PHP's SimpleXML: How to use colons in names

Question

I am trying to generate an RSS Google Merchant, using SimpleXML.

The sample given by Google is:

Answer 1

As @ceejayoz said, you need to add the "http://base.google.com/ns/1.0" namespace to the root node so that SimpleXML knows the namespace has already been declared and doesn't emit a duplicate prefix binding.

I think you may need to read a tutorial on XML Namespaces, because I'm not sure you really understand what the "g:" is doing here.

Here is a more complete example. XML:

$xml = << 
 
   
     
    http://www.example.com 
    A description of your content 
     
       
       http://www.example.com/item1-info-page.html 
      Comfortable and soft, this sweater will keep you warm on those cold winter nights. 
      http://www.example.com/image1.jpg 
      25 
      1a 
     
   
 
EOT 
; 

Code:

$rss = new SimpleXMLElement($xml); 
$NS = array( 
    'g' => 'http://base.google.com/ns/1.0' 
); 
$rss->registerXPathNamespace('g', $NS['g']); 
$product = $rss->channel->item[0]; // example 

// Use the complete namespace. 
// Don't add "g" prefix to element name--what prefix will be used is 
// something SimpleXML takes care of. 
$product->addChild('condition', 'new', $NS['g']); 

echo $rss->asXML(); 

I usually use this pattern to deal with namespaces easily:

$rss = new SimpleXMLElement($xml); 
$NS = array( 
    'g' => 'http://base.google.com/ns/1.0' 
    // whatever other namespaces you want 
); 
// now register them all in the root 
foreach ($NS as $prefix => $name) { 
    $rss->registerXPathNamespace($prefix, $name); 
} 
// Then turn $NS to an object for more convenient syntax 
$NS = (object) $NS; 
// If I need the namespace name later, I access like so: 
$element->addChild('localName', 'Value', $NS->g);