Django comes with an optional “form preview” application that helps automate the following workflow:
“Display an HTML form, force a preview, then do something with the submission.”
To force a preview of a form submission, all you have to do is write a short Python class.
Given a django.forms.Form subclass that you define, this application takes care of the following workflow:
The framework enforces the required preview by passing a shared-secret hash to the preview page via hidden form fields. If somebody tweaks the form parameters on the preview page, the form submission will fail the hash-comparison test.
Point Django at the default FormPreview templates. There are two ways to do this:
Create a FormPreview subclass that overrides the done() method:
from django.contrib.formtools.preview import FormPreview from myapp.models import SomeModel class SomeModelFormPreview(FormPreview): def done(self, request, cleaned_data): # Do something with the cleaned_data, then redirect # to a "success" page. return HttpResponseRedirect('/form/success')
This method takes an HttpRequest object and a dictionary of the form data after it has been validated and cleaned. It should return an HttpResponseRedirect that is the end result of the form being submitted.
Change your URLconf to point to an instance of your FormPreview subclass:
from myapp.preview import SomeModelFormPreview from myapp.forms import SomeModelForm from django import forms
...and add the following line to the appropriate model in your URLconf:
where SomeModelForm is a Form or ModelForm class for the model.
Run the Django server and visit /post/ in your browser.
A FormPreview class is a simple Python class that represents the preview workflow. FormPreview classes must subclass django.contrib.formtools.preview.FormPreview and override the done() method. They can live anywhere in your codebase.
By default, the form is rendered via the template formtools/form.html, and the preview page is rendered via the template formtools/preview.html. These values can be overridden for a particular form preview by setting preview_template and form_template attributes on the FormPreview subclass. See django/contrib/formtools/templates for the default templates.
Given a validated form, performs any extra processing before displaying the preview page, and saves any extra data in context.
By default, this method is empty. It is called after the form is validated, but before the context is modified with hash information and rendered.