+ private static $USER_AGENT = "Mozilla/5.0 (Windows NT 6.1; rv:22.0) Gecko/20130405 Firefox/22.0";
+
+ public function __construct($generate_enclosure = FALSE) {
+ $this->generate_enclosure = $generate_enclosure;
+ }
+
+ public static function epoch_to_gmdate($timestamp)
+ {
+ if (!is_numeric($timestamp) || is_nan($timestamp)) {
+ $timestamp = 0;
+ }
+
+ return gmdate('D, d M Y H:i:s', $timestamp) . ' GMT';
+ }
+
+ public static function str_to_gmdate($date)
+ {
+ $timestamp = strtotime($date);
+ if (FALSE === $timestamp) {
+ $timestamp = 0;
+ }
+
+ return Tweeper::epoch_to_gmdate($timestamp);
+ }
+
+ private static function get_contents($url)
+ {
+ $ch = curl_init($url);
+ curl_setopt_array($ch, array(
+ CURLOPT_HEADER => FALSE,
+ CURLOPT_FOLLOWLOCATION => TRUE, // follow http redirects to get the real URL
+ CURLOPT_RETURNTRANSFER => TRUE,
+ CURLOPT_SSL_VERIFYHOST => FALSE,
+ CURLOPT_SSL_VERIFYPEER => FALSE,
+ CURLOPT_HTTPHEADER => array('Accept-language: en'),
+ CURLOPT_USERAGENT => Tweeper::$USER_AGENT,
+ ));
+ $contents = curl_exec($ch);
+ curl_close($ch);
+
+ return $contents;
+ }
+
+ private static function get_info($url)
+ {
+ $ch = curl_init($url);
+ curl_setopt_array($ch, array(
+ CURLOPT_HEADER => TRUE,
+ CURLOPT_NOBODY => TRUE,
+ CURLOPT_FOLLOWLOCATION => TRUE, // follow http redirects to get the real URL
+ CURLOPT_RETURNTRANSFER => TRUE,
+ CURLOPT_SSL_VERIFYHOST => FALSE,
+ CURLOPT_SSL_VERIFYPEER => FALSE,
+ CURLOPT_USERAGENT => Tweeper::$USER_AGENT,
+ ));
+ curl_exec($ch);
+ $url_info = curl_getinfo($ch);
+ curl_close($ch);
+
+ return $url_info;
+ }
+
+ public static function generate_enclosure($url)
+ {
+ $supported_content_types = array(
+ "application/ogg",
+ "audio/aac",
+ "audio/mp4",
+ "audio/mpeg",
+ "audio/ogg",
+ "audio/vorbis",
+ "audio/wav",
+ "audio/webm",
+ "audio/x-midi",
+ "image/gif",
+ "image/jpeg",
+ "video/avi",
+ "video/mp4",
+ "video/mpeg",
+ "video/ogg",
+ );
+
+ // The RSS specification says that the enclosure element url must be http.
+ // See http://sourceforge.net/p/feedvalidator/bugs/72/
+ $http_url = preg_replace("/^https/", "http", $url);
+
+ $url_info = Tweeper::get_info($http_url);
+
+ $supported = in_array($url_info['content_type'], $supported_content_types);
+ if (!$supported) {
+ error_log("Unsupported enclosure content type \"" . $url_info['content_type'] . "\" for URL: " . $url_info['url']);
+ return '';
+ }
+
+ $dom = new DomDocument();
+ $enc = $dom->createElement('enclosure');
+ $enc->setAttribute('url', $url_info['url']);
+ $enc->setAttribute('length', $url_info['download_content_length']);
+ $enc->setAttribute('type', $url_info['content_type']);
+
+ $dom->appendChild($enc);
+
+ return $dom->saveXML($enc);
+ }
+
+ /* Mimic the message from libxml.c::php_libxml_ctx_error_level() */
+ private function log_xml_error($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);
+ }
+
+ private function load_stylesheet($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;
+ }