class Rack::ShowExceptions

def dump_exception(exception)
  if exception.respond_to?(:detailed_message)
    message = exception.detailed_message(highlight: false)
  else
    message = exception.message
  end
  string = "#{exception.class}: #{message}\n".dup
  string << exception.backtrace.map { |l| "\t#{l}" }.join("\n")
  string
end