original_string: public static function autodiscover_feed_url($url){
              $rss =  new moodle_simplepie();
              $rss->set_feed_url($url);
              $rss->set_autodiscovery_level(SIMPLEPIE_LOCATOR_ALL);
              // When autodiscovering an RSS feed, simplepie will try lots of
              // rss links on a page, so set the timeout high
              $rss->set_timeout(20);
              $rss->init();
  
              if($rss->error()){
                  return $url;
              }
  
              // return URL without quoting..
              $discoveredurl = new moodle_url($rss->subscribe_url());
              return $discoveredurl->out(false);
      }
code: public static function autodiscover_feed_url($url){
              $rss =  new moodle_simplepie();
              $rss->set_feed_url($url);
              $rss->set_autodiscovery_level(SIMPLEPIE_LOCATOR_ALL);
              // When autodiscovering an RSS feed, simplepie will try lots of
              // rss links on a page, so set the timeout high
              $rss->set_timeout(20);
              $rss->init();
  
              if($rss->error()){
                  return $url;
              }
  
              // return URL without quoting..
              $discoveredurl = new moodle_url($rss->subscribe_url());
              return $discoveredurl->out(false);
      }
code_tokens: public static function autodiscover_feed_url ( $ url ) { $ rss = new moodle_simplepie ( ) ; $ rss -> set_feed_url ( $ url ) ; $ rss -> set_autodiscovery_level ( SIMPLEPIE_LOCATOR_ALL ) ; // When autodiscovering an RSS feed, simplepie will try lots of // rss links on a page, so set the timeout high $ rss -> set_timeout ( 20 ) ; $ rss -> init ( ) ; if ( $ rss -> error ( ) ) { return $ url ; } // return URL without quoting.. $ discoveredurl = new moodle_url ( $ rss -> subscribe_url ( ) ) ; return $ discoveredurl -> out ( false ) ; }
docstring: Autodiscovers a feed url from a given url, to be used by the formslibs
  filter function
  
  Uses simplepie with autodiscovery set to maximum level to try and find
  a feed to subscribe to.
  See: http://simplepie.org/wiki/reference/simplepie/set_autodiscovery_level
  
  @param string URL to autodiscover a url
  @return string URL of feed or original url if none found
docstring_tokens: Autodiscovers a feed url from a given url to be used by the formslibs filter function