ks/apps/examination/exampaper/serializers.py

# coding=utf-8

from rest_framework import serializers
from .models import ExamPaper
from utils.exceptions import CustomError

class ExamPaperSerializer(serializers.ModelSerializer):
    subject_name = serializers.CharField(source='subject.name', read_only=True)

    class Meta:
        model = ExamPaper
        fields = "__all__"

    def validate(self, attrs):
        if 'subject' in attrs and attrs['subject'].delete:
            raise CustomError(u'科目[%s]已被删除！' % attrs['subject'].name)
        return attrs

    def create(self, validated_data):
        validated_data['create_user'] = self.context['request'].user
        instance = super(ExamPaperSerializer, self).create(validated_data)
        instance.update_count()
        instance.save()
        return instance

    def update(self, instance, validated_data):
        if instance.delete:
            raise CustomError(u'试卷[%s]已经被删除,禁止操作' % instance.name)
        instance = super(ExamPaperSerializer, self).update(instance, validated_data)
        instance.update_count()
        instance.save()
        return instance