A simple random string generator

randomstr

#!/usr/bin/env python3

import argparse
import random
import re
import string


def random_str(length, lower=False, upper=False, digits=False, special=False,
			   whitespace=False, hexidecimal=False, octal=False, exclude=None):
	if hexidecimal:
		return ''.join(random.choice(string.hexdigits) for _ in range(length))
	if octal:
		return ''.join(random.choice(string.hexdigits) for _ in range(length))
	if not lower and not upper and not digits and not special:
		raise ValueError('One or more of `lower`, `upper`, `digits`, or `special` must be `True`')
	selection = []
	if lower:
		selection.extend(string.ascii_lowercase)
	if upper:
		selection.extend(string.ascii_uppercase)
	if digits:
		selection.extend(string.digits)
	if special:
		selection.extend(string.punctuation)
	if whitespace:
		selection.extend(re.sub(r'(\n|\r)', '', string.whitespace))
	if exclude:
		for char in exclude:
			try:
				selection.pop(selection.index(char))
			except IndexError:
				pass
	return ''.join(random.choice(selection) for _ in range(length))

def main():
	parser = argparse.ArgumentParser()
	parser.add_argument('-l', '--lower', action='store_true', default=None,
						help=string.ascii_lowercase)
	parser.add_argument('-u', '--upper', action='store_true', default=None,
						help=string.ascii_uppercase)
	parser.add_argument('--letters', action='store_true', default=False,
					    help=string.ascii_letters)
	parser.add_argument('-d', '--digits', action='store_true', default=None,
						help=string.digits)
	parser.add_argument('--letters-numbers', action='store_true', default=False,
					    help=string.ascii_letters+string.digits)
	parser.add_argument('-s', '--special', action='store_true', default=None,
						help=string.punctuation.replace('%', '%%'))
	parser.add_argument('--non-whitespace', action='store_true', default=False,
						help=string.ascii_letters+string.digits+string.punctuation.replace('%', '%%'))
	parser.add_argument('-w', '--whitespace', action='store_true', default=None,
						help='space and tab')
	parser.add_argument('-a', '--all', action='store_true', default=False,
						help=re.sub(r'(\n|\r)', '', string.printable.replace('%', '%%'))+' plus space and tab')
	parser.add_argument('-x', '--hex', action='store_true', default=False,
						help=string.hexdigits)
	parser.add_argument('-o', '--octal', action='store_true', default=False,
						help=string.octdigits)
	parser.add_argument('-e', '--exclude', default=None,
					    help='A string of characters to exclude from the'
							 ' random output. Newline and carriage return are'
							 ' excluded by default.')
	parser.add_argument('length', type=int, default=None)
	args = parser.parse_args()
	length = args.length
	if not length:
		length = random.randint(16, 48)
	if args.hex:
		print(random_str(length, hexidecimal=True, exclude=args.exclude))
		return
	if args.octal:
		print(random_str(length, octal=True, exclude=args.exclude))
		return
	if args.letters:
		print(random_str(length, lower=True, upper=True, exclude=args.exclude))
		return
	if args.letters_numbers:
		print(random_str(length, lower=True, upper=True, digits=True,
				         exclude=args.exclude))
		return
	if args.non_whitespace:
		print(random_str(length, lower=True, upper=True, digits=True,
						 special=True, exclude=args.exclude))
		return
	if args.all:
		print(random_str(length, lower=True, upper=True, digits=True,
				         special=True, whitespace=True, exclude=args.exclude))
		return
	if not args.lower and not args.upper and not args.digits and not args.special and not args.whitespace:
		print(random_str(length, lower=True, upper=True,
						 digits=True, exclude=args.exclude))
		return
	print(random_str(length, lower=args.lower, upper=args.upper,
				     digits=args.digits, special=args.special,
					 whitespace=args.whitespace, exclude=args.exclude))

if __name__ == '__main__':
	main()