simplexml_load_string correct parameters for namespace

I am currently trying to pull information from the google contacts api. Using the sample code provided in the libraries:

$response = json_encode(simplexml_load_string($val->getResponseBody())); 
$result = json_decode($response, true);

the simplexml_load_string function does not pick up on namespaces. Looking at php.net and how to add the parameters I am a little lost.

$xml = json_encode(simplexml_load_string(null, $val->getResponseBody(), null, 'gd', true));

event with trying to pull the ‘gd’ namespace from my xml string I am receiving an error. Is there anyone who can assist in this?

The output error is this:

simplexml_load_string() expects parameter 2 to be a class name derived from SimpleXMLElement

But on top of this error it also correctly prints the info I want…I am confused.

Example of info I need to pull:

<gd:extendedProperty xmlns:gs='http://schemas.google_apps_sync.com' name='google_apps_sync'>
    <gs:em_odn1>[e-mail]</gs:em_odn1>
    <gs:em_dn1>First Name Last Name</gs:em_dn1>
    <gs:em_ad1>[e-mail]</gs:em_ad1>
    <gs:em_t1>SMTP</gs:em_t1>
    <gs:f_c>32791</gs:f_c>
    <gs:f>Last, First</gs:f>
  </gd:extendedProperty>

EDIT

$xmlResponse = simplexml_load_string($val->getResponseBody(), null, 0, 'gd', true);
$xmlResponse->registerXPATHNamespace('gd', 'http://schemas.google_apps_sync.com');
$xmlResponse->registerXPATHNamespace('gs', 'http://schemas.google_apps_sync.com/contact/2008');

The above code allows me to access the namespaces that I need, but only one at a time….for instance:

$email = json_encode($xmlResponse->xpath('//gd:email'), true));
$postal = json_encode($xmlResponse->xpath('//gd:postalAddress'), true);
$name = json_encode($xmlResponse->xpath('//gs:em_dn1'), true);

if I print these variables I get the respective information I need, but is there not a way for me to access the original $xmlResponse variable after I have initiated the namespaces that I want?

ex:

json_decode($xmlResponse, true);

Won’t give me the xml information with the namespaces I have defined.

Answer

I found after hours of combing info on stackoverflow and relatively undocumented on google… if you add ?alt=json to the end of your contacts api uri you will receive the response in JSON!