Validator for serializer field with source= kwargs #3844
Description
I've drafted a API with DRF, and there're two models, django.contrib.auth.models.User and Customer, code for Customer model:
from django.db import models
from django.contrib.auth.models import User
class Customer(models.Model):
SEXES = (
('Male', 'Male'),
('Female', 'Female'),
)
user = models.OneToOneField(User, on_delete=models.CASCADE)
sex = models.CharField(max_length=10, choices=SEXES)
mobile_number = models.CharField(max_length=20, unique=True)
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now=True)
def __unicode__(self):
return u'<%s, %s, %s>' % (self.user.username, self.sex,
self.mobile_number)
Note that Customer has a user = models.OneToOneField(User, on_delete=models.CASCADE) field, thus we can still use django's built authentication while add some extra field to our own Customer model.
The code for CustomerSerializer:
class CustomerSerializer(serializers.HyperlinkedModelSerializer):
created_at = serializers.DateTimeField(read_only=True,
format='%Y-%m-%dT%H:%M:%SZ')
updated_at = serializers.DateTimeField(read_only=True,
format='%Y-%m-%dT%H:%M:%SZ')
mobile_number = serializers.CharField(min_length=6, max_length=20,
validators=[UniqueValidator(queryset=Customer.objects.all())])
username = serializers.CharField(source='user.username',
validators=[UniqueValidator(queryset=User.objects.all())])
email = serializers.CharField(source='user.email')
first_name = serializers.CharField(source='user.first_name')
last_name = serializers.CharField(source='user.last_name')
password = serializers.CharField(source='user.password',
min_length=6, max_length=32,
write_only=True)
...
But when I work with CustomerSerializer, it will raise an exception:
E FieldError: Cannot resolve keyword u'user' into field. Choices are: auth_token, customer, date_joined, email, first_name, groups, id, is_active, is_staff, is_superuser, last_login, last_name, logentry, masseuse, password, user_permissions, username
I've checked DRF's code, and I think this exception comes from https://github.com/tomchristie/django-rest-framework/blob/master/rest_framework/validators.py#L38
self.field_name = serializer_field.source_attrs[0]
I've read DRF's documentation: http://www.django-rest-framework.org/api-guide/fields/, it says
source
The name of the attribute that will be used to populate the field. May be a method that only takes a self argument, such as URLField(source='get_absolute_url'), or may use dotted notation to traverse attributes, such as EmailField(source='user.email').
And for EmailField(source='user.email'), the code self.field_name = serializer_field.source_attrs[0] will return user instead of email, which is not right and will lead to a FieldError.
For my case,
username = serializers.CharField(source='user.username',
validators=[UniqueValidator(queryset=User.objects.all())])
I think it's better to change self.field_name = serializer_field.source_attrs[0] to self.field_name = serializer_field.source_attrs[-1].