Chat using TCP Sockets - prototype !

import socket
listeningPortNumber = 8081

#------------
def send_text( sending_socket, text ):
    text = text + "\n"
    data = text.encode()
    sending_socket.send(data)
#-----------
def get_text( receiving_socket ):
    buffer = ""

    socket_open = True
    while socket_open:
        # read any data from the socket
        data = receiving_socket.recv(1024)

        # if no data is returned the socket must be closed
        if not data:
            socket_open = False

        # add the data to the buffer
        buffer = buffer + data.decode()

        # is there a terminator in the buffer
        terminator_pos = buffer.find("\n")
        # if the value is greater than -1, a \n must exist
        while terminator_pos > -1:
            # get the message from the buffer
            message = buffer[:terminator_pos]
            # remove the message from the buffer
            buffer = buffer[terminator_pos + 1:]

            # yield the message (see below)
            yield message
            # is there another terminator in the buffer
            terminator_pos = buffer.find("\n")
#----------------------
print('')
print('Welcome to the Chat program')
print('***************************')
print('Chat program can run as a server or a client.')
print('.. a chat Server must be running before any client !')

chatType = input('Enter "c" for Client mode .. else default is a Server ..\n=> ')

if chatType != "c": # not 'c' so launch Server
    server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server_socket.bind(("0.0.0.0", listeningPortNumber))
    server_socket.listen()
    print("SERVER: waiting for connection")

    connection_socket, address = server_socket.accept()
    print("SERVER: client connected")

else: # 'c' so launch Client
    #------------------------------
    # CLIENT: connect to TCP Server
    ipAddress = input('Please enter IP address of server ..\n=> ')
    connection_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    #connection_socket.connect(("127.0.0.1", listeningPortNumber))
    connection_socket.connect((ipAddress, listeningPortNumber))
    print("CLIENT: Connected to server")
    message = "Thanks for connecting me mate"
    send_text( connection_socket, message )
#-------------------------------------------
# OK, got a connection_socket
while True:
    # receive msg ..
    message = next( get_text( connection_socket ))
    #message =  get_text( connection_socket )
    print(message)
    message = input('Please enter chat text ..\n=> ')
    send_text( connection_socket, message )
    print('Waiting for next chat message from network ..')

connection_socket.close()
#server_socket.close()
print('SERVER: sockets CLOSED !')