There's no documentation for this item.

Source Code

# File action_controller/response.rb, line 46
def handle_conditional_get!
  if body.is_a?(String) && (headers['Status'] ? headers['Status'][0..2] == '200' : true)  && !body.empty?
    self.headers['ETag'] ||= %("#{Digest::MD5.hexdigest(body)}")
    self.headers['Cache-Control'] = 'private, max-age=0, must-revalidate' if headers['Cache-Control'] == DEFAULT_HEADERS['Cache-Control']

    if request.headers['HTTP_IF_NONE_MATCH'] == headers['ETag']
      self.headers['Status'] = '304 Not Modified'
      self.body = ''
    end
  end
end