Convert XML to array and vice versa in PHP

As a developer, it is common to search the web for an existing (open source) code snippet to re-use for an application, but it is rare for the developer to just copy code online and use it straight in their application without modifying it first.

I am one of many developers who like to save time if possible by using open source code if coding from scratch takes longer than a couple of minutes, but there are times when one cannot be found. I ran into such situation when I wanted a function that converts an XML string into an array. Unfortunately, most are overly complicated for what I wanted, so I decided to create my own and share with the world. The following function converts XML strings into a PHP array while retaining the level depths of the XML but all attributes are ignored.

/**
 * Simple XML to array conversion.
 *
 * Warning: Ignores all attributes!
 *
 * Link: http://18.237.84.250/?p=79
 *
 * @author johnro
 * @param xml $string
 */
function convert_xml_to_array($string) {
	$parser = xml_parser_create();
	xml_parser_set_option($parser, XML_OPTION_CASE_FOLDING, 0);
	xml_parse_into_struct($parser, $string, $vals, $index);
	xml_parser_free($parser);

	$array = array();
	$curr = &amp;$array;
	$levels = array();
	$item = array();
	foreach($vals as $val) {
		switch($val['type']) {
			case 'open':
				if(!empty($item)) {
					foreach($item as $key =&gt; $value) {
						$curr[$key] = $value;
					}
					$item = array();
				}
				$levels[$val['level']] = &amp;$curr;
				$curr[$val['tag']] = array();
				$curr = &amp;$curr[$val['tag']];
				break;
			case 'complete':
				$item[$val['tag']] = $val['value'];
				break;
			case 'close':
				if(!empty($item)) {
					foreach($item as $key =&gt; $value) {
						$curr[$key] = $value;
					}
					$item = array();
				}
				$curr = &amp;$levels[$val['level']];

				break;
		}
	}

	return $array;
}

/**

* Simple XML to array conversion.

* Warning: Ignores all attributes!

* Link: http://18.237.84.250/?p=79

* @author johnro

* @param xml $string

function convert_xml_to_array($string) {

$parser = xml_parser_create();

xml_parser_set_option($parser, XML_OPTION_CASE_FOLDING, 0);

xml_parse_into_struct($parser, $string, $vals, $index);

xml_parser_free($parser);

$array = array();

$curr = &$array;

$levels = array();

$item = array();

foreach($vals as $val) {

switch($val['type']) {

case 'open':

if(!empty($item)) {

foreach($item as $key => $value) {

$curr[$key] = $value;

}

$item = array();

}

$levels[$val['level']] = &$curr;

$curr[$val['tag']] = array();

$curr = &$curr[$val['tag']];

break;

case 'complete':

$item[$val['tag']] = $val['value'];

break;

case 'close':

if(!empty($item)) {

foreach($item as $key => $value) {

$curr[$key] = $value;

}

$item = array();

}

$curr = &$levels[$val['level']];

break;

}

return $array;

}

The following is a sample XML:

<?xml version="1.0"?>
<note>
    <to>Everyone</to>
    <from>John</from>
    <heading>Test</heading>
    <other>
		<type>cool</type>
		<words>
			<first>cat</first>
			<second>dog</first>
			<random>
				<a>piano</a>
				<b>flute</a>
			</random>
		</words>
	</other>
</note>

<?xml version="1.0"?>

<note>

<to>Everyone</to>

<other>

<words>

<a>piano</a>

<b>flute</a>

</random>

</words>

</other>

</note>

which gets converted to the following array

array (
  'note' => 
  array (
    'to' => 'Everyone',
    'from' => 'John',
    'heading' => 'Test',
    'other' => 
    array (
      'type' => 'cool',
      'words' => 
      array (
        'first' => 'cat',
        'second' => 
        array (
        ),
      ),
    ),
  ),
)

array (

'note' =>

array (

'to' => 'Everyone',

'from' => 'John',

'heading' => 'Test',

'other' =>

array (

'type' => 'cool',

'words' =>

array (

'first' => 'cat',

'second' =>

array (

)

To complete this library, I have also included a function to convert the array back to XML string.

/**
 * Simple array to XML conversion.
 *
 * Warning: Ignores all attributes!
 *
 * Link: http://18.237.84.250/?p=79
 *
 * @author johnro
 * @param array $array
 * @param string $namespace
 */
function convert_array_to_xml($array, $namespace = '') {
	$xml = '';
	foreach($array as $key => $value) {
		if(is_array($value)) {
			$value = convert_array_to_xml($value);
		}
		$xml .= "<$key" . rtrim(" $namespace") . ">$value</$key>";
	}
	
	return $xml;
}

/**

* Simple array to XML conversion.

* Warning: Ignores all attributes!

* Link: http://18.237.84.250/?p=79

* @author johnro

* @param array $array

* @param string $namespace

function convert_array_to_xml($array, $namespace = '') {

$xml = '';

foreach($array as $key => $value) {

if(is_array($value)) {

$value = convert_array_to_xml($value);

}

$xml .= "<$key" . rtrim(" $namespace") . ">$value</$key>";

}

return $xml;

}

Feel free to use and any word of advice is appreciated.

i enhanced it a bit:

/**
* Simple array to XML conversion.
*
* Warning: Ignores all attributes!
*
* Link: http://18.237.84.250/?p=79
*
* @author johnro
* @param array $array
* @param string $namespace
*/
function array2xml($array, $depth=0, $namespace = ”) {
$nl=”
“;
$tab=” “;
$xml = ”;
foreach($array as $key => $value) {
if(is_array($value)) {
$value = array2xml($value,$depth+1);
}
if(is_numeric($key)){
$key_start=’item nr=”‘.$key.'”‘;
$key_end=’item’;
}else {
$key_start=$key;
$key_end=$key;
}
if(isset($value[0]) and $value[0]=='<') {
// childnote:
$xml .= $nl.str_repeat($tab,$depth)."” . $nl.str_repeat($tab,$depth+1) . ($value) . $nl . str_repeat($tab,$depth) . “”;
} else $xml .= $nl.str_repeat($tab,$depth).”” . XMLStrFormat($value) . “”;
}

return trim($xml);
}

function XMLStrFormat($str){
/* In XML gilt wie in HTML: Zeichen, die bei der XML-Syntax besondere Bedeutung haben,
müssen Sie umschreiben, wenn Sie sie im normalen Text zwischen den Tags verwenden wollen.
Folgende Zeichen sind betroffen:
Zeichen Notation in XML
>
& &
” "
‘ '

*/
$str = str_replace(“&”, “&”, $str);
$str = str_replace(“”, “>”, $str);
$str = str_replace(“‘”, “'”, $str);
$str = str_replace(“””, “"”, $str);
$str = str_replace(”
“, “”, $str);
// xml generates an error for some characters below Ascii(32) (space):
$str = str_replace(chr(11), “”, $str);
$str = strtr($str,$GLOBALS[‘asc2uni’]);
return $str;
}

$GLOBALS[‘asc2uni’] = Array();
for($i=128;$i<256;$i++){
$GLOBALS['asc2uni'][chr($i)] = "&#x".dechex($i).";";
}

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