SimpleXML Reading node with a hyphenated name

Question

I have the following XML:

<?xml version="1.0" encoding="UTF-8"?>
<gnm: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">
  <office: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" xmlns:ooo="http://openoffice.org/2004/office" office:version="1.1">
    <office:meta>
      <dc:creator>Mark Baker</dc:creator>
      <dc:date>2010-09-01T22:49:33Z</dc:date>
      <meta:creation-date>2010-09-01T22:48:39Z</meta:creation-date>
      <meta:editing-cycles>4</meta:editing-cycles>
      <meta:editing-duration>PT00H04M20S</meta:editing-duration>
      <meta:generator>OpenOffice.org/3.1$Win32 OpenOffice.org_project/310m11$Build-9399</meta:generator>
    </office:meta>
  </office:document-meta>
</gnm:Workbook>

And am trying to read the office:document-meta node to extractthe various elements below it (dc:creator, meta:creation-date, etc.)

The following code:

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

gives me:

object(SimpleXMLElement)[91]
  public 'document-meta' => 
    object(SimpleXMLElement)[93]
      public '@attributes' => 
        array
          'version' => string '1.1' (length=3)
      public 'meta' => 
        object(SimpleXMLElement)[94]

but if I try to read the document-meta element using:

$xml = simplexml_load_string($gFileData);
$namespacesMeta = $xml->getNamespaces(true);
$officeXML = $xml->children($namespacesMeta['office']);
$docMeta = $officeXML->document-meta;
var_dump($docMeta);
echo '<hr />';

I get

Notice: Use of undefined constant meta - assumed 'meta' in /usr/local/apache/htdocsNewDev/PHPExcel/Classes/PHPExcel/Reader/Gnumeric.php on line 273
int 0

I assume that SimpleXML is trying to extract a non-existent node "document" from $officeXML, then subtract the value of (non-existent) constant "meta", resulting in forcing the integer 0 result rather than the document-meta node.

Is there a way to resolve this using SimpleXML, or will I be forced to rewrite using XMLReader? Any help appreciated.

Answer 1

Your assumption is correct. Use

$officeXML->{'document-meta'}

to make it work.

Please note that the above applies to Element nodes. Attribute nodes (those within the @attributes property when dumping the SimpleXmlElement) do not require any special syntax to be accessed when hyphenated. They are regularly accessible via array notation, e.g.

$xml = <<< XML
<root>
    <hyphenated-element hyphenated-attribute="bar">foo</hyphenated-element>
</root>
XML;
$root = new SimpleXMLElement($xml);
echo $root->{'hyphenated-element'}; // prints "foo"
echo $root->{'hyphenated-element'}['hyphenated-attribute']; // prints "bar"

See the SimpleXml Basics in the Manual for further examples.