How to use a redirect with Form builder to prevent double submission¶
It is common for form submission HTTP responses to be a
302 Found temporary redirection to a new page.
wagtail.contrib.forms.models.FormPage success responses don’t do this, meaning there is a risk that users will refresh the success page and re-submit their information.
Instead of rendering the
render_landing_page content in the POST response, we will redirect to a
route of the
FormPage instance at a child URL path.
The content will still be managed within the same form page’s admin.
This approach uses the additional contrib module
An alternative approach is to redirect to an entirely different page, which does not require the
See Custom landing page redirect.
"wagtail.contrib.routable_page" is added to
INSTALLED_APPS, see RoutablePageMixin documentation.
from django.shortcuts import redirect from wagtail.contrib.forms.models import AbstractEmailForm from wagtail.contrib.routable_page.models import RoutablePageMixin, route class FormPage(RoutablePageMixin, AbstractEmailForm): # fields, content_panels, … @route(r"^$") def index_route(self, request, *args, **kwargs): """Serve the form, and validate it on POST""" return super(AbstractEmailForm, self).serve(request, *args, **kwargs) def render_landing_page(self, request, form_submission, *args, **kwargs): """Redirect instead to self.thank_you route""" url = self.reverse_subpage("thank_you") # If a form_submission instance is available, append the ID to URL. if form_submission: url += "?id=%s" % form_submission.id return redirect(self.url + url, permanent=False) @route(r"^thank-you/$") def thank_you(self, request): """Return the superclass's landing page, after redirect.""" form_submission = None try: submission_id = int(request.GET["id"]) except (KeyError, TypeError): pass else: submission_class = self.get_submission_class() try: form_submission = submission_class.objects.get(id=submission_id) except submission_class.DoesNotExist: pass return super().render_landing_page(request, form_submission)