I think you'd rather use the default serialization behavior and write
the Choice and Poll objects, letting the Choice objects contain the FK
back to the Poll.
However, if you write your own serializer you'd want to look for
*class* attributes of type
'django.db.models.fields.related.ForeignRelatedObjectsDescriptor'.
This is due (I believe) the code found in the class definition for
django.db.models.fields.related.ForeignKey:
def contribute_to_related_class(self, cls, related):
setattr(cls, related.get_accessor_name(),
ForeignRelatedObjectsDescriptor(related))
So you'd end up doing something like this:
user = User.objects.get(id=1)
from django.db.models.fields.related import
ForeignRelatedObjectsDescriptor
related = [k for k,v in user.__class__.__dict__.items() if type(v)
== ForeignRelatedObjectsDescriptor]
# Assume len(related) > 1 and includes 'message_set' at index 0.
user_messages = user.__getattribute__(related[0]).all()
But I think you'll find this to be a little dangerous as you'll need
to make sure when you write out the related objects you don't re-write
the current object (e.g., A has set of Bs, each B has an A. You need
to make sure you have a base case when writing the B objects, like a
global dict of objects currently written).
for what that's worth...
doug.
The better way to approach this would be to write the
On Oct 16, 7:38 am, JohnnyLeitrim <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I am quite new to django, so the following question may have an
> obvious answer, but I could not find it.
>
> I have defined the model from the django tutorial, Poll and Choice:
>
> class Poll(models.Model):
> question = models.CharField(max_length=200)
> pub_date = models.DateTimeField('date published')
>
> class Choice(models.Model):
> poll = models.ForeignKey(Poll)
> choice = models.CharField(max_length=200)
>
> I can see all the choices related to a poll though its attribute:
> <poll_instance>.choice_set.
> My question is, what method or attribute is there on poll that tells
> me that it has a model attribute 'choice_set' ?
>
> My specific problem is that if I use the django serialization
> framework, when I give it a poll it will only print the 'question' and
> 'pub_date' fields, but not 'choice_set'. I guess this is because
> there is no mention of the set in Poll._meta.local_fields, but there
> doesn't appear to be an option for serializing nested model sets:
>
> serializers.serialize('xml', Poll.objects.all()) produces:
>
> <?xml version="1.0" encoding="utf-8"?>
> <django-objects version="1.0">
> <object pk="1" model="polls.poll">
> <field type="CharField" name="question">What's up?</field>
> <field type="DateTimeField" name="pub_date">2008-10-08
> 11:21:12</field>
> </object>
> </django-objects>
>
> I know that if it included the choice set directly then the cycle
> would cause an infinite loop, but I would write my own serializer that
> would only output a reference to the other entities.
>
> Any help is appreciated!
>
> Thanks,
> John.
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