Django: running a method on all queryset objects - django

Question

I want to know if the following is possible and if someone could explain how. I'm using Django REST Framework
I have a model, in that model I have a class called Product. Product has method called is_product_safe_for_user. It requires the user object and the self (product).
model.py
class Product(models.Model):
title = models.CharField(max_length=60, help_text="Title of the product.")
for_age = models.CharField(max_length=2,)
def is_product_safe_for_user(self, user):
if self.for_age > user.age
return "OK"
(ignore the syntax above, its just to give you an idea)
What I want to do is run the method for to all of the queryset objects, something like below, but I don't know how...
class ProductListWithAge(generics.ListAPIView):
permission_classes = (permissions.IsAuthenticated,)
model = Product
serializer_class = ProductSerializer
def get_queryset(self):
Product.is_product_safe_for_user(self,user)
# then somehow apply this to my queryset
return Product.objects.filter()
there will also be times when I want to run the methoud on just one object.
Or should it go into the Serializer? if so how?...
class ProductSerializer(serializers.ModelSerializer):
safe = serializers.Field(Product='is_product_safe_for_user(self,user)')
class Meta:
model = Product
fields = ('id', 'title', 'active', 'safe')

Answer 1

You could write a custom manager for your model. Something like this:
class OnlySafeObjects(models.Manager):
def filter_by_user(self, user):
return super(OnlySafeObjects, self).get_query_set().filter(for_age__gte=user.age)
class Product(models.Model):
# your normal stuff
onlysafeobjects = OnlySafeObjects()
Then you would use it like this:
safe_products = Product.onlysafeobjects.filter_by_user(request.user)