gistfile1.py

from __future__ import print_function
import socket
import struct

def tryVNC(host, port=5900):
	try:
		s = socket.create_connection((host, port))
	except socket.error:
		return None
	# version negotiation
	try:
		srv_version = s.recv(3 + 1 + 3 + 1 + 3 + 1)
	except socket.timeout:
		return None
	if len(srv_version) < 3 + 1 + 3 + 1 + 3 + 1:
		return None
	assert s.send(srv_version) == len(srv_version)

	# security negotiation
	try:
		security = bytes(s.recv(2))
	except socket.timeout:
		return None
	if len(security) != 2 or security[1] != "\x01":
		print(repr(security), len(security))
		return None

	# attempt authentication
	assert s.send(security[1]) == 1
	try:
		security_result = bytes(s.recv(4))
	except socket.timeout:
		return None
	assert security_result == bytes('\x00' * 4)

	# send "share desktop" request
	assert s.send('\x01') == 1

	# get framebuffer parameters
	try:
		rv = dict()
		rv["width"] = struct.unpack("!H", s.recv(2))[0]
		rv["height"] = struct.unpack("!H", s.recv(2))[0]

		s.recv(1 + 1)
		s.recv(1 + 1)
		s.recv(2 + 2 + 2)
		s.recv(1 + 1 + 1)
		s.recv(3)

		namelen = struct.unpack("!L", s.recv(4))[0]
		rv["name"] = s.recv(namelen)
	except socket.timeout:
		return None
	return rv