Dynamic Fields On A Serializer For A ForeignKey - django

Question

I set up a serializer that is able to dynamically serialize the desired fields as specified in the Django Rest Framework docs.
class DynamicFieldsModelSerializer(serializers.ModelSerializer):
"""
A ModelSerializer that takes an additional `fields` argument that
controls which fields should be displayed.
"""
def __init__(self, *args, **kwargs):
# Don't pass the 'fields' arg up to the superclass
fields = kwargs.pop('fields', None)
# Instantiate the superclass normally
super(DynamicFieldsModelSerializer, self).__init__(*args, **kwargs)
if fields is not None:
# Drop any fields that are not specified in the `fields` argument.
allowed = set(fields)
existing = set(self.fields)
for field_name in existing - allowed:
self.fields.pop(field_name)
>>> class UserSerializer(DynamicFieldsModelSerializer):
>>> class Meta:
>>> model = User
>>> fields = ['id', 'username', 'email']
>>>
>>> print(UserSerializer(user))
{'id': 2, 'username': 'jonwatts', 'email': 'jon#example.com'}
>>>
>>> print(UserSerializer(user, fields=('id', 'email')))
{'id': 2, 'email': 'jon#example.com'}
How would I then add in a model that is related by ForeignKey to this and dynamically serialize the desired fields from that model?
We could make the models
class User(models.Model):
id = IntegerField()
username = CharField()
email = EmailField()
class Vehicle(models.Model):
color = CharField()
type = CharField
year = DateField()
driver = ForeignKey(User)
and then based on the view either include color, type, year, or any combination of those.
I would like something like this.
{
'id': 27,
'username': 'testuser',
'vehicle: {
'color': 'Blue',
'type': 'Truck',
}
}

Answer 1

If you want a nested dict you could simply do
class VehicleSeralizer(serialzers.ModelSerializer):
class Meta:
model = Vehicle
fields = '__all__'
class UserSerializer(seralizers.ModelSerializer):
vehicle = VehicleSerializer()
class Meta:
model = User
fields = ['id', 'username', 'email'] # you might need to add 'vehicle'