code: func (s *Static) match(url string) (string, error) {
  	log.Debug("trying to match static url: " + url)
  
  	if url == "/" {
  		url = "/index.html"
  	}
  
  	for k, v := range s.serving {
  		if strings.Index(url, k) == 0 {
  			log.Debugf("replacing %s with %s", url, k)
  			file := strings.Replace(url, k, "", 1)
  
  			if k == "/" {
  				file = k + file
  			}
  
  			path := v + file
  			log.Debug("found possible result. Path: " + path)
  
  			if s.canBeServed(path) {
  				return path, nil
  			} else if s.canBeServed(path + "/index.html") {
  				return path + "/index.html", nil
  			}
  		}
  	}
  
  	return "", errors.New("cannot match " + url + " in static")
  }
docs: // Trying to find file from passed url.
  // If you have called ``app.Assert("/some", "./dir")``, then if url is ``/some/path/file.txt``,
  // then method will look for file at ``./dir/path/file.txt``.