math_server.py

import socket
from subprocess import Popen, STDOUT, PIPE
from threading import Thread

class ProcessOutputThread(Thread): #OOPS
	def __init__(self, proc, conn):
		Thread.__init__(self)
		self.proc = proc
		self.conn = conn
		
	def run(self):
		while not self.proc.stdout.closed:
			conn.sendall(self.proc.stdout.readline())

HOST = ''
PORT = 8877

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind((HOST, PORT))
s.listen()
conn, addr = s.accept()
print("{} connected with back port {}".format(addr[0], addr[1]))
conn.sendall("Simple Math Server developed by LAHTP \n\nGive any math expressions, and I will answer you :) \n\n$ ".encode())

p = Popen(['bc'], stdout=PIPE, stdin=PIPE, stderr=STDOUT, shell=True)
output = ProcessOutputThread(p, conn)
output.start()

while not p.stdout.closed:
	data = conn.recv(1024)
	if not data:
		break
	else:
		data = data.decode()
		query = data.strip()
		if query == 'quit' or query == 'exit':
			p.communicate(query.encode(), timeout=1)
			if p.poll() is not None:
				break
		query = query + '\n'
		p.stdin.write(query.encode())
		p.stdin.flush()
s.close()