DOMXPath
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DOMXPath::registerNamespace

(PHP 5)

DOMXPath::registerNamespace — Registers the namespace with the DOMXPath object

说明

public bool DOMXPath::registerNamespace ( string $prefix , string $namespaceURI )

Registers the namespaceURI and prefix with the DOMXPath object.

参数

prefix

The prefix.

namespaceURI

The URI of the namespace.

返回值

成功时返回 TRUE， 或者在失败时返回 FALSE.

DOMXPath
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PHP手册 - N: Registers the namespace with the DOMXPath object

用户评论:

xmedeko at gmail dot com (20-Sep-2011 12:58)

A general way to register the root default namespace:

<?php
$xml = new DomDocument();
$xml->load('data.xml');
$xpath = new DOMXPath($xml);
$rootNamespace = $xml->lookupNamespaceUri($xml->namespaceURI);
$xpath->registerNamespace('x', $rootNamespace);
?>

And then just query:

<?php $elementList = $xpath->query('//x:items/x:name'); ?>

dulao5 at gmail dot com (16-Jun-2009 08:01)

The following code can work for XML default namespace.
<?php
$xml = <<<EOT
<?xml version="1.0" encoding="UTF-8"?>
<entry xmlns="http://www.w3.org/2005/Atom" xmlns:other="http://other.w3.org/other" >
        <id>uYG7-sPwjFg</id>
        <published>2009-05-17T18:29:31.000Z</published>
</entry>
EOT;

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

$xpath->registerNamespace('atom', "http://www.w3.org/2005/Atom");

$xpath_str = '//atom:entry/atom:published/text()';

$entries = $xpath->evaluate($xpath_str);

print $entries->item(0)->nodeValue ."\n";

?>

agent009 (31-Mar-2009 12:55)

Ok, here's a function that extends XPath syntax with the following special characters:

~ inserts default namespace prefix if defined

# shorthand for text()

% shorthand for comment()

$ shorthand for node()

?* shorthand for processing-instruction()

?foo shorthand for processing-instruction("foo")

? shorthand for processing-instruction("")

^ escapes following character (with literal or SGML entity as needed)

All of the above except ^ are ignored within quoted strings

<?php
function extendXPath($str, $defns = NULL) {
   $quote = false;
   $map = array(
      '~' => isset($defns) ? "$defns:" : '',
      '#' => 'text()',
      '%' => 'comment()',
      '$' => 'node()'
   );
   $out = '';
  
   for ($i = 0, $len = strlen($str); $i < $len; $i++) {
      $c = $str[$i];
      if (!$quote && array_key_exists($c, $map)) {
         $out .= $map[$c];
      } else switch ($c) {
         case '^':
            $out .= htmlspecialchars($str[++$i], ENT_QUOTES);
            break;
         case '?':
            if ($quote) {
               $out .= $c;
            } elseif ($str[$i + 1] == '*') {
               $out .= 'processing-instruction()';
               $i++;
            } else {
               preg_match('/^\w+/', substr($str, $i + 1), $matches);
               $out .= 'processing-instruction("'.$matches[0].'")';
               $i += strlen($matches[0]);
            };
            break;
         case '"':
            $quote = !$quote;
         default:
            $out .= $c;
      };
   };
  
   return $out;
}
?>

adam dot prall at thinkingman dot com (08-Jun-2008 10:49)

Just a quick "gotcha" that may sound stupid:

If you've registered your namespaces, loaded your XHTML, etc., into your XPath's DOMDocument object and <i>still</i> can't get it to work, check to make sure you haven't used the DOMDocument's loadHTML() or loadHTMLFile() function. For XHTML <i>always use the XML versions</i>, otherwise your XPath will never, ever work. Save yourself a couple hours of frustration...

cameron kellough (15-Apr-2007 06:33)

This is called prefix mapping and it is necessary to use xpath to handle documents which have default namespaces. //root/item will search for items with no namespace, not items with the namespace described as the default in the xmlns declaration.  This problem is maddening as it just looks on the surface like xpath isn't working.

spam at spam dot spam (31-Mar-2005 08:46)

It is mentioned in a few places on the web, but it wasn't mentioned here. You need to use this function to set up a prefix for the default namespace of a document.

For instance, if you are trying to parse a Microsoft Spreadsheet XML file, which has the default namespace of "urn:schemas-microsoft-com:office:spreadsheet":

$doc = DOMDocument::load("my_spreadsheet.xml);
$xpath = new DOMXPath($doc);
$xpath->registerNamespace("m",
        "urn:schemas-microsoft-com:office:spreadsheet");
$query = '/m:Workbook/m:Worksheet[1]/m:Table';
$result = $xpath->query($query, $doc);

You can use anything in place of the 'm', but you have to specify something! Just asking for "/Workbook/Worksheet/Table" doesn't work.