Password Generator for PY2 and PY3

genpw

#!/usr/bin/python
"""
A cryptographically useful password generator.
Totally re-written by Kionmaru.
Modified again by blade2005
"""

import string
import argparse

class PWGen(object):
    """
    Abstract out python2 / python3 differences,
    and provide a stable API allowing PW gen.
    """
    def __init__(self, allowed_chars):
        self.allowed_chars = allowed_chars
        super(PWGen, self).__init__()
    def generate_pw(self, length):
        """
        Generate the PW, using whichever cryptographically useful method is
        available to us.
        """
        try:
            import secrets
            pwd = (secrets.choice(self.allowed_chars) for i in range(length))
        except ImportError as _:
            from os import urandom
            pwd = (
                self.allowed_chars[ord(urandom(1)) % len(self.allowed_chars)]
                for i in range(length))
        return ''.join(pwd)


def parse_opts():
    """Parse CLI options"""
    parser = argparse.ArgumentParser(
        description='Generate a cryptographically useful password.',
        epilog='By default, the characters used are {0}.'.format(
            string.ascii_letters + string.digits + string.punctuation))
    parser.add_argument('--length', '-l', dest='length', default=32, type=int,
                        help='Length of password in characters')
    parser.add_argument('--no-lowercase', dest='nolc', action='store_true',
                        default=False, help='No lowercase characters')
    parser.add_argument('--no-digits', dest='nodigits', action='store_true',
                        default=False, help='No digits characters')
    parser.add_argument('--no-uppercase', dest='nouc', action='store_true',
                        default=False, help='No uppercase characters')
    parser.add_argument('--less-special', '-s', dest='mspec',
                        action='store_false', default=True,
                        help='Use the less special characters')
    parser.add_argument('--no-special', dest='nospec', action='store_true',
                        default=False, help='No special characters at all')
    parser.add_argument('-e', '--enforce-min', dest='enforce', action='store_true',
                        default=False,
                        help='Enforce at least one of each type.')
    parser.add_argument('-q', '--quiet', dest='quiet', action='store_true',
                        default=False, help='Output only the password.')
    args = parser.parse_args()
    return vars(args)

def main():
    """
    Main function - where the magic happens!
    """
    args = parse_opts()
    chars = ''
    if not args['nodigits']:
        chars += string.digits
    if not args['nolc']:
        chars += string.ascii_lowercase
    if not args['nouc']:
        chars += string.ascii_uppercase
    if not args['nospec']:
        if args['mspec']:
            chars += string.punctuation
        else:
            chars += '!?_-'
    makepw = PWGen(chars)
    while True:
        newpw = makepw.generate_pw(args['length'])
        if not args['enforce']:
            break
        if (any(string.ascii_lowercase for c in newpw)
                and any(string.ascii_uppercase for c in newpw)
                and any(string.digits for c in newpw)
                and any(string.punctuation for c in newpw)):
            break
    if args['quiet']:
        print(newpw)
    else:
        print("Using characters: {0}".format(chars))
        print("The new password is: {0}".format(newpw))
    return 0

if __name__ == '__main__':
    main()