A simple echo server which just echo the client supplied data or string
server.py
#!/usr/bin/python
import socket
tcpSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
tcpSocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
tcpSocket.bind(("0.0.0.0", 8000))
tcpSocket.listen(2)
while 1:
print "Waiting for a Client ... "
(client, (ip, sock)) = tcpSocket.accept()
print "Received connection from : ", ip
client.send("Press Return or Ctrl+C to close..\n")
print "Starting ECHO output ... "
data = 'dummy'
while len(data):
data = client.recv(2048)
if len(data)==1:
print "Closing connection with ", ip
client.close()
print "Connection closed successfully.!!"
print "---------------------------------"
break
if len(data)==0:
print "Some Error in connection with ", ip
print "Connection closed with ", ip
print "---------------------------------"
break
print "Client sent:", data
client.send(data)
tcpSocket.close()
But the above server code process only a single client at a time.
Now with the use of threading we can solve this problem. Here is the second echo server which handle multiple connection with threads
threaded_server.py
#!/usr/bin/python
import thread
import socket
tcpSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
tcpSocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
tcpSocket.bind(("0.0.0.0", 8000))
tcpSocket.listen(2)
def conn_handler(client, ip, thread_id):
print "[T%d]Received connection from : %r" % (thread_id, ip)
client.send("Press Return or Ctrl+C to close..\n")
print "[T%d]Starting echo output..." % thread_id
data = 'dummy'
while len(data):
data = client.recv(2048)
if len(data)==1:
print "[T%d]Closing connection with %r" % (thread_id, ip)
client.close()
print "[T%d]Connection closed successfully.!!" % thread_id
print "------------------------------------"
break
if len(data)==0:
print "[T%d]Some Error in connection with %r" % (thread_id, ip)
print "[T%d]Connection closed with %r" % (thread_id, ip)
print "------------------------------------"
break
print "[T%d]Client sent: %s" % (thread_id, data)
client.send(data)
thread_id = 0
while 1:
thread_id = thread_id + 1
print "Waiting for Client ...\n"
(client, (ip, sock)) = tcpSocket.accept()
try:
thread.start_new_thread(conn_handler, (client, ip, thread_id, ))
except:
print "Error: Unable to start thread [T%d]\n" % thread_id
tcpSocket.close()
Multi-Process Echo Server
#!/usr/bin/python
from multiprocessing import Process
import socket
import os
import signal
tcpSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
tcpSocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
tcpSocket.bind(("0.0.0.0", 8000))
tcpSocket.listen(2)
def conn_handler(client, ip, Child_id):
print "[C%d]Received connection from : %r" % (Child_id, ip)
print "[C%d]Starting echo output... " % Child_id
data = 'dummy'
while len(data):
data = client.recv(2048)
if len(data)==0:
print "[C%d]Closing connection with %r" % (Child_id, ip)
client.close()
print "[C%d]Connection closed with %r" % (Child_id, ip)
os.kill(os.getpid(), signal.SIGTERM)
print "[C%d]Client sent: %s" % (Child_id, data)
client.send(data)
def main():
Child_id = 0
while 1:
Child_id = Child_id + 1
print "Waiting for Client ...\n"
(client, (ip, sock)) = tcpSocket.accept()
try:
Process(target=conn_handler, args=(client, ip, Child_id)).start()
except:
print "Error: Uable to start Child Process.!![C%d]" % Child_id
tcpSocket.close()
if __name__ == "__main__":
main()
you can try it out with nc, to close the connection just press 'Ctrl + C' or use the below client.py code to communicate with multiprocess_server.py
client.py
#!/usr/bin/python
import socket
import sys
tcpSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
tcpSocket.connect((sys.argv[1], int(sys.argv[2])))
print "Input some string : ['quit' to exit]"
data = "dummy"
while 1:
data = raw_input("|> ")
if data=="quit":
tcpSocket.close()
break
tcpSocket.sendall(data)
result = tcpSocket.recv(2048)
print result
