echo serverとか。

cyclone版

import cyclone.web

class MainHandler(cyclone.web.RequestHandler):
    def get(self):
        self.write("hello, world")
Application = lambda: cyclone.web.Application([(r"/", MainHandler)])

echo_server.py

import socket

host = socket.gethostbyname('localhost')
port = 8080

socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
socket.bind((host,port))
socket.listen(1)

print 'wating for connetion ...'

(client_sock, client_addr) = socket.accept()

client_sock.send("server: connetion start \n\n")
print 'connnection start'

while True:
    msg = client_sock.recv(1024)
    msg = msg.rstrip()

    if msg == "bye":
        client_sock.send("server:connetion end \n\n")
        print "connection end"
        break

    else:
        client_sock.send("server :%s \n" % msg)
        print "client: %s" %msg


client_sock.close()

socket.close()

tornado

import tornado.ioloop
import tornado.web

class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.write("Hello, world")

application = tornado.web.Application([
    (r"/", MainHandler),
])

if __name__ == "__main__":
    application.listen(8888)
    tornado.ioloop.IOLoop.instance().start()