/symphony/lib/toolkit/data-sources/class.datasource.dynamic_xml.php

<?php

	/**
	 * @package data-sources
	 */
	/**
	 * The `DynamicXMLDatasource` allows a user to retrieve XML from an URL.
	 * This datasource supports namespaces, partial results using XPath and
	 * caching the result for a number of minutes.
	 *
	 * @since Symphony 2.3
	 */

	require_once(TOOLKIT . '/class.gateway.php');
	require_once(TOOLKIT . '/class.xsltprocess.php');
	require_once(CORE . '/class.cacheable.php');

	Class DynamicXMLDatasource extends Datasource {

		public function execute(array &$param_pool = null) {

			$result = new XMLElement($this->dsParamROOTELEMENT);

			$this->dsParamURL = $this->parseParamURL($this->dsParamURL);

			if(isset($this->dsParamXPATH)) $this->dsParamXPATH = $this->__processParametersInString($this->dsParamXPATH, $this->_env);

			$stylesheet = new XMLElement('xsl:stylesheet');
			$stylesheet->setAttributeArray(array('version' => '1.0', 'xmlns:xsl' => 'http://www.w3.org/1999/XSL/Transform'));

			$output = new XMLElement('xsl:output');
			$output->setAttributeArray(array('method' => 'xml', 'version' => '1.0', 'encoding' => 'utf-8', 'indent' => 'yes', 'omit-xml-declaration' => 'yes'));
			$stylesheet->appendChild($output);

			$template = new XMLElement('xsl:template');
			$template->setAttribute('match', '/');

			$instruction = new XMLElement('xsl:copy-of');

			// Namespaces
			if(isset($this->dsParamFILTERS) && is_array($this->dsParamFILTERS)){
				foreach($this->dsParamFILTERS as $name => $uri) $instruction->setAttribute('xmlns' . ($name ? ":{$name}" : NULL), $uri);
			}

			// XPath
			$instruction->setAttribute('select', $this->dsParamXPATH);

			$template->appendChild($instruction);
			$stylesheet->appendChild($template);

			$stylesheet->setIncludeHeader(true);

			$xsl = $stylesheet->generate(true);

			$cache_id = md5($this->dsParamURL . serialize($this->dsParamFILTERS) . $this->dsParamXPATH);

			$cache = new Cacheable(Symphony::Database());

			$cachedData = $cache->check($cache_id);
			$writeToCache = false;
			$valid = true;
			$creation = DateTimeObj::get('c');
			$timeout = (isset($this->dsParamTIMEOUT)) ? (int)max(1, $this->dsParamTIMEOUT) : 6;

			// Execute if the cache doesn't exist, or if it is old.
			if(
				(!is_array($cachedData) || empty($cachedData)) // There's no cache.
				|| (time() - $cachedData['creation']) > ($this->dsParamCACHE * 60) // The cache is old.
			){
				if(Mutex::acquire($cache_id, $timeout, TMP)) {
					$ch = new Gateway;
					$ch->init($this->dsParamURL);
					$ch->setopt('TIMEOUT', $timeout);
					$ch->setopt('HTTPHEADER', array('Accept: text/xml, */*'));

					$data = $ch->exec();
					$info = $ch->getInfoLast();

					Mutex::release($cache_id, TMP);

					$data = trim($data);
					$writeToCache = true;

					// Handle any response that is not a 200, or the content type does not include XML, plain or text
					if((int)$info['http_code'] != 200 || !preg_match('/(xml|plain|text)/i', $info['content_type'])){
						$writeToCache = false;

						$result->setAttribute('valid', 'false');

						// 28 is CURLE_OPERATION_TIMEOUTED
						if($info['curl_error'] == 28) {
							$result->appendChild(
								new XMLElement('error',
									sprintf('Request timed out. %d second limit reached.', $timeout)
								)
							);
						}
						else{
							$result->appendChild(
								new XMLElement('error',
									sprintf('Status code %d was returned. Content-type: %s', $info['http_code'], $info['content_type'])
								)
							);
						}

						return $result;
					}

					// Handle where there is `$data`
					else if(strlen($data) > 0) {
						// If the XML doesn't validate..
						if(!General::validateXML($data, $errors, false, new XsltProcess)) {
							$writeToCache = false;
						}

						// If the `$data` is invalid, return a result explaining why
						if($writeToCache === false) {
							$element = new XMLElement('errors');

							$result->setAttribute('valid', 'false');

							$result->appendChild(new XMLElement('error', __('Data returned is invalid.')));

							foreach($errors as $e) {
								if(strlen(trim($e['message'])) == 0) continue;
								$element->appendChild(new XMLElement('item', General::sanitize($e['message'])));
							}

							$result->appendChild($element);

							return $result;
						}
					}
					// If `$data` is empty, set the `force_empty_result` to true.
					else if(strlen($data) == 0){
						$this->_force_empty_result = true;
					}
				}

				// Failed to acquire a lock
				else {
					$result->appendChild(
						new XMLElement('error', __('The %s class failed to acquire a lock, check that %s exists and is writable.', array(
							'<code>Mutex</code>',
							'<code>' . TMP . '</code>'
						)))
					);
				}
			}

			// The cache is good, use it!
			else {
				$data = trim($cachedData['data']);
				$creation = DateTimeObj::get('c', $cachedData['creation']);
			}

			// If `$writeToCache` is set to false, invalidate the old cache if it existed.
			if(is_array($cachedData) && !empty($cachedData) && $writeToCache === false) {
				$data = trim($cachedData['data']);
				$valid = false;
				$creation = DateTimeObj::get('c', $cachedData['creation']);

				if(empty($data)) $this->_force_empty_result = true;
			}

			// If `force_empty_result` is false and `$result` is an instance of
			// XMLElement, build the `$result`.
			if(!$this->_force_empty_result && is_object($result)) {
				$proc = new XsltProcess;
				$ret = $proc->process($data, $xsl);

				if($proc->isErrors()) {
					$result->setAttribute('valid', 'false');
					$error = new XMLElement('error', __('Transformed XML is invalid.'));
					$result->appendChild($error);
					$element = new XMLElement('errors');
					foreach($proc->getError() as $e) {
						if(strlen(trim($e['message'])) == 0) continue;
						$element->appendChild(new XMLElement('item', General::sanitize($e['message'])));
					}
					$result->appendChild($element);
				}

				else if(strlen(trim($ret)) == 0) {
					$this->_force_empty_result = true;
				}

				else {
					if($writeToCache) $cache->write($cache_id, $data, $this->dsParamCACHE);

					$result->setValue(PHP_EOL . str_repeat("\t", 2) . preg_replace('/([\r\n]+)/', "$1\t", $ret));
					$result->setAttribute('status', ($valid === true ? 'fresh' : 'stale'));
					$result->setAttribute('creation', $creation);
				}

			}

			return $result;
		}
	}