搜索文本并替换为lxml

Question

I need to search text in multi-line XML file where I have multiple tags. My XML file looks like this

<?xml version="1.0" encoding="utf-8"?>
<nc:data xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0">
    <system xmlns="http://www.abc.xyz">
      <context>
            <name>context_1</name>
            <host>
                <name>xyz</name>
                <tag1>
                    <name>pqr</name>
                    <role>s1</role>
                    <tag2>test</tag2>
                </tag1>
                <tag2>
                    <name>pqr</name>
                    <role>s1</role>
                    <tag2>test</tag2>
                </tag2>              
            </host>
      </context>
    </system>
</nc:data>

I want to search appearances of text "test" in the XML file and list their parent tag in the output. Unfortunately I am unable to do so.

The Python code that I have written is :

import os
import xml 
import sys 
from xml.dom import minidom
import xml.etree.ElementTree as ET

def xml_parsing():
    ''' 
    with open('file.xml', 'rt') as f:
        tree = ET.parse(f)
        for node in tree.findall('.//context'):
            print node, node.tag, node.attrib
            url = node.attrib.get('tag1')
            print url 

xml_parsing()

I am getting blank result as output and unable to do anything beyond it. I have tried both ElementTree and lxml . I believe it has something to do with the search pattern that I am trying to find using findall .

Please advise with your expert comments what should be tried now.

I tried the SAX way as well and code is like this:

xmldoc = minidom.parse('file.xml')
reflist = xmldoc.getElementsByTagName('tag1')
print reflist[0].toxml()

But this returns me the complete line other than just the value between tags.

Answer 1

XPath expression to find element, regardless of the element name and location in the XML document, having text value equals test is //*[text()='test'] or alternatively //*[.='test'] .

Consider the following working lxml example that demonstrate finding such elements and update the value :

from lxml import etree as ET

xml = '''<?xml version="1.0" encoding="utf-8"?>
<nc:data xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0">
    <system xmlns="http://www.abc.xyz">
      <context>
            <name>context_1</name>
            <host>
                <name>xyz</name>
                <tag1>
                    <name>pqr</name>
                    <role>s1</role>
                    <tag2>test</tag2>
                </tag1>
                <tag2>
                    <name>pqr</name>
                    <role>s1</role>
                    <tag2>test</tag2>
                </tag2>              
            </host>
      </context>
    </system>
</nc:data>'''

tree = ET.fromstring(xml)
for node in tree.xpath("//*[.='test']"):
    #update node value with new text 'foo'
    node.text = 'foo'
    print ET.tostring(node)

output :

<tag2 xmlns="http://www.abc.xyz" xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0">foo</tag2>

<tag2 xmlns="http://www.abc.xyz" xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0">foo</tag2>