Re: [Engine-devel] Issue with XML namespaces in engine-setup

On Tue, Apr 10, 2012 at 01:54:51PM +0200, Juan Hernandez wrote: > Hello, > > The code that we use in engine-setup to modify JBoss AS XML > configuration files uses the following pattern: > > datasourceStr = ''' > <datasource ...> > ... > </datasource> > ''' > > xmlObj.addNodes("//datasource:subsystem/datasource:datasources", > datasourceStr) > > This looks correct but is in fact generating a incorrect XML document, > as the tags being added are not associated to a namespace. The resulting > XML file will be correct, but the temporary representation in memory is > not. This causes problems if you later, before writing out the modified > file, try to use xpath expressions matching the added nodes: there will > be no match. > > I would suggest that we change the pattern to something like this: > > datasourceStr = ''' > <any_dummy_tag xmlns="urn:jboss:domain:datasources:1.0"> > <datasource ...> > ... > </datasource> > </any_dummy_tag> > ''' > datasourceNodes = libxml2.parseDoc(datasourceStr).getRootElement().children > > xmlObje.addNodes("//datasource:subsystem/datasource:datasources", > datasourceNodes) > > This way both the representation in memory and the resulting file are > correct. > > Le me know what you think. I think it's dangerous to move nodes from one document to another especially if there is namespaces (I assume you're operating in an environment on top of libxml2 as I saw a reference to it ;-) For libxml2 there is an API in C: http://xmlsoft.org/html/libxml-parser.html#xmlParseInNodeContext which could do what you expect. Maybe there is a binding/wrapper available you could use.

Also your "//datasource:subsystem/datasource:datasources" XPath query could lead to multiple result nodes, I would suggest to pick the first result only, I suppose you don't want to add the set of nodes to multiple places xmlObje.addNodes("(//datasource:subsystem/datasource:datasources)[1]", datasourceNodes) or something equivalent (unless addNodes() takes care to handle that properly ...)