+ /**
+ * Mimic the message from libxml.c::php_libxml_ctx_error_level()
+ */
+ private function logXmlError($error) {
+ $output = "";
+
+ switch ($error->level) {
+ case LIBXML_ERR_WARNING:
+ $output .= "Warning $error->code: ";
+ break;
+
+ case LIBXML_ERR_ERROR:
+ $output .= "Error $error->code: ";
+ break;
+
+ case LIBXML_ERR_FATAL:
+ $output .= "Fatal Error $error->code: ";
+ break;
+ }
+
+ $output .= trim($error->message);
+
+ if ($error->file) {
+ $output .= " in $error->file";
+ }
+ else {
+ $output .= " in Entity,";
+ }
+
+ $output .= " line $error->line";
+
+ error_log($output);
+ }
+
+ /**
+ * Load a stylesheet if the web site is supported.
+ */
+ private function loadStylesheet($host) {
+ $stylesheet = "file://" . __DIR__ . "/rss_converter_" . $host . ".xsl";
+ if (FALSE === file_exists($stylesheet)) {
+ trigger_error("Conversion to RSS not supported for $host ($stylesheet not found)", E_USER_ERROR);
+ return NULL;
+ }
+
+ $stylesheet_contents = Tweeper::getUrlContents($stylesheet);
+
+ $xslDoc = new DOMDocument();
+ $xslDoc->loadXML($stylesheet_contents);
+
+ $xsltProcessor = new XSLTProcessor();
+ $xsltProcessor->registerPHPFunctions();
+ $xsltProcessor->setParameter('', 'generate-enclosure', $this->generate_enclosure);
+ $xsltProcessor->importStylesheet($xslDoc);
+
+ return $xsltProcessor;
+ }
+
+ /**
+ * Convert json to xml.
+ */
+ private function jsonToXml($json, $root_node_name) {
+ // Apparently the ObjectNormalizer used afterwards is not able to handle
+ // the stdClass object created by json_decode() with the default setting
+ // $assoc = false; so use $assoc = true.
+ $data = json_decode($json, $assoc = TRUE);
+ if (!$data) {
+ return NULL;
+ }
+
+ $encoder = new XmlEncoder();
+ $normalizer = new ObjectNormalizer();
+ $serializer = new Serializer(array($normalizer), array($encoder));
+
+ $serializer_options = array(
+ 'xml_encoding' => "UTF-8",
+ 'xml_format_output' => TRUE,
+ 'xml_root_node_name' => $root_node_name,
+ );
+
+ $xml_data = $serializer->serialize($data, 'xml', $serializer_options);
+ if (!$xml_data) {
+ trigger_error("Cannot serialize data", E_USER_ERROR);
+ return NULL;
+ }
+
+ return $xml_data;
+ }
+
+ /**
+ * Convert the Instagram content to XML.
+ */
+ private function getXmlInstagramCom($html) {
+ // Extract the json data from the html code.
+ $json_match_expr = '/window._sharedData = (.*);/';
+ $ret = preg_match($json_match_expr, $html, $matches);
+ if ($ret !== 1) {
+ trigger_error("Cannot match expression: $json_match_expr\n", E_USER_ERROR);
+ return NULL;
+ }
+
+ return $this->jsonToXml($matches[1], 'instagram');
+ }
+
+ /**
+ * Make the Facebook HTML processable.
+ */
+ private function preprocessHtmlFacebookCom($html) {
+ $html = str_replace('<!--', '', $html);
+ $html = str_replace('-->', '', $html);
+ return $html;
+ }