class WEBrick::HTTPResponse

def setup_header() # :nodoc:
  @reason_phrase    ||= HTTPStatus::reason_phrase(@status)
  @header['server'] ||= @config[:ServerSoftware]
  @header['date']   ||= Time.now.httpdate
  if @upgrade
    @header['connection'] = 'upgrade'
    @header['upgrade'] = @upgrade
    @keep_alive = false
    return
  end
  # HTTP/0.9 features
  if @request_http_version < "1.0"
    @http_version = HTTPVersion.new("0.9")
    @keep_alive = false
  end
  # HTTP/1.0 features
  if @request_http_version < "1.1"
    if chunked?
      @chunked = false
      ver = @request_http_version.to_s
      msg = "chunked is set for an HTTP/#{ver} request. (ignored)"
      @logger.warn(msg)
    end
  end
  # Determine the message length (RFC2616 -- 4.4 Message Length)
  if @status == 304 || @status == 204 || HTTPStatus::info?(@status)
    @header.delete('content-length')
    @body = ""
  elsif chunked?
    @header["transfer-encoding"] = "chunked"
    @header.delete('content-length')
  elsif %r{^multipart/byteranges} =~ @header['content-type']
    @header.delete('content-length')
  elsif @header['content-length'].nil?
    if @body.respond_to?(:bytesize)
      @header['content-length'] = @body.bytesize.to_s
    else
      @header['connection'] = 'close'
    end
  end
  # Keep-Alive connection.
  if @header['connection'] == "close"
     @keep_alive = false
  elsif keep_alive?
    if chunked? || @header['content-length'] || @status == 304 || @status == 204 || HTTPStatus.info?(@status)
      @header['connection'] = "Keep-Alive"
    else
      msg = "Could not determine content-length of response body. Set content-length of the response or set Response#chunked = true"
      @logger.warn(msg)
      @header['connection'] = "close"
      @keep_alive = false
    end
  else
    @header['connection'] = "close"
  end
  # Location is a single absoluteURI.
  if location = @header['location']
    if @request_uri
      @header['location'] = @request_uri.merge(location).to_s
    end
  end
end