Xpath returns nothing to nokigiri

Question

Possible duplicate:
Nokogiri / Xpath namespace query

Assume XML exists

<?xml version="1.0" encoding="utf-8"?> <SomeResponse xmlns="some_namespace"> <Timestamp>......</Timestamp> <Ack>Failure</Ack> <Errors> <ShortMessage>ShortMessage111.</ShortMessage> <LongMessage>LongMessage111.</LongMessage> <ErrorCode>1</ErrorCode> <SeverityCode>Warning</SeverityCode> </Errors> <Errors> <ShortMessage>ShortMessage222.</ShortMessage> <LongMessage>LongMessage222.</LongMessage> <ErrorCode>2</ErrorCode> <SeverityCode>Warning2</SeverityCode> </Errors> <!-- there might be many Errors nodes --> <Version>123</Version> <Build>122345abt_3423423</Build> </SomeResponse> 

I try to find all errors and their long and short messages using Nokogiri.

I do:

 doc = Nokogiri.XML(xml) errors = doc.xpath("//Errors") puts errors errors2 = doc.xpath("//Errors//ShortMessage") puts errors 

and shows nothing.

What am I doing wrong?

Answer 1

Your xml is in the namespace "some_namespace", but your xpaths do not have a namespace binding. You essentially request different elements than in your XML. Using Clark's notation , the element you are trying to find is {some_namespace} ShortMessage, but you are requesting ShortMessage in the no namespace. Just because there is no prefix, i.e. The namespace is the default namespace, does not mean that you can ignore it.

Answer 2

If you do not want to deal with namespaces, you can use

 doc.remove_namespaces! 

This is Lazy (= effective), but it is not recommended.