A very quick and dirty implementation of an xpath filter for ansible.

gistfile1.py

#/usr/bin/python
# By Dan Pool
# Custom filter for parsing XML variables using xpath

from functools import partial
from io import BytesIO

try:
    from lxml import etree
    import lxml
except:
    etree = none
    lxml = none

from ansible import errors

def xpath_match(value, xpath, nspace = ''):

    if not xpath:
        return False

    encoded_value = BytesIO(value.encode('utf-8'))
    
    # Try to parse the value as XML
    try:
       parser = etree.XMLParser(remove_blank_text=False)
       xml = etree.parse(encoded_value, parser)
    except etree.XMLSyntaxError as e:
       raise errors.AnsibleFilterError("Error parsing value: {0}".format(e.msg))

    try:
        if not nspace:
            match = xml.xpath(xpath, smart_strings=False)
        else:
            prefix,uri = nspace.split("=",1)
            ns = {}
            ns[prefix] = uri
            match = xml.xpath(xpath, namespaces=ns, smart_strings=False)
    except etree.XPathSyntaxError as e:
        raise errors.AnsibleFilterError("Error with xpath syntax: {0}".format(e.error_log.last_error))
    except etree.XPathEvalError as e:
        raise errors.AnsibleFilterError("Error evalutating xpath: {0}".format(e.error_log.last_error))

    match_xpaths = []
    for m in match:
        match_xpaths.append(m)

    if len(match_xpaths) > 1:
        return match_xpaths
    elif len(match_xpaths) == 1:
        return match_xpaths[0]
    else:
        return False

def _need_lxml(f_name, *args, **kwargs):
    raise errors.AnsibleFilterError('The {0} filter requires python-lxml be'
            ' installed on the ansible controller'.format(f_name))

# ---- Ansible filters ----

class FilterModule(object):

    filter_map =  {
        'xpath' : xpath_match
    }

    def filters(self):
        if lxml:
            return self.filter_map
        else:
            # Need to install python-lxml for these filters to work
            return dict((f, partial(_need_lxml, f)) for f in self.filter_map)

No doubt it could be cleaned up by anyone who's been doing python for more than one afternoon. Example usage:

- name: Info | Get some XML content                                                             
  environment: proxy_env                                                                        
  uri: method=GET url="{{ xml_href }}" return_content=yes                                       
  register: stuff                                                                             

- name: Set | Extract info from the content                                               
  set_fact:                                                                                     
    href: "{{ stuff.content | xpath("/x:foo/x:bar[@name="unique"]/@href", "x=http://www.example.com") }}"
    href_list: "{{ stuff.content | xpath("/x:foo/x:bar/@href", "x=http://www.example.com") }}"

- name: Info | Get new XML content
  environment: proxy_env                                                                        
  uri: method=GET url="{{ href }}" return_content=yes                                       
  register: new_stuff

- name: Info | Get lots of XML content
  environment: proxy_env                                                                        
  uri: method=GET url="{{ item }}" return_content=yes
  with_items: href_list.results
  register: loads_of_stuff