Wagtail is a CMS framework built on top of Django that takes away some of tedium of creating a CMS from scratch. It has a nice extendable interface for editors to interact with, page reversion tracking, a spiffy admin UI, easy uploading of images, and lots of other goodies.
I'll be honest -- coming from Django where I have a pretty good grasp of how things work (and where to figure things out if I need to) was a hard transition to Wagtail. It definitely took a little time to understand its philosophy around content.
But, at this point, I have come to appreciate all of the benefits that Wagtail provides... and work around some of the pieces that I like less. One thing that took me a while to understand is that Wagtail uses the term snippet to refer to Django models that aren't explicitly a Page. Coming from Django, I am used to defining a data model and tying models together with many-to-many or foreign key relationships. Snippets are where to store those pieces of information that could be shared with many different Page models. However, snippets feel like they are not completely integrated into the Wagtail experience, and they lose a lot of the nice functionality that comes "for free" with a page model -- one glaring omission is the lack of revisions for snippets. There are a few open issues for this in Wagtail (notably https://github.com/wagtail/wagtail/issues/4541 and https://github.com/wagtail/wagtail/issues/2270).
One package that I have really appreciated in the past with a normal Django application is django-reversion which integrates tightly into the Django admin and automatically saves versions of an object as an audit trail. Wagtail provides something very similar for Page models, but snippets eren't invited to the party and feel very left out.
All is well in Wagtail-land, though! With a little perserverance, Wagtail snippets can also get automatic revisions and it isn't too hard.
django-reversion with the normal installation steps. Unfortunately, Wagtail won't tie into the same automatic magic that
django-reversion uses for the Django admin, but it has a stellar API you can call explicitly.
For snippet models, you will need to add the
@reversion.register() decorator above the
from django.db import models import reversion from wagtail.core.models import ClusterableModel, Orderable from wagtail.snippets.models import register_snippet @reversion.register() @register_snippet class Book(Orderable, ClusterableModel): title = models.CharField(max_length=255)
Next, you will need to override the Wagtail views for the snippets you want to audit in
from reversion.revisions import add_to_revision, create_revision, set_comment, set_user from wagtail.contrib.modeladmin.options import ModelAdmin from wagtail.contrib.modeladmin.views import CreateView, EditView from .models import Book class RevisionEditView(EditView): def form_valid(self, form, *args, **kwargs): form_valid_return = super().form_valid(form, *args, **kwargs) with create_revision(): set_comment(self.get_success_message(self.instance)) add_to_revision(self.instance) set_user(self.request.user) return form_valid_return class RevisionCreateView(CreateView): def form_valid(self, form, *args, **kwargs): form_valid_return = super().form_valid(form, *args, **kwargs) # Call form.save() explicitly to get access to the instance instance = form.save() with create_revision(): set_comment(self.get_success_message(instance)) add_to_revision(instance) set_user(self.request.user) return form_valid_return class BookAdmin(ModelAdmin): model = Book edit_view_class = RevisionEditView create_view_class = RevisionCreateView
Overriding the ModelAdmin classes by setting the
create_view_class settings and
django-revision is the real magic here. But, be sure to note the weirdness in the
CreateView to get an
instance that is usable. In testing it doesn't create multiple instances of the model, however, I would not be surprised if there are duplicate database calls because of the implementation.
Originally published on adamghill.com.
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