webssh/webssh/utils.py

62 lines
1.3 KiB
Python

import ipaddress
import re
try:
from types import UnicodeType
except ImportError:
UnicodeType = str
numeric = re.compile(r'[0-9]+$')
allowed = re.compile(r'(?!-)[a-z0-9-]{1,63}(?<!-)$', re.IGNORECASE)
def to_str(bstr, encoding='utf-8'):
if isinstance(bstr, bytes):
return bstr.decode(encoding)
return bstr
def to_bytes(ustr, encoding='utf-8'):
if isinstance(ustr, UnicodeType):
return ustr.encode(encoding)
return ustr
def is_valid_ipv4_address(ipstr):
ipstr = to_str(ipstr)
try:
ipaddress.IPv4Address(ipstr)
except ipaddress.AddressValueError:
return False
return True
def is_valid_ipv6_address(ipstr):
ipstr = to_str(ipstr)
try:
ipaddress.IPv6Address(ipstr)
except ipaddress.AddressValueError:
return False
return True
def is_valid_port(port):
return 0 < port < 65536
def is_valid_hostname(hostname):
if hostname[-1] == '.':
# strip exactly one dot from the right, if present
hostname = hostname[:-1]
if len(hostname) > 253:
return False
labels = hostname.split('.')
# the TLD must be not all-numeric
if numeric.match(labels[-1]):
return False
return all(allowed.match(label) for label in labels)