/lib/Cake/Utility/Xml.php

<?php
/**
 * XML handling for Cake.
 *
 * The methods in these classes enable the datasources that use XML to work.
 *
 * PHP 5
 *
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright 2005-2012, Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright 2005-2012, Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @package       Cake.Utility
 * @since         CakePHP v .0.10.3.1400
 * @license       MIT License (http://www.opensource.org/licenses/mit-license.php)
 */

/**
 * XML handling for Cake.
 *
 * The methods in these classes enable the datasources that use XML to work.
 *
 * @package       Cake.Utility
 */
class Xml {

/**
 * Initialize SimpleXMLElement or DOMDocument from a given XML string, file path, URL or array.
 *
 * ### Usage:
 *
 * Building XML from a string:
 *
 * `$xml = Xml::build('<example>text</example>');`
 *
 * Building XML from string (output DOMDocument):
 *
 * `$xml = Xml::build('<example>text</example>', array('return' => 'domdocument'));`
 *
 * Building XML from a file path:
 *
 * `$xml = Xml::build('/path/to/an/xml/file.xml');`
 *
 * Building from a remote URL:
 *
 * `$xml = Xml::build('http://example.com/example.xml');`
 *
 * Building from an array:
 *
 * {{{
 * 	$value = array(
 * 		'tags' => array(
 * 			'tag' => array(
 * 				array(
 * 					'id' => '1',
 * 					'name' => 'defect'
 * 				),
 * 				array(
 * 					'id' => '2',
 * 					'name' => 'enhancement'
 *				)
 * 			)
 * 		)
 * 	);
 * $xml = Xml::build($value);
 * }}}
 *
 * When building XML from an array ensure that there is only one top level element.
 *
 * ### Options
 *
 * - `return` Can be 'simplexml' to return object of SimpleXMLElement or 'domdocument' to return DOMDocument.
 * - `loadEntities` Defaults to false.  Set to true to enable loading of `<!ENTITY` definitions.  This
 *   is disabled by default for security reasons.
 * - If using array as input, you can pass `options` from Xml::fromArray.
 *
 * @param string|array $input XML string, a path to a file, an URL or an array
 * @param array $options The options to use
 * @return SimpleXMLElement|DOMDocument SimpleXMLElement or DOMDocument
 * @throws XmlException
 */
	public static function build($input, $options = array()) {
		if (!is_array($options)) {
			$options = array('return' => (string)$options);
		}
		$defaults = array(
			'return' => 'simplexml',
			'loadEntities' => false,
		);
		$options = array_merge($defaults, $options);

		if (is_array($input) || is_object($input)) {
			return self::fromArray((array)$input, $options);
		} elseif (strpos($input, '<') !== false) {
			return self::_loadXml($input, $options);
		} elseif (file_exists($input) || strpos($input, 'http://') === 0 || strpos($input, 'https://') === 0) {
			$input = file_get_contents($input);
			return self::_loadXml($input, $options);
		} elseif (!is_string($input)) {
			throw new XmlException(__d('cake_dev', 'Invalid input.'));
		}
		throw new XmlException(__d('cake_dev', 'XML cannot be read.'));
	}

/**
 * Parse the input data and create either a SimpleXmlElement object or a DOMDocument.
 *
 * @param string $input The input to load.
 * @param array  $options The options to use. See Xml::build()
 * @return SimpleXmlElement|DOMDocument.
 */
	protected static function _loadXml($input, $options) {
		$hasDisable = function_exists('libxml_disable_entity_loader');
		$internalErrors = libxml_use_internal_errors(true);
		if ($hasDisable && !$options['loadEntities']) {
			libxml_disable_entity_loader(true);
		}
		if ($options['return'] === 'simplexml' || $options['return'] === 'simplexmlelement') {
			$xml = new SimpleXMLElement($input, LIBXML_NOCDATA);
		} else {
			$xml = new DOMDocument();
			$xml->loadXML($input);
		}
		if ($hasDisable && !$options['loadEntities']) {
			libxml_disable_entity_loader(false);
		}
		libxml_use_internal_errors($internalErrors);
		return $xml;
	}

/**
 * Transform an array into a SimpleXMLElement
 *
 * ### Options
 *
 * - `format` If create childs ('tags') or attributes ('attribute').
 * - `version` Version of XML document. Default is 1.0.
 * - `encoding` Encoding of XML document. If null remove from XML header. Default is the some of application.
 * - `return` If return object of SimpleXMLElement ('simplexml') or DOMDocument ('domdocument'). Default is SimpleXMLElement.
 *
 * Using the following data:
 *
 * {{{
 * $value = array(
 *    'root' => array(
 *        'tag' => array(
 *            'id' => 1,
 *            'value' => 'defect',
 *            '@' => 'description'
 *         )
 *     )
 * );
 * }}}
 *
 * Calling `Xml::fromArray($value, 'tags');`  Will generate:
 *
 * `<root><tag><id>1</id><value>defect</value>description</tag></root>`
 *
 * And calling `Xml::fromArray($value, 'attribute');` Will generate:
 *
 * `<root><tag id="1" value="defect">description</tag></root>`
 *
 * @param array $input Array with data
 * @param array $options The options to use
 * @return SimpleXMLElement|DOMDocument SimpleXMLElement or DOMDocument
 * @throws XmlException
 */
	public static function fromArray($input, $options = array()) {
		if (!is_array($input) || count($input) !== 1) {
			throw new XmlException(__d('cake_dev', 'Invalid input.'));
		}
		$key = key($input);
		if (is_integer($key)) {
			throw new XmlException(__d('cake_dev', 'The key of input must be alphanumeric'));
		}

		if (!is_array($options)) {
			$options = array('format' => (string)$options);
		}
		$defaults = array(
			'format' => 'tags',
			'version' => '1.0',
			'encoding' => Configure::read('App.encoding'),
			'return' => 'simplexml'
		);
		$options = array_merge($defaults, $options);

		$dom = new DOMDocument($options['version'], $options['encoding']);
		self::_fromArray($dom, $dom, $input, $options['format']);

		$options['return'] = strtolower($options['return']);
		if ($options['return'] === 'simplexml' || $options['return'] === 'simplexmlelement') {
			return new SimpleXMLElement($dom->saveXML());
		}
		return $dom;
	}

/**
 * Recursive method to create childs from array
 *
 * @param DOMDocument $dom Handler to DOMDocument
 * @param DOMElement $node Handler to DOMElement (child)
 * @param array $data Array of data to append to the $node.
 * @param string $format Either 'attribute' or 'tags'.  This determines where nested keys go.
 * @return void
 * @throws XmlException
 */
	protected static function _fromArray($dom, $node, &$data, $format) {
		if (empty($data) || !is_array($data)) {
			return;
		}
		foreach ($data as $key => $value) {
			if (is_string($key)) {
				if (!is_array($value)) {
					if (is_bool($value)) {
						$value = (int)$value;
					} elseif ($value === null) {
						$value = '';
					}
					$isNamespace = strpos($key, 'xmlns:');
					if ($isNamespace !== false) {
						$node->setAttributeNS('http://www.w3.org/2000/xmlns/', $key, $value);
						continue;
					}
					if ($key[0] !== '@' && $format === 'tags') {
						$child = null;
						if (!is_numeric($value)) {
							// Escape special characters
							// http://www.w3.org/TR/REC-xml/#syntax
							// https://bugs.php.net/bug.php?id=36795
							$child = $dom->createElement($key, '');
							$child->appendChild(new DOMText($value));
						} else {
							$child = $dom->createElement($key, $value);
						}
						$node->appendChild($child);
					} else {
						if ($key[0] === '@') {
							$key = substr($key, 1);
						}
						$attribute = $dom->createAttribute($key);
						$attribute->appendChild($dom->createTextNode($value));
						$node->appendChild($attribute);
					}
				} else {
					if ($key[0] === '@') {
						throw new XmlException(__d('cake_dev', 'Invalid array'));
					}
					if (is_numeric(implode('', array_keys($value)))) { // List
						foreach ($value as $item) {
							$itemData = compact('dom', 'node', 'key', 'format');
							$itemData['value'] = $item;
							self::_createChild($itemData);
						}
					} else { // Struct
						self::_createChild(compact('dom', 'node', 'key', 'value', 'format'));
					}
				}
			} else {
				throw new XmlException(__d('cake_dev', 'Invalid array'));
			}
		}
	}

/**
 * Helper to _fromArray(). It will create childs of arrays
 *
 * @param array $data Array with informations to create childs
 * @return void
 */
	protected static function _createChild($data) {
		extract($data);
		$childNS = $childValue = null;
		if (is_array($value)) {
			if (isset($value['@'])) {
				$childValue = (string)$value['@'];
				unset($value['@']);
			}
			if (isset($value['xmlns:'])) {
				$childNS = $value['xmlns:'];
				unset($value['xmlns:']);
			}
		} elseif (!empty($value) || $value === 0) {
			$childValue = (string)$value;
		}

		if ($childValue) {
			$child = $dom->createElement($key, $childValue);
		} else {
			$child = $dom->createElement($key);
		}
		if ($childNS) {
			$child->setAttribute('xmlns', $childNS);
		}

		self::_fromArray($dom, $child, $value, $format);
		$node->appendChild($child);
	}

/**
 * Returns this XML structure as a array.
 *
 * @param SimpleXMLElement|DOMDocument|DOMNode $obj SimpleXMLElement, DOMDocument or DOMNode instance
 * @return array Array representation of the XML structure.
 * @throws XmlException
 */
	public static function toArray($obj) {
		if ($obj instanceof DOMNode) {
			$obj = simplexml_import_dom($obj);
		}
		if (!($obj instanceof SimpleXMLElement)) {
			throw new XmlException(__d('cake_dev', 'The input is not instance of SimpleXMLElement, DOMDocument or DOMNode.'));
		}
		$result = array();
		$namespaces = array_merge(array('' => ''), $obj->getNamespaces(true));
		self::_toArray($obj, $result, '', array_keys($namespaces));
		return $result;
	}

/**
 * Recursive method to toArray
 *
 * @param SimpleXMLElement $xml SimpleXMLElement object
 * @param array $parentData Parent array with data
 * @param string $ns Namespace of current child
 * @param array $namespaces List of namespaces in XML
 * @return void
 */
	protected static function _toArray($xml, &$parentData, $ns, $namespaces) {
		$data = array();

		foreach ($namespaces as $namespace) {
			foreach ($xml->attributes($namespace, true) as $key => $value) {
				if (!empty($namespace)) {
					$key = $namespace . ':' . $key;
				}
				$data['@' . $key] = (string)$value;
			}

			foreach ($xml->children($namespace, true) as $child) {
				self::_toArray($child, $data, $namespace, $namespaces);
			}
		}

		$asString = trim((string)$xml);
		if (empty($data)) {
			$data = $asString;
		} elseif (!empty($asString)) {
			$data['@'] = $asString;
		}

		if (!empty($ns)) {
			$ns .= ':';
		}
		$name = $ns . $xml->getName();
		if (isset($parentData[$name])) {
			if (!is_array($parentData[$name]) || !isset($parentData[$name][0])) {
				$parentData[$name] = array($parentData[$name]);
			}
			$parentData[$name][] = $data;
		} else {
			$parentData[$name] = $data;
		}
	}

}