aurweb/aurweb/captcha.py
2022-08-22 22:40:45 +02:00

59 lines
1.8 KiB
Python

""" This module consists of aurweb's CAPTCHA utility functions and filters. """
import hashlib
from jinja2 import pass_context
from aurweb.db import query
from aurweb.models import User
from aurweb.templates import register_filter
def get_captcha_salts():
"""Produce salts based on the current user count."""
count = query(User).count()
salts = []
for i in range(0, 6):
salts.append(f"aurweb-{count - i}")
return salts
def get_captcha_token(salt):
"""Produce a token for the CAPTCHA salt."""
return hashlib.md5(salt.encode()).hexdigest()[:3]
def get_captcha_challenge(salt):
"""Get a CAPTCHA challenge string (shell command) for a salt."""
token = get_captcha_token(salt)
return f"LC_ALL=C pacman -V|sed -r 's#[0-9]+#{token}#g'|md5sum|cut -c1-6"
def get_captcha_answer(token):
"""Compute the answer via md5 of the real template text, return the
first six digits of the hexadecimal hash."""
text = r"""
.--. Pacman v%s.%s.%s - libalpm v%s.%s.%s
/ _.-' .-. .-. .-. Copyright (C) %s-%s Pacman Development Team
\ '-. '-' '-' '-' Copyright (C) %s-%s Judd Vinet
'--'
This program may be freely redistributed under
the terms of the GNU General Public License.
""" % tuple(
[token] * 10
)
return hashlib.md5((text + "\n").encode()).hexdigest()[:6]
@register_filter("captcha_salt")
@pass_context
def captcha_salt_filter(context):
"""Returns the most recent CAPTCHA salt in the list of salts."""
salts = get_captcha_salts()
return salts[0]
@register_filter("captcha_cmdline")
@pass_context
def captcha_cmdline_filter(context, salt):
"""Returns a CAPTCHA challenge for a given salt."""
return get_captcha_challenge(salt)