16.10.7.RDF Cartridges Use Cases
This section contains examples of Web resources which can be transformed by RDF Cartridges. It also states where additional setup for given cartridges is needed i.e. keys account names etc.
Service based:
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amazon
needs: api key example: http://www.amazon.com/gp/product/0553383043
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ebay
needs: account, api-key example: http://cgi.ebay.com/RARE-DAY-IN-FAIRY-LAND-ELEPHANT-FOLIO-20-FULL-COLOR_W0QQitemZ140209597189QQihZ004QQcategoryZ29223QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
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flickr needs: api-key example: http://farm1.static.flickr.com/212/496684670_7122c831ed.jpg
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mbz
example: http://musicbrainz.org/release/37e955d4-a53c-45aa-a812-1b23b88dbc13.html
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mql (freebase)
example: http://www.freebase.com/view/en/beta_ursae_majoris
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facebook
needs: api-key, secret, persistent-session-id example: http://www.facebook.com/profile.php?id=841100003
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yahoo-stock
example: http://finance.yahoo.com/q?s=AAPL
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yahoo-traffic
example: http://local.yahooapis.com/MapsService/V1/trafficData?appid=YahooDemo&street=701+First+Street&city=Sunnyvale&state=CA
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Bugzilla
example: https://bugzilla.mozilla.org/show_bug.cgi?id=251714
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SVG
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OO document
needs: unzip plugin
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Wikipedia
needs: php plugin & dbpedia extractor example: http://wikipedia.org/wiki/London
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Opencalais
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iCalendar
GRDDL
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Google Base (google)
example: http://www.google.com/base/feeds/snippets/17891817243016304554
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eRDF
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RDFa
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hCard
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hCalendar
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hReview
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relLicense
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XBRL
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HR-XML
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DC
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geoURL
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Ning
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XFN
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xFolk
URN handlers
Table16.11.URN handlers List
| URN handler | Sample URI | Resource Description | Linked Data View | Linked Data Graph | Needs |
|---|---|---|---|---|---|
| LSID | urn:lsid:ubio.org:namebank:12292 | HTML Representation | Linked Data View | Data Explorer View | none |
| DOI | doi:10.1038/35057062 | HTML Representation | Linked Data View | Data Explorer View | Needs hslookup plugin, relevant html, pdf, xml etc. mappers enabled. |
| OAI | oai:dcmi.ischool.washington.edu:article/8 | HTML Representation | Linked Data View | Data Explorer View | none |
SPARQL IRI Dereferencing
The Virtuoso SPARQL engine (called for brevity just SPARQL below) supports IRI Dereferencing, however it understands only RDF data, that is it can retrieve only files containing RDF/XML, turtle or N3 serialized RDF data, if format is unknown it will try mapping with built-in WebDAV metadata extractor. In order to extend this feature with dereferencing web or file resources which naturally don't have RDF data (like PDF, JPEG files for example) is provided a special mechanism in SPARQL engine. This mechanism is called RDF mappers for translation of non-RDF data files to RDF.
In order to instruct the SPARQL to call a RDF mapper it needs to be registered and it will be called for a given URL or MIME type pattern. In other words, when unknown for SPARQL format is received during URL dereferencing process, it will look into a special registry (a table) to match either the MIME type or IRI using a regular expression, if match is found the mapper function will be called.
Sponger Proxy service
Sponger functionality is also exposed via Virtuoso's "/proxy/rdf/" endpoint, as an in-built REST style Web service available in any Virtuoso standard installation. This web service takes a target URL and either returns the content "as is" or tries to transform (by sponging) to RDF. Thus, the proxy service can be used as a 'pipe' for RDF browsers to browse non-RDF sources.
For more information see RDF Sponger Proxy service
Cache Invalidation
To clear cache on all values of HS_LOCAL_IRI of the SYS_HTTP_SPONGE table use:
SPARQL clear graph <A-Named-Graph>;