Function to reliably retrieve a local IP address on OS X + Linux in Python. Interface specification only works on Linux.

gistfile1.txt

# get_ip is from http://stackoverflow.com/questions/166506/finding-local-ip-addresses-using-pythons-stdlib, added a fallback to making a connection for OS X/local testing
def get_ip(iface = 'eth0'):
  import socket, struct, fcntl
	sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
	sockfd = sock.fileno()
	SIOCGIFADDR = 0x8915

	ifreq = struct.pack('16sH14s', iface, socket.AF_INET, '\x00'*14)

	try:
		res = fcntl.ioctl(sockfd, SIOCGIFADDR, ifreq)
	except:
		s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
		s.connect(("gmail.com",80))
		ip = s.getsockname()[0]
		s.close()

		return ip

	ip = struct.unpack('16sH2x4s8x', res)[2]
	return socket.inet_ntoa(ip)