On Monday 22 July 2013 13:25:38 Anssi Kääriäinen wrote:
> On Monday, July 22, 2013 1:16:04 PM UTC+3, Loic Bistuer wrote:
> > On Jul 22, 2013, at 4:38 PM, Chris Wilson
> > <ch...@aptivate.org<javascript:>>
> >
> > wrote:
> > > I think that's very true. How about this?
> > >
> > >> class MyQuerySet(models.QuerySet):
> > >> def published(self):
> > >> return self.filter(published_date__lte=now())
> > >>
> > >> class MyModel(models.Model):
> > >> published_date = models.DateTimeField()
> > >>
> > >> objects = CustomManager(MyQuerySet)
> >
> > That was my original proposal; the first 20 comments on the ticket and
> > one nearly complete implementation are based on this idea.
> >
> > That approach has the downside of requiring the use of `__getattr__` or
> > `__getattribute__` which is IMO much more of a hack than a class factory,
> > especially with backward compatibility in mind.
>
> The Manager(MyQuerySet) approach might actually work with dynamically
> created methods, too. I believe __new__ can be used for this, or maybe one
> could just create a dynamic class of self.__class__ in Manager.__init__ and
> assign it back to self.__class__. If this way works it seems cleaner than
> the as_manager() way.
>
+1 -- except I would use Aymeric's syntax Manager.from_queryset(qset_class),
where from_queryset is a classmethod; this, then, also gives a very elegant
solution to manager-only methods:
class MyQuerySet(QuerySet):
pass
class MyManager(Manager):
def manager_only_method(self):
pass
class MyModel(Model):
objects = MyManager.from_queryset(MyQuerySet)
The reason I'd prefer this over playing with __new__ and __init__ is just
because it looks a lot less like black magic. Functionally, I think you can
get pretty much the same either way.
Shai.
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