Passing PHP associative arrays to and from XML

Question

Is there an easy way to marshal a PHP associative array to and from XML? For example, I have the following array:

$items = array("1", "2",
    array(
        "item3.1" => "3.1",
        "item3.2" => "3.2"
        "isawesome" => true
    )
);

How would I turn it into something similar to the following XML in as few lines as possible, then back again?

<items>
    <item>1</item>
    <item>2</item>
    <item>
        <item3_1>3.1</item3_1>
        <item3_2>3.2</item3_2>
        <isawesome>true</isawesome>
    </item>
</items>

I don't really care if I have to change the array structure a bit or if the XML that comes out is different to the above example. I've been trying to work with PHP's XMLReader and XMLWriter, but the documentation is so poor and the code I've produced as a consequence looks nothing like what I feel it should look like:

$xml = SomeXMLWriter::writeArrayToXml($items);
$array = SomeXMLWriter::writeXmlToArray($xml);

Does it really have to be any harder than that to get a basic, raw XML dump of a PHP array without writing my own custom class?

I try to avoid PEAR. In addition to the configuration headaches I've had with it, I've never stuck with any of the packages I've ever used from it.

Answer 1

SimpleXML works great for your use.

Answer 2

For those of you not using the PEAR packages, but you've got PHP5 installed. This worked for me:

/**
 * Build A XML Data Set
 *
 * @param array $data Associative Array containing values to be parsed into an XML Data Set(s)
 * @param string $startElement Root Opening Tag, default fx_request
 * @param string $xml_version XML Version, default 1.0
 * @param string $xml_encoding XML Encoding, default UTF-8
 * @return string XML String containig values
 * @return mixed Boolean false on failure, string XML result on success
 */
public function buildXMLData($data, $startElement = 'fx_request', $xml_version = '1.0', $xml_encoding = 'UTF-8') {
    if(!is_array($data)) {
        $err = 'Invalid variable type supplied, expected array not found on line '.__LINE__." in Class: ".__CLASS__." Method: ".__METHOD__;
        trigger_error($err);
        if($this->_debug) echo $err;
        return false; //return false error occurred
    }
    $xml = new XmlWriter();
    $xml->openMemory();
    $xml->startDocument($xml_version, $xml_encoding);
    $xml->startElement($startElement);

    /**
     * Write XML as per Associative Array
     * @param object $xml XMLWriter Object
     * @param array $data Associative Data Array
     */
     function write(XMLWriter $xml, $data) {
         foreach($data as $key => $value) {
             if(is_array($value)) {
                 $xml->startElement($key);
                 write($xml, $value);
                 $xml->endElement();
                 continue;
             }
             $xml->writeElement($key, $value);
         }
     }
     write($xml, $data);

     $xml->endElement();//write end element
     //Return the XML results
     return $xml->outputMemory(true); 
}