start.py

#!/usr/bin/env python

import getpass
import sys
from optparse import OptionParser

from minecraft import authentication
from minecraft.exceptions import YggdrasilError
from minecraft.networking.connection import Connection
from minecraft.networking.packets import (
    ChatMessagePacket, ChatPacket
)
from minecraft.networking.packets.serverbound.play import ClientStatusPacket
from minecraft.compat import input


def get_options():
    parser = OptionParser()

    parser.add_option("-u", "--username", dest="username", default=None,
                      help="username to log in with")

    parser.add_option("-p", "--password", dest="password", default=None,
                      help="password to log in with")

    parser.add_option("-s", "--server", dest="server", default=None,
                      help="server to connect to")

    parser.add_option("-o", "--offline", dest="offline", action="store_true",
                      help="connect to a server in offline mode")

    (options, args) = parser.parse_args()

    if not options.username:
        options.username = input("Enter your username: ")

    if not options.password and not options.offline:
        options.password = getpass.getpass("Enter your password: ")

    if not options.server:
        options.server = input("Please enter server address"
                               " (including port): ")
    # Try to split out port and address
    if ':' in options.server:
        server = options.server.split(":")
        options.address = server[0]
        options.port = int(server[1])
    else:
        options.address = options.server
        options.port = 25565

    return options


def main():
    options = get_options()

    if options.offline:
        print("Connecting in offline mode")
        connection = Connection(
            options.address, options.port, username=options.username)
    else:
        auth_token = authentication.AuthenticationToken()
        try:
            auth_token.authenticate(options.username, options.password)
        except YggdrasilError as e:
            print(e)
            sys.exit()
        print("Logged in as " + auth_token.username)
        connection = Connection(
            options.address, options.port, auth_token=auth_token)

    connection.connect()

    def print_chat(chat_packet):
        print("Position: " + str(chat_packet.position))
        print("Data: " + chat_packet.json_data)

    connection.register_packet_listener(print_chat, ChatMessagePacket)
    while True:
        try:
            text = input()
            if text == "/respawn":
                print("respawning...")
                packet = ClientStatusPacket()
                packet.action_id = ClientStatusPacket.RESPAWN
                connection.write_packet(packet)
            else:
                packet = ChatPacket()
                packet.message = text
                connection.write_packet(packet)
        except KeyboardInterrupt:
            print("Bye!")
            sys.exit()


if __name__ == "__main__":
    main()