Python TCP chat server and client

tcp.py

from threading import Thread
import socket
import sys


class Server(Thread):
    def __init__(self, host='', port=1337):
        super().__init__()
        self.host = host
        self.port = port
        self.backlog = 5
        self.size = 1024
        self.server = None
        self.threads = []

    def open_socket(self):
        try:
            self.server = socket.socket()
            self.server.bind((self.host, self.port))
            self.server.listen(self.backlog)
        except socket.error:
            if self.server:
                self.server.close()
            sys.exit('Could not open socket')
        print('Server running on port', self.port)

    def run(self):
        self.open_socket()
        self.running = True
        while self.running:
            c = Connection(self, *self.server.accept())
            c.start()
            self.threads.append(c)
            print('Connection from', c.addr)
            self.broadcast('{} has joined the server'.format(c.addr), c)

    def broadcast(self, data, client=None):
        for sock in self.threads:
            if sock is not client:
                try:
                    sock.client.send(data.encode())
                except:
                    self.threads.remove(sock)
                    self.broadcast('{} has left the server'
                        .format(sock.addr))

    def terminate(self):
        self.running = False
        self.server.close()
        for c in self.threads:
            c.join()
        self.join()


class Client(Thread):
    def __init__(self, host, port):
        super().__init__()
        self.host = host
        self.port = port
        self.size = 1024
        self.conn = None

    def connect(self):
        try:
            self.conn = socket.socket()
            self.conn.connect((self.host, self.port))
        except socket.error:
            if self.conn:
                self.conn.close()
            sys.exit('Could not connect to socket')
        print('Connected to {}:{}'.format(self.host, self.port))

    def run(self):
        self.connect()
        self.running = True
        while self.running:
            data = self.conn.recv(self.size).decode()
            print(data)

    def terminate(self):
        self.running = False
        self.conn.close()
        self.join()


class Connection(Thread):
    def __init__(self, server, client, addr):
        super().__init__()
        self.server = server
        self.client = client
        self.addr = addr
        self.size = 1024

    def run(self):
        running = True
        while running:
            data = self.client.recv(self.size)
            if data:
                msg = '{}: "{}"'.format(self.addr, data.decode())
                self.server.broadcast(msg, self)
                print(msg)
            else:
                self.client.close()
                running = False


if __name__ == '__main__':
    try:
        if sys.argv[1] == '-s':
            s = Server()
            s.start()
            input()
            s.terminate()

        elif sys.argv[2]:
            c, s = Client(sys.argv[1], int(sys.argv[2])), True
            c.start()
            while s:
                s = input()
                c.conn.send(s.encode())
            c.terminate()

    except IndexError:
        print('Usage: python {} [-s | addr port] '.format(__file__))