php xpath problems

Question

I'm doing a cURL POST and get the error response back, parse it into an array but having issues with xpath now.

// XML

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<errors xmlns="http://host/project">
   <error code="30" description="[] is not a valid email address."/>
   <error code="12" description="id[] does not exist."/>
   <error code="3" description="account[] does not exist."/>
   <error code="400" description="phone[] does not exist."/>
</errors>

// Function / Class

class parseXML
{
    protected $xml;

    public function __construct($xml) {
        if(is_file($xml)) {
            $this->xml = simplexml_load_file($xml);
        } else {
            $this->xml = simplexml_load_string($xml);
        }
    }

    public function getErrorMessage() {
        $in_arr = false;
        $el = $this->xml->xpath("//@errors");        
        $returned_errors = count($el);

        if($returned_errors > 0) {
            foreach($el as $element) {
                if(is_object($element) || is_array($element)) {
                    foreach($element as $item) {
                        $in_arr[] = $item;
                    }
                }
            }
        } else {
            return $returned_errors;
        }            
        return $in_arr;
    }
}

// Calling function

// $errorMessage is holding the XML value in an array index
// something like: $arr[3] = $xml;
$errMsg = new parseXML($arr[3]); 
$errMsgArr = $errMsg->getErrorMessage();

What I would like is all the error code and description attribute values

EDIT:

OK this is print_r($this->xml,true);

SimpleXMLElement Object
(
    [error] => Array
        (
            [0] => SimpleXMLElement Object
                (
                    [@attributes] => Array
                        (
                            [code] => 30
                            [description] => [] is not a valid email address.
                        )

                )

            [1] => SimpleXMLElement Object
                (
                    [@attributes] => Array
                        (
                            [code] => 12
                            [description] => Id[12345] does not exist.
                        )

                )

            [2] => SimpleXMLElement Object
                (
                    [@attributes] => Array
                        (
                            [code] => 3
                            [description] => account[] does not exist.
                        )

                )

            [3] => SimpleXMLElement Object
                (
                    [@attributes] => Array
                        (
                            [code] => 400
                            [description] => phone[] does not exist.
                        )

                )

        )

)

for the life of me I can't figure out why I can get the code and description, any thoughts?

EDIT #2 Okay so I guess I will break it down.

I'm using cURL to POST a request to one of our servers, I parse out the HTTP response headers and xml (if xml is returned). each line in the header/xml I explode into an array. so if there is an error I see an extra index to the array. I then do something like this.

$if_err_from_header = $http_return_response[10]; 
// I know that index 10 is where if any the error message in xml is (the one posted above).

after that I do this:

$errMsg = new parseXML($if_err_from_header); 
$errMsgArr = $errMsg->getErrorMessage();

still I can not get the code and description from the attributes in error, what am I missing?

EDIT #3 Okay why does this work?

$in_arr = false;
// This returns all the code attributes
$el = $this->xml->xpath("//@code");

# if $el is false, nothing returned from xpath(), set to an empty array
$el = $el == false ? array() : $el;

foreach($el as $element) {
    $in_arr[] = array("code" => $element["code"], "description" => $element["description"]);
}
return $in_arr;

EDIT #4:

Okay this gets that values I want but it's kinda a hack, would like to select specific elements but...

$el = $this->xml->xpath("//*");

Answer 1

Make sure you take the namespace into account:

$this->xml->registerXPathNamespace('n', 'http://host/project');
$el = $this->xml->xpath("/n:errors/n:error");
$returned_errors = count($el);

And example of accessing values for lower down..

foreach($el as $element) {
   print "code: " . $element["code"] . "\n";
}

Answer 2

@ in XPath is the attribute selector. You're trying to select the root element so it should be:

  $el = $this->xml->xpath("/errors");

If you want to select all error elements, use

  $el = $this->xml->xpath("/errors/error");

or

  $el = $this->xml->xpath("//error");