I should add patches that I promise to add ;)
--Lennart
On Monday, December 7, 2015 at 9:23:19 PM UTC+1, Lennart Buit wrote:
>
> Hey all,
>
> One of my minor annoyances with the class based view system in django is
> that there is no clear way to model a confirmable action. The concept does
> exists in cbv, but only for deleting objects. I however think that there
> are more usages for confirming actions other then delete.
>
> Lets look at an example, a news site can CRUD newsaticles. But this news
> site has some articles for free, and some other behind a paywall. Also,
> editors on this site can publish newsarticles (after which they come in the
> pay section), and then promote them to free articles. The views in django
> would then look as follows (with some brevity):
>
> # This also goes for Update/Delete/...
> class NewsArticleCreateView(CreateView):
> model = NewsArticle
>
> # This also goes for Promote
> class NewsArticlePublishView(DetailView):
> model = NewsArticle
> success_url = 'somewhere'
>
> def post(self, *args, **kwargs):
> self.object = self.get_object()
> success_url = self.get_success_url()
> self.object.published = True
> self.object.save()
>
> return HttpResponseRedirect(success_url)
>
> def get_success_url(self):
> if self.success_url:
> return self.success_url.format(**self.object.__dict__)
> else:
> raise ImproperlyConfigured(
> "No URL to redirect to. Provide a success_url.")
>
> The problem, I think, is that we are copying most of a DeleteView for a
> fairly standard confirmable action. The get_success_url function is almost
> the same, and most of the code found in the post function is that of delete
> in DeleteView. I think therefore that we should consider splitting the
> DeleteMixin in a more generic ConfirmMixin, make DeleteMixin a subclass of
> ConfirmMixin, and introduce the (more) generic BaseConfirmView and
> ConfirmView. The above example will then look as follows:
>
> class NewsArticlePublishView(ConfirmView):
> model = NewsArticle
> success_url = 'somewhere'
>
> def action_confirmed(self):
> self.object.published = True
> self.object.save()
>
> I think the benefits of this solution are clear, we introduce readability
> in these types of views (look at the class declaration, its a confirm view
> alright!) at the cost of library size (another 3 classes got added).
>
> Please be gentle, I am new here ;). But, I enjoy a technical discussion!
> And I attached a patch that implement this proposal, it however should be
> treated as a POC, not a complete implementation with tests and docs and
> such.
>
> --Lennart
>
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diff --git a/django/views/generic/edit.py b/django/views/generic/edit.py
index 644110f..23c4832 100644
--- a/django/views/generic/edit.py
+++ b/django/views/generic/edit.py
@@ -247,26 +247,22 @@ class UpdateView(SingleObjectTemplateResponseMixin, BaseUpdateView):
template_name_suffix = '_form'
-class DeletionMixin(object):
+class ConfirmMixin(object):
"""
- A mixin providing the ability to delete objects
+ A mixin providing the ability to do a confirmed action on an object
"""
success_url = None
- def delete(self, request, *args, **kwargs):
- """
- Calls the delete() method on the fetched object and then
- redirects to the success URL.
- """
+ def action_confirmed(self):
+ raise ImproperlyConfigured(
+ "No confirmable action was defined. Implement action_confirmed().")
+
+ def post(self, request, *args, **kwargs):
self.object = self.get_object()
success_url = self.get_success_url()
- self.object.delete()
+ self.action_confirmed()
return HttpResponseRedirect(success_url)
- # Add support for browsers which only accept GET and POST for now.
- def post(self, request, *args, **kwargs):
- return self.delete(request, *args, **kwargs)
-
def get_success_url(self):
if self.success_url:
return self.success_url.format(**self.object.__dict__)
@@ -275,6 +271,44 @@ class DeletionMixin(object):
"No URL to redirect to. Provide a success_url.")
+class DeletionMixin(ConfirmMixin):
+ """
+ A mixin providing the ability to delete objects
+ """
+ success_url = None
+
+ def delete(self, request, *args, **kwargs):
+ """
+ Calls the delete() method on the fetched object and then
+ redirects to the success URL.
+ """
+ return self.post(request, *args, **kwargs)
+
+ def action_confirmed(self):
+ """
+ A DeletionMixin should delete its object as the confirmed action
+ """
+ self.object.delete()
+
+
+class BaseConfirmView(ConfirmMixin, BaseDetailView):
+ """
+ Base view for confirming an action on an object. If your objective is to
+ delete an object, use DeleteView.
+
+ Using this base class requires subclassing to provide a response mixin.
+ """
+
+
+class ConfirmView(SingleObjectTemplateResponseMixin, BaseConfirmView):
+ """
+ View that invokes an action on an object after confirmation,
+ implement `action_confirmed` to specify the action that should happen
+ after confirmation
+ """
+ template_name_suffix = '_confirm'
+
+
class BaseDeleteView(DeletionMixin, BaseDetailView):
"""
Base view for deleting an object.
