[FIXED] Get value of another field in Field level Validation in DRF

Issue

I am using Field level Validation in my serializer and I have situation where I need value of first field while validating second field. I know in object level validation I can have access to that but my serailzer have many=True and in object level validation I cannot tell client side which iteration have raised the error.

Serailzer :

class Keys_Serializer(serializers.Serializer):
    """
    """
    key_id = serializers.IntegerField(required=True)
    key_name = serializers.CharField(required=True)
    value_id = serializers.IntegerField(required=False)

    def validate_key_id(self, value):
        """
        validate key id
        """
         *** validate key_id here ***
        return value

    def validate_value_id(self, value):
        """
        validate value_id w.r.t key_id
        """
         *** I need key_id of current iteration here so that I can validate value_id. ***
        return value

Is there any way of accessing the value of key_id in value_id validation.

Solution

No that is not possible. If you need to access more than one value you have to use the Object-level validation (see docs):

class Keys_Serializer(serializers.Serializer):

    key_id = serializers.IntegerField(required=True)
    key_name = serializers.CharField(required=True)
    value_id = serializers.IntegerField(required=False)

    def validate(self, data):
        # here you can access all values
        key_id = data['key_id']
        value_id = data['value_id']
        # perform you validation
        if key_id != value_id:
            raise serializers.ValidationError("key_id must be equal to value_id")
        return data

Answered By - ilse2005