Parsing Zimbra SOAP response with SimpleXML and xpath - php

Question

So, I'm using PHP to talk to a Zimbra SOAP server. The response is in a <soap:Envelope> tag. I'm having trouble parsing the XML response because of the namespace(s).
The XML looks like this:
<soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope">
<soap:Header>
<context xmlns="urn:zimbra">
<change token="20333"/>
</context>
</soap:Header>
<soap:Body>
<CreateAccountResponse xmlns="urn:zimbraAdmin">
<account id="83ebf344-dc51-47ae-9a36-3eb24281d53e" name="iamtesting#example.com">
<a n="zimbraId">83ebf344-dc51-47ae-9a36-3eb24281d53e</a>
<a n="zimbraMailDeliveryAddress">iamtesting#example.com</a>
</account>
</CreateAccountResponse>
</soap:Body>
</soap:Envelope>
I make a new SimpleXMLElement object:
$xml = new SimpleXMLElement($data);
After Googling a bit, I found I need to register the namespace. So I do that:
$xml->registerXPathNamespace('soap', 'http://www.w3.org/2003/05/soap-envelope');
Then I can get the <soap:Body> tag easily.
$body = $xml->xpath('//soap:Body');
But I can't get any elements after that (using xpath):
$CreateAccountResponse = $xml->xpath('//soap:Body/CreateAccountResponse');
This returns an empty array. I can traverse the XML though, to get that element.
$CreateAccountResponse = $body[0]->CreateAccountResponse;
This works fine, but now I want to get the <a> tags, specifically the zimbraId one. So I tried this:
$zimbraId = $CreateAccountResponse->account->xpath('a[#n=zimbraId]');
No luck, I get a blank array. What's going on? Why can't I use xpath to get elements (that don't start with soap:)?
How can I get the <a> tags based on their n attribute?
P.S. I'm aware that the id and name are also in the <account> tag's attributes, but there are a bunch more <a> tags that I want to get using the n attribute.
Note: I'm trying to improve the Zimbra library for my application for work. The current code to get the <a> tags is as follows:
$zimbraId = strstr($data, "<a n=\"zimbraId\"");
$zimbraId = strstr($zimbraId, ">");
$zimbraId = substr($zimbraId, 1, strpos($zimbraId, "<") - 1);
Obviously, I want to remove this code (there's also some regexes (shudder) later on in the code), and use an XML parser.

Answer 1

The elements you want to retrieve have a namespace as well, namely urn:zimbraAdmin.
<CreateAccountResponse xmlns="urn:zimbraAdmin">
The xmlns attribute states the default namespace for any child elements, so the elements you are trying to retrieve actually have a namespace, even though no prefix is used (see the wikipedia article for some examples). If you specify a namespace prefix as you did for http://www.w3.org/2003/05/soap-envelope you should be fine.
$xml->registerXPathNamespace('soap', 'http://www.w3.org/2003/05/soap-envelope');
$xml->registerXPathNamespace('zimbra', 'urn:zimbraAdmin');
$CreateAccountResponse = $xml->xpath('//soap:Body/zimbra:CreateAccountResponse');