PHP DOM: How to get child elements by tag name in an elegant manner?

Question

I\'m parsing some XML with PHP DOM extension in order to store the data in some other form. Quite unsurprisingly, when I parse an element I pretty often need to obtain all c

Answer 1

My solution used in a production:

Finds a needle (node) in a haystack (DOM)

function getAttachableNodeByAttributeName(\DOMElement $parent = null, string $elementTagName = null, string $attributeName = null, string $attributeValue = null)
{
    $returnNode = null;

    $needleDOMNode = $parent->getElementsByTagName($elementTagName);

    $length = $needleDOMNode->length;
    //traverse through each existing given node object
    for ($i = $length; --$i >= 0;) {

        $needle = $needleDOMNode->item($i);

        //only one DOM node and no attributes specified?
        if (!$attributeName && !$attributeValue && 1 === $length) return $needle;
        //multiple nodes and attributes are specified
        elseif ($attributeName && $attributeValue && $needle->getAttribute($attributeName) === $attributeValue) return $needle;
    }

    return $returnNode;
}

Usage:

$countryNode = getAttachableNodeByAttributeName($countriesNode, 'country', 'iso', 'NL');

Returns DOM element from parent countries node by specified attribute iso using country ISO code 'NL', basically like a real search would do. Find a certain country by it's name in an array / object.

Another usage example:

$productNode = getAttachableNodeByAttributeName($products, 'partner-products');

Returns DOM node element containing only single (root) node, without searching by any attribute. Note: for this you must make sure that root nodes are unique by elements' tag name, e.g. countries->country[ISO] - countries node here is unique and parent to all child nodes.