Socket Programming in Python

README.md

Socket Programming in Python

• SimpleSocketServer.py--socket server in single thread
• ThreadedSocketServer.py--socket server in multiple thread
• PollingSocketServer.py--socket server using select function

Using telnet socket client to debug your program

Run telnet localhost 8080 and type anything you want. To exit, type Escape character and then type q to quit telnet.

Reference

• simple socket server in python on binarytides

PollingSocketServer.py

__author__ = 'will'
__version__ = "0.1"
__all__ = ["start_socket_server"]

import select
import socket

def start_socket_server():
    CONNECTION_LIST = []
    BUFFER_SIZE = 1024
    PORT = 8080
    HOST = '127.0.0.1'
    MAX_QUEUE_SIZE = 10

    server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR , 1)
    server_socket.bind((HOST, PORT))
    server_socket.listen(MAX_QUEUE_SIZE)

    CONNECTION_LIST.append(server_socket)

    print 'Chat Server listening on port ' + str(PORT)

    while True:
        read_sockets, write_sockets, error_sockets = select.select(CONNECTION_LIST, [], [])

        for sock in read_sockets:
            # new connection
            if sock == server_socket:
                sockfd, addr = server_socket.accept()
                CONNECTION_LIST.append(sockfd)
                print "Client %s:%s connected" % addr

            # message from client
            else:
                # try to process the incoming data
                try:
                    data = sock.recv(BUFFER_SIZE)
                    if data:
                        reply = str(len(data)) + ' bytes received\n' + 'Data contents: ' + str(data) + '\n'
                        sock.send(reply)
                except:
                    print "Client %s:%s is offline" % addr
                    CONNECTION_LIST.remove(sock)
                    # for conn in CONNECTION_LIST:
                    #     conn.send("Client " + str(addr[0]) + ':' + str(addr[1]) + " is offline")
                    sock.close()
                    continue

# if current script is the main script run start_socket_server()
if __name__ == "__main__":
    start_socket_server()

SimpleSocketServer.py

__author__ = 'will'
__version__ = "0.1"
__all__ = ["start_socket_server"]

import sys
import socket

def start_socket_server():
    PORT = 8080
    HOST = ''
    MAX_QUEUE_NUM = 10

    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    print 'Socket created'

    try:
        s.bind((HOST, PORT))
    except socket.error as msg:
        print 'Bind failed. Error Code: ' + str(msg[0]) + ' Message: ' + msg[1]
        sys.exit()

    print 'Socket bind completed'

    s.listen(MAX_QUEUE_NUM)
    print 'Socket listening on ' + str(PORT)

    while True:
        conn, addr = s.accept()
        print 'Socket connected with ' + addr[0] + ':' + str(addr[1])

    # close opened socket
    s.close()

# if current script is the main script run start_socket_server()
if __name__ == "__main__":
    start_socket_server()

ThreadedSocketServer.py

__author__ = 'will'
__version__ = "0.1"
__all__ = ["start_socket_server"]

import sys
import socket
import thread

def client_thread(conn, addr):
    conn.send('You have successfully connected to ThreadedSocketServer\n')

    while True:
        BUFFER_SIZE = 1024
        # receive
        data = conn.recv(BUFFER_SIZE)
        if not data:
            break
        reply = str(len(data)) + ' bytes received\n' + 'Data contents: ' + data
        conn.sendall(reply)

    conn.close()
    print 'connection to ' + addr[0] + ':' + str(addr[1]) + ' closed'

def start_socket_server():
    PORT = 8080
    HOST = ''
    MAX_QUEUE_NUM = 10

    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    print 'Socket created'

    try:
        s.bind((HOST, PORT))
    except socket.error as msg:
        print 'Bind failed. Error Code: ' + str(msg[0]) + ' Message: ' + msg[1]
        sys.exit()

    print 'Socket bind completed'

    s.listen(MAX_QUEUE_NUM)
    print 'Socket listening on ' + str(PORT)

    while True:
        conn, addr = s.accept()
        print 'Socket connected with ' + addr[0] + ':' + str(addr[1])
        thread.start_new_thread(client_thread, (conn, addr))

    # close opened socket
    s.close()

# if current script is the main script run start_socket_server()
if __name__ == "__main__":
    start_socket_server()