random string script using Click library

random.py

#!/usr/bin/env python
from __future__ import print_function

import random

import click


@click.command()
@click.argument('length', type=click.INT)
@click.option('--chartype', type=click.Choice(['alphanumeric', 'alpha', 'numeric', 'all']),
              default='all')
@click.option('--case', type=click.Choice(['both', 'upper', 'lower']), default='both')
@click.option('--unique', is_flag=True)
def random_cli(length, chartype, case, unique):
    """Return random string of chars"""
    print(randchars(length, chartype=chartype, alphacase=case, unique=unique))


def randchars(n=12, chartype='alphanumeric', alphacase='both', unique=False):
    if alphacase == 'both':
        alphalist = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
    elif alphacase == 'upper':
        alphalist = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
    elif alphacase == 'lower':
        alphalist = 'abcdefghijklmnopqrstuvwxyz'
    else:
        raise ValueError('alphacase "%s" not recognized' % alphacase)

    if chartype == 'alphanumeric':
        charlist = alphalist + '0123456789'
    elif chartype == 'alpha':
        charlist = alphalist
    elif chartype == 'numeric':
        charlist = '0123456789'
    elif chartype == 'all':
        charlist = alphalist + '0123456789' + """`~!@#$%^&*()_-+={}|[]\:";'<>?,./"""
    else:
        raise ValueError('chartype "%s" not recognized' % chartype)

    retval = []
    for _ in range(n):
        chosen = random.choice(charlist)
        if unique:
            charlist = charlist.replace(chosen, '')
        retval.append(chosen)

    return ''.join(retval)


if __name__ == '__main__':
    random_cli()