DRF序列化

序列化組件

# 序列化，序列化器會(huì)把模型對象轉(zhuǎn)換成字典，經(jīng)過response以后變成json字符串
# 反序列化，將客戶端發(fā)送過來的數(shù)據(jù)，經(jīng)過數(shù)據(jù)校驗(yàn)后變成字典，用序列化器將字典轉(zhuǎn)成模型

序列化

# 注冊rest_framework

# 在models.py中定義表模型
class Book(models.Model):
    id = models.AutoField(primary_key=True)
    name = models.CharField(max_length=32)
    price = models.DecimalField(max_digits=6,decimal_places=2)
    author = models.CharField(max_length=32)
    public = models.CharField(max_length=64)

# 在自定義文件中定義序列化器
from rest_framework import serializers


class BooksSerializer(serializers.Serializer):
    name = serializers.CharField()
    price = serializers.DecimalField(max_digits=6,decimal_places=2)
    author = serializers.CharField()
    public = serializers.CharField()

# 在views中定義視圖類
class BookView(APIView):
    def get(self,request,id):
        book = Book.objects.filter(id=id).first()
        book_ser = BooksSerializer(book) # 參數(shù)就是要序列化的對象
        # book_ser.data就是序列化后的字典
        return Response(book_ser.data) # 也可以用JsonResponse返回，這樣不用注冊rest_framework，但不能通過判斷請求信息區(qū)別渲染

# 配置路由信息

序列化類的字段類型

序列化類型的選項(xiàng)參數(shù)

通用參數(shù)：

反序列化

# 注意，序列化器中字段的參數(shù)條件應(yīng)該在表模型字段要求的范圍內(nèi)再做限制

def put(self, request, id):
    response_msg = {'status': 100, 'msg': '成功'}
    book = Book.objects.filter(id=id).first()

    book_ser = BooksSerializer(instance=book, validated_data=request.data)  # put反序列化 第二個(gè)參數(shù)是修改需要的數(shù)據(jù)

    if book_ser.is_valid(): # 數(shù)據(jù)校驗(yàn)
        book_ser.save()
        response_msg['data'] = book_ser.data
    else:
        response_msg['status'] = 101
        response_msg['msg'] = '數(shù)據(jù)校驗(yàn)失敗'
        response_msg['data'] = book_ser.errors
        return Response(response_msg)

put反序列化需要實(shí)現(xiàn)序列器類父類的update方法

def update(self, instance, validated_data): # 更新想要反序列化的字段
    # instance是book對象，即要修改的對象
    # validated_data是校驗(yàn)后的數(shù)據(jù)
    instance.name = validated_data.get('name')
    instance.price = validated_data.get('price')
    instance.author = validated_data.get('author')
    instance.public = validated_data.get('public')
    instance.save()
    return instance

反序列化校驗(yàn)

# 序列化器中定義字段校驗(yàn)
class BooksSerializer(serializers.Serializer):
    name = serializers.CharField(max_length=5)

# 序列化器中定義字段校驗(yàn)2
def check_author(data):
    if 'sb' in data:
        raise ValidationError('含不當(dāng)詞匯')
    else:
        return data

class BooksSerializer(serializers.Serializer):
    author = serializers.CharField(validators=[check_author]) # 此列表傳入函數(shù)內(nèi)存地址


# 序列化器中定義局部鉤子
class BooksSerializer(serializers.Serializer):
    def validate_price(self, data):
        if float(data) > 10:
            return data
        else:
            raise ValidationError('價(jià)格太低，校驗(yàn)不通過')

# 序列化器中定義全局鉤子
class BooksSerializer(serializers.Serializer):
    def validate(self, validated_data):
        if float(validated_data.get('price')) > 50 and validated_data.get('public') == '忘記出版社':
            raise ValidationError('忘記出版社是廉價(jià)書出版社，你這個(gè)不對')
        else:
            return validated_data

read_only和write_only

# 在字段參數(shù)中設(shè)置read_only=True則該字段只從數(shù)據(jù)庫讀出，不從外部獲取數(shù)據(jù)修改
# 在字段參數(shù)中設(shè)置write_only=True則該字段只用于獲取外部數(shù)據(jù)修改數(shù)據(jù)庫，而不提供數(shù)據(jù)庫查詢展示

查詢所有

# 將需要過濾參數(shù)的請求放在一個(gè)視圖類，例如查詢部分，修改部分，將不需要過濾參數(shù)的請求放在另外一個(gè)視圖類，例如查詢所有，新增

# 配置URL
# 新建視圖類
class BooksView(APIView):

    def get(self,request):
        response_msg = {'status': 100, 'msg': '成功'}
        books = Book.objects.all()
        books_ser = BooksSerializer(books,many=True) # 序列化多條時(shí)需many參數(shù)
        response_msg['data'] = books_ser.data
        return Response(response_msg)

新增數(shù)據(jù)

class BooksView(APIView):
    def post(self, request):
        response_msg = {'status': 100, 'msg': '成功'}
        book_ser = BooksSerializer(data=request.data)
        # 校驗(yàn)字段
        if book_ser.is_valid():
            book_ser.save()
            response_msg['data'] = book_ser.data
        else:
            response_msg['status'] = 102
            response_msg['msg'] = '數(shù)據(jù)校驗(yàn)失敗'
            response_msg['data'] = book_ser.errors
        return Response(response_msg)
# 需要重寫create方法
class BooksSerializer(serializers.Serializer):
    def create(self, validated_data):
        book = Book.objects.create(**validated_data)
        return book # 這個(gè)對象將序列化后作為data返回給請求端

刪除數(shù)據(jù)

class BookView(APIView):
    def delete(self,request,id):
        response_msg = {'status': 100, 'msg': '成功'}
        book = Book.objects.filter(id=id).delete()
        response_msg['data'] = ''
        return Response(response_msg)

自定義封裝Response對象

class MyResponse():
    def __init__(self):
        self.status = '100'
        self.msg = '成功'
    @property
    def get_dict(self):
        return self.__dict__

模型類序列化器

class BookModelSerializer(serializers.ModelSerializer):
    class Meta:
        model = Book # 指定對應(yīng)哪個(gè)表模型
        fields = '__all__'
        # fields = ('name','price') 指定字段
        # exclude=('name'，) # 排除某個(gè)字段，不能同時(shí)與fields = '__all__'一起寫，注意元組
        # read_only_fields = ('price',)
        # write_only_fields = ('name',) # 棄用
        extra_kwargs = {
            'price': {'write_only':True,'min_value':0}
        }

# 不需要重寫update和create方法

源碼

# 序列化多條需要傳參many=True
def __new__(cls,*args,**kwargs):
    if kwargs.pop('many',False):
        return cls.many_init(*args,**kwargs) # return list_serializer
    return super().__new__(cls,*args,**kwargs)

Serializer高級用法

# 為避免返回?cái)?shù)據(jù)中key值與數(shù)據(jù)庫字段名完全一致而被惡意攻擊，需要在序列化器中將字段名變化，即在序列化器類字段參數(shù)中增加參數(shù)：'序列化器字段名'=serializers.CharField(source='數(shù)據(jù)庫字段名')

# source支持models類中的方法
# source支持跨表
# '序列化器字段名'=serializers.CharField(source='跨表表名.字段名')

# 外鍵
# authors = serializers.SerislizerMethodField() #需要一個(gè)配套方法，get_字段名
def get_authors(self,instance): # instance即book
    authors=instance.authors.all()
    authors_list = []
    for author in authors:
        authors_list.append('name':author.name,'age':author.age)
    return authors_list