Socket Example -- Python library reference

5.7.2. Example

Here are two minimal example programs using the TCP/IP protocol: a server that echoes all data that it receives back (servicing only one client), and a client using it. Note that a server must perform the sequence socket, bind, listen, accept (possibly repeating the accept to service more than one client), while a client only needs the sequence socket, connect. Also note that the server does not send/receive on the socket it is listening on but on the new socket returned by accept.

# Echo server program
from socket import *

HOST = ''                 # Symbolic name meaning the local host

PORT = 50007              # Arbitrary non-privileged server

s = socket(AF_INET, 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

    conn.send(data)

conn.close()

# Echo client program
from socket import *

HOST = 'daring.cwi.nl'    # The remote host

PORT = 50007              # The same port as used by the server

s = socket(AF_INET, SOCK_STREAM)

s.connect(HOST, PORT)

s.send('Hello, world')

data = s.recv(1024)

s.close()

print 'Received', `data`