课程介绍
模型类序列化器ModelSerializer
- 1. 定义
BookInfoSerializer():
id = IntegerField(label=’ID’, read_only=True)
btitle = CharField(label=’名称’, max_length=20)
bpub_date = DateField(allow_null=True, label=’发布日期’, required=False)
bread = IntegerField(label=’阅读量’, max_value=2147483647, min_value=0, required=True)
bcomment = IntegerField(label=’评论量’, max_value=2147483647, min_value=0, required=True)

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                    课程介绍
                ](_index_)

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              [
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                    引入DjangoRESTframework
                ](c01-introducetodrf_index)
        - 
                [
                    Web应用模式
                ](c01-introducetodrf_separatedfrontendandbackend)

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              [
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                    认识RESTful
                ](c01-introducetodrf_introducetorest)

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                    RESTful设计方法
                ](c01-introducetodrf_howtodesignrest)

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                    使用Django开发REST接口
                ](c01-introducetodrf_developrestapiwithdjango)

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                    明确REST接口开发的核心任务
                ](c01-introducetodrf_coretasktodeveloprestapi)

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                    DjangoRESTframework简介
                ](c01-introducetodrf_aboutdrf)

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                    DRF工程搭建
                ](c02-drfproject_index)
        - 
                [
                    环境安装与配置
                ](c02-drfproject_installandconfig)

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                    见识DRF的魅力
                ](c02-drfproject_thefirstdrfprogram)

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                    Serializer序列化器
                ](c03-serializer_index)
        - 
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                    定义Serializer
                ](c03-serializer_declaring)

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                    序列化使用
                ](c03-serializer_serializing)

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                    反序列化使用
                ](c03-serializer_deserializing)

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                    模型类序列化器ModelSerializer
                ](c03-serializer_modelserializer)

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                    视图
                ](c04-view_index)
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                    Request与Response
                ](c04-view_requestandresponse)

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                    视图概览
                ](c04-view_view)

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                    视图说明
                ](c04-view_viewintroduction)

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                    视图集ViewSet
                ](c04-view_viewset)

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                    路由Router
                ](c04-view_routers)

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                    其他功能
                ](c05-components_index)
        - 
                [
                    认证
                ](c05-components_authentication)

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                    权限
                ](c05-components_permissions)

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                    限流
                ](c05-components_throttling)

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                    过滤
                ](c05-components_filtering)

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                    排序
                ](c05-components_ordering)

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                    分页
                ](c05-components_pagination)

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                    版本
                ](c05-components_versioning)

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                    异常处理
                ](c05-components_exceptions)

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                    自动生成接口文档
                ](c05-components_documents)

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课程介绍

模型类序列化器ModelSerializer

如果我们想要使用序列化器对应的是Django的模型类，DRF为我们提供了ModelSerializer模型类序列化器来帮助我们快速创建一个Serializer类。
ModelSerializer与常规的Serializer相同，但提供了：

基于模型类自动生成一系列字段
基于模型类自动为Serializer生成validators，比如unique_together
包含默认的create()和update()的实现
1. 定义
比如我们创建一个BookInfoSerializer ``` class BookInfoSerializer(serializers.ModelSerializer): “””图书数据序列化器””” class Meta:
```
  model = BookInfo
  fields = '__all__'
```


- model  指明参照哪个模型类
- fields  指明为模型类的哪些字段生成
我们可以在python manage.py shell中查看自动生成的BookInfoSerializer的具体实现

from booktest.serializers import BookInfoSerializer serializer = BookInfoSerializer() serializer BookInfoSerializer(): id = IntegerField(label=’ID’, read_only=True) btitle = CharField(label=’名称’, max_length=20) bpub_date = DateField(allow_null=True, label=’发布日期’, required=False) bread = IntegerField(label=’阅读量’, max_value=2147483647, min_value=-2147483648, required=False) bcomment = IntegerField(label=’评论量’, max_value=2147483647, min_value=-2147483648, required=False) image = ImageField(allow_null=True, label=’图片’, max_length=100, required=False)

## 2.  指定字段
1) 使用**fields**来明确字段，`__all__`表名包含所有字段，也可以写明具体哪些字段，如

class BookInfoSerializer(serializers.ModelSerializer): “””图书数据序列化器””” class Meta: model = BookInfo fields = (‘id’, ‘btitle’, ‘bpub_date’)

2) 使用**exclude**可以明确排除掉哪些字段

class BookInfoSerializer(serializers.ModelSerializer): “””图书数据序列化器””” class Meta: model = BookInfo exclude = (‘image’,)

3) 默认ModelSerializer使用主键作为关联字段，但是我们可以使用**depth**来简单的生成嵌套表示，depth应该是整数，表明嵌套的层级数量。如：

class HeroInfoSerializer2(serializers.ModelSerializer): class Meta: model = HeroInfo fields = ‘all‘ depth = 1

形成的序列化器如下：

HeroInfoSerializer(): id = IntegerField(label=’ID’, read_only=True) hname = CharField(label=’名称’, max_length=20) hgender = ChoiceField(choices=((0, ‘male’), (1, ‘female’)), label=’性别’, required=False, validators=[, ]) hcomment = CharField(allow_null=True, label=’描述信息’, max_length=200, required=False) hbook = NestedSerializer(read_only=True): id = IntegerField(label=’ID’, read_only=True) btitle = CharField(label=’名称’, max_length=20) bpub_date = DateField(allow_null=True, label=’发布日期’, required=False) bread = IntegerField(label=’阅读量’, max_value=2147483647, min_value=-2147483648, required=False) bcomment = IntegerField(label=’评论量’, max_value=2147483647, min_value=-2147483648, required=False) image = ImageField(allow_null=True, label=’图片’, max_length=100, required=False)

4) 显示指明字段，如：

class HeroInfoSerializer(serializers.ModelSerializer): hbook = BookInfoSerializer()

class Meta:
    model = HeroInfo
    fields = ('id', 'hname', 'hgender', 'hcomment', 'hbook')

5)  指明只读字段<br />可以通过**read_only_fields**指明只读字段，即仅用于序列化输出的字段

class BookInfoSerializer(serializers.ModelSerializer): “””图书数据序列化器””” class Meta: model = BookInfo fields = (‘id’, ‘btitle’, ‘bpub_date’， ‘bread’, ‘bcomment’) read_only_fields = (‘id’, ‘bread’, ‘bcomment’)

## 3.  添加额外参数
我们可以使用**extra_kwargs**参数为ModelSerializer添加或修改原有的选项参数

class BookInfoSerializer(serializers.ModelSerializer): “””图书数据序列化器””” class Meta: model = BookInfo fields = (‘id’, ‘btitle’, ‘bpub_date’, ‘bread’, ‘bcomment’) extra_kwargs = { ‘bread’: {‘min_value’: 0, ‘required’: True}, ‘bcomment’: {‘min_value’: 0, ‘required’: True}, }

BookInfoSerializer():

id = IntegerField(label=’ID’, read_only=True)

btitle = CharField(label=’名称’, max_length=20)

bpub_date = DateField(allow_null=True, label=’发布日期’, required=False)

bread = IntegerField(label=’阅读量’, max_value=2147483647, min_value=0, required=True)

bcomment = IntegerField(label=’评论量’, max_value=2147483647, min_value=0, required=True)

```

ModelSerializer