一

# 宣告序列化器
from rest_framework import serializers
from djangoDome.models import Book

class PublisherSerializer(serializers.Serializer):
    id = serializers.IntegerField()
    title = serializers.CharField(max_length=32)

class AuthorSerializer(serializers.Serializer):
    id = serializers.IntegerField()
    name = serializers.CharField(max_length=32)


#自定義欄位
def my_validate(value):
    if 'xxoo' in value.lower():
        #拋敏感詞彙
        raise serializers.ValidationError('敏感詞彙')
    return value


class BookSerializer(serializers.Serializer):
    id = serializers.IntegerField(required=False)
    title = serializers.CharField(max_length=32,)# 自定義的加這個引數 validators=[my_validate,]
    pub_time = serializers.DateField()
    category=serializers.CharField(source='get_category_display',read_only=True) #此處為多選時用
    #read_only = True 正序查詢
    publisher=PublisherSerializer(read_only=True) #多對一
    authors=AuthorSerializer(many=True,read_only=True) #多對多用 many=True

    #write_only =True  反序查詢  要重新定義
    post_category = serializers.IntegerField(write_only=True)
    publisher_id = serializers.IntegerField(write_only=True)
    author_list = serializers.ListField(write_only=True)

    #重寫 create 方法
    def create(self, validated_data):
        #validated_data 校驗通過的資料 就是book_obj
        # 通過ORM操作給Book表增加資料
        book_obj=Book.objects.create(title=validated_data['title'],
                                     pub_time=validated_data["pub_time"],
                                     category=validated_data["post_category"],
                                     publisher_id=validated_data["publisher_id"]
                                     )
        book_obj.authors.add(*validated_data['author_list'])
        return book_obj

    # 對單個值進行校驗
    def validate_title(self,value):
        # value就是title的值 對value處理
        if 'xxoo' not in value.lower():
            raise serializers.ValidationError('少東西了')
        return value

    #對所有欄位進行 校驗
    def validate(self, attrs):
        # attrs 字典有你傳過來的所有的欄位
        if 'xxoo' in attrs['title'].lower() and attrs["post_category"] == 1:
            return attrs
        else:
            raise serializers.ValidationError('分類或標題不合符要求')