How do I iterate through DOM elements in PHP? - php

Question

I have an XML file loaded into a DOM document,
I wish to iterate through all 'foo' tags, getting values from every tag below it. I know I can get values via
$element = $dom->getElementsByTagName('foo')->item(0);
foreach($element->childNodes as $node){
$data[$node->nodeName] = $node->nodeValue;
}
However, what I'm trying to do, is from an XML like,
<stuff>
<foo>
<bar></bar>
<value/>
<pub></pub>
</foo>
<foo>
<bar></bar>
<pub></pub>
</foo>
<foo>
<bar></bar>
<pub></pub>
</foo>
</stuff>
iterate over every foo tag, and get specific bar or pub, and get values from there.
Now, how do I iterate over foo so that I can still access specific child nodes by name?

Answer 1

Not tested, but what about:
$elements = $dom->getElementsByTagName('foo');
$data = array();
foreach($elements as $node){
foreach($node->childNodes as $child) {
$data[] = array($child->nodeName => $child->nodeValue);
}
}

Answer 2

It's generally much better to use XPath to query a document than it is to write code that depends on knowledge of the document's structure. There are two reasons. First, there's a lot less code to test and debug. Second, if the document's structure changes it's a lot easier to change an XPath query than it is to change a bunch of code.
Of course, you have to learn XPath, but (most of) XPath isn't rocket science.
PHP's DOM uses the xpath_eval method to perform XPath queries. It's documented here, and the user notes include some pretty good examples.

Answer 3

Here's another (lazy) way to do it.
$data[][$node->nodeName] = $node->nodeValue;

Answer 4

With FluidXML you can query and iterate XML very easly.
$data = [];
$store_child = function($i, $fooChild) use (&$data) {
$data[] = [ $fooChild->nodeName => $fooChild->nodeValue ];
};
fluidxml($dom)->query('//foo/*')->each($store_child);
https://github.com/servo-php/fluidxml