Django Rest Framework - Limiting fields of nesting serializer - django

Question

I have User and Item models, and am having an issue with nested Items in a Item.objects.all() view. Specifically, I'm getting the following in the ItemListView resource:
[ {
"id": 3,
"description": "Some test item description",
"user": {
"id": 10,
"username": "jason",
"email": "test#test.com",
"token": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ0aW1lIjoiRnJpIE1hciAyNCAyMDo1NDo1OSAyMDE3IiwidXNlcm5hbWUiOiJqYXNvbiJ9.x4qdTF5eVKGLnrkcunm63n4d_X8xEzEYM0z48E5HKh4",
"items": [
{
"id": 3,
"description": "Some item description",
"timestamp": "2017-03-25T15:50:08.265780Z",
"user": 10
},
{
"id": 2,
"description": "test item description",
"timestamp": "2017-03-24T22:28:49.904198Z",
"user": 10
}
]
},
"timestamp": "2017-03-25T15:50:08.265780Z"
},
What I want is the User.items excluded from the output. How can I do that with the serializers and models below:
class UserSerializer(serializers.ModelSerializer):
password = serializers.CharField(write_only = True, required = False)
confirm_password = serializers.CharField(required = False)
class Meta:
model = User
fields = ('id', 'username', 'email', 'password', 'confirm_password', 'token', 'posts')
read_only_fields = ('confirm_password', )
depth = 1
def create(self, validated_data):
return User.objects.create_user(**validated_data)
def validate(self, data):
if data['password'] != data['confirm_password']:
raise ValidationError('Passwords do not match')
return data
class ItemSerializer(serializers.ModelSerializer):
user = UserSerializer(read_only = True)
def create(self, validated_data):
return Item.objects.create(**validated_data)
class Meta:
fields = ('id', 'content', 'user', 'timestamp')
read_only_fields = ('timestamp', )
model = Item
depth = 1
Models:
class User(AbstractBaseUser, PermissionsMixin):
username = models.CharField(max_length = 50,
unique = True)
email = models.EmailField(unique = True, blank = False, null = False)
token = models.CharField(max_length = 255,
default = '')
objects = UserManager()
USERNAME_FIELD = 'username'
def generate_token(self):
self.token = User.objects.generate_token(user = self)
self.save()
#python_2_unicode_compatible
def __str__(self):
return '{} [Username: {}] [Email: {}]'.format(self.pk,
self.username,
self.email)
class Meta:
verbose_name = 'user'
verbose_name_plural = 'users'
class Item(models.Model):
description = models.CharField(db_index = True, max_length = 1000)
timestamp = models.DateTimeField(auto_now_add = True, db_index = True)
user = models.ForeignKey(User,
on_delete = models.CASCADE,
related_name = 'items')
def __str__(self):
return '{} [User: {}] [Timestamp: {}] [Slug {}]'.format(self.pk, self.user.pk, self.timestamp, self.description[:20])
class Meta:
verbose_name = 'item'
verbose_name_plural = 'items'
ordering = ['-timestamp']

Answer 1

There is no out of the box solution to dynamically set which fields you want to serialize on related models.
You either need to define a stripped copy of UserSerializer and use it inside ItemSerializer (can define it right inside ItemSerializer class to not pollute the namespace), or extend the ModelSerializer and manually implement some support for dynamic field serialization, see here for some ideas (this could get tricky if you want to go a few layers deep I would imagine).