DOMXPath::registerPhpFunctions

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

DOMXPath::registerPhpFunctions — Register PHP functions as XPath functions

Descrizione

public DOMXPath::registerPhpFunctions(string|array|null $restrict = null): void

This method enables the ability to use PHP functions within XPath expressions.

Elenco dei parametri

restrict

Use this parameter to only allow certain functions to be called from XPath.

This parameter can be one of the following: a string (a function name), an indexed array of function names, or an associative array with keys being the function name and the associated value being the callable.

Valori restituiti

Nessun valore viene restituito.

Errori/Eccezioni

Throws a ValueError if a callback name is not valid.
Throws a ValueError if options contains an invalid option.
Throws a ValueError if overrideEncoding is an unknown encoding.
Throws a TypeError if a given callback is not callable.

Log delle modifiche

Versione	Descrizione
8.4.0	Invalid callback names now throws a ValueError. Passing a non-callable entry now throws a TypeError.
8.4.0	It is now possible to use callables for callbacks when using `restrict` with array entries.

Esempi

The following examples use book.xml which contains the following:

Example #1 book.xml

<?xml version="1.0" encoding="UTF-8"?>
<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>

Example #2 DOMXPath::registerPhpFunctions() with php:functionString

<?php
$doc = new DOMDocument;
$doc->load('examples/book-simple.xml');

$xpath = new DOMXPath($doc);

// Register the php: namespace (required)
$xpath->registerNamespace("php", "http://php.net/xpath");

// Register PHP functions (no restrictions)
$xpath->registerPhpFunctions();

// Call substr function on the book title
$nodes = $xpath->query('//book[php:functionString("substr", 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";
}

?>

Il precedente esempio visualizzerà qualcosa simile a:

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

Example #3 DOMXPath::registerPhpFunctions() with php:function

<?php
$doc = new DOMDocument;
$doc->load('examples/book-simple.xml');

$xpath = new DOMXPath($doc);

// Register the php: namespace (required)
$xpath->registerNamespace("php", "http://php.net/xpath");

// Register PHP functions (has_multiple only)
$xpath->registerPhpFunctions("has_multiple");
 
function has_multiple($nodes) {
    // Return true if more than one author
    return count($nodes) > 1;
}
// Filter books with multiple authors
$books = $xpath->query('//book[php:function("has_multiple", author)]');

echo "Books with multiple authors:\n";
foreach ($books as $book) {
    echo $book->getElementsByTagName("title")->item(0)->nodeValue . "\n";
}

?>

Il precedente esempio visualizzerà qualcosa simile a:

Books with multiple authors:
PHP Basics

Example #4 DOMXPath::registerPhpFunctions() with a callable

<?php
$doc = new DOMDocument;
$doc->load('examples/book-simple.xml');

$xpath = new DOMXPath($doc);

// Register the php: namespace (required)
$xpath->registerNamespace("php", "http://php.net/xpath");

// Register PHP functions (has_multiple only)
$xpath->registerPhpFunctions(["has_multiple" => fn ($nodes) => count($nodes) > 1]);

// Filter books with multiple authors
$books = $xpath->query('//book[php:function("has_multiple", author)]');

echo "Books with multiple authors:\n";
foreach ($books as $book) {
    echo $book->getElementsByTagName("title")->item(0)->nodeValue . "\n";
}

?>

Il precedente esempio visualizzerà qualcosa simile a:

Books with multiple authors:
PHP Basics

Vedere anche:

DOMXPath::registerNamespace() - Registers the namespace with the DOMXPath object
DOMXPath::query() - Evaluates the given XPath expression
DOMXPath::evaluate() - Evaluates the given XPath expression and returns a typed result if possible
XSLTProcessor::registerPHPFunctions() - Enables the ability to use PHP functions as XSLT functions