What's the appropriate way of overriding the a Model class's
__getattr__ in Django 1.4?
I have a model structure like:
class Main(models.Model):
[blah]
class Detail(models.Model):
main = models.ForeignKey(Main)
name = models.CharField(max_length=255)
value= models.CharField(max_length=255)
I had overridden my Main._getattr__ so I could reference Detail
records as though they were normal Main attributes. e.g. a simple meta-
model pattern like
>>> m = Main.objects.create()
>>> Detail.objects.create(main=m, name='name', value='value')
>>> print m.name
'value'
To do this, my pre-1.4 __getattr__ looked like:
def __getattr__(self, attrname):
qs = self.details.filter(name=attrname)
c = len(qs)
if c == 0:
raise AttributeError
elif c == 1:
return qs[0].value
else:
return [d.value for d in qs]
This worked perfectly until I upgraded to 1.4. Now I get all types
"attribute X does not exist" errors. I tried something like the
following, but had no luck. It seems to especially conflict with the
"_*_cache" attributes Django generates for ForeignKey references.
def __getattr__(self, attrname):
try:
return super(Main, self).__getattr__(attrname)
except AttributeError:
pass
qs = self.details.filter(name=attrname)
c = len(qs)
if c == 0:
raise AttributeError
elif c == 1:
return qs[0].value
else:
return [d.value for d in qs]
How do I resolve this?
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