Document xpath with namespace example.

[madelaney]

All,

I'm trying to use sxd-xpath (v0.4), in a static XML file with namespaces defined. I was wondering if it would be possible to create a basic example that shows how to find elements within a given namespace.

• Mike D.

[kmkaplan]

There's an example of using namespace in the documentation for sxd_xpath::context::Context

[thomas725]

If I take the most basic sample from your docs and add an xmlns attribute to the root tag, value.string() gives an empty string instead of the expected "hello".

fn xpath_example() {
    let package = parser::parse("<root xmlns=\"https://some.place.com/metadata\">hello</root>").expect("failed to parse XML");
    let document = package.as_document();

    let value = evaluate_xpath(&document, "/root").expect("XPath evaluation failed");
    println!("{}", value.string());
    assert_eq!("hello", value.string());
}

[AHSauge]

Indeed, that's due to the namespace. From experience, evaluate_xpath won't work with that. Instead, you need to make yourself a context as suggested in the comment prior

fn xpath_example() {
    let package = parser::parse("<root xmlns=\"https://some.place.com/metadata\">hello</root>").expect("failed to parse XML");
    let document = package.as_document();
    let mut context = Context::new();
    context.set_namespace("foobar", "https://some.place.com/metadata");
    let xpath = Factory::new().build("/foobar:root").expect("Unable to build xpath").expect("Unable to build xpath");
    let value = xpath.evaluate(&context, document.root()).expect("XPath evaluation failed");

    println!("{}", value.string());
    assert_eq!("hello", value.string());
}