+ Follow

XSLT+SPARQL: Scripting the Semantic Web with SPARQL embedded into XSLT stylesheets

by Diego Berrueta on May 22, 2009

2,977 views

Slides presented in the SFSW2008 workshop at Tenerife (co-located with ESWC2008). 02 Jun 2008.

More…

Slides presented in the SFSW2008 workshop at Tenerife (co-located with ESWC2008). 02 Jun 2008.

Less

1 Embed 14

http://www.slideshare.net

Statistics

Favorites: 5
Downloads: 0
Comments: 1
Embed Views: 14
Views on SlideShare: 2,963
Total Views: 2,977

XSLT+SPARQL: Scripting the Semantic Web with SPARQL embedded into XSLT stylesheets — Presentation Transcript

XSLT+SPARQL: Scripting the Semantic Web with SPARQL embedded into XSLT stylesheets Diego Berrueta, Jose E. Labra and Ivan Herman CTIC Foundation / Universidad de Oviedo / CWI Scripting for the Semantic Web (SFSW’08) Tenerife, 02/Jun/2008

Outline 1. Introduction 2. Description of XSLT+SPARQL 3. Implementation and examples 4. Conclusions 2

The problem Many applications need to transform RDF into markup (e.g. XHTML) In the XML world, we have XSLT (XML transformations) ... what do we have in the RDF world? 3

Why I cannot use XSLT? RDF/XML is complex, messy, cumbersome ⇒ non-standard XML serializations are required XPath expressions (and patterns) are designed for trees, not graphs XSLT is designed for a different data model 4

RDF is not XML, therefore...

RDF is not XML, therefore... I will not use XSLT to transform RDF/XML I will not use XSLT to transform RDF/XML I will not use XSLT to transform RDF/XML I will not use XSLT to transform RDF/XML I will not use XSLT to transform RDF/XML I will not use XSLT to transform RDF/XML I will not use XSLT to transform RDF/XML I will not use XSLT to transform RDF/XML

Related work TriX, RDFXSLT: “alternative” RDF syntaxes in XML RDF Twig, TreeHugger: add intelligence to XSLT processors Topia: XSLT functions to query Sesame using pre-SPARQL languages XSPARQL: unification of SPARQL and XQuery in a single language 6

Scripting RDF transformations Many scripting languages have RDF APIs, but they’re not standard Coding transformations in script languages leads is messy (e.g.: Vapour) 7

XSLT+SPARQL Two sets of XPath functions to query RDF models using SPARQL Intended to be used in @select expressions of XSLT stylesheets Return plain, standard XML easily tractable with XSLT 8

Query results XML syntax <results> <result> <binding name=quot;fnamequot;><value>Tom</value>/binding> <binding name=quot;emailquot;><value>tom@example.org</value></binding> </result> <result> <binding name=quot;fnamequot;><value>Dick</value></binding> <binding name=quot;emailquot;><value>dick@example.org</value></binding> </result> </results> W3C Recommendation (Jan 2008) 9

Basic functions sparql:sparql(query [, documentUrl, ...]) sparql:sparqlEndpoint(query, endpointUrl) Execute SPARQL queries locally or remotely (endpoint) Model can be extended with “FROM” clauses 10

Advanced functions (I) Retrieving and parsing RDF data is expensive Advanced functions designed for: ‣ Efficently query the same model multiple times ‣ Create custom models programatically 11

Advanced functions (II) sparql’:parseString(string, syntax) Creates a model by parsing a string containg serialized RDF Support for different syntaxes: RDF/ XML, N3, TriX... 12

Advanced functions (III) sparql’:readModel(documentUrl, syntax) sparql’:readModel(nodeset) Create models by parsing: 1. A document retrieved from the web 2. An XML subtree (from the XSLT input document or even from the XSLT itself) 13

Advanced functions (IV) sparql’:mergeModels(model1, model2, ...) Combines two or more RDF models into a new one 14

Advanced functions (V) sparql’:sparqlModel(query, model) Executes a SPARQL query against an in-memory model 15

Two implementations 1. Java-based extension to Apache Xalan using Jena Exploits the extensibility of XSLT 2. Pure XSLT implementation Incomplete, XSLT “document()” cannot perform conneg 16

Applications of XSLT+SPARQL Transform RDF data for presentation in XHTML, SVG... Generate reports beyond SPARQL capabilities Develop scripts that retrieve and operate with RDF data from the (semantic) web 17

Example: Ivan’s acquittances <xsl:template match=quot;/quot;> <xsl:apply-templates select=quot;sparql:sparql(concat(sparql:commonPrefixes(), 'SELECT ?name ?mbox_sha1sum ?homepage FROM <http://www.ivan-herman.net/foaf.rdf> WHERE { <http://www.ivan-herman.net/Ivan_Herman> foaf:knows ?x . ?x foaf:name ?name . OPTIONAL { ?x foaf:mbox_sha1sum ?mbox_sha1sum . ?x foaf:homepage ?homepage }}'))quot;/> </xsl:template> <xsl:template match=quot;results:resultsquot;> <html> ... </html> </xsl:template> 18

Advanced examples Querying DBPedia endpoint HTML displays of SKOS thesauri Alphabetic display Systematic display (tree-like) “Spider” agent for LoD 19

Conclusions and future work XSLT+SPARQL overcomes the limitations of XSLT to process RDF XSLT+SPARQL can be used to write declarative scripts for the semantic web Future extensions: inference support 20

Thank you for your attention diego.berrueta@fundacionctic.org

XSLT+SPARQL: Scripting the Semantic Web with SPARQL embedded into XSLT stylesheets

by Diego Berrueta on May 22, 2009

Accessibility

Categories

Tags

Upload Details

Usage Rights

1 Embed 14

Statistics

XSLT+SPARQL: Scripting the Semantic Web with SPARQL embedded into XSLT stylesheets — Presentation Transcript