[XML-SIG] Using XML Namespaces in XPath Expressions from Python

[JonTom Kittredge]

Uche, I have it working now. Thanks for your help!
Yours, JonTom

       JT Kittredge
       ITA Software, Inc.
       Cambridge, Massachusetts

On 2005-06-13 at 09:33, Uche Ogbuji wrote:
>  On Mon, 2005-06-13 at 10:29 -0400, JonTom Kittredge wrote:
>  > Uche, Thanks for your response. My comments are below.
>  
>  > On 2005-06-09 at 06:26, Uche Ogbuji wrote:
>  > >  On Wed, 2005-06-08 at 10:27 -0400, JonTom Kittredge wrote:
>  > >  > I'm having trouble using PyXML to evaluate XPath expressions that
>  > >  > include namespace references.
>  > >  > 
>  > >  > Here is a sample Python snipped:
>  > >  > 
>  > >  >     #!/usr/bin/env pystart
>  > >  > 
>  > >  >     import sys
>  > >  >     import xml.dom.minidom
>  > >  > 
>  > >  >     from xml.xpath.Context import Context
>  > >  >     from xml.xpath import Evaluate
>  > >  >     from xml.xpath.NamespaceNode import NamespaceNode
>  > >  > 
>  > >  > 
>  > >  >     if __name__ == "__main__":
>  > >  >       sys.stderr.write("XPathTest: 18\n")
>  > >  > 
>  > >  >       inputDom = xml.dom.minidom.parse(open("xpathtest-input.xml"))
>  > >  > 
>  > >  >       sys.stderr.write("Node: %s\n" % (inputDom.documentElement))
>  > >  >       outContext = Context(inputDom.documentElement)
>  > >  
>  > >  Where are you passing in the NS mapping here?  Did I miss a PyXML XPath
>  > >  update that defaults mappings to in-scope namespaces on the node passed
>  > >  in?
>  > 
>  > That's the nub of my question. How do I pass namespace mappings into
>  > Evaluate()? 
>  
>  outContext = Context(inputDom.documentElement, processorNss={u'dbq':
>  DBQNS})
>  
>  > The only thing I could see to try, from looking at the documentation,
>  > was to use the context argument. The Context object holds namespace
>  > objects, so I thought that that might be the way to pass in my
>  > definition. 
>  
>  Yes, but you have to give it the namespace defs, as above.
>  
>  > As you can see from the output, the Context I get from the document
>  > node already has the "dbq" namespace defined (since it appears in the
>  > input), before I call Evaluate(). However, it apparently gets reset
>  > during the call to Evaluate().
>  
>  That's what's confusing me.  I'm not sure why it automatically has that
>  namespace at any point.  Anyway, see if my suggestion helps.
>  
>  
>  -- 
>  Uche Ogbuji                               Fourthought, Inc.
>  http://uche.ogbuji.net                    http://fourthought.com
>  http://copia.ogbuji.net                   http://4Suite.org
>  Use CSS to display XML, part 2 - http://www-128.ibm.com/developerworks/edu/x-dw-x-xmlcss2-i.html
>  XML Output with 4Suite & Amara - http://www.xml.com/pub/a/2005/04/20/py-xml.html
>  Use XSLT to prepare XML for import into OpenOffice Calc - http://www.ibm.com/developerworks/xml/library/x-oocalc/
>  Schema standardization for top-down semantic transparency - http://www-128.ibm.com/developerworks/xml/library/x-think31.html