res := GetSourceIP(req)
	if res != "8.8.8.8" {
		t.Errorf("wrong header, xff takes precedence: got %s, want: 8.8.8.8", res)
	}

	// When explicitly disabled, the XFF header is ignored and X-Real-IP is used.
	enableXFFHeader = false
	defer func() {
		enableXFFHeader = true
	}()
	res = GetSourceIP(req)
	if res != "1.1.1.1" {
		t.Errorf("wrong header, xff is disabled: got %s, want: 1.1.1.1", res)
	}

  if [[ ! -f ${tmp_png_file} ]] ; then
    echo "pdftoppm does not work."
    exit 1
  fi
  ${im_cmd} -thumbnail ${image_size} ${tmp_png_file} "${output_file}"
  rm -f ${tmp_png_prefix}*png
elif [[ x"${cmd_type}" = "xpdf" ]] ; then
  im_cmd=$(get_imagemagick_cmd)
  if [[ -z "${im_cmd}" ]] ; then
    echo "ImageMagick (convert or magick) does not exist."
    exit 1
  fi
  check_command pdftoppm