import socket
import asyncore
import sys

MSG_SIZE = 4096
DATA = (MSG_SIZE * ' ' + '\n').encode()
LOOP_TIMEOUT = .020

class Server(asyncore.dispatcher):
    def __init__(self, address):
        asyncore.dispatcher.__init__(self)
        self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
        self.set_reuse_addr()
        self.bind(address)
        self.listen(1)

    def handle_accept(self):
        sock, addr = self.accept()
        Reader(sock)
        self.close()

class Reader(asyncore.dispatcher):
    def __init__(self, sock):
        asyncore.dispatcher.__init__(self, sock)

    def writable(self):
        return False

    def handle_read(self):
        self.recv(64)
        self.close()

class Writer(asyncore.dispatcher_with_send):
    def __init__(self, address):
        asyncore.dispatcher_with_send.__init__(self)
        self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
        self.connect(address)
        self.cnt = 0

    def handle_connect(self, *args):
        self.send(DATA)

    def handle_write(self):
        print('handle_write')
        asyncore.dispatcher_with_send.handle_write(self)

    def handle_read(self):
        print('handle_read')
        self.recv(MSG_SIZE)

    def handle_close(self):
        print('handle_close')
        if not self.writable():
            self.close()

        # abort to stop infinite calls to handle_read handle_close
        self.cnt += 1
        if self.cnt == 20:
            print('Aborting: too many calls to handle_close.')
            sys.exit()

def main():
    address = ('localhost', 3220)
    Server(address)
    Writer(address)
    asyncore.loop(timeout=LOOP_TIMEOUT)

if __name__ == "__main__":
    main()