text: # Copyright (c) Twisted Matrix Laboratories.
  # See LICENSE for details.
  
  """
  Simple echo server that echoes back client input.
  
  You can run this .tac file directly with:
      twistd -ny telnet_echo.tac
  
  This demo sets up a listening port on 6023 which accepts telnet connections.
  No login for the telnet server is required.
  """
  
  from twisted.conch.telnet import TelnetTransport, TelnetProtocol
  from twisted.internet.protocol import ServerFactory
  from twisted.application.internet import TCPServer
  from twisted.application.service import Application
  
  
  class TelnetEcho(TelnetProtocol):
      def enableRemote(self, option):
          self.transport.write(b"You tried to enable " + option + b" (I rejected it)\r\n")
          return False
  
      def disableRemote(self, option):
          self.transport.write(b"You disabled " + option + b"\r\n")
  
      def enableLocal(self, option):
          self.transport.write(
              b"You tried to make me enable "
              + option
              + b" (I rejected it)\r\n" % (option,)
          )
          return False
  
      def disableLocal(self, option):
          self.transport.write(b"You asked me to disable " + option + "\r\n")
  
      def dataReceived(self, data):
          self.transport.write(b"I received " + data + b" from you\r\n")
  
  
  factory = ServerFactory()
  factory.protocol = lambda: TelnetTransport(TelnetEcho)
  service = TCPServer(6023, factory)
  
  application = Application("Telnet Echo Server")
  service.setServiceParent(application)
  