rcon-client.py

import socket
import struct
import select
import sys

packet_id = 0


SERVERDATA_AUTH = 3
SERVERDATA_AUTH_RESPONSE = 2
SERVERDATA_EXECCOMMAND = 2
SERVERDATA_RESPONSE_VALUE  = 0


def make_message(msg, type):
    global packet_id
    length = len(msg) + 10
    data = struct.pack('iii', length, packet_id, type) + msg.encode() + b'\x00\x00'
    packet_id += 1
    return data



s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('127.0.0.1', 27015))
password_data = make_message('test', SERVERDATA_AUTH)
s.send(password_data)

while True:
    socket_list = [sys.stdin, s]
    # Get the list sockets which are readable
    read_sockets, write_sockets, error_sockets = select.select(socket_list , [], [])
    for sock in read_sockets:
        #incoming message from remote server
        if sock == s:
            length = int.from_bytes(sock.recv(4), 'little')
            data = sock.recv(length)
            if not data:
                print('\nDisconnected from server')
                sys.exit()
            else:
                try:
                    print('Data: "%s"' % data[8:-2].decode().strip())
                except Exception as e:
                    print('Unable to decode: %r: %s' % (data[8:-2], e))

        #user entered a message
        else:
            msg = sys.stdin.readline().strip()
            if msg:
                if not msg.startswith('/'):
                    msg = '/silent-command ' + msg
                print('Sending command: "%s"' % msg)
                s.send(make_message(msg, SERVERDATA_EXECCOMMAND))