class WEBrick::HTTPResponse

def error_body(backtrace, ex, host, port)
  @body = +""
  @body << <<-_end_of_html_
CTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN">
L>
EAD><TITLE>#{HTMLUtils::escape(@reason_phrase)}</TITLE></HEAD>
ODY>
<H1>#{HTMLUtils::escape(@reason_phrase)}</H1>
#{HTMLUtils::escape(ex.message)}
<HR>
  _end_of_html_
  if backtrace && $DEBUG
    @body << "backtrace of '#{HTMLUtils::escape(ex.class.to_s)}' "
    @body << "#{HTMLUtils::escape(ex.message)}"
    @body << "<PRE>"
    ex.backtrace.each{|line| @body << "\t#{line}\n"}
    @body << "</PRE><HR>"
  end
  @body << <<-_end_of_html_
<ADDRESS>
 #{HTMLUtils::escape(@config[:ServerSoftware])} at
 #{host}:#{port}
</ADDRESS>
BODY>
ML>
  _end_of_html_
end