One of the main tasks Ngashint as a release management application is to have a build automation system for code deployment from SVN repository tags to production/test/dev servers. I used Phing for building software release/deployment like people use Ant for Java projects.

Phing is XML based build tool that allows you to easily write build recipe. While using Phing, at one point I needed to dynamically build “build” XML file for automation.That means having to edit or create XML file on the fly. One way to do is to use native XML library or functions supported by PHP traverse through DOM tree and modify or creating nodes and attributes. I find that path boring or tedious. I wonder what if we can update data like an array. So I decided to write code to convert from XML to associative array (yeah …one nice thing about PHP) and then being able to convert generated array into same XML file, back and forth maintaining symmetric relationship.

Here is how an associative array is used to represent XML nodes and attributes conceptually.

• “key” => “text value” is for attribute i.e   associative array key will be attribute name where its value will be attribute value.
• [0-9] => “text value” is for text node i.e if the key is numeric, array element will become a text node
• “key” => array() for child node i.e key will be parent node name and “array()” value will be a child node
• [0-9] => array() for child node, same idea as above but to represent multiple child nodes with the same node name at the same depth level

Here is now to use:

        $obj = new XmlArray();
        $xmlString = '<root id="test">Hello World</root>';

        $array = $obj->getArray($xmlString);
        var_dump($array);

        $xml = $obj->getXML($array);
        echo $xml;

Output will be like

array(1) {
  ["root"]=>
  array(2) {
    ["id"]=>
    string(4) "test"
    [0]=>
    string(11) "Hello World"
  }
}
<root id="test">Hello World</root>

Following is the complete class code you can use.

class XmlArray {

    /**
     * @desc : "key" => "text value" is for attribute
     * 		    [0-9] => "text value" is for text node
     * 			"key" => array()  for child node
     * 			[0-9] => array() for child node to have same name of child node at the same tree depth level
     * @param array $A
     * @return unknown_type
     */
    public function getXML(array $A) {
        if (count($A) != 1)
            throw new Exception('There can be only one root for XML document');

        $dom = new DOMDocument('1.0', 'UTF-8');

        if ($this->is_assoc($A)) {
            foreach ($A as $key => $value) {
                $rootNode = $dom->createElement($key);
                if (is_array($value) && !empty($value)) {
                    $this->processNode($value, $rootNode, $dom);
                } else if (is_array($value) && empty($value)) {
                    $text = $dom->createTextNode($key);
                    $rootNode->appendChild($text);
                } else {
                    throw new Exception('Malformed array for XML representation!');
                }
            }
        } else {
            $rootNode = $dom->createElement($A[0]);
        }

        return $dom->saveXML($rootNode);
    }

    public function getArray($xmlString) {
        if (empty($xmlString))
            throw new Exception('Empty XML string');
        $doc = new DOMDocument();
        $doc->loadXML($xmlString);

        $A = array($doc->documentElement->nodeName => array());

        $this->processArray($A[$doc->documentElement->nodeName], $doc->documentElement);

        return $A;
    }

    private function processNode(array $A, &$parent, $dom) {
        if ($this->is_assoc($A)) {
            foreach ($A as $key => $value) {

                if (is_numeric($key) && is_array($value)) {
                    if ($this->is_assoc($value)) {
                        $this->processNode($value, $parent, $dom);
                    } else {
                        foreach ($value as $each)
                            $this->processNode($each, $parent, $dom);
                    }
                } else if (is_numeric($key) && !is_array($value)) {
                    $text = $dom->createTextNode($value);
                    $parent->appendChild($text);
                } else if (is_array($value) && !empty($value)) {
                    $node = $dom->createElement($key);
                    $parent->appendChild($node);
                    $this->processNode($value, $node, $dom);
                } else {
                    $parent->setAttribute($key, $value);
                }
            }
        } else {
            foreach ($A as $a) {
                if (is_array($a)) {
                    $this->processNode($a, $parent, $dom);
                }
                else
                    $parent->appendChild($dom->createTextNode($a));
            }
        }
    }

    private function processArray(&$currentA, $currentNode) {

        $numericKey = 0;

        if ($currentNode->hasAttributes()) {
            foreach ($currentNode->attributes as $attr) {
                $currentA[$attr->nodeName] = $attr->nodeValue;
            }
        }

        if ($currentNode->hasChildNodes()) {
            foreach ($currentNode->childNodes as $child) {
                if ($child->nodeType === XML_TEXT_NODE) {
                    //Text Node
                    if (!empty($child->wholeText)) {
                        $currentA[$numericKey] = $child->wholeText;
                        $numericKey++;
                    }
                } else {
                    if (isset($currentA[$child->nodeName])) {
                        $currentA[$numericKey] = array($child->nodeName => array());
                        $this->processArray($currentA[$numericKey][$child->nodeName], $child);
                        $numericKey++;
                    } else {
                        $currentA[$child->nodeName] = array();
                        $this->processArray($currentA[$child->nodeName], $child);
                    }
                }
            }
        }
    }

    protected function is_assoc($array) {
        return (is_array($array) && 0 !== count(array_diff_key($array, array_keys(array_keys($array)))));
    }

}

Download link for the class : http://www.megaupload.com/?d=EIBGVAIO