89 lines
2.8 KiB
Python
89 lines
2.8 KiB
Python
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import datetime
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import hashlib
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import logging
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import random
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import time
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from django.db import models
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from django.utils import timezone
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from django.utils.encoding import smart_str
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from captcha.conf import settings as captcha_settings
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# Heavily based on session key generation in Django
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# Use the system (hardware-based) random number generator if it exists.
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if hasattr(random, "SystemRandom"):
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randrange = random.SystemRandom().randrange
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else:
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randrange = random.randrange
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MAX_RANDOM_KEY = 18446744073709551616 # 2 << 63
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logger = logging.getLogger(__name__)
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class CaptchaStore(models.Model):
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id = models.AutoField(primary_key=True)
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challenge = models.CharField(blank=False, max_length=32)
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response = models.CharField(blank=False, max_length=32)
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hashkey = models.CharField(blank=False, max_length=40, unique=True)
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expiration = models.DateTimeField(blank=False)
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def save(self, *args, **kwargs):
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self.response = self.response.lower()
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if not self.expiration:
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self.expiration = timezone.now() + datetime.timedelta(
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minutes=int(captcha_settings.CAPTCHA_TIMEOUT)
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)
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if not self.hashkey:
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key_ = (
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smart_str(randrange(0, MAX_RANDOM_KEY))
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+ smart_str(time.time())
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+ smart_str(self.challenge, errors="ignore")
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+ smart_str(self.response, errors="ignore")
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).encode("utf8")
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self.hashkey = hashlib.sha1(key_).hexdigest()
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del key_
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super(CaptchaStore, self).save(*args, **kwargs)
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def __str__(self):
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return self.challenge
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def remove_expired(cls):
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cls.objects.filter(expiration__lte=timezone.now()).delete()
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remove_expired = classmethod(remove_expired)
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@classmethod
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def generate_key(cls, generator=None):
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challenge, response = captcha_settings.get_challenge(generator)()
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store = cls.objects.create(challenge=challenge, response=response)
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return store.hashkey
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@classmethod
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def pick(cls):
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if not captcha_settings.CAPTCHA_GET_FROM_POOL:
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return cls.generate_key()
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def fallback():
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logger.error("Couldn't get a captcha from pool, generating")
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return cls.generate_key()
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# Pick up a random item from pool
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minimum_expiration = timezone.now() + datetime.timedelta(
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minutes=int(captcha_settings.CAPTCHA_GET_FROM_POOL_TIMEOUT)
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)
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store = (
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cls.objects.filter(expiration__gt=minimum_expiration).order_by("?").first()
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)
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return (store and store.hashkey) or fallback()
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@classmethod
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def create_pool(cls, count=1000):
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assert count > 0
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while count > 0:
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cls.generate_key()
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count -= 1
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