Adding REAME, and initial project with form code.

README

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+Provides form widgets and class mixin for django newforms. This allows adding a recaptcha test to any django form.
+
+Make sure to set these settings in your django settings file:
+RECAPTCHA_PUB_KEY
+RECAPTCHA_PRIV_KEY
+
+Requires recaptcha library: http://pypi.python.org/pypi/recaptcha-client
+
+For more information about recaptcha, and to get a recaptcha key, visit: http://www.google.com/recaptcha

recaptcha_form/forms.py

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+# This code is public domain.
+# Thanks to SmileyChris for the original implementation
+
+import django.forms as forms
+from django.conf import settings
+from django.utils.translation import ugettext_lazy as _
+from django.utils.safestring import mark_safe
+
+import recaptcha.client.captcha as captcha
+
+
+# Do you want to bypass reCAPTCHA validation while in DEBUG mode?
+SKIP_IF_IN_DEBUG_MODE = False
+
+RECAPTCHA_LANG = settings.LANGUAGE_CODE[:2]
+RECAPTCHA_THEME = getattr(settings, 'RECAPTCHA_THEME', 'red')
+
+
+### ERROR_CODES
+ERROR_CODES = {
+    "unknown" :    _("Unknown error."),
+    "invalid-site-public-key" :    _("We weren't able to verify the public key. Please try again later."),
+    "invalid-site-private-key" : _("We weren't able to verify the private key. Please try again later."),
+    "invalid-request-cookie" : _("The challenge parameter of the verify script was incorrect."),
+    "incorrect-captcha-sol" : _("The CAPTCHA solution was incorrect."),
+    "verify-params-incorrect" : _("The parameters to /verify were incorrect, make sure you are passing all the required parameters.  Please try again later."),
+    "invalid-referrer" : _("reCAPTCHA API keys are tied to a specific domain name for security reasons.  Please try again later."),
+    "recaptcha-not-reachable" :    _("Unable to contact the reCAPTCHA verify server.  Please try again later.")
+}
+
+
+class RecaptchaWidget(forms.Widget):
+    def __init__(self):
+       super(RecaptchaWidget, self).__init__()
+
+    def render(self, name, value, attrs=None):
+        html = captcha.displayhtml(settings.RECAPTCHA_PUB_KEY,
+                                        theme=RECAPTCHA_THEME,
+                                        lang=RECAPTCHA_LANG)
+        return mark_safe(html)
+
+    def value_from_datadict(self, data, files, name):
+        challenge = data.get('recaptcha_challenge_field')
+        response = data.get('recaptcha_response_field')
+        return (challenge, response)
+
+    def id_for_label(self, id_):
+        return None
+
+
+class RecaptchaField(forms.Field):
+    widget = RecaptchaWidget
+
+    def __init__(self, remote_ip, *args, **kwargs):
+        self.remote_ip = remote_ip
+        super(RecaptchaField, self).__init__(*args, **kwargs)
+
+    def clean(self, value):
+        if SKIP_IF_IN_DEBUG_MODE and settings.DEBUG:
+            return True
+        value = super(RecaptchaField, self).clean(value)
+        challenge, response = value
+
+        if not challenge:
+            raise forms.ValidationError(_('An error occured with the CAPTCHA service. Please try again.'))
+        if not response:
+            raise forms.ValidationError(_('Please enter the CAPTCHA solution.'))
+
+        rc = captcha.submit(challenge, response,
+                              settings.RECAPTCHA_PRIV_KEY,
+                              self.remote_ip)
+        if not rc.is_valid:
+            msg = ERROR_CODES.get(rc.error_code, ERROR_CODES['unknown'])
+            raise forms.ValidationError(msg)
+
+        # reCAPTCHA validates!
+        return True
+
+
+class RecaptchaFieldPlaceholder(forms.Field):
+    '''
+    Placeholder field for use with RecaptchaBaseForm which gets replaced with
+    RecaptchaField (which is passed the remote_ip) when RecaptchaBaseForm is
+    initialised.
+    '''
+    def __init__(self, *args, **kwargs):
+        self.args = args
+        self.kwargs = kwargs
+
+
+class RecaptchaBaseForm(forms.BaseForm):
+    def __init__(self, remote_ip, *args, **kwargs):
+        for key, field in self.base_fields.items():
+            if isinstance(field, RecaptchaFieldPlaceholder):
+                self.base_fields[key] = RecaptchaField(remote_ip, *field.args, **field.kwargs)
+        super(RecaptchaBaseForm, self).__init__(*args, **kwargs)
+
+
+class RecaptchaForm(RecaptchaBaseForm, forms.Form):
+    '''
+    Inheriting from this form gives you a reCAPTCHA field at the bottom.
+    '''
+    def __init__(self, remote_ip, *args, **kwargs):
+        self.base_fields['captcha'] = RecaptchaFieldPlaceholder(
+                                   label=_('Are you human?') )
+        super(RecaptchaForm, self).__init__(remote_ip, *args, **kwargs)
+