Source code for server.iptools

"""
Tools related to IP operations, mainly getting IP's and checking if servers exist at a certain IP:port combination.
"""
import netifaces

__author__ = 'Curtis West'
__copyright__ = 'Copyright 2017, Curtis West'
__version__ = '3.0'
__maintainer__ = 'Curtis West'
__email__ = 'curtis@curtiswest.net'
__status__ = 'Development'


class IPTools(object):
    """
    Static methods that work on IPv4-based connections, such as getting current IP, gateway IP, etc.
    """

    @staticmethod
    def current_ips():
        # type: () -> [str]
        """
        Gets the best-candidate IPs of this computer on the network.
        """
        candidates = []
        gateway = None
        for interface in netifaces.interfaces():
            try:
                candidates.append(netifaces.ifaddresses(interface)[netifaces.AF_INET][0]['addr'])
                gateway = IPTools.gateway_ip()
            except (KeyError, IndexError):
                pass

        if gateway:
            gateway_subnet = IPTools.get_first_digits_from(gateway, 1)
            if any(c.startswith(gateway_subnet) for c in candidates):
                candidates = (c for c in candidates if c.startswith(gateway_subnet))
        elif any(not c.startswith('127') for c in candidates):
            candidates = (c for c in candidates if not c.startswith('127'))  # Remove any localhost 127.x.x.x IPs
        return list(candidates)

    @staticmethod
    def gateway_ip():
        # type: () -> str
        """
        Gets the IP of this computer's gateway, if it exists.
        """
        try:
            return str(netifaces.gateways()['default'][netifaces.AF_INET][0])
        except (KeyError, IndexError):
            return None

    @staticmethod
    def get_first_digits_from(ip, num_digits, with_dot=True):
        # type: (str, int, bool) -> str
        """
        Gets the given sets of digits from an IP, with or without
        the trailing period.

        :note: if ``num_digits`` exceeds 4, the ``ip`` is returned unchanged.

        :param ip: the IP address string to trim
        :param num_digits: the number of digit sets to keep
        :param with_dot: True to keep the trailing period, False to not
        """
        if num_digits > 4:
            return ip
        return ".".join(ip.split('.')[0:num_digits]) + ('.' if with_dot else '')

    @staticmethod
    def get_subnet_from(ip, with_dot=True):
        # type: (str, bool) -> str
        """
        Gets the first 3 sets of digits from an IP, with or
        without the trailing period.

        :param ip: the IP address string to trim
        :param with_dot: True to keep the trailing period, False to not
        """
        if len(ip.split('.')) < 4:
            return ip if ip[-1] == '.' and with_dot else ip[0:-1]
        return ".".join(ip.split('.')[0:3]) + ('.' if with_dot else '')