drf中 连表深度查询和ListSerializer类包括drf中Response二次封装
drf中Response二次封装:
from rest_framework.response import Response ''' return MyResponse(status=1,msg='error',results=[],token='a.b.c',http_status=400,exception=True) Response模块的响应数据 data,最终数据results,Response模块需要向前台展示的一般有响应数据data(包括data里面的results),网络状态码status,是否异常exception return Response( data={ 'status':1, 'msg':'error', 'results':[], token:'a.b.c' }, status=400, exception=True ''' class APIResponse(Response): def __init__(self,status=0,msg='ok',results=None,http_status=None, headers=None,exception=False,content_type=None,**kwargs): #将status、msg、results、kwargs格式化成data data={ 'status':status, 'msg':msg, } #results只要不为空都是数据:False、0、''都是数据==》条件不能写if results if results is not None: data['results']=results #将kwargs中额外的k-v数据添加data中 字典的update方法 data.update(**kwargs) super().__init__(data=data,status=http_status,headers=headers,exception=exception,content_type=content_type)
连表深度查询:
- 外键字段默认显示的是外键值(int类型),不会自己进行深度查询
- 深度查询方式:
- 子序列化:必须有子序列化类配合,不能反序列化
- 配置depth:自动深度查询的是关联表的所有字段,数据量太多
- 插拔式@property:名字不能与外键名同名
#serializers.py class BookModelSerializer(serializers.ModelSerializer): class Meta: list_serializer_class = BookListSerializer model = models.Book fields = ['name', 'price', 'publish', 'authors', 'publish_info', 'author_list'] extra_kwargs = { 'publish': { 'write_only': True }, 'authors': { 'write_only': True } } #models.py class Book(BaseModel): name = models.CharField(max_length=64) price = models.DecimalField(max_digits=10, decimal_places=2) publish = models.ForeignKey(to='Publish', related_name='books', db_constraint=False, on_delete=models.DO_NOTHING, null=True) authors = models.ManyToManyField(to='Author', related_name='books', db_constraint=False) @property def publish_info(self): #单个数据 return { 'name': self.publish.name, 'address':self.publish.address, } @property def author_list(self): author_list_temp = [] # 存放所有作者格式化成数据的列表 authors=self.authors.all() #所有作者 for author in authors: #遍历处理所有作者 author_dic={ 'name':author.name, } try: #有详情才处理详情信息 author_dic['mobile']=author.detail.mobile except: author_dic['mobile']='无' author_list_temp.append(author_dic) #将处理过的数据添加到数据列表中 return author_list_temp #返回处理后的结果 def __str__(self): return self.name
单查群查接口:
class BookAPIView(APIView): # 单查群查 def get(self, request, *args, **kwargs): pk = kwargs.get('pk') if pk: book_obj = models.Book.objects.filter(is_delete=False, pk=pk).first() book_ser = serializers.BookModelSerializer(book_obj) else: book_query = models.Book.objects.filter(is_delete=False).all() book_ser = serializers.BookModelSerializer(book_query, many=True) return Response({ 'status': 0, 'msg': 'ok', 'results': book_ser.data })
单删群删接口:
# 单删群删 def delete(self, request, *args, **kwargs): ''' 单删:接口:/books/(pk)/ 数据:空 群删:接口/books/ 数据:[pk1,...pkn] 逻辑:修改is_delete字段,修改成功代表删除成功 ''' pk = kwargs.get('pk') if pk: pks = [pk] # 将单删格式化成群删一条 else: pks = request.data # 群删 try: # 数据如果有误,数据库执行会出错 rows = models.Book.objects.filter(is_delete=False, pk__in=pks).update(is_delete=True) except: return APIResponse(1, '数据有误') if rows: return APIResponse(0, '删除成功') return APIResponse(1, '删除失败')
单增群增接口:
# 单增群增 def post(self, request, *args, **kwargs): ''' 单增:接口:/books/数据:{...} 群增:接口:/books/数据:[{...},...,{...}] 逻辑:将数据给序列化类处理,数据的类型关系到many属性是否为True ''' if isinstance(request.data, dict): many = False elif isinstance(request.data, list): many = True else: return Response(data={'detail': '数据有误'}, status=400) book_ser = serializers.BookModelSerializer(data=request.data, many=many) book_ser.is_valid(raise_exception=True) book_obj_or_list = book_ser.save() return APIResponse(results=serializers.BookModelSerializer(book_obj_or_list, many=many).data)
ListSerializer类分析
- ModelSerializer默认没有群改功能,所以它配置了ListSerializer辅助类,帮助完成群增群改,需要在ModelSerializer类的Meta中设置list_serializer_class
- 自定义ListSerializer子类,将子类绑定给list_serializer_class
- 如果除了群增还有群改,就不需要自定义配置,但是需要群改,必须自定义配置
class BookListSerializer(serializers.ListSerializer): # 自定义的群增群改辅助类,没有必要重写create方法 def create(self, validated_data): return super().create(validated_data) def update(self, instance_list, validated_data_list): return [ self.child.update(instance_list[index], attrs) for index, attrs in enumerate(validated_data_list) ]
put方法的整体单改和群改:
# 整体单改群改 def put(self, request, *args, **kwargs): """ 单改:接口:/books/(pk)/ 数据:{...} 群增:接口:/books/ 数据:[{pk, ...}, ..., {pk, ...}] 逻辑:将数据给系列化类处理,数据的类型关系到 many 属性是否为True """ pk = kwargs.get('pk') if pk: # 单改 try: # 与增的区别在于,需要明确被修改的对象,交给序列化类 book_instance = models.Book.objects.get(is_delete=False, pk=pk) except: return Response({'detail': 'pk error'}, status=400) book_ser = serializers.BookModelSerializer(instance=book_instance, data=request.data) book_ser.is_valid(raise_exception=True) book_obj = book_ser.save() return APIResponse(results=serializers.BookModelSerializer(book_obj).data) else: # 群改 # 分析(重点): # 1)数据是列表套字典,每个字典必须带pk,就是指定要修改的对象,如果有一条没带pk,整个数据有误 # 2)如果pk对应的对象已被删除,或是对应的对象不存在,可以认为整个数据有误(建议),可以认为将这些错误数据抛出即可 request_data = request.data try: pks = [] for dic in request_data: pk = dic.pop('pk') # 解决分析1,没有pk pop方法就会抛异常 pks.append(pk) book_query = models.Book.objects.filter(is_delete=False, pk__in=pks).all() if len(pks) != len(book_query): raise Exception('pk对应的数据不存在') except Exception as e: return Response({'detail': '%s' % e}, status=400) book_ser = serializers.BookModelSerializer(instance=book_query, data=request_data, many=True) book_ser.is_valid(raise_exception=True) book_list = book_ser.save() return APIResponse(results=serializers.BookModelSerializer(book_list, many=True).data)
局部单改群改:
- 设置partial=True的序列化类,参与反序列化的字段,都会置为选填字段
- 提供了值得字段发生修改。
- 没有提供的字段采用被修改对象原来的值
- 设置context的值,目的:在序列化完成自定义校验(局部与全局钩子)时,可能需要视图类中的变量,如请求对象request
- 可以通过context将其传入,在序列化校验方法中,self.context就能拿到传入的视图类中的变量
# 局部单改群改 def patch(self, request, *args, **kwargs): pk = kwargs.get('pk') if pk: # 单改 try: book_instance = models.Book.objects.get(is_delete=False, pk=pk) except: return Response({'detail': 'pk error'}, status=400) book_ser = serializers.BookModelSerializer(instance=book_instance, data=request.data, partial=True, context={'request': request}) book_ser.is_valid(raise_exception=True) book_obj = book_ser.save() return APIResponse(results=serializers.BookModelSerializer(book_obj).data) else: # 群改 request_data = request.data try: pks = [] for dic in request_data: pk = dic.pop('pk') pks.append(pk) book_query = models.Book.objects.filter(is_delete=False, pk__in=pks).all() if len(pks) != len(book_query): raise Exception('pk对应的数据不存在') except Exception as e: return Response({'detail': '%s' % e}, status=400) book_ser = serializers.BookModelSerializer(instance=book_query, data=request_data, many=True, partial=True) book_ser.is_valid(raise_exception=True) book_list = book_ser.save() return APIResponse(results=serializers.BookModelSerializer(book_list, many=True).data)