DOMXPath
PHP Manual

DOMXPath::registerPhpFunctions

(PHP 5 >= 5.3.0, PHP 7)

DOMXPath::registerPhpFunctions — Register PHP functions as XPath functions

Descrição

public void DOMXPath::registerPhpFunctions ([ mixed $restrict ] )

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

Parâmetros

restrict

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

This parameter can be either a string (a function name) or an array of function names.

Valor Retornado

Não há valor retornado.

Exemplos

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

Exemplo #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>

Exemplo #2 DOMXPath::registerPHPFunctions() with php:functionString

<?php
$doc = new DOMDocument;
$doc->load('book.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";
}

?>

O exemplo acima irá imprimir algo similar à:

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

Exemplo #3 DOMXPath::registerPHPFunctions() with php:function

<?php
$doc = new DOMDocument;
$doc->load('book.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";
}

?>

O exemplo acima irá imprimir algo similar à:

Books with multiple authors:
PHP Basics

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