTML more
specifically.

HTML publishing really took off when it became easy for anyone to
publish. Originally that was word processors that converted their
output to HTML, but you still had to deploy your document to a server.

Then it was CMS systems that could be used as easily by small
businesses and schools as large corporations, but you still needed to
have a server.

Then it became blogs, where someone else did the server install, and
you just typed in the content.

Then it was wikis -- ditto.

Now it's Google Docs, Facebook pages, Tweets, and more.

In other words, publishing HTML just gets easier and easier, and
that's the infrastructure that's important -- the HTML publishing
infrastructure.

So to publish RDF, we should simply be leveraging that enormous infrastructure.

This theme was one of the major motivations for the creation of RDFa
(née RDF/XHTML), and I would say that it's an even more important
theme today; so much so that I made it the core of a presentation I
did at SemTech last week, on 'RDFa: The Semantic Web's Missing Link'.
[1].)

Regards,

Mark

[1] 


-- 
Mark Birbeck, webBackplane

mark.birb...@webbackplane.com

http://webBackplane.com/mark-birbeck

webBackplane is a trading name of Backplane Ltd. (company number
05972288, registered office: 2nd Floor, 69/85 Tabernacle Street,
London, EC2A 4RR)

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Kingsley Idehen]

Martin Hepp (UniBW) wrote:
As mostly, recently ;-), I agree with Kingsley - I did not want to say 
that proper usage of http is bad or obsolete. But it turned out 
unfeasible for broad adoption my owners of small Web sites.


For huge data sources and for vocabularies, the current recipes are 
fine. But I want every single business in the world to use 
GoodRelations for publishing at least their opening hours - 19 Million 
companies in Europe alone. I cannot explain to every single one of 
them how to configure their server.


Another thing that might have gone lost in the discussion: Even though 
we knew the recipes, helping the site owners was difficult, because we 
experienced hundreds of different environments - preexisting 
.htaccess, MS IIS, hoster-specific scenarios, etc. So the problem is 
really that such a low-level technique is not feasible if you face so 
much diversity as far as the target system is concerned.


Maybe some day a certain LOD/SW package will be installed by default 
on most servers. But we cannot wait till then.


BTW: We did not even require the full beauty of LOD best practices. We 
simply want them to do as described here:


http://www.ebusiness-unibw.org/wiki/GoodRelations_Recipe_8

Best
Martin

Martin,

So for this particular Linked Data deployment and consumption scenario, 
we are going to end up with the following:


Content creators:
Describe your stuff (you, your offerings, your needs etc.) using RDFa 
within (X)HTML. Use your current publishing worflow to publish your RDFa 
embellished docs.


User Agents (Browsers, Crawlers, etc.):
Get RDFa enabled (i.e., become an RDFa processor) so you can do 
something with Linked Data for Web users that enriches their overall 
experience courtesy of #1 above.


Re. Virtuoso, you've always been able to SPARQL against any (X)HTML 
resource using Virtuoso's SPARQL processor (which leverages the Sponger 
Middleware & its RDFa Cartridge); simply use the RDFa embellished 
document's URL as the Named Graph IRI in your SPARQL query.


Examples:

1. http://linkeddata.uriburner.com/sparql
2. http://lod2.openlinksw.com/sparql
3. http://bbc.openlinksw.com/sparql
4. Any other Virtuoso instance that enables the Sponging.


Kingsley


Kingsley Idehen wrote:

Giovanni Tummarello wrote:
That can then be inserted as code snippets via copy-and-paste to 
any XHTML

document.

Any opinions?



Great, why bother with any other solution.
even talking about any other solution is extraordinarely bad for the
public perception of the semantic web community.

Giovanni


  

Giovanni,

We don't need mutual exclusivity re. Linked Data Deployment.

There's nothing wrong with an array of options that cover a broad 
range of Linked Data deployment circumstances.


HTTP is the essence of the Web (what makes it what it is), and 
Content Negotiation is intrinsic to HTTP.


Don't throw the baby out with the bathwater, really.







--


Regards,

Kingsley Idehen   Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software Web: http://www.openlinksw.com

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Diego Berrueta Muñoz]

Hi Tom, all,

El 25/06/2009, a las 20:30, Tom Heath escribió:

Are you referring to the best practices at [1]? Unfortunately the
recipes in that document that use .htaccess and mod_rewrite for conneg
no longer count as best practices, precisely due to mod_rewrite and
.htaccess not being adequate for the conneg/303-redirects pattern.
This has been a known issue since WWW2007 at least, and documented at
[2] in July 2007. As far as I know, that recipes document hasn't yet
been updated/deprecated :( (please someone correct me if I'm wrong).


A revision of the Recipes is coming down the pipe. The new version  
will slightly improve how this issue is tackled, but it won't provide  
a complete solution. I believe the document is fair wrt this point: it  
acknowledges the problem and it provides "best effort" recipes to  
partially implement conneg using exclusively Apache directives (as  
opposed to implementing them using PHP, for instance).


I would like to emphasize that there are two different issues here:

1) the Recipes do not correctly implement conneg in its full extension  
and,


2) the Recipes are difficult to deploy due to the inability to access  
to the .htaccess file.


From my POV, both issues are serious, and consequently I also think  
that RDFa is a much more (1) correct and (2) user-friendly way to  
publish RDF data.


Best,

Diego.



The easiest pattern I've found is to use a RewriteRule to catch all
incoming requests and pass them through a small PHP script that
examines the Accept header and sends back 303s (or 200s) as
appropriate. The code is about 6 lines; I'll publish it somewhere if I
didn't already.

Admittedly, this doesn't solve the problem of access to .htaccess
files. This bottleneck sounds to me like someone circa mid-1990s
saying "my sysadmins won't let me have access to space on the web
server". I guess we need to use lessons learned from that era to
address the problems of this one. Anyway fancy doing a Linked Data for
Sysadmins tutorial at a sysadmin conference?

Cheers,

Tom.

[1] http://www.w3.org/TR/swbp-vocab-pub/
[2] http://lists.w3.org/Archives/Public/public-swbp-wg/2007Jul/0001.html



--
Diego Berrueta
R&D Department  -  CTIC Foundation
E-mail: diego.berru...@fundacionctic.org
Phone: +34 984 29 12 12
Parque Científico Tecnológico Gijón-Asturias-Spain
www.fundacionctic.org

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Jeremy Carroll]

Pat Hayes wrote:


RDF should be text, in documents. One should be able to use it without 
knowing about anything more than the RDF spec and the XML spec. If it 
requires people to tinker with files with names starting with a dot, 
or write code, or deploy scripts, then the entire SWeb architecture is 
fundamentally broken.




Largely agreeing with you Pat, I think I would want to go a step further 
and say that you should be able to use RDF without knowing anything 
about the RDF spec or the XML spec, or any other spec. Web users are not 
required to read the specs.


Using RDF includes publishing it. The "infrastructure" whatever that is 
should achieve the ability to publish my data in an appropriate way.


Jeremy

Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Pat Hayes]

With the sincerest respect, Tom, your attitude here is part of the  
problem. Maybe, along with many other people, I am indeed still stuck  
in the mid-1990s. You have permission to be as condescending as you  
like. But still, here I am, stuck. Thoroughly stuck. So no amount of  
condescending "sooo-20th-century, my dear" chatter is going to  
actually enable me to get to a place where I can do what you think I  
should be doing. I cannot use a rewrite rule to catch incoming  
requests, or do whatever you are talking about here. I live in an  
environment where I simply do not have access at all to the workings  
of my server at a level that close to the metal, because it is already  
woven into a clever maze of PHP machinery which is too fragile to  
allow erks like me to mess with it. Some of the best W3C techies have  
taken a look, and they can't find a way through it, either. Maybe Im  
in a special position, but I bet a whole lot of people, especially in  
the corporate world, are in a similar bind. System level access to a  
server is quite a different beast than being allowed to publish HTML  
on a website somewhere. I can, and do, publish HTML, or indeed just  
about any file I like, but I don't get to insert code. So 6 lines or  
600, it makes no difference.


But in any case, this is ridiculous. RDF is just XML text, for  
goodness sake.  I need to insert lines of code into a server file,   
and write PHP scripts, in order to publish some RDF or HTML?  That is  
insane. It would have been insane in the mid-1990s and its even more  
insane now. IMO, it is you (and Tim and the rest of the W3C) who are  
stuck in the past here.  Most Web users do not, and will not, write  
code. They will be publishing content in a cloud somewhere, even  
further away from the gritty world of scripts and lines of code than  
people - most people - are now. Most actual content providers are  
never going to want to even know that PHP scripts exist, let alone be  
obliged to write or copy one. Martin is exactly right: this is a MAJOR  
bottleneck to SWeb adoption. Its up to the people in the TAG to listen  
to this fact and do something about it, not to keep issuing useless   
'best practice' advice that cannot be followed by 99% of the world.


RDF should be text, in documents. One should be able to use it without  
knowing about anything more than the RDF spec and the XML spec. If it  
requires people to tinker with files with names starting with a dot,  
or write code, or deploy scripts, then the entire SWeb architecture is  
fundamentally broken.


Pat Hayes


On Jun 25, 2009, at 1:30 PM, Tom Heath wrote:


Hi Martin, all,

2009/6/25 Martin Hepp (UniBW) :

Hi all:

After about two months of helping people generate RDF/XML metadata  
for their

businesses using the GoodRelations annotator [1],
I have quite some evidence that the current best practices of using
.htaccess are a MAJOR bottleneck for the adoption of Semantic Web
technology.


Are you referring to the best practices at [1]? Unfortunately the
recipes in that document that use .htaccess and mod_rewrite for conneg
no longer count as best practices, precisely due to mod_rewrite and
.htaccess not being adequate for the conneg/303-redirects pattern.
This has been a known issue since WWW2007 at least, and documented at
[2] in July 2007. As far as I know, that recipes document hasn't yet
been updated/deprecated :( (please someone correct me if I'm wrong).

The easiest pattern I've found is to use a RewriteRule to catch all
incoming requests and pass them through a small PHP script that
examines the Accept header and sends back 303s (or 200s) as
appropriate. The code is about 6 lines; I'll publish it somewhere if I
didn't already.

Admittedly, this doesn't solve the problem of access to .htaccess
files. This bottleneck sounds to me like someone circa mid-1990s
saying "my sysadmins won't let me have access to space on the web
server". I guess we need to use lessons learned from that era to
address the problems of this one. Anyway fancy doing a Linked Data for
Sysadmins tutorial at a sysadmin conference?

Cheers,

Tom.

[1] http://www.w3.org/TR/swbp-vocab-pub/
[2] http://lists.w3.org/Archives/Public/public-swbp-wg/2007Jul/0001.html






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Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

[Martin Hepp (UniBW)]

Hi John:
We also thought of hosting meta-data for the users, but I don't like 
that because I want the shop operators to feel ownership for the data:
If the opening hours expressed in RDF are wrong but on the personal Web 
page of that restaurant, anybody facing closed doors will blame the 
restaurant.
If the outdated opening hours in RDF are on my SW server, the unlucky 
customer will blame the Semantic Web for having crappy data.


So maybe the snippet solution in RDFa is the best.

Best
Martin


John Graybeal wrote:
This is a principal reason MMI decided to offer a vocabulary server 
for its community. The idea that 1000 different providers would all 
develop a level of web competency (for which there is evidence at only 
a minority of providers) for serving their RDF and OWL content -- let 
alone the capability to do versioning, adopt best practices, learn 
SKOS, and whatever other nuances are called for -- seemed like a 
non-starter.


This is not exactly the same problem you're facing, but something to 
consider (if the model allows it) is creating a way to serve the 
annotations from another place than the host institution.  The 
institution can refer to those served files from their own sites, and 
even update them remotely, but not have to incur all the management 
overhead as standards improve, files change, authorship changes, etc.


(Which is not to disagree with your plan either. That sounds fine.)

One other delivery model could be for them to give you an existing 
HTML, you give them back the modified HTML (saves them cutting and 
pasting steps?).


I'm a little ignorant on your tools and processes, so apologies if 
these are non-starters.


John


On Jun 25, 2009, at 9:44 AM, Martin Hepp (UniBW) wrote:


Hi all:

After about two months of helping people generate RDF/XML metadata 
for their businesses using the GoodRelations annotator [1],
I have quite some evidence that the current best practices of using 
.htaccess are a MAJOR bottleneck for the adoption of Semantic Web 
technology.


Just some data:
- We have several hundred entries in the annotator log - most people 
spend 10 or more minutes to create a reasonable description of 
themselves.
- Even though they all operate some sort of Web sites, less than 30 % 
of them manage to upload/publish a single *.rdf file in their root 
directory.
- Of those 30%, only a fraction manage to set up content negotiation 
properly, even though we provide a step-by-step recipe.


The effects are
- URIs that are not dereferencable,
- incorrect media types and
and other problems.

When investigating the causes and trying to help people, we 
encountered a variety of configurations and causes that we did not 
expect. It turned out that helping people just managing this tiny 
step of publishing  Semantic Web data would turn into a full-time job 
for 1 - 2 administrators.


Typical causes of problems are
- Lack of privileges for .htaccess (many cheap hosting packages give 
limited or no access to .htaccess)
- Users without Unix background had trouble name a file so that it 
begins with a dot

- Microsoft IIS require completely different recipes
- Many users have access just at a CMS level

Bottomline:
- For researchers in the field, it is a doable task to set up an 
Apache server so that it serves RDF content according to current best 
practices.
- For most people out there in reality, this is regularly a 
prohibitively difficult task, both because of a lack of skills and a 
variety in the technical environments that turns into an engineering 
challenge what is easy on the textbook-level.


As a consequence, we will modify our tool so that it generates 
"dummy" RDFa code with span/div that *just* represents the meta-data 
without interfering with the presentation layer.
That can then be inserted as code snippets via copy-and-paste to any 
XHTML document.


Any opinions?

Best
Martin

[1]  http://www.ebusiness-unibw.org/tools/goodrelations-annotator/

Danny Ayers wrote:

Thank you for the excellent questions, Bill.

Right now IMHO the best bet is probably just to pick whichever format
you are most comfortable with (yup "it depends") and use that as the
single source, transforming perhaps with scripts to generate the
alternate representations for conneg.

As far as I'm aware we don't yet have an easy templating engine for
RDFa, so I suspect having that as the source is probably a good choice
for typical Web applications.

As mentioned already GRDDL is available for transforming on the fly,
though I'm not sure of the level of client engine support at present.
Ditto providing a SPARQL endpoint is another way of maximising the
surface area of the data.

But the key step has clearly been taken, that decision to publish data
directly without needing the human element to interpret it.

I claim *win* for the Semantic Web, even if it'll still be a few years
before we see applications exploiting it in a way that provides real
benefit for the end user.

my 2 cents.

Che