# -*- coding: utf-8 -*-
"""
This module contains utility functions used by the Hosts and HostsEntry methods
"""
import os
import re
import socket
[docs]
def is_ipv4(entry):
"""Return ``True`` if ``entry`` is a valid IPv4 address."""
try:
socket.inet_aton(entry)
except socket.error:
return False
return True
[docs]
def is_ipv6(entry):
"""Return ``True`` if ``entry`` is a valid IPv6 address."""
try:
socket.inet_pton(socket.AF_INET6, entry)
except socket.error:
return False
return True
[docs]
def valid_hostnames(hostname_list):
"""Return ``True`` if all items in ``hostname_list`` are valid hostnames."""
allowed = re.compile(r'(?!-)[A-Z\d-]{1,63}(?<!-)$', re.IGNORECASE)
return all(len(entry) <= 255 and
all(allowed.match(x) for x in entry.split('.'))
for entry in hostname_list)
[docs]
def is_readable(path=None):
"""Return ``True`` if ``path`` exists and is readable."""
return os.path.isfile(path) and os.access(path, os.R_OK)
[docs]
def dedupe_list(seq):
"""
Utility function to remove duplicates from a list
:param seq: The sequence (list) to deduplicate
:return: A list with original duplicates removed
"""
seen = set()
return [x for x in seq if not (x in seen or seen.add(x))]