php simpleXMLElement to array: null value

Question

I\'ve got following XML:

    123
    
    ACTIVE



        

Answer 1

I cannot add a comment, but I think this will work for you, it should be faster then a regex or a loop:

//after you json_encode, before you decode
$str = str_replace(':[]',':null',json_encode($array));

An empty array in JSON is represented by "[]". Sometimes the arrays are parsed as objects, in that case (or as a fallback) you can replace ":{}" too.

Answer 2

Check performance str_replace vs recursive loop

• Iterations: 100000
• XML length: 4114 bytes
• Init script time: ~1.2264486691986E-6 seconds
• JSON encode/decode time: ~9.8956169957496E-5 seconds
• str_replace average time: 0.00010692856433176 seconds
• recursive loop average time: 0.00011844366600813 seconds

The str_replace quickly on ~0.00001 seconds. The difference will be noticeable in many calls

Answer 3

An empty SimpleXMLElement object will be casted to an empty array. You can change this by by extending from SimpleXMLElement and implementing the JsonSerializable interface and casting an it to null.

/**
 * Class JsonXMLElement
 */
class JsonXMLElement extends SimpleXMLElement implements JsonSerializable
{

    /**
     * Specify data which should be serialized to JSON
     *
     * @return mixed data which can be serialized by json_encode.
     */
    public function jsonSerialize()
    {
        $array = array();

        // json encode attributes if any.
        if ($attributes = $this->attributes()) {
            $array['@attributes'] = iterator_to_array($attributes);
        }

        // json encode child elements if any. group on duplicate names as an array.
        foreach ($this as $name => $element) {
            if (isset($array[$name])) {
                if (!is_array($array[$name])) {
                    $array[$name] = [$array[$name]];
                }
                $array[$name][] = $element;
            } else {
                $array[$name] = $element;
            }
        }

        // json encode non-whitespace element simplexml text values.
        $text = trim($this);
        if (strlen($text)) {
            if ($array) {
                $array['@text'] = $text;
            } else {
                $array = $text;
            }
        }

        // return empty elements as NULL (self-closing or empty tags)
        if (!$array) {
            $array = NULL;
        }

        return $array;
    }
}

Then tell simplexml_load_string to return an object of JsonXMLElement class

$xml = <<<XML
<account>
   <id>123</id>
   <email></email>
   <status>ACTIVE</status>
</account>
XML;

$obj = simplexml_load_string($xml, 'JsonXMLElement');

// print_r($obj);

print json_encode($obj, true);

/*
 * Output...
{
   "id": 123,
   "email": null,
   "status": "ACTIVE"
}
*/

Credit: hakre