This is an interesting question and one which we've been thinking
about here at Talis as well.
As we build linked data apps, with a view to the linked data being
used as an api for other applications, we've thought that it is worth
putting more into the response, typically we try to put everything
you'd need to recreate the HTML representation.
When you say it has important implications, can you expand on those? I
had been thinking it was harmless. As I see it a client that expects
only a DESCRIBE ?s should simply ignore the additional data provided,
whereas clients that are crawling and merging into a graph will find
they already have things as they expand what they know about.
I can see that understanding what is likely to come back has big
optimisation benefits for things like Sindice.
What is the 'correct' thing to do?
rob
On 14 Mar 2009, at 12:12, Giovanni Tummarello wrote:
Hi Jamie,
i see that your RDF per URI is more "expressive" than the "usual"
instead of just giving triples out of (or into) the subject of the
page you also give the description of other notable entities inside
for example in the blade runner movie you give the full description of
all the "film performances" (tying the real actor, the fictional
character and the movie). Each film performance then has its URI
which is itself resolvable so "in theory" to give the detail of the
"film performance" was not necessary, according to LOD, but in
practice its definitly useful as we know.
Would you know the rule by which you decide to put multiple entities
in the description that you give out?
this has important implications.
On the one hand if there was a simple rule, always the same, it makes
it easy for me to get your snapshot and index each URI rdf description
by applying this same rule (what we do for LOD datasets which simply
split "all the triples with subject or object X"). Else i can crawl
and do my things internally, under the assumption that what you are
providing are not a bunch of unrelated RDF files, but are really
"slices" of the same dataset.
to assert this is the case (and allow me to play more freely with the
information) it would be useful to have a semantic sitemap linked in
your robot.txt stating the URI of the dataset, with the name and the
prefix at which you're serving its content as LinkedData.
example sitemap. Here the "slicing" is set to "subject-object" in your
case i guess not setting it is the most appropriate option probably.
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9";
xmlns:sc="http://sw.deri.org/2007/07/sitemapextension/scschema.xsd
">
<sc:dataset>
<sc:datasetLabel>Example Corp. Product Catalog</sc:datasetLabel>
<sc:datasetURI>http://example.com/catalog.rdf#catalog</
sc:datasetURI>
<sc:linkedDataPrefix
slicing="subject-object">http://example.com/products/</
sc:linkedDataPrefix>
<sc:sampleURI>http://example.com/products/widgets/X42</
sc:sampleURI>
<sc:sparqlEndpointLocation
slicing="subject-object">http://example.com/sparql</
sc:sparqlEndpointLocation>
<sc:dataDumpLocation>http://example.com/data/catalogdump.rdf.gz</
sc:dataDumpLocation>
<changefreq>weekly</changefreq>
</sc:dataset>
</urlset>
in your case would it be technically simple to also provide an RDF
dump?
"no its too time consuming" is a prefectly good answer :-) (which
means we have to live with it, e.g. by politely crawling)
Giovanni
On Fri, Mar 13, 2009 at 8:37 PM, Jamie Taylor <ja...@metaweb.com>
wrote:
Seo -
Yes, this is a bug in the current LOD/RDF interface to Freebase. I
believe
it is fixed in the upcoming release, which can be previewed at
http://rdftest.mqlx.com/ns/en.blade_runner..
I checked turtle output with:
rapper -i turtle http://rdftest.mqlx.com/ns/en.blade_runner
Please give this sandbox version of the interface a try. I'm
interested in
feedback from others on the list as well.
I hope to have the new version in production sometime next week.
Jamie
On Mar 10, 2009, at 10:31 PM, Seo Sanghyeon wrote:
Hello, new to the list,
I am trying to figure out how to use Freebase RDF service.
(See http://blog.freebase.com/2008/10/30/introducing_the_rdf_service/)
$ curl -L http://rdf.freebase.com/ns/en.blade_runner -o
en.blade_runner
$ rdfproc freebase parse en.blade_runner turtle
It is Turtle, right? Above errors with:
rdfproc: Parsing URI
file:///home/tinuviel/devel/freebase/en.blade_runner with turtle
parser
rdfproc: Error - URI
file:///home/tinuviel/devel/freebase/en.blade_runner:2: The
namespace
prefix in "http:" was not declared.
URI file:///home/tinuviel/devel/freebase/en.blade_runner:2 raptor
fatal error - turtle_qname_to_uri failed
rdfproc: Error - URI
file:///home/tinuviel/devel/freebase/en.blade_runner:2: syntax error
rdfproc: Failed to parse into the graph
rdfproc: The parsing returned 2 errors and 0 warnings
Help?
--
Seo Sanghyeon
Rob Styles
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