RecaptchaForm

from django import newforms as forms
from django.newforms import ValidationError
from django.conf import settings
import captcha

class RecaptchaWidget(forms.Widget):
    """ A Widget which "renders" the output of captcha.displayhtml """
    def render(self, *args, **kwargs):
        return captcha.displayhtml(settings.RECAPTCHA_PUBLIC_KEY)

class DummyWidget(forms.Widget):
    """
    A dummy Widget class for a placeholder input field which will
    be created by captcha.displayhtml

    """
    # make sure that labels are not displayed either
    is_hidden=True
    def render(self, *args, **kwargs):
        return ''

class RecaptchaForm(forms.Form):
    """ 
    A form class which uses reCAPTCHA for user validation.
    
    If the captcha is not guessed correctly, a ValidationError is raised
    for the appropriate field
    """
    recaptcha_challenge_field = forms.CharField(widget=DummyWidget)
    recaptcha_response_field = forms.CharField(widget=RecaptchaWidget, label='')

    def __init__(self, request, *args, **kwargs):
        super(RecaptchaForm, self).__init__(*args, **kwargs)
        self._request = request

    def clean_recaptcha_response_field(self):
        if 'recaptcha_challenge_field' in self.cleaned_data:
            self.validate_captcha()
        return self.cleaned_data['recaptcha_response_field']

    def clean_recaptcha_challenge_field(self):
        if 'recaptcha_response_field' in self.cleaned_data:
            self.validate_captcha()
        return self.cleaned_data['recaptcha_challenge_field']

    def validate_captcha(self):
        rcf = self.cleaned_data['recaptcha_challenge_field']
        rrf = self.cleaned_data['recaptcha_response_field']
        ip_address = self._request.META['REMOTE_ADDR']
        check = captcha.submit(rcf, rrf, settings.RECAPTCHA_PRIVATE_KEY, ip_address)
        if not check.is_valid:
            raise ValidationError('You have not entered the correct words')