Opened 12 years ago
Closed 10 years ago
#18355 closed New feature (fixed)
Add ordering mixin for class based generic views
Reported by: | Aymeric Augustin | Owned by: | pjrharley |
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Component: | Generic views | Version: | dev |
Severity: | Normal | Keywords: | |
Cc: | marc.tamlyn@… | Triage Stage: | Accepted |
Has patch: | yes | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description
Currently, if the model used by by a date-based generic view doesn't have an ordering
and pagination is enabled, results will be random. Defining an ordering
on the model isn't totally satisfying because it has global effects, and it adds an overhead to every query involving the model.
Another workaround is to define queryset = MyModel.objects.order_by('-<date_field>')
in every view. But CBVs are precisely about removing as much boilerplate as possible.
So here's a draft of an API for ordering:
class BaseDateListView(...): ordering = None def get_ordering(self): return self.get_date_field() if self.ordering is None else self.ordering def get_dated_queryset(self, **lookups): ... if not qs.ordered(): qs = qs.order_by(self.get_ordering()) ...
self.get_ordering()
could return '-<date_field>'
for the archive view for backwards compatibility.
This would be a better fix for #18354.
Change History (12)
comment:1 by , 12 years ago
Owner: | changed from | to
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comment:2 by , 12 years ago
Triage Stage: | Unreviewed → Accepted |
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comment:3 by , 12 years ago
Summary: | Date-based generic views should enforce ordering → Add ordering mixin for class based generic views |
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comment:4 by , 11 years ago
Cc: | added |
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Would this functionality apply only to list views? This would certainly give a good advantage as one's instinct is to apply the get_queryset
changes to every view with the same Model, but ordering is rather useless when we're simply doing a DetailView
(and could impose a performance problem). So the code would perhaps live in BaseListView
rather than MultipleObjectMixin
.
That said, if this functionality is only hitting list views, it actually fits in with a larger subject area of search/ordering/filtering as defined by the user. In reality this is probably just one of the first hooks we might need to implement that kind of functionality well, but it may be worth considering the larger list-view-customisation issue.
comment:5 by , 11 years ago
The goals were clear to me when I was working on the date-based views, but unfortunately I've lost track of it since then...
I think it's just about implementing the API in the ticket description, documenting it, and taking advantage of it in the date-based views while preserving backwards-compat.
You're very welcome to take over on this ticket if you'd like to as it's pretty low on my priority list.
comment:6 by , 11 years ago
Status: | new → assigned |
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comment:7 by , 11 years ago
Owner: | removed |
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Status: | assigned → new |
comment:8 by , 11 years ago
Has patch: | set |
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Owner: | set to |
Status: | new → assigned |
I've added a PR for this here:
https://github.com/django/django/pull/2097
Not sure if the approach is right - feedback welcome. I suspect the docs need improvement - more than happy to do that if the code is looking good.
comment:9 by , 11 years ago
Owner: | changed from | to
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Try assigning to myself while signed in instead...
comment:10 by , 10 years ago
Patch needs improvement: | set |
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I left comments for improvement on PR. Please uncheck "Patch needs improvement" when you update it, thanks.
comment:12 by , 10 years ago
Resolution: | → fixed |
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Status: | assigned → closed |
I accept the problem in general, but don't see how this is limited to date based views. This is perfect for a mixin, so let's write a
OrderingViewMixin
or similar.