drf--day4

一个不起眼的码农
49 阅读6分钟

序列化类常用字段和字段参数

序列化类--字段类 CharField  除了这些还有其他的
序列化类---》字段类，字段类上，传属性的 ，序列化类上，也可以写属性
【models.CharField(max_length=32)】

常用字段类

1 BooleanField	      BooleanField()

2 NullBooleanField	  NullBooleanField()

3 CharField	CharField(max_length=None, min_length=None, allow_blank=False, trim_whitespace=True)

4 EmailField	EmailField(max_length=None, min_length=None, allow_blank=False)

5 RegexField	RegexField(regex, max_length=None, min_length=None, allow_blank=False)

6 SlugField	SlugField(max_length=50, min_length=None, allow_blank=False) 正则字段，验证正则模式 [a-zA-Z0-9-]+

7 URLField	URLField(max_length=200, min_length=None, allow_blank=False)

8 UUIDField	UUIDField(format=’hex_verbose’) format: 1) 'hex_verbose' 如"5ce0e9a5-5ffa-654b-cee0-1238041fb31a" 2） 'hex' 如 "5ce0e9a55ffa654bcee01238041fb31a" 3）'int' - 如: "123456789012312313134124512351145145114" 4）'urn' 如: "urn:uuid:5ce0e9a5-5ffa-654b-cee0-1238041fb31a"

9 IPAddressField	IPAddressField(protocol=’both’, unpack_ipv4=False, **options)

10 IntegerField	IntegerField(max_value=None, min_value=None)

11 FloatField	FloatField(max_value=None, min_value=None)

12 DecimalField	DecimalField(max_digits, decimal_places, coerce_to_string=None, max_value=None, min_value=None) max_digits: 最多位数 decimal_palces: 小数点位置

13 DateTimeField	DateTimeField(format=api_settings.DATETIME_FORMAT, input_formats=None)

14 DateField	DateField(format=api_settings.DATE_FORMAT, input_formats=None)

15 TimeField	TimeField(format=api_settings.TIME_FORMAT, input_formats=None)

16 DurationField	DurationField()

17 ChoiceField	ChoiceField(choices) choices与Django的用法相同

18 MultipleChoiceField	MultipleChoiceField(choices)

19 FileField	FileField(max_length=None, allow_empty_file=False, use_url=UPLOADED_FILES_USE_URL)

20 ImageField	ImageField(max_length=None, allow_empty_file=False, use_url=UPLOADED_FILES_USE_URL)

----------重要，后面讲-----------
ListField	ListField(child=, min_length=None, max_length=None)
DictField	DictField(child=)


记住的：CharField  IntegerField  DecimalField  DateTimeField BooleanField
ListField
DictField

常用字段参数

选项参数：

* CharField及其子类的(EmailField) ---》反序列化的校验,字段自己的规则
    max_length	最大长度
    min_lenght	最小长度
    allow_blank	是否允许为空
    trim_whitespace	是否截断空白字符

* IntegerField
    max_value	最小值
    min_value	最大值


* 所有字段类都有的
required	表明该字段在反序列化时必须输入，默认True
default	    反序列化时使用的默认值
allow_null	表明该字段是否允许传入None，默认False
validators	该字段使用的验证器
----看一眼忘掉-----
error_messages	包含错误编号与错误信息的字典
label	用于HTML展示API页面时，显示的字段名称
help_text	用于HTML展示API页面时，显示的字段帮助提示信息


* 重点：
read_only	表明该字段仅用于序列化输出，默认False
write_only	表明该字段仅用于反序列化输入，默认False


* 反序列化校验执行流程
    1 先执行字段自己的校验规则----》最大长度，最小长度，是否为空，是否必填，最小数字。。。。
    2 validators=[方法，] ----》单独给这个字段加校验规则
        name=serializers.CharField(validators=[方法,])
    3 局部钩子校验规则
    4 全局钩子校验规则

序列化高级用法之source

  • 创建关联表

      class Book(models.Model):
      name = models.CharField(max_length=32)
      price = models.CharField(max_length=32)

      publish = models.ForeignKey(to='Publish', on_delete=models.CASCADE)  # 留住，还有很多
      authors = models.ManyToManyField(to='Author')


  class Publish(models.Model):
      name = models.CharField(max_length=32)
      addr = models.CharField(max_length=32)


  class Author(models.Model):
      name = models.CharField(max_length=32)
      phone = models.CharField(max_length=11)

  • 迁移，录入数据

序列化定制字段名字

# 重点：source可以指定序列化字段的名字
        自有字段，直接写字段名字
        name_real = serializers.CharField(max_length=8, source='name')
    关联字段，一对多的关联，直接点
        -publish = serializers.CharField(source='publish.name')
    多对多，搞不了,source不能用
        -authors=serializers.CharField(source='authors.all')


# 序列化类
class BookSerializer(serializers.Serializer):
    # 字段参数，通用的，所有字段都可以写  通过source指定哪个字段
    # 自有字段，直接写字段名字
    name_real = serializers.CharField(max_length=8, source='name')
    real_price = serializers.CharField(source='price')

    # 关联字段，一对多的关联，直接点
    publish = serializers.CharField(source='publish.name')

    #多对多，搞不了,source不能用
    authors=serializers.CharField(source='authors.all')

序列化高级用法之定制字段的两种方式

SerializerMethodField定制

# 定制关联字段的显示形式
        -一对多的，显示字典
    -多对多，显示列表套字典



# 代码
class BookSerializer(serializers.Serializer):
    name = serializers.CharField(max_length=8)
    price = serializers.CharField()

    # 定制返回格式---》方式一
    publish_detail = serializers.SerializerMethodField()

    def get_publish_detail(self, obj):
        return {'name': obj.publish.name, 'addr': obj.publish.addr}

    author_list = serializers.SerializerMethodField()

    def get_author_list(self, obj):
        l = []
        for author in obj.authors.all():
            l.append({'name': author.name, 'phone': author.phone})
        return l

在表模型中定制

  • 表模型

      class Book(models.Model):
      name = models.CharField(max_length=32)
      price = models.CharField(max_length=32)

      publish = models.ForeignKey(to='Publish', on_delete=models.CASCADE)  # 留住，还有很多
      authors = models.ManyToManyField(to='Author')

      def publish_detail(self):
          return {'name': self.publish.name, 'addr': self.publish.addr}

      def author_list(self):
          l = []
          for author in self.authors.all():
              l.append({'name': author.name, 'phone': author.phone})
          return l

  • 序列化类

      class BookSerializer(serializers.Serializer):
      name = serializers.CharField(max_length=8)
      price = serializers.CharField()

      # publish_detail = serializers.CharField()
      publish_detail = serializers.DictField()
      author_list = serializers.ListField()

多表关联反序列化保存

新增图书接口

前端传入的数据格式：{name:红楼梦,price:19,publish:1,authors:[1,2]}
# 视图类
class BookView(APIView):
    def post(self, request):
        ser = BookSerializer(data=request.data)
        if ser.is_valid():
            ser.save()
            return Response({'code': 100, 'msg': '新增成功'})
        else:
            return Response({'code': 101, 'msg': ser.errors})


# 序列化类
class BookSerializer(serializers.Serializer):
    # name和price  既用来序列化，又用来反序列化   即写又读 ,不用加read_only，write_only
    name = serializers.CharField(max_length=8)
    price = serializers.CharField()

# 只用来做序列化   只读  read_only

修改图书接口

前端传入的数据格式：{name:红楼梦,price:19,publish:1,authors:[1,2]}

  • 视图类

    class BookDetailView(APIView):
    def put(self, request, pk):
        book = Book.objects.filter(pk=pk).first()
        ser = BookSerializer(data=request.data, instance=book)
        if ser.is_valid():
            ser.save()
            return Response({'code': 100, 'msg': '修改成功'})
        else:
            return Response({'code': 101, 'msg': ser.errors})

  • 序列化类

     反序列化的多表关联的保存
class BookSerializer(serializers.Serializer):
    # name和price  既用来序列化，又用来反序列化   即写又读 ,不用加read_only，write_only
    name = serializers.CharField(max_length=8)
    price = serializers.CharField()

# 只用来做反序列化  只写  write_only
publish = serializers.CharField(write_only=True)
authors = serializers.ListField(write_only=True)


# 修改要重写update
def update(self, instance, validated_data):
    # validated_data 校验过后的数据，{name:红楼梦,price:19,publish:1,authors:[1,2]}
    instance.name = validated_data.get('name')
    instance.price = validated_data.get('price')
    instance.publish_id = validated_data.get('publish')

# 先清空，再add
authors = validated_data.get('authors')
instance.authors.clear()
instance.authors.add(*authors)

instance.save()

return instance
publish_detail = serializers.DictField(read_only=True)
author_list = serializers.ListField(read_only=True)

# 只用来做反序列化  只写  write_only
publish = serializers.CharField(write_only=True)
authors = serializers.ListField(write_only=True)

# 新增要重写create方法
def create(self, validated_data):
    # validated_data 校验过后的数据，{name:红楼梦,price:19,publish:1,authors:[1,2]}
    # 新增一本图书
    book = Book.objects.create(name=validated_data.get('name'), price=validated_data.get('price'),
                               publish_id=validated_data.get('publish'))

# 作者也要关联上
# book.authors   add remove set clear....
book.authors.add(*validated_data.get('authors'))
# book.authors.add(1,2)
return book

修改图书接口

前端传入的数据格式：{name:红楼梦,price:19,publish:1,authors:[1,2]}

  • 视图类

      class BookDetailView(APIView):
      def put(self, request, pk):
          book = Book.objects.filter(pk=pk).first()
          ser = BookSerializer(data=request.data, instance=book)
          if ser.is_valid():
              ser.save()
              return Response({'code': 100, 'msg': '修改成功'})
          else:
              return Response({'code': 101, 'msg': ser.errors})

  • 序列化类

      反序列化的多表关联的保存
  class BookSerializer(serializers.Serializer):
      # name和price  既用来序列化，又用来反序列化   即写又读 ,不用加read_only，write_only
      name = serializers.CharField(max_length=8)
      price = serializers.CharField()

  # 只用来做反序列化  只写  write_only
  publish = serializers.CharField(write_only=True)
  authors = serializers.ListField(write_only=True)


  # 修改要重写update
  def update(self, instance, validated_data):
      # validated_data 校验过后的数据，{name:红楼梦,price:19,publish:1,authors:[1,2]}
      instance.name = validated_data.get('name')
      instance.price = validated_data.get('price')
      instance.publish_id = validated_data.get('publish')

  # 先清空，再add
  authors = validated_data.get('authors')
  instance.authors.clear()
  instance.authors.add(*authors)

  instance.save()

  return instance

反序列化字段校验其他

1 字段自己的：举例：name = serializers.CharField(max_length=8, error_messages={'max_length': '太长了'})
2 validators=[方法，]   忽略掉
3 局部钩子
4 全局钩子

ModelSerializer使用

# ModelSerializer 继承自Serializer，帮咱们完成了很多操作
        -跟表模型强关联
        -大部分请求，不用写create和update了

# 如何使用

### ModelSerializer的使用
class BookSerializer(serializers.ModelSerializer):
    # 跟表有关联
    class Meta:
        model = Book  # 跟book表建立了关系     序列化类和表模型类
        # fields = '__all__'  # 序列化所有Book中的字段  id name price publish authors
        fields = ['name', 'price', 'publish_detail', 'author_list', 'publish', 'authors']  # 序列化所有Book中的name和price字段字段

        # 定制name反序列化时，最长不能超过8   给字段类加属性---方式一
        extra_kwargs = {'name': {'max_length': 8},
                        'publish_detail': {'read_only': True},
                        'author_list': {'read_only': True},
                        'publish': {'write_only': True},
                        'authors': {'write_only': True},
                        }

    # 如果Meta写了__all__ ,就相当于，复制了表模型中的所有字段，放在了这里，做了个映射
    # name = serializers.CharField(max_length=32)
    # price = serializers.CharField(max_length=32)

    # 定制name反序列化时，最长不能超过8   给字段类加属性---方式二，重写name字段
    # name = serializers.CharField(max_length=8)

    # 同理，所有的read_only和wirte_only都可以通过重写或使用extra_kwargs传入

    # 终极，把这个序列化类写成跟之前一模一样项目
    # publish_detail = serializers.SerializerMethodField(read_only=True)
    # def get_publish_detail(self, obj):
    #     return {'name': obj.publish.name, 'addr': obj.publish.addr}
    # author_list = serializers.SerializerMethodField(read_only=True)
    # def get_author_list(self, obj):
    #     l = []
    #     for author in obj.authors.all():
    #         l.append({'name': author.name, 'phone': author.phone})
    #     return l

    # 局部钩子和全局钩子跟之前完全一样
    def validate_name(self, name):
        if name.startswith('sb'):
            raise ValidationError('不能sb')

        else:
            return name
avatar
文章
阅读
粉丝