server.py

#!/usr/bin/env python

"""
A simple echo server for axochat
"""

import binascii
import socket
import threading
import sys
from time import time
from random import randint

HOST = '0.0.0.0'
PORT = 50000
BACKLOG = 10
while True:
    try:
        PORT = raw_input('TCP port (1 for random choice, 50000 is default): ')
        PORT = int(PORT)
        break
    except ValueError:
        PORT = 50000
        break
if PORT >= 1025 and PORT <= 65535:
    pass
elif PORT == 1:
    PORT = 1025 + randint(0, 64510)
    print 'PORT is ' + str(PORT)

ans = raw_input('Keep a log of the (encrypted) traffic? y/N ')
if ans == 'y' or ans == 'Y' or ans == 'yes':
    LOGTRAFFIC = True
else:
    LOGTRAFFIC = False

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind((HOST,PORT))
s.listen(BACKLOG)
client_list = {}
client_list_index = 0
address_list = []

def receiveData(client, address, index):
    global client_list
    global address_list
    for i, item in client_list.iteritems():
        item.send('SYSMSG' + str(len(client_list)) + ' users connected\nEOP')
    while True:
        data = ''
        while data[-3:] != 'EOP':
            rcv = client.recv(1024)
            if not rcv:
                del client_list[index]
                address_list.remove(address)
                for i, item in client_list.iteritems():
                    item.send('SYSMSG' + 'Disconnection: only ' + str(len(client_list)) + ' users connected\nEOP')
                print str(address) + ' disconnected'
                sys.exit()
            data = data + rcv
        data_list = data.split('EOP')
        for data in data_list:
            if data != '':
                if LOGTRAFFIC:
                    with open('server.traffic.log', 'a') as f:
                        f.write(binascii.b2a_base64(data[3:]))
                for i, item in client_list.iteritems():
                    try:
                        if (data[:3] != '998' and client != item) and (data[:3] == '999' or int(data[:3]) == i):
                            item.send(data[3:] + 'EOP')
                    except ValueError:
                        pass

try:
    while True:
        client, address = s.accept()
        data = ''
        while data[-5:] != 'START':
            rcv = client.recv(1024)
            data = data + rcv
        my_index = int(data[:-5])
        client_list[my_index] = client
        address_list = address_list + [address]
        threading.Thread(target=receiveData,args=(client,address,my_index)).start()
        print str(my_index) + ': ' +str(address) + ' connected'
except KeyboardInterrupt:
    print 'Server stopped'