13 多表序列化与反序列化

多表序列化与反序列化

1）外键字段要参与反序列化，所以外键字段设置为write_only
2）外键关系需要连表序列化结果给前台，可以用@property来自定义连表序列化

连表序列化用自定义@property完成：内部实现可以自定义逻辑，也可以走序列化类
外键字段留给反序列化来使用

案例

urls.py

url(r'^books/$', views.BookAPIView.as_view()),
url(r'^books/(?P<pk>\d+)/$', views.BookAPIView.as_view()),

models.py

class Book(BaseModel):
    # ...
 
    @property  # @property字段默认就是read_only，且不允许修改
    def publish_name(self):
        return self.publish.name
 
    @property  # 自定义序列化过程
    def author_list(self):
        temp_author_list = []
        for author in self.authors.all():
            author_dic = {
                "name": author.name
            }
            try:
                author_dic['phone'] = author.detail.phone
            except:
                author_dic['phone'] = ''
            temp_author_list.append(author_dic)
        return temp_author_list
 
    @property  # 借助序列化类完成序列化过程
    def read_author_list(self):
        from .serializers import AuthorModelSerializer
        return AuthorModelSerializer(self.authors.all(), many=True).data

serializers.py

# 辅助序列化类
class AuthorDetailModelSerializer(serializers.ModelSerializer):
    class Meta:
        model = models.AuthorDetail
        fields = ['phone']
 
# 辅助序列化类
class AuthorModelSerializer(serializers.ModelSerializer):
    detail = AuthorDetailModelSerializer(many=False, read_only=True)
    class Meta:
        model = models.Author
        fields = ['name', 'detail']
 
 
# 主序列化类
class BookModelSerializer(serializers.ModelSerializer):
    class Meta:
        model = models.Book
        fields = ('name', 'price', 'image', 'publish', 'authors', 'publish_name', 'author_list', 'read_author_list')
        extra_kwargs = {
            'image': {
                'read_only': True,
            },
            'publish': {  # 系统原有的外键字段，要留给反序列化过程使用，序列化外键内容，用@property自定义
                'write_only': True,
            },
            'authors': {
                'write_only': True,
            }
        }

views.py

# 六个必备接口：单查、群查、单增、单删、单整体改(了解)、单局部改
# 四个额外接口：群增、群删、群整体改、群局部改
class BookAPIView(APIView):
    # 单查群查
    def get(self, request, *args, **kwargs):
        pk = kwargs.get('pk')
        if pk:
            obj = models.Book.objects.filter(is_delete=False, pk=pk).first()
            serializer = serializers.BookModelSerializer(instance=obj)
            return APIResponse(result=serializer.data)
        else:
            queryset = models.Book.objects.filter(is_delete=False).all()
            serializer = serializers.BookModelSerializer(instance=queryset, many=True)
            return APIResponse(results=serializer.data)
 
 
    # 单增群增
    def post(self, request, *args, **kwargs):
        # 如何区别单增群增：request.data是{}还是[]
        if not isinstance(request.data, list):
            # 单增
            serializer = serializers.BookModelSerializer(data=request.data)
            serializer.is_valid(raise_exception=True)  # 如果校验失败，会直接抛异常，返回给前台
            obj = serializer.save()
            # 为什么要将新增的对象重新序列化给前台：序列化与反序列化数据不对等
            return APIResponse(result=serializers.BookModelSerializer(obj).data, http_status=201)
        else:
            # 群增
            serializer = serializers.BookModelSerializer(data=request.data, many=True)
            serializer.is_valid(raise_exception=True)  # 如果校验失败，会直接抛异常，返回给前台
            objs = serializer.save()
            # 为什么要将新增的对象重新序列化给前台：序列化与反序列化数据不对等
            return APIResponse(result=serializers.BookModelSerializer(objs, many=True).data, http_status=201)
 
# 友情注释：群增其实是借助了ListSerializer来的create方法完成的