Using xpath for an xml with xmlns defined

vcage · 03-04-2010, 11:13 AM

Hello,
I want to read tag values of an xml using xpath in firefox extension (basically javascript). The example from w3schools works perfectly fine as long as the XML does not have XMLNS attribute to the root element. The same example code does not work with xmlns attribute specified.

Similarly, the xml I receive from my SOAP service has xmlns as below:

<DescribeInstancesResponse xmlns="http://ec2.amazonaws.com/doc/2009-07-15/">

However, I am unable to read values from my xml, inspite of specifying a 'name space resolver'. I have tried with simple namespace resolver which just returns the above URI as a string and also tried creating NSResolver following the instructions given here.

Could anyone help me how to solve this?

Regards,
vcage

Dormilich · 03-04-2010, 12:21 PM

maybe MDC can help, from glancing over the text, it might be what you need (esp. the later examples)

vcage · 03-04-2010, 12:52 PM

Hi Dormilich,

I have already followed the guide lines given at the above link and created the nsresolver. It didn't help.

Anyway, thanks for the response.

Regards,
vcage

Dormilich · 03-04-2010, 01:18 PM

can I see your code, maybe I can spot something …

vcage · 03-04-2010, 01:35 PM

Hi,
Thanks for your response again. Here is my code.. This is w3schools example tweaked.

I have created the resolver as suggested by MDC. If I manually modify the xmlns attribute to contain a prefix like "xmlns:xyz" everything works fine without a resolver. But my SOAP service doesnot return any prefix by default.

Could you help with the right approach to handle this scenario?
Many thanks in advance,
Regards,
vcage

Code:

<html>
<body>
<script type="text/javascript">

function loadXMLDoc(dname)
{

  xhttp=new XMLHttpRequest();
  xhttp.open("GET",dname,false);
  xhttp.send("");
  return xhttp.responseXML;
}

// load the xml
xml=loadXMLDoc("book.xml");

path="/bookstore/book/title";

// Steps suggested by mozilla MDC
var evaluator = new XPathEvaluator();
var resolver = evaluator.createNSResolver(xml.documentElement);

var nodes=evaluator.evaluate(path, xml.documentElement, resolver, XPathResult.ANY_TYPE, null);

var result=nodes.iterateNext();

while (result)
{
  document.write(result.childNodes[0].nodeValue);
  document.write("<br />");
  result=nodes.iterateNext();
}

</script>

</body>
</html>

Dormilich · 03-05-2010, 06:34 AM

I think that’s the wrong resolver, from what I read, you need a custom resolver (examples quite at the end of the page)