DOMXPath::registerPhpFunctions
Register PHP functions as XPath functions
&reftitle.description;
public voidDOMXPath::registerPhpFunctions
stringarraynullrestrict&null;
This method enables the ability to use PHP functions within XPath expressions.
&reftitle.parameters;
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.
&reftitle.returnvalues;
&return.void;
&reftitle.errors;
Throws a ValueError if
a callback name is not valid.
&dom.errors.compliant.common;
Throws a TypeError if
a given callback is not callable.
&reftitle.changelog;
&Version;
&Description;
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.
&reftitle.examples;
The following examples use book.xml which contains the following:
book.xml
PHP Basics
Jim Smith
Jane Smith
PHP Secrets
Jenny Smythe
XML basics
Joe Black
]]>
<methodname>DOMXPath::registerPhpFunctions</methodname> with <literal>php:functionString</literal>
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";
}
?>
]]>
&example.outputs.similar;
<methodname>DOMXPath::registerPhpFunctions</methodname> with <literal>php:function</literal>
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";
}
?>
]]>
&example.outputs.similar;
<methodname>DOMXPath::registerPhpFunctions</methodname> with a <type>callable</type>
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";
}
?>
]]>
&example.outputs.similar;
&reftitle.seealso;
DOMXPath::registerNamespace
DOMXPath::query
DOMXPath::evaluate
XSLTProcessor::registerPHPFunctions