django-rest-framework how to make model serializer fields required

Question

I have a model that I\'m filling out step by step, it means I\'m making a form wizard.

Because of that most fields in this model are required but have null=Tru

Answer 1

You need to override the field specifically and add your own validator. You can read here for more detail http://www.django-rest-framework.org/api-guide/serializers/#specifying-fields-explicitly. This is the example code.

def required(value):
    if value is None:
        raise serializers.ValidationError('This field is required')

class GameRecord(serializers.ModelSerializer):
    score = IntegerField(validators=[required])

    class Meta:
        model = Game

Answer 2

The best option according to docs here is to use extra_kwargs in class Meta, For example you have UserProfile model that stores phone number and is required

class UserProfileSerializer(serializers.ModelSerializer):
    class Meta:
        model = UserProfile
        fields = ('phone_number',)
        extra_kwargs = {'phone_number': {'required': True}} 

Answer 3

This is my way for multiple fields. It based on rewriting UniqueTogetherValidator.

from django.utils.translation import ugettext_lazy as _
from rest_framework.exceptions import ValidationError
from rest_framework.utils.representation import smart_repr
from rest_framework.compat import unicode_to_repr

class RequiredValidator(object):
    missing_message = _('This field is required')

    def __init__(self, fields):
        self.fields = fields

    def enforce_required_fields(self, attrs):

        missing = dict([
            (field_name, self.missing_message)
            for field_name in self.fields
            if field_name not in attrs
        ])
        if missing:
            raise ValidationError(missing)

    def __call__(self, attrs):
        self.enforce_required_fields(attrs)

    def __repr__(self):
        return unicode_to_repr('<%s(fields=%s)>' % (
            self.__class__.__name__,
            smart_repr(self.fields)
        ))

Usage:

class MyUserRegistrationSerializer(serializers.ModelSerializer):

    class Meta:
        model = User
        fields = ( 'email', 'first_name', 'password' )
        validators = [
            RequiredValidator(
                fields=('email', 'first_name', 'password')
            )
        ]

Answer 4

Another option is to use required and trim_whitespace if you're using a CharField:

class CustomObjectSerializer(serializers.Serializer):
    name = serializers.CharField(required=True, trim_whitespace=True)

required doc: http://www.django-rest-framework.org/api-guide/fields/#required trim_whitespace doc: http://www.django-rest-framework.org/api-guide/fields/#charfield

Answer 5

According to link1 and link2, and due to the intended field is null=True, blank=True (like email field of django.contrib.auth.models.User in my example) this will work:

class UserSerializer(serializers.ModelSerializer):

    class Meta:
        model = User
        fields = ('username', 'email', 'password')
        extra_kwargs = {'email': {'required': True,
                                  'allow_blank': False}}