Feature request: Have Saxon resolve doc() and collection() from xmldb

[wshager]

Saxon or other XSLT engines could benefit from resolving docs and collections from eXist's storage directly.

[adamretter]

We would need to create a Resolver that can access the eXist database and configure Saxon to use it.

[adamretter]

I have assigned this to eXist-3.0 as (I guess without investigating) it could introduce backwards compatibility issues with those already using various URI in their fn:doc and fn:collection statements of XSLT executed with Saxon in eXist.

[dizzzz]

I am pretty sure such a resolver already eXists; I coded it myself :-) I'll try to find it back :-)

[shabanovd]

This should work. @wshager can you confirm that this actually do not work in last develop branch?

[wshager]

I'll check, but this issue was opened @adamretter 's request, so perhaps he had different intentions with the resolver, i.e. replacing the current one.

[adamretter]

@wshager Do you have tests that show this doesn't work?

[wshager]

AFAIK doc() does work, but collection() doesn't. Here's the stack trace for <xsl:for-each select="collection('xmldb:///db/test/collection')"><xsl:copy-of select="."/></xsl:for-each>

2015-04-08 22:03:53,211 [eXistThread-233] WARN (Transform.java [fatalError]:816) - XSL transform reports fatal error: Error reported by XML parser
; Line#: -1; Column#: -1
net.sf.saxon.trans.XPathException: Error reported by XML parser
at net.sf.saxon.lib.StandardErrorHandler.reportError(StandardErrorHandler.java:95)
at net.sf.saxon.lib.StandardErrorHandler.fatalError(StandardErrorHandler.java:80)
at org.apache.xerces.util.ErrorHandlerWrapper.fatalError(Unknown Source)
at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
at org.apache.xerces.impl.XMLVersionDetector.determineDocVersion(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
at org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)
at net.sf.saxon.event.Sender.sendSAXSource(Sender.java:405)
at net.sf.saxon.event.Sender.send(Sender.java:178)
at net.sf.saxon.Configuration.buildDocument(Configuration.java:3516)
at net.sf.saxon.lib.StandardCollectionURIResolver.catalogContents(StandardCollectionURIResolver.java:236)
at net.sf.saxon.lib.StandardCollectionURIResolver.resolve(StandardCollectionURIResolver.java:122)
at net.sf.saxon.functions.Collection.iterate(Collection.java:106)
at net.sf.saxon.expr.instruct.ForEach.processLeavingTail(ForEach.java:414)
at net.sf.saxon.expr.instruct.Template.applyLeavingTail(Template.java:212)
at net.sf.saxon.trans.Mode.applyTemplates(Mode.java:1034)
at net.sf.saxon.Controller.transformDocument(Controller.java:1959)
at net.sf.saxon.TransformerHandlerImpl.endDocument(TransformerHandlerImpl.java:148)
at org.exist.util.serializer.ReceiverToSAX.endDocument(ReceiverToSAX.java:85)
at org.exist.storage.serializers.XIncludeFilter.endDocument(XIncludeFilter.java:165)
at org.exist.storage.serializers.Serializer.toSAX(Serializer.java:931)
at org.exist.xquery.functions.transform.Transform.eval(Transform.java:266)
at org.exist.xquery.BasicFunction.eval(BasicFunction.java:70)
at org.exist.xquery.InternalFunctionCall.eval(InternalFunctionCall.java:56)
at org.exist.xquery.AbstractExpression.eval(AbstractExpression.java:71)
at org.exist.xquery.PathExpr.eval(PathExpr.java:264)
at org.exist.xquery.AbstractExpression.eval(AbstractExpression.java:71)
at org.exist.xquery.XQuery.execute(XQuery.java:297)
at org.exist.xquery.XQuery.execute(XQuery.java:217)
at org.exist.http.servlets.XQueryServlet.process(XQueryServlet.java:491)
at org.exist.http.servlets.XQueryServlet.doPost(XQueryServlet.java:197)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:755)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:669)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:457)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:575)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1075)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:384)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:193)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1009)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)
at org.eclipse.jetty.server.Dispatcher.forward(Dispatcher.java:229)
at org.eclipse.jetty.server.Dispatcher.forward(Dispatcher.java:103)
at org.exist.http.urlrewrite.Forward.doRewrite(Forward.java:50)
at org.exist.http.urlrewrite.XQueryURLRewrite.doRewrite(XQueryURLRewrite.java:556)
at org.exist.http.urlrewrite.XQueryURLRewrite.service(XQueryURLRewrite.java:356)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:669)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1448)
at de.betterform.agent.web.filter.XFormsFilter.doFilter(XFormsFilter.java:164)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1419)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:455)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:533)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1075)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:384)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:193)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1009)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:154)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
at org.eclipse.jetty.server.Server.handle(Server.java:368)
at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:488)
at org.eclipse.jetty.server.AbstractHttpConnection.content(AbstractHttpConnection.java:943)
at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.content(AbstractHttpConnection.java:1004)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:861)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:240)
at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:628)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
at java.lang.Thread.run(Thread.java:745)
Caused by: org.xml.sax.SAXParseException: Premature end of file.
at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source)
... 79 more

[dizzzz]

collection() will never work right? we can stream out XML data, but we can't give saxon access to the exist-db internals. Different products, different domains. It is a fundamental thingy ...

[wshager]

@dizzzz I'd probably never need collection() ...

[adamretter]

@dizzzz I don't see why we could not do collection(). It just resolves a URI to n nodes

[dizzzz]

Just have it another thought again. It will require changes in saxon.

[shabanovd]

It's simple to do, here some links:

• http://www.saxonica.com/html/documentation/javadoc/net/sf/saxon/lib/CollectionURIResolver.html
• http://www.saxonica.com/documentation9.3/javadoc/net/sf/saxon/Configuration.html#setCollectionURIResolver(net.sf.saxon.lib.CollectionURIResolver)