如何使用lxml在AWS响应中查找元素（命名空间问题？）

Question

I'm trying to use lxml to read a response from the AWS REST API but not having any luck. I can easily parse the response and print it, but none of the find or xpath functions find anything. For example, take this document fragment:

<DistributionConfig xmlns="http://cloudfront.amazonaws.com/doc/2013-11-11/">
  <CallerReference>e6d6909d-f1ed-47f1-83d9-290acf10f324</CallerReference>
  <Aliases>
    <Quantity>1</Quantity>
    <Items>

And this code:

from lxml import etree
root = etree.XML( ... )
node = root.find( 'Quantity' ) 

node is always None . I've tried a variety of xpaths like //Quanity , .//Quantity , and also the xpath function, but can't find anything.

How do I use this library on this type of document?

Answer 1

Seems you will need to supply the namespace of the element as well:

>>> root.find('.//aws:Quantity', namespaces={'aws': 'http://cloudfront.amazonaws.com/doc/2013-11-11/'})
<Element {http://cloudfront.amazonaws.com/doc/2013-11-11/}Quantity at 0xb6c16aa4>