+function get_url_info($url)
+{
+  $ch = curl_init($url);
+  curl_setopt_array($ch, array(
+      CURLOPT_HEADER => TRUE,
+      CURLOPT_NOBODY => TRUE,
+      CURLOPT_FOLLOWLOCATION => TRUE,  // follow http redirects to get the real URL
+      CURLOPT_RETURNTRANSFER => TRUE,
+      CURLOPT_SSL_VERIFYHOST => FALSE,
+      CURLOPT_SSL_VERIFYPEER => FALSE,
+      CURLOPT_USERAGENT => USER_AGENT,
+  ));
+  curl_exec($ch);
+  $url_info = curl_getinfo($ch);;
+  curl_close($ch);
+
+  return $url_info;
+}
+
+function generate_enclosure($url)
+{
+  $url_info = get_url_info($url);
+
+  switch($url_info['content_type']) {
+    case "video/avi":
+    case "image/gif":
+    case "image/jpeg":
+    case "audio/x-midi":
+    case "audio/mpeg":
+    case "video/mpeg":
+    case "audio/vorbis":
+    case "application/ogg":
+    case "audio/webm":
+    case "audio/aac":
+    case "audio/mp4":
+    case "audio/wav":
+    case "video/mp4":
+    case "video/ogg":
+      $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);
+    default:
+        return;
+  }
+}
+