一、Mixin类
提供了几种后端视图（对数据资源进行增删改查）处理流程的实现，如果需要编写的视图属于这五种，则视图可以通过继承相应的扩展类来复用代码，减少自己编写的代码量。
这五个扩展类需要搭配GenericAPIView通用视图基类来开发业务接口
1、ListModelMixin
列表视图扩展类，提供 list(request, *args, **kwargs)方法快速实现列表视图，返回200状态码。
该Mixin的list方法会对数据进行过滤和分页，如果不重写过滤和分页的方法是不会进行过滤和分页的。
源码简化
class ListModelMixin:
def list(self,request,*args,**kwargs):
queryset=self.get_queryset()
serializer=self.get_serializer(instance=queryset,many=True)
return Response(serializer.data)
源码
class ListModelMixin:
"""
List a queryset.
"""
def list(self, request, *args, **kwargs):
queryset = self.filter_queryset(self.get_queryset())
page = self.paginate_queryset(queryset)
if page is not None:
serializer = self.get_serializer(page, many=True)
return self.get_paginated_response(serializer.data)
serializer = self.get_serializer(queryset, many=True)
return Response(serializer.data)
2、CreateModelMixin
创建视图扩展类，提供 create(request, *args, **kwargs)方法快速实现创建资源的视图，成功返回201状态码。
如果序列化器对前端发送的数据验证失败，返回400错误；所以要对反序列化输入字段要进行验证，校验不通过提供指定的报错。
源码简化
class CreateModelMixin:
def create(self,request,*args,**kwargs):
serializer=self.get_serializer(data=request.data)
serializer.is_valid(raise_exception=True)
serializer.save()
return Response(serializer.data)
源码
class CreateModelMixin:
"""
Create a model instance.
"""
def create(self, request, *args, **kwargs):
serializer = self.get_serializer(data=request.data)
serializer.is_valid(raise_exception=True)
self.perform_create(serializer)
headers = self.get_success_headers(serializer.data)
return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
def perform_create(self, serializer):
serializer.save()
def get_success_headers(self, data):
try:
return {'Location': str(data[api_settings.URL_FIELD_NAME])}
except (TypeError, KeyError):
return {}
3、RetrieveModelMixin
详情视图扩展类，提供 retrieve(request, *args, **kwargs)方法，可以快速实现返回一个存在的数据对象。
如果存在，返回200， 否则返回404。
源码
class RetrieveModelMixin:
def retrieve(self,request,*args,**kwargs):
instance=self.get_object()
serializer=ProjectsSerializer(instance=instance)
return Response(serializer.data)
4、UpdateModelMixin
更新视图扩展类，提供 update(request, *args, **kwargs)方法，可以快速实现更新一个存在的数据对象。
同时也提供 partial_update(request, *args, **kwargs)方法，可以实现局部更新。
成功返回200，序列化器校验数据失败时，返回400错误。
源码简化
class UpdateModelMixin:
def update(self,request,*args,**kwargs):
obj=self.get_object()
serializer=ProjectsSerializer(instance=obj,data=request.data)
serializer.is_valid(raise_exception=True)
serializer.save()
return Response(serializer.data)
源码
class UpdateModelMixin:
"""
Update a model instance.
"""
def update(self, request, *args, **kwargs):
partial = kwargs.pop('partial', False)
instance = self.get_object()
serializer = self.get_serializer(instance, data=request.data, partial=partial)
serializer.is_valid(raise_exception=True)
self.perform_update(serializer)
if getattr(instance, '_prefetched_objects_cache', None):
# If 'prefetch_related' has been applied to a queryset, we need to
# forcibly invalidate the prefetch cache on the instance.
instance._prefetched_objects_cache = {}
return Response(serializer.data)
def perform_update(self, serializer):
serializer.save()
def partial_update(self, request, *args, **kwargs):
kwargs['partial'] = True
return self.update(request, *args, **kwargs)
5、DestroyModelMixin
删除视图扩展类，提供 destroy(request, *args, **kwargs)方法，可以快速实现删除一个存在的数据对象。
成功返回204，不存在返回404。
源码简化
class DestroyModelMixin
def destroy(self,request,*args,**kwargs):
obj=self.get_object()
obj.delete()
return Response({'msg':'删除数据成功'},status=204)
源码
class DestroyModelMixin:
"""
Destroy a model instance.
"""
def destroy(self, request, *args, **kwargs):
instance = self.get_object()
self.perform_destroy(instance)
return Response(status=status.HTTP_204_NO_CONTENT)
def perform_destroy(self, instance):
instance.delete()
二、GenericAPIView的视图子类
1、CreateAPIView
提供post方法
继承关系：CreateModelMixin、GenericAPIView
使用：基本属性定义：queryset、serializer_class
class CreateAPIView(mixins.CreateModelMixin,
GenericAPIView):
"""
Concrete view for creating a model instance.
"""
def post(self, request, *args, **kwargs):
return self.create(request, *args, **kwargs)
2、ListAPIView
提供get方法
继承关系：ListModelMixin、GenericAPIView
使用：基本属性定义：queryset、serializer_class
class ListAPIView(mixins.ListModelMixin,
GenericAPIView):
"""
Concrete view for listing a queryset.
"""
def get(self, request, *args, **kwargs):
return self.list(request, *args, **kwargs)
3、RetrieveAPIView
提供get方法
继承关系：RetrieveModelMixin、GenericAPIView
使用：基本属性定义：queryset、serializer_class
class RetrieveAPIView(mixins.RetrieveModelMixin,
GenericAPIView):
"""
Concrete view for retrieving a model instance.
"""
def get(self, request, *args, **kwargs):
return self.retrieve(request, *args, **kwargs)
4、UpdateAPIView
提供put、patch方法
继承关系：UpdateModelMixin、GenericAPIView
使用：基本属性定义：queryset、serializer_class
class UpdateAPIView(mixins.UpdateModelMixin,
GenericAPIView):
"""
Concrete view for updating a model instance.
"""
def put(self, request, *args, **kwargs):
return self.update(request, *args, **kwargs)
def patch(self, request, *args, **kwargs):
return self.partial_update(request, *args, **kwargs)
5、DestoryAPIView
提供delete方法
继承关系：DestoryModelMixin、GenericAPIView
使用：基本属性定义：queryset、serializer_class
class DestroyAPIView(mixins.DestroyModelMixin,
GenericAPIView):
"""
Concrete view for deleting a model instance.
"""
def delete(self, request, *args, **kwargs):
return self.destroy(request, *args, **kwargs)
6、ListCreateAPIView
提供get、post方法
继承关系：ListModelMixin、CreateModelMixin、GenericAPIView
使用：基本属性定义：queryset、serializer_class
class ListCreateAPIView(mixins.ListModelMixin,
mixins.CreateModelMixin,
GenericAPIView):
"""
Concrete view for listing a queryset or creating a model instance.
"""
def get(self, request, *args, **kwargs):
return self.list(request, *args, **kwargs)
def post(self, request, *args, **kwargs):
return self.create(request, *args, **kwargs)
7、RetrieveUpdateAPIView
提供get、put、patch方法
继承关系：RetrieveModelMixin、UpdateModelMixin、GenericAPIView
使用：基本属性定义：queryset、serializer_class
class RetrieveUpdateAPIView(mixins.RetrieveModelMixin,
mixins.UpdateModelMixin,
GenericAPIView):
"""
Concrete view for retrieving, updating a model instance.
"""
def get(self, request, *args, **kwargs):
return self.retrieve(request, *args, **kwargs)
def put(self, request, *args, **kwargs):
return self.update(request, *args, **kwargs)
def patch(self, request, *args, **kwargs):
return self.partial_update(request, *args`
8、RetrieveDestoryAPIView
提供get、delete方法
继承关系：RetrieveModelMixin、DestoryModelMixin、GenericAPIView
使用：基本属性定义：queryset、serializer_class
class RetrieveDestroyAPIView(mixins.RetrieveModelMixin,
mixins.DestroyModelMixin,
GenericAPIView):
"""
Concrete view for retrieving or deleting a model instance.
"""
def get(self, request, *args, **kwargs):
return self.retrieve(request, *args, **kwargs)
def delete(self, request, *args, **kwargs):
return self.destroy(request, *args, **kwargs)
9、RetrieveUpdateDestoryAPIView
提供get、put、patch、delete方法
继承关系：RetrieveModelMixin、UpdateModelMixin、DestoryModelMixin、GenericAPIView
使用：基本属性定义：queryset、serializer_class
class RetrieveUpdateDestroyAPIView(mixins.RetrieveModelMixin,
mixins.UpdateModelMixin,
mixins.DestroyModelMixin,
GenericAPIView):
"""
Concrete view for retrieving, updating or deleting a model instance.
"""
def get(self, request, *args, **kwargs):
return self.retrieve(request, *args, **kwargs)
def put(self, request, *args, **kwargs):
return self.update(request, *args, **kwargs)
def patch(self, request, *args, **kwargs):
return self.partial_update(request, *args, **kwargs)
def delete(self, request, *args, **kwargs):
return self.destroy(request, *args, **kwargs)
