+ * 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;
+ }
+
+ /**