Selecting xml node by attribute id

Question

My aim is simple, I just need to get the value by an attrbiute. For example consider this xml:

<?xml version="1.0" encoding="UTF-8"?>
<preferences>
    <custom-preferences>
        <staging>
             <preference preference-id="foo">true</preference>
             <preference preference-id="bar">true</preference>
        </staging>
    <custom-preferences>
<preferences>
</xml>

The xml is in a file, this is what I have so far:

var fs = require('fs'),
xml2js = require('xml2js');
 
var parser = new xml2js.Parser();
fs.readFile(pref, function(err, data) {parser.parseString(data, function (err, result) {

    console.log(result.preferences['custom-preferences'][0].staging[0].preference[0]);

    });
});

So if I hard code the index it will work, but can I select the node where preference-id = foo or bar etc.

I'm trying to avoid reading the parent node and performing a for each. I am happy and willing to use other package or libraries if it will help me to achieve the goal.

"Select ... in xml", i (intuitively) think: xpath! [document.evaluate()](https://developer.mozilla.org/en-US/docs/Web/XPath/Introduction_to_using_XPath_in_JavaScript) can do this. — xerx593, Dec 23 '22 at 20:23

score 1 · Accepted Answer · answered Dec 23 '22 at 21:55

It is possible by jsdom or xml.etree.ElementTree

Code by node.js

const jsdom = require("jsdom");

const response = `
<?xml version="1.0" encoding="UTF-8"?>
<preferences>
    <custom-preferences>
        <staging>
             <preference preference-id="foo">true</preference>
             <preference preference-id="bar">true</preference>
        </staging>
    </custom-preferences>
</preferences>`

const dom = new jsdom.JSDOM(response);
console.log('foo: '   + dom.window.document.querySelector('[preference-id="foo"]').textContent)
console.log('bar: '   + dom.window.document.querySelector('[preference-id="bar"]').textContent)

Result

$ node find-attribute.js
foo: true
bar: true

Code by Python

import xml.etree.ElementTree as ET
document = """\
<?xml version="1.0" encoding="UTF-8"?>
<preferences>
    <custom-preferences>
        <staging>
             <preference preference-id="foo">true</preference>
             <preference preference-id="bar">true</preference>
        </staging>
    </custom-preferences>
</preferences>
"""

root = ET.fromstring(document)
print("preference-id='foo' " + root.find(".//*[@preference-id='foo']").text)
print("preference-id='bar' " + root.find(".//*[@preference-id='bar']").text)

Result

$ python find-attribute.py
preference-id='foo' true
preference-id='bar' true

Selecting xml node by attribute id

1 Answers1