code: @GetMapping(path = {"/swivel/turingImage"})
      public void generate(final HttpServletResponse response, final HttpServletRequest request) throws Exception {
          response.setContentType("image/png");
          val principal = request.getParameter("principal");
          if (StringUtils.isBlank(principal)) {
              throw new IllegalArgumentException("No principal is specified in the turing image request");
          }
          generateImage(response.getOutputStream(), principal);
      }
docs: Generate.
  
  @param response the response
  @param request  the request
  @throws Exception the exception