code: func PrintablePathCheckHandler(next http.Handler, input *HandlerInput) http.Handler {
  	// Nil-check on input to make it optional
  	if input == nil {
  		input = &HandlerInput{
  			ErrStatus: http.StatusBadRequest,
  		}
  	}
  
  	// Default to http.StatusBadRequest on error
  	if input.ErrStatus == 0 {
  		input.ErrStatus = http.StatusBadRequest
  	}
  
  	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  		if r != nil {
  			// Check URL path for non-printable characters
  			idx := strings.IndexFunc(r.URL.Path, func(c rune) bool {
  				return !unicode.IsPrint(c)
  			})
  
  			if idx != -1 {
  				w.WriteHeader(input.ErrStatus)
  				return
  			}
  
  			if next != nil {
  				next.ServeHTTP(w, r)
  			}
  		}
  
  		return
  	})
  }
docs: // PrintablePathCheckHandler is a middleware that ensures the request path
  // contains only printable runes.