Django REST Framework: object is None only on one attribute, but not other

Django REST Framework: object is None only on one attribute, but not other

I have been having trouble understanding why the object (obj) passed into
field_to_native() changes from Nonetype to a correct object once I change
the attribute...
Here's the original issue: Splitting model instance for serializer into 3
different fields
mariodev from stackoverflow helped me on the original issue, but a strange
bug both of us cannot figure out:
Here's the code where it seems to have the problem:
COORD = dict(x=0, y=1, z=2)
class CoordField(serializers.Field):
def field_to_native(self, obj, field_name):
#retrieve and split coords
coor = obj.xyz.split('x')
return int(coor[COORD[field_name]])
class NoteSerializer(serializers.ModelSerializer):
owner = serializers.Field(source='owner.username')
firstname = serializers.Field(source='owner.first_name')
lastname = serializers.Field(source='owner.last_name')
x = CoordField()
y = CoordField()
z = CoordField()
class Meta:
model = Note
fields =
('id','owner','firstname','lastname','text','color','time','x', 'y',
'z')
xyz is a instance in the model Note. According to the traceback, when I do
obj.xyz, the obj = None.
Weirdly, if I do obj.color, the obj returns correctly (Note: someuser)
I don't understand how the obj can change just by changing the attribute.
What's beyond me is that the JSON data 'x' 'y' and 'z' ARE being passed to
the view, and my div boxes get the correct left, top, and z-index CSS
data. If this works, why am I getting an error?
If there's an error, why is the data still getting through?
style="left: 343px; top: 110px; z-index: 3;"
As you can see, the x,y,z DID pass through.
Any enlightenment would be wonderful! Thanks a bunch!
Here's the traceback in text view:
Traceback: File
"/home1/thecupno/python2.7/lib/python2.7/site-packages/django/core/handlers/base.py"
in get_response 140. response = response.render() File
"/home1/thecupno/python2.7/lib/python2.7/site-packages/django/template/response.py"
in render 105. self.content = self.rendered_content File
"/home1/thecupno/python2.7/lib/python2.7/site-packages/rest_framework/response.py"
in rendered_content 59. ret = renderer.render(self.data, media_type,
context) File
"/home1/thecupno/python2.7/lib/python2.7/site-packages/rest_framework/renderers.py"
in render 582. post_form = self.get_rendered_html_form(view, 'POST',
request) File
"/home1/thecupno/python2.7/lib/python2.7/site-packages/rest_framework/renderers.py"
in get_rendered_html_form 485. data = serializer.data File
"/home1/thecupno/python2.7/lib/python2.7/site-packages/rest_framework/serializers.py"
in data 510. self._data = self.to_native(obj) File
"/home1/thecupno/python2.7/lib/python2.7/site-packages/rest_framework/serializers.py"
in to_native 309. value = field.field_to_native(obj, field_name) File
"/home1/thecupno/django/notes/desk/serializers.py" in field_to_native 10.
coor = obj.xyz#.split('x') <-- I commented out .split, and the problem
still persists.
Exception Type: AttributeError at /desk/restnote/ Exception Value:
'NoneType' object has no attribute 'xyz'