DOMXPath::registerPhpFunctionNS

    (PHP >= 8.4.0)

    DOMXPath::registerPhpFunctionNS — Register a PHP functions as namespaced XPath function

    Beschreibung

    public DOMXPath::registerPhpFunctionNS(string $namespaceURI, string $name, callable $callable): void

    This method enables the ability to use a PHP function as a namespaced XPath function inside XPath expressions.

    Parameter-Liste

    namespaceURI
    The URI of the namespace.
    name
    The local function name inside the namespace.
    callable
    The PHP function to call when the XPath function gets called within the XPath expression. When a node list is passed as parameter to the callback, they are arrays containing the matched DOM nodes.

    Fehler/Exceptions

    • Throws a ValueError if a callback name is not valid.
    • Wenn options eine ungültige Option enthält, wird ein ValueError ausgelöst.
    • Wenn overrideEncoding eine unbekannte Kodierung ist, wird ein ValueError ausgelöst.
    • Throws a TypeError if a given callback is not callable.

    Rückgabewerte

    Es wird kein Wert zurückgegeben.

    Beispiele

    Beispiel #1 Register a namespaced XPath function and call it from the XPath expression

    <?php

    $xml     = <<<EOB
    <books>
    <book>
    <title>PHP Basics</title>
    <author>Jim Smith</author>
    <author>Jane Smith</author>
    </book>
    <book>
    <title>PHP Secrets</title>
    <author>Jenny Smythe</author>
    </book>
    <book>
    <title>XML basics</title>
    <author>Joe Black</author>
    </book>
    </books>
    EOB;

    $doc = new DOMDocument();
    $doc->loadXML($xml);

    $xpath = new DOMXPath($doc);

    // Register the my: namespace (required)
    $xpath->registerNamespace("my", "urn:my.ns");

    // Register PHP function
    $xpath->registerPHPFunctionNS(
    'urn:my.ns',
    'substring',
    fn (array     $arg1, int $start, int $length) => substr($arg1[0]->textContent, $start, $length)
    );

    // Call substr function on the book title
    $nodes = $xpath->query('//book[my:substring(title, 0, 3) = "PHP"]');

    echo     "Found {$nodes->length} books starting with 'PHP':\n";
    foreach (    $nodes as $node) {
    $title = $node->getElementsByTagName("title")->item(0)->nodeValue;
    $author = $node->getElementsByTagName("author")->item(0)->nodeValue;
    echo     "$title by $author\n";
    }

    ?>

    Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:

    Found 2 books starting with 'PHP':
PHP Basics by Jim Smith
PHP Secrets by Jenny Smythe

    Siehe auch

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