Tornado echo TCP Server & Client. Refer to the corresponding repo for the full working example: https://github.com/Databrawl/real_time_tcp/tree/3147a3f4bddf70616f19a7e4c41df6118d5f348a.

client.py

from tornado import gen
from tornado.ioloop import IOLoop
from tornado.tcpclient import TCPClient


class Client(TCPClient):
    msg_separator = b'\r\n'

    @gen.coroutine
    def run(self, host, port):
        stream = yield self.connect(host, port)
        while True:
            data = input(">> ").encode('utf8')
            data += self.msg_separator
            if not data:
                break
            else:
                yield stream.write(data)
            data = yield stream.read_until(self.msg_separator)
            body = data.rstrip(self.msg_separator)
            print(body)


if __name__ == '__main__':
    Client().run('localhost', 5567)
    print('Connecting to server socket...')
    IOLoop.instance().start()
    print('Socket has been closed.')

server.py

from tornado import gen
from tornado.ioloop import IOLoop
from tornado.iostream import StreamClosedError
from tornado.tcpserver import TCPServer


class Server(TCPServer):
    message_separator = b'\r\n'

    @gen.coroutine
    def handle_stream(self, stream, address):
        while True:
            try:
                request = yield stream.read_until(self.message_separator)
            except StreamClosedError:
                stream.close(exc_info=True)
                return
            try:
                yield stream.write(request)
            except StreamClosedError:
                stream.close(exc_info=True)
                return


if __name__ == '__main__':
    Server().listen(5567)
    print('Starting the server...')
    IOLoop.instance().start()
    print('Server has shut down.')