LMF 3.1.0 - Retrieve data from remote ld store

[hagbeck]

Hi,

I'm trying to retrieve data from a remote linked data service which is linked in the data stored in a local lmf instance. But it fails.

I have two LMF instances. In the first one I have data like this

@prefix schema: <http://schema.org/> .
<http://lxsisis2.ub.tu-dortmund.de:8199/LMF-3.1.0/resouce/isbn/3936771723> a schema:WebPage ;
    schema:about <http://data.ub.tu-dortmund.de/resource/manifestation/32d8f198-5ec0-4afc-8fe9-0b0388852459> ;
    schema:sameAs <http://worldcat.org/isbn/3936771723> .

The resource <http://data.ub.tu-dortmund.de/resource/manifestation/32d8f198-5ec0-4afc-8fe9-0b0388852459> in the schema:about statement is stored in the second instance.

If I try to build a semantic search neither the data from data.ub.tu-dortmund.de nor from worldcat.org are used. Only the data from the first local instance is used.

@prefix library : <http://purl.org/library/> ;
@prefix schema : <http://schema.org/> ;
@filter rdf:type is schema:WebPage ;
about = schema:about :: xsd:anyURI ;
sameAs = schema:sameAs :: xsd:anyURI ;
isbn = schema:sameAs / schema:about / schema:workExample / schema:isbn :: xsd:string ;
oclcnum = schema:sameAs / schema:about / library:oclcnum :: xsd:string ;
ddc = schema:sameAs / schema:about / schema:about :: xsd:anyURI ;
lcsh = schema:sameAs / schema:about / schema:about :: xsd:anyURI ;
creator = schema:sameAs / schema:about / schema:creator :: xsd:anyURI ;
contributor = schema:sameAs / schema:about / schema:contributor :: xsd:anyURI ;
exampleOfWork = schema:sameAs / schema:about / schema:exampleOfWork :: xsd:anyURI ;

I've tried to request

http://lxsisis2.ub.tu-dortmund.de:8199/LMF-3.1.0/cache/live?uri=http://data.ub.tu-dortmund.de/resource/manifestation/32d8f198-5ec0-4afc-8fe9-0b0388852459

and gettting "I/O error while trying to retrieve resource http://data.ub.tu-dortmund.de/resource/manifestation/32d8f198-5ec0-4afc-8fe9-0b0388852459". Same for the worldcat.org resource. But it works if I try to get resources from dbpedia.

All resource are available during curl requests.

Any ideas for solving the problem?

Best,
Hans-Georg

[Jakob Frank]

Hi Hans-Georg,

> If I try to build a semantic search neither the data from
> data.ub.tu-dortmund.de nor from worldcat.org are used. Only the data
> from the first local instance is used.

please check the configuration settings for lmf-search, especially the
values of omit_cached, local_only:

With local_only = true, lmf-search will only index resources that start
with the baseURI of the LMF-Instance.

omit_cached = true will ignore resources that are retrieved via the
ldcache module.

> I've tried to request
>
> http://lxsisis2.ub.tu-dortmund.de:8199/LMF-3.1.0/cache/live?uri=http://data.ub.tu-dortmund.de/resource/manifestation/32d8f198-5ec0-4afc-8fe9-0b0388852459
>
> and gettting "I/O error while trying to retrieve resource
> http://data.ub.tu-dortmund.de/resource/manifestation/32d8f198-5ec0-4afc-8fe9-0b0388852459".
> Same for the worldcat.org resource. But it works if I try to get
> resources from dbpedia.

I did a quick check of the resource you want to test:

curl -i -H "Accept: text/turtle"
http://data.ub.tu-dortmund.de/resource/manifestation/32d8f198-5ec0-4afc-8fe9-0b0388852459

HTTP/1.1 303 See Other
Date: Mon, 01 Sep 2014 10:01:31 GMT
Server: Jetty(8.0.4.v20111024)
Location:
http://data.ub.tu-dortmund.de/resource/manifestation/32d8f198-5ec0-4afc-8fe9-0b0388852459/about.rdf.ttl
Vary: Accept
Content-Length: 1
Content-Type: text/plain

curl -i -H "Accept: text/turtle"
http://data.ub.tu-dortmund.de/resource/manifestation/32d8f198-5ec0-4afc-8fe9-0b0388852459/about.rdf.ttl
HTTP/1.1 200 OK
Date: Mon, 01 Sep 2014 10:02:02 GMT
Server: Jetty(8.0.4.v20111024)
Access-Control-Allow-Origin: *
Content-Type: text/html;charset=UTF-8
Content-Length: 1961

[... content stripped]

Looks like the remote server is sending an incorrect Content-Type: While
the request is sending "Accept: text/turtle", in the response
"Content-Type: text/html" is returned (while the actual content is turtle)
Therefore the caching fails.


Best,
Jakob

--
DI Jakob Frank
Knowledge and Media Technologies

Salzburg Research Forschungsgesellschaft mbH
Jakob Haringer-Strasse 5/3 | 5020 Salzburg, Austria
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