ping.py

import socket
import sys

def get_info(host, port):
    #Set up our socket
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.settimeout(2.0)
    s.connect((host, port))

    #Send 0xFE: Server list ping
    s.send('\xfe')
    #Send a payload of 0x01 to trigger a new response if the server supports it
    s.send('\x01')

    #Read as much data as we can (max packet size: 241 bytes)
    d = s.recv(256)
    s.close()

    #Check we've got a 0xFF Disconnect
    assert d[0] == '\xff'

    #Remove the packet ident (0xFF) and the short containing the length of the string
    #Decode UCS-2 string
    d = d[3:].decode('utf-16be')

    #If the response string starts with simolean1, then we're dealing with the new response
    if (d.startswith(u'\xa7' + '1')):
        d = d.split(u'\x00')
        #Return a dict of values
        return {'protocol_version': int(d[1]),
                'minecraft_version':    d[2],
                'motd':                 d[3],
                'players':          int(d[4]),
                'max_players':      int(d[5])}
    else:
        d = d.split(u'\xa7')
        #Return a dict of values
        return {'motd':         d[0],
                'players':   int(d[1]),
                'max_players': int(d[2])}
                    
if (len(sys.argv) < 2):
    print "Please provide an address to ping"
else:
    port = 25565
    if (len(sys.argv) == 3):
        #Port provided, use that
        port = int(sys.argv[2])
    print "Pinging " + sys.argv[1] + ":" + str(port)
    print get_info(sys.argv[1], port)