Hi,
While running the latest version of the extraction framework on the
German data dump, I got some property names that have round brackets in
them "(" ")" like for example:
"http://de.dbpedia.org/property/Austragungsort(e)" . The problem is that
Pubby crashes when a page is requested that contains such a property.
The crash is due to Jena, which executes a remote sparql query on
Virtuoso and recieves invalid XML as a response. The problem is that I
don't even know where to fix the bug, The URL RFC [1] Section 2.2 states
that round brackets can be used without escaping them, the URI RFC [2]
section 2.4.3 also doesn't mention them being dissalowed so the
extracted URIs should be valid. However I don't know if the RDF spec
allows property names to contain round brackets .
Is the extracted data invalid, or is there a rdf-spec problem ?
Here is an example of an invalid RDF/XML file with the offending
property URI:
<?xml version="1.0" encoding="utf-8" ?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#";
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#";>
<rdf:Description
rdf:about="http://de.dbpedia.org/resource/Mercedes-Benz_Championship_(European_Tour)"><n0pred:Austragungsort(e)
xmlns:n0pred="http://de.dbpedia.org/property/";
rdf:resource="http://de.dbpedia.org/resource/Berlin"/></rdf:Description>
</rdf:RDF>
The error looks like this:
com.hp.hpl.jena.shared.JenaException: org.xml.sax.SAXParseException:
Element type "n0pred:Austragungsort" must be followed by either
attribute specifications, ">" or "/>".
com.hp.hpl.jena.rdf.model.impl.RDFDefaultErrorHandler.fatalError(RDFDefaultErrorHandler.java:45)
com.hp.hpl.jena.rdf.arp.impl.ARPSaxErrorHandler.fatalError(ARPSaxErrorHandler.java:35)
com.hp.hpl.jena.rdf.arp.impl.XMLHandler.warning(XMLHandler.java:225)
com.hp.hpl.jena.rdf.arp.impl.XMLHandler.fatalError(XMLHandler.java:255)
org.apache.xerces.util.ErrorHandlerWrapper.fatalError(Unknown Source)
org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
org.apache.xerces.impl.XMLScanner.reportFatalError(Unknown Source)
org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanStartElement(Unknown
Source)
org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown
Source)
org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown
Source)
org.apache.xerces.parsers.DTDConfiguration.parse(Unknown Source)
org.apache.xerces.parsers.DTDConfiguration.parse(Unknown Source)
org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
com.hp.hpl.jena.rdf.arp.impl.RDFXMLParser.parse(RDFXMLParser.java:142)
com.hp.hpl.jena.rdf.arp.JenaReader.read(JenaReader.java:158)
com.hp.hpl.jena.rdf.arp.JenaReader.read(JenaReader.java:145)
com.hp.hpl.jena.rdf.arp.JenaReader.read(JenaReader.java:215)
com.hp.hpl.jena.rdf.model.impl.ModelCom.read(ModelCom.java:197)
com.hp.hpl.jena.sparql.engine.http.QueryEngineHTTP.execModel(QueryEngineHTTP.java:161)
com.hp.hpl.jena.sparql.engine.http.QueryEngineHTTP.execDescribe(QueryEngineHTTP.java:154)
com.hp.hpl.jena.sparql.engine.http.QueryEngineHTTP.execDescribe(QueryEngineHTTP.java:152)
de.fuberlin.wiwiss.pubby.RemoteSPARQLDataSource.execDescribeQuery(RemoteSPARQLDataSource.java:74)
de.fuberlin.wiwiss.pubby.RemoteSPARQLDataSource.getResourceDescription(RemoteSPARQLDataSource.java:52)
de.fuberlin.wiwiss.pubby.servlets.BaseServlet.getResourceDescription(BaseServlet.java:62)
de.fuberlin.wiwiss.pubby.servlets.PageURLServlet.doGet(PageURLServlet.java:38)
de.fuberlin.wiwiss.pubby.servlets.BaseURLServlet.doGet(BaseURLServlet.java:33)
de.fuberlin.wiwiss.pubby.servlets.BaseServlet.doGet(BaseServlet.java:89)
javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
Kind Regards,
Alexandru Todor
[1] http://www.ietf.org/rfc/rfc1738.txt
[2] http://www.ietf.org/rfc/rfc2396.txt
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