djangosubclass.py

@@ -0,0 +1,39 @@
+class SubclassingQuerySet(QuerySet):
+    def __getitem__(self, k):
+        result = super(SubclassingQuerySet, self).__getitem__(k)
+        if isinstance(result, models.Model):
+            return result.as_leaf_class()
+        else:
+            return result
+
+    def __iter__(self):
+        for item in super(SubclassingQuerySet, self).__iter__():
+            yield item.as_leaf_class()
+
+
+class ObjectManager(models.Manager):
+    def get_query_set(self):
+        return SubclassingQuerySet(self.model)
+
+    def get(self, *args, **kwargs):
+        obj = super(ObjectManager, self).get(*args, **kwargs)
+        return obj.as_leaf_class()
+
+
+class MyObject(models.Model):
+    name = models.CharField(max_length=255, verbose_name=_("Name"), blank=True, null=True, editable=True)
+    content_type = models.ForeignKey(ContentType, editable=False, null=True)
+    objects = ObjectManager()
+
+
+    def save(self, *args, **kwargs):
+        if(not self.content_type):
+            self.content_type = ContentType.objects.get_for_model(self.__class__)
+        super(Device, self).save(*args, **kwargs)
+
+    def as_leaf_class(self):
+        content_type = self.content_type
+        model = content_type.model_class()
+        if (model == Device):
+            return self
+        return model.objects.get(id=self.id)