1_echo_client_twisted.py

#!/usr/bin/env python

# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.


from twisted.internet.protocol import ClientFactory
from twisted.protocols.basic import LineReceiver
from twisted.internet import reactor
import sys

class EchoClient(LineReceiver):
    end="Bye-bye!"
    def connectionMade(self):
        self.sendLine("Hello, world!")
        self.sendLine("What a fine day it is.")
        self.sendLine(self.end)

    def lineReceived(self, line):
        print "receive:", line
        if line==self.end:
            self.transport.loseConnection()

class EchoClientFactory(ClientFactory):
    protocol = EchoClient

    def clientConnectionFailed(self, connector, reason):
        print 'connection failed:', reason.getErrorMessage()
        reactor.stop()

    def clientConnectionLost(self, connector, reason):
        print 'connection lost:', reason.getErrorMessage()
        reactor.stop()

def main():
    factory = EchoClientFactory()
    reactor.connectTCP('localhost', 8000, factory)
    reactor.run()

if __name__ == '__main__':
    main()

2_echo_client_gevent.py

from gevent import socket
 
end = "Bye-bye!\n"
 
conn = socket.create_connection(('localhost', 8000))
conn.sendall("Hello, world\n")
conn.sendall("What a fine day it is.\n")
conn.sendall(end)
 
for line in conn.makefile():
    if line == end:
        conn.close()
        break
 
# explicit error handling is not needed as exceptions will be raised in case of errors
# normal try/except/finally/else mechanism is available to manage them

Sorry, actually I haven't. Updated to run.