python tcp ip example (addition of 2 numbers) Example taken from http://docs.python.org/2/library/socket.html

client.py

#! /usr/bin/python
# Echo client program
import socket

def parse_file(fName):
    list = []
    with open(fName) as f:
        for line in f:
            list.append(line.strip())
    return list


HOST = 'localhost'    # The remote host
PORT = 50007              # The same port as used by the server
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))

# s.sendall('Hello, world')
# data = s.recv(1024)
# s.close()
# print 'Received', repr(data)

input_data = parse_file('foo')

for i in input_data:
    s.sendall(str(i))
    sum = s.recv(1024)
    print "CLIENT RECIEVED : Sum ", sum

s.close()

foo

12 
34

server.py

#! /usr/bin/python
# Echo server program
import socket

def compute_sum(line):
    result = sum(int(i) for i in line)
    return result

HOST = 'localhost'                 # Symbolic name meaning all available interfaces
PORT = 50007              # Arbitrary non-privileged port
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(1)
conn, addr = s.accept()
print 'Connected by', addr
while 1:
    data = conn.recv(1024)
    if not data: break
    print "SERVER RECIEVED : ", repr(data)
    compute_sum(data)

    conn.sendall(data)
conn.close()