目录
Django REST framwork 提供的视图的主要作用：
REST framework 提供了众多的通用视图基类与扩展类，以简化视图的编写。
rest_framework.views.APIView
APIView是REST framework提供的所有视图的基类，继承自Django的View父类。
APIView与View的不同之处：Request对象，而不是Django的HttpRequeset对象；Response对象，视图会为响应数据设置（render）符合前端要求的格式；APIException异常都会被捕获到，并且处理成合适的响应信息；rest_framework.generics.GenericAPIView
继承自APIVIew，主要增加了操作序列化器和数据库查询的方法，作用是为下面Mixin扩展类的执行提供方法支持。通常在使用时，可搭配一个或多个Mixin扩展类。
| 方法 | 作用 |
|---|---|
| self.get_object() | 根据pk获取单个数据 |
| self.get_serializer() | 获取要使用的序列化类 |
| self.get_queryset() | 获取所有要序列化的数据 |
queryset = None
serializer_class = None
lookup_field = 'pk'【是get_obj方法拆寻对象是的条件， key=value的形式， key是lookup_field的值，value是路由匹配中的又名分组捉着转换器】
filter_backends 【用于queryset过来的filter后端类】
pagination_class 【分页类】
get_queryset() 获取所有要序列化的数据
get_object() 根据pk获取单个数据
get_serializer() 获取要使用的序列化器， 直接使用【调用了get_serializer_class并加括号】
get_serializer_class 【return self.serializer_class , 拿到的是序列化类】
filter_queryset() 【过滤相关】
pagination_queryset【分页相关】
from rest_framework.views import APIView
from rest_framework.generics import GenericAPIView
from .serializers import UserSerializers
from .models import User
from rest_framework.response import Response
class UserView(APIView):
def get(self, request):
query_set = User.objects.all()
ser = UserSerializers(instance=query_set, many=True)
return Response(ser.data)
def post(self, request):
ser = UserSerializers(data=request.data)
if ser.is_valid():
return Response(ser.data)
return Response(ser.errors)
class User2View(APIView):
def get(self, request, pk):
obj = User.objects.filter(pk=pk).first()
ser = UserSerializers(instance=obj)
return Response(ser.data)
def put(self, request, pk):
obj = User.objects.filter(pk=pk).first()
ser = UserSerializers(instance=obj, data=request.data)
if ser.is_valid():
return Response(ser.data)
return Response(ser.errors)
def delete(self, request, pk):
User.objects.filter(pk=pk).delete()
return Response()
class UserView(GenericAPIView):
queryset = User.objects.all()
serializer_class = UserSerializers
def get(self, request):
queryset = self.get_queryset()
ser = self.get_serializer(instance=queryset, many=True)
return Response(ser.data)
def post(self, request):
ser = self.get_serializer(data=request.data)
if ser.is_valid():
ser.save()
return Response(ser.data)
return Response(ser.errors)
class User2View(GenericAPIView):
queryset = User.objects.all()
serializer_class = UserSerializers
def get(self, request):
obj = self.get_object()
ser = self.get_serializer(instance=obj)
return Response(ser.data)
def put(self, request):
obj = self.get_object()
ser = self.get_serializer(instance=obj, data=request.data)
if ser.is_valid():
ser.save()
return Response(ser.data)
return Response(ser.errors)
def delete(self, request, pk):
self.get_queryset().filter(pk=pk).delete()
return Response('')
类中有一个list方法， 就是上面基于GenericAPIView写的五个接口中的get获取全部
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)
类中有一个create方法，就是上面写的基于GenericAPIView写的五个接口中的post
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 {}
类中有一个retrieve方法，就是上边写的基于GenericAPIView写的get方法获取单条数据。
class RetrieveModelMixin:
"""
Retrieve a model instance.
"""
def retrieve(self, request, *args, **kwargs):
instance = self.get_object()
serializer = self.get_serializer(instance)
return Response(serializer.data)
类中有一个update方法，就是上边写的基于GenericAPIView写的put方法修改一条数据。
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)
类中有一个destroy方法，就是上边写的基于GenericAPIView写的delete方法。
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()
因为五个视图扩展类用到了GenericAPIView类中的属性和方法，所以必须结合GenericAPIView一起使用。
需要什么功能就继承GenericAPIView和试图扩展类
from rest_framework.Mixins import ListModelMixin, CreateModelMixin, RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin
class UserView(GenericAPIView, ListModelMixin, CreateModelMixin):
queryset = User.objects # 可以加.all()，也可以不用加，get_queryset方法会自动加
serializer_class = UserSerializers
def get(self, request, *args, **kwargs):
return self.list(request, *args, **kwargs)
def post(self, request, *args, **kwargs):
return self.create(request, *args, **kwargs)
class User2View(GenericAPIView, RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin):
queryset = User.objects # 可以加.all()，也可以不用加，get_queryset方法会自动加
serializer_class = UserSerializers
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 delete(self, request, *args, **kwargs):
return self.destroy(request, *args, **kwargs)
from rest_framework.generics import ListAPIView, CreateAPIView, RetrieveAPIView, UpdateAPIView, DestroyAPIView, \
ListCreateAPIView, RetrieveUpdateDestroyAPIView, RetrieveUpdateAPIView, RetrieveDestroyAPIView
class ListAPIView(mixins.ListModelMixin,
GenericAPIView):
"""
Concrete view for listing a queryset.
"""
def get(self, request, *args, **kwargs):
return self.list(request, *args, **kwargs)
class CreateAPIView(mixins.CreateModelMixin,
GenericAPIView):
"""
Concrete view for listing a queryset.
"""
def get(self, request, *args, **kwargs):
return self.create(request, *args, **kwargs)
class RetrieveAPIView(mixins.RetrieveModelMixin,
GenericAPIView):
"""
Concrete view for retrieving a model instance.
"""
def get(self, request, *args, **kwargs):
return self.retrieve(request, *args, **kwargs)
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)
class DestroyAPIView(mixins.DestroyModelMixin,
GenericAPIView):
"""
Concrete view for deleting a model instance.
"""
def delete(self, request, *args, **kwargs):
return self.destroy(request, *args, **kwargs)
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)
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, **kwargs)
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)
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)
class UserView(ListAPIView):
queryset = User.objects
serializer_class = UserSerializers
class User2View(RetrieveAPIView):
queryset = User.objects
serializer_class = UserSerializers
重写了as_view方法，只要继承了ViewsetMixin就必须在as_view中传actions参数，以字典的形式，key值是请求方式，value是方法名。
class ViewSetMixin:
@classonlymethod
# ViewsetMixin的as_view
def as_view(cls, actions=None, **initkwargs):
# actions参数不能为空
# actions = {'get': 'list', 'post':'create'}
if not actions:
raise TypeError("The `actions` argument must be provided when "
"calling `.as_view()` on a ViewSet. For example "
"`.as_view({'get': 'list'})`")
# 当路由匹配成功会执行view
def view(request, *args, **kwargs):
# method = get
# action = list
for method, action in actions.items():
# 反射 视图类的对象找'list'方法
# 如果继承了五个视图基类 就可以找到list方法
handler = getattr(self, action)
# 给对象设置属性
self.get = 视图基类的list方法
setattr(self, method, handler)
# 执行dispatch 是APIView里的dispatch
return self.dispatch(request, *args, **kwargs)
return csrf_exempt(view)
继承了ViewSetMixin和APIView
class ViewSet(ViewSetMixin, views.APIView):
"""
The base ViewSet class does not provide any actions by default.
"""
pass
继承了ViewSetMixin和GenericAPIView
class GenericViewSet(ViewSetMixin, generics.GenericAPIView):
"""
The GenericViewSet class does not provide any actions by default,
but does include the base set of generic view behavior, such as
the `get_object` and `get_queryset` methods.
"""
pass
继承了五个视图扩展类和GenericViewSet
class ModelViewSet(mixins.CreateModelMixin,
mixins.RetrieveModelMixin,
mixins.UpdateModelMixin,
mixins.DestroyModelMixin,
mixins.ListModelMixin,
GenericViewSet):
"""
A viewset that provides default `create()`, `retrieve()`, `update()`,
`partial_update()`, `destroy()` and `list()` actions.
"""
pass
继承了ListModelMixin、RetrieveModelMixin和GenericViewSet
class ReadOnlyModelViewSet(mixins.RetrieveModelMixin,
mixins.ListModelMixin,
GenericViewSet):
"""
A viewset that provides default `list()` and `retrieve()` actions.
"""
pass
from rest_framework.viewsets import ViewSetMixin, ViewSet, GenericViewSet, ModelViewSet, ReadOnlyModelViewSet
class UserView(ModelViewSet):
queryset = User.objects
serializer_class = UserSerializers
路由必须传actions参数
path('users/', views.UserView.as_view({'get': 'list', 'post':'create'})),
path('users/<int:pk>/', views.UserView.as_view({'get': 'retrieve', 'put': 'update', 'delete': 'destroy'})),
GenericaAPIVIew
五个视图
