django-recaptcha in wizard forms

[barseghyanartur]

At the moment when used in form wizards, captcha becomes invalid on the last step. Any solution to this?

[adamchainz]

Can you expand a bit more - is the captcha in the last step, or is it in an earlier step and then counts as invalid later? I can see the problem in the latter case, as presumably validation runs again when the whole form wizard is done and the captcha value can only be validated once.

[Pringels]

This will be a problem regardless of what step you place the captcha on. (as the validation will run again at the end of the wizard anyway)
A simple workaround is to isolate your captcha to its own view/form.

[adamchainz]

Isn't there something the field could do to work with wizards by caching the 'passed' state of the captcha after the first validation run?

[Pringels]

Good suggestion. So it just locks to a validated state? Will look into it :)

[realmhamdy]

I'm using django-formtools for a wizard and struggled with the same issue. I found the sys._getframe() hack in ReCaptchaField.get_remote_ip() method and could use it to let the ReCaptchaField know when it's a relvalidation.
First create a ReCaptchaField subclass:

import sys
from captcha.fields import ReCaptchaField


class ValidateOnceReCaptchaField(ReCaptchaField):

    def clean(self, values):
        # find the 'revalidating' value in stack
        frame = sys._getframe()
        max_depth = 25
        while frame and max_depth != 0:
            if 'revalid' in frame.f_locals:
                return values[0]
            max_depth -= 1
            frame = frame.f_back
        return super(ValidateOnceReCaptchaField, self).clean(values)

And in your WizardView subclass, override render_done:

class MyView(WizardView):
  
    def render_done(self, form, **kwargs):
        revalid = True
        return super(MyView, self).render_done(form, **kwargs)

This way only the ReCaptcha revalidation is skipped. If someone knows a better way to pass values from a view to a form field please post it here.

[richtier]

we solved the problem in a different way that does not use the sys._getframe() hack.

https://github.com/uktrade/directory-ui-supplier/pull/337/files