from captcha.conf import settings as captcha_settings
from django.db import models
from django.utils import timezone
from django.utils.encoding import smart_text
import datetime
import random
import time
import hashlib
import logging
# Heavily based on session key generation in Django
# Use the system (hardware-based) random number generator if it exists.
14 ↛ 17line 14 didn't jump to line 17, because the condition on line 14 was never falseif hasattr(random, 'SystemRandom'):
randrange = random.SystemRandom().randrange
else:
randrange = random.randrange
MAX_RANDOM_KEY = 18446744073709551616 # 2 << 63
logger = logging.getLogger(__name__)
class CaptchaStore(models.Model):
challenge = models.CharField(blank=False, max_length=32)
response = models.CharField(blank=False, max_length=32)
hashkey = models.CharField(blank=False, max_length=40, unique=True)
expiration = models.DateTimeField(blank=False)
def save(self, *args, **kwargs):
self.response = self.response.lower()
if not self.expiration:
self.expiration = timezone.now() + datetime.timedelta(minutes=int(captcha_settings.CAPTCHA_TIMEOUT))
if not self.hashkey:
key_ = (
smart_text(randrange(0, MAX_RANDOM_KEY)) +
smart_text(time.time()) +
smart_text(self.challenge, errors='ignore') +
smart_text(self.response, errors='ignore')
).encode('utf8')
self.hashkey = hashlib.sha1(key_).hexdigest()
del(key_)
super(CaptchaStore, self).save(*args, **kwargs)
def __unicode__(self):
return self.challenge
def remove_expired(cls):
cls.objects.filter(expiration__lte=timezone.now()).delete()
remove_expired = classmethod(remove_expired)
@classmethod
def generate_key(cls, generator=None):
challenge, response = captcha_settings.get_challenge(generator)()
store = cls.objects.create(challenge=challenge, response=response)
return store.hashkey
@classmethod
def pick(cls):
if not captcha_settings.CAPTCHA_GET_FROM_POOL:
return cls.generate_key()
def fallback():
logger.error("Couldn't get a captcha from pool, generating")
return cls.generate_key()
# Pick up a random item from pool
minimum_expiration = timezone.now() + datetime.timedelta(minutes=int(captcha_settings.CAPTCHA_GET_FROM_POOL_TIMEOUT))
store = cls.objects.filter(expiration__gt=minimum_expiration).order_by('?').first()
return (store and store.hashkey) or fallback()
@classmethod
def create_pool(cls, count=1000):
assert count > 0
while count > 0:
cls.generate_key()
count -= 1
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