#!/usr/bin/env python
     # encoding: utf-8
     #
     # Copyright (c) 2009 Doug Hellmann All rights reserved.
     #
     """
     """
     #end_pymotw_header
     
     import asynchat
     import logging
     
     
     class EchoHandler(asynchat.async_chat):
         """Handles echoing messages from a single client.
         """
     
         # Artificially reduce buffer sizes to illustrate
         # sending and receiving partial messages.
         ac_in_buffer_size = 64
         ac_out_buffer_size = 64
         
         def __init__(self, sock):
             self.received_data = []
             self.logger = logging.getLogger('EchoHandler')
             asynchat.async_chat.__init__(self, sock)
             # Start looking for the ECHO command
             self.process_data = self._process_command
             self.set_terminator('\n')
             return
     
         def collect_incoming_data(self, data):
             """Read an incoming message from the client and put it into our outgoing queue."""
             self.logger.debug('collect_incoming_data() -> (%d bytes)\n"""%s"""', len(data), data)
             self.received_data.append(data)
     
         def found_terminator(self):
             """The end of a command or message has been seen."""
             self.logger.debug('found_terminator()')
             self.process_data()
         
         def _process_command(self):        
             """We have the full ECHO command"""
             command = ''.join(self.received_data)
             self.logger.debug('_process_command() "%s"', command)
             command_verb, command_arg = command.strip().split(' ')
             expected_data_len = int(command_arg)
             self.set_terminator(expected_data_len)
             self.process_data = self._process_message
             self.received_data = []
         
         def _process_message(self):
             """We have read the entire message to be sent back to the client"""
             to_echo = ''.join(self.received_data)
             self.logger.debug('_process_message() echoing\n"""%s"""', to_echo)
             self.push(to_echo)
             # Disconnect after sending the entire response
             # since we only want to do one thing at a time
             self.close_when_done()