project/cmsplugin_contact_plus/simplemathcaptcha/widgets.py

   1 from __future__ import absolute_import
   2 from __future__ import unicode_literals
   3
   4 from django import forms
   5 from django.template.defaultfilters import mark_safe
   6 from django.utils.translation import ugettext_lazy as _
   7
   8 from .utils import hash_answer, get_operator, get_numbers, calculate
   9
  10
  11 class MathCaptchaWidget(forms.MultiWidget):
  12     def __init__(self, start_int=1, end_int=10, question_tmpl=None,
  13                  question_class=None, attrs=None):
  14         self.start_int, self.end_int = self.verify_numbers(start_int, end_int)
  15         self.question_class = question_class or 'captcha-question'
  16         self.question_tmpl = (
  17             question_tmpl or _('What is %(num1)i %(operator)s %(num2)i? '))
  18         self.question_html = None
  19         widget_attrs = {'size': '5'}
  20         widget_attrs.update(attrs or {})
  21         widgets = (
  22             # this is the answer input field
  23             forms.TextInput(attrs=widget_attrs),
  24
  25             # this is the hashed answer field to compare to
  26             forms.HiddenInput()
  27         )
  28         super(MathCaptchaWidget, self).__init__(widgets, attrs)
  29
  30     def decompress(self, value):
  31         return [None, None]
  32
  33     def format_output(self, rendered_widgets):
  34         output = super(MathCaptchaWidget, self).format_output(rendered_widgets)
  35         output = '%s%s' % (self.question_html, output)
  36         return output
  37
  38     def render(self, name, value, attrs=None):
  39         # hash answer and set as the hidden value of form
  40         hashed_answer = self.generate_captcha()
  41         value = ['', hashed_answer]
  42
  43         return super(MathCaptchaWidget, self).render(name, value, attrs=attrs)
  44
  45     def generate_captcha(self):
  46         # get operator for calculation
  47         operator = get_operator()
  48
  49         # get integers for calculation
  50         x, y = get_numbers(self.start_int, self.end_int, operator)
  51
  52         # set question to display in output
  53         self.set_question(x, y, operator)
  54
  55         # preform the calculation
  56         total = calculate(x, y, operator)
  57
  58         return hash_answer(total)
  59
  60     def set_question(self, x, y, operator):
  61         # make multiplication operator more human-readable
  62         operator_for_label = '&times;' if operator == '*' else operator
  63         question = self.question_tmpl % {
  64             'num1': x,
  65             'operator': operator_for_label,
  66             'num2': y
  67         }
  68
  69         html = '<span class="%s">%s</span>' % (self.question_class, question)
  70         self.question_html = mark_safe(html)
  71
  72     def verify_numbers(self, start_int, end_int):
  73         start_int, end_int = int(start_int), int(end_int)
  74         if start_int < 0 or end_int < 0:
  75             raise Warning('MathCaptchaWidget requires positive integers '
  76                           'for start_int and end_int.')
  77         elif end_int < start_int:
  78             raise Warning('MathCaptchaWidget requires end_int be greater '
  79                           'than start_int.')
  80         return start_int, end_int