How to Access Hyphenated XML Node Names Using SimpleXML in PHP?

Reading XML Node with Hyphenated Name Using SimpleXML

In PHP, using SimpleXML to extract data from XML documents becomes challenging when you encounter elements with hyphenated names. Let's delve into this problem and find a solution.

Consider the following XML:

<workbook xmlns:gnm="http://www.gnumeric.org/v10.dtd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemalocation="http://www.gnumeric.org/v9.xsd">
  <document-meta xmlns:office="urn:oasis:names:tc:opendocument:xmlns:office:1.0" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:meta="urn:oasis:names:tc:opendocument:xmlns:meta:1.0" office:version="1.1">
    <meta>
  </document-meta>
</workbook>

To read the document-meta element and its child elements, consider the following initial code:

$xml = simplexml_load_string($gFileData);
$namespacesMeta = $xml->getNamespaces(true);
$officeXML = $xml->children($namespacesMeta['office']);
var_dump($officeXML);

echo '<hr>';

This code dumps all immediate child elements of the office element, which includes document-meta. However, trying to access document-meta directly using $officeXML->document-meta fails and returns int 0.

The reason for this behavior lies in SimpleXML's handling of hyphenated names. By default, it converts hyphenated element names to camelCase. In this case, "document-meta" becomes "documentMeta". To access this element, use the following syntax:

$docMeta = $officeXML->{'document-meta'};
var_dump($docMeta);

By using curly braces and string notation, you can access the actual element name without SimpleXML's default case conversion. This will successfully dump the document-meta element.

Note: This syntax applies only to element nodes. Attribute nodes within @attributes can be accessed directly using array notation, regardless of their hyphenation.

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