Django REST framework 源码剖析-视图集详解(ViewSet)
Django REST framework视图图解
- 视图类(View)
视图是DRF中处理用户请求的基本单元。它们可以是函数视图(FBV)或类视图(CBV)。函数视图使用函数来处理请求,而类视图则使用类来处理请求。类视图默认会自动dispatch特定的HTTP方法,如GET、POST等,不需要像函数视图那样通过单独的条件判断来处理不同的HTTP方法。此外,类视图可以使用面向对象的技术,如Mixin(多继承、混用),将代码拆解成可复用的组件,GenericAPIView可以与ListModelMixin、CreateModelMixin、RetrieveModelMixin、UpdateModelMixin、DestroyModelMixin等Mixin结合使用,以实现增删改查等功能。
- 视图集(ViewSet)
视图集是DRF中用于组织相关视图的集合。它们继承自APIView或GenericAPIView,并且可以定义多个方法(如list、create、retrieve、update、destroy等),这些方法对应不同的HTTP请求。视图集可以解决路由匹配和合并的问题,并且方法名可以自定义,路由匹配规则也需要相应修改。视图集还可以与Mixin结合使用,以实现更复杂的业务逻辑。
视图集 ViewSet
- 使用视图集ViewSet,可以将一系列逻辑相关的动作放到一个类中
- ViewSet视图集类不再实现get()、post()等方法,而是实现动作 action 如 list() 、create() 等
- 视图集只在使用as_view()方法的时候,才会将action动作与具体请求方式对应上
动作 action
- list() 提供一组数据
- retrieve() 提供单个数据(详情)
- create() 创建数据
- update() 保存数据
- destory() 删除数据
常用视图集父类 ViewSet
- 继承自APIView与ViewSetMixin,作用也与APIView基本类似,提供了身份认证、权限校验、流量管理等
- ViewSet主要通过继承ViewSetMixin来实现在调用as_view()时传入字典(如{‘get’:’list’})的映射处理工作
- 在ViewSet中,没有提供任何动作action方法,需要我们自己实现action方法
视图示例
from rest_framework.response import Response
from rest_framework import viewsets
from myproject.models import BookInfo
from myproject.serializer import BookInfoSerializer
class BookInfoViewSet(viewsets.ViewSet):
def list(self, request):
books = BookInfo.objects.all()
serializer = BookInfoSerializer(books, many=True)
return Response(serializer.data)
def retrieve(self, request, pk=None):
try:
books = BookInfo.objects.get(id=pk)
except BookInfo.DoesNotExist:
return Response(status=status.HTTP_404_NOT_FOUND)
serializer = BookInfoSerializer(books)
return Response(serializer.data)
路由示例
from django.urls import path, re_path
from myproject.viewsets import BookInfoViewSet
urlpatterns = [
url(r'^books/$', BookInfoViewSet.as_view({'get':'list'}),
url(r'^books/(?P<pk>\d+)/$', BookInfoViewSet.as_view({'get': 'retrieve'})
]
常用视图集父类 GenericViewSet
- 使用ViewSet通常并不方便,因为list、retrieve、create、update、destory等方法都需要自己编写,而这些方法与前面讲过的Mixin扩展类提供的方法同名,所以我们可以通过继承Mixin扩展类来复用这些方法而无需自己编写,但是Mixin扩展类依赖与GenericAPIView,所以还需要继承GenericAPIView
- GenericViewSet就帮助我们完成了这样的继承工作,继承自GenericAPIView与ViewSetMixin,在实现了调用as_view()时传入字典(如{‘get’:‘list’})的映射处理工作的同时,还提供了GenericAPIView提供的基础方法,可以直接搭配Mixin扩展类使用
视图示例
from rest_framework.viewsets import GenericViewSet
from rest_framework.mixins import ListModelMixin,CreateModelMixin,RetrieveModelMixin,UpdateModelMixin,DestroyModelMixin
class EmployeeViewSet(GenericViewSet,ListModelMixin,CreateModelMixin,RetrieveModelMixin,UpdateModelMixin,DestroyModelMixin):
queryset = Student.objects.all()
serializer_class = StudentModelSerializer
路由示例
from django.urls import path, re_path
from myproject import views
urlpatterns = [
path("employee/", views.EmployeeViewSet.as_view({"get": "list", "post": "create"})),
re_path("employee/(?P<pk>\d+)/", views.EmployeeViewSet.as_view({"get": "retrieve","put":"update","delete":"destroy"})),
]
常用视图集父类 ModelViewSet
- 继承自GenericViewSet,同时包括了ListModelMixin、RetrieveModelMixin、CreateModelMixin、UpdateModelMixin、DestoryModelMixin
视图示例
from rest_framework.viewsets import ModelViewSet
from myproject.models import Book
from myproject.serializer import BookSerializer
class CustomModelViewSet(ModelViewSet):
"""
list:获取列表数据
retrieve:获取详情数据
crate:新增数据
update:更新信息
DELETE:删除
"""
queryset = Book.objects.all()
serializer_class = BookSerilizer
路由示例
from django.urls import path, re_path
from myproject import views
urlpatterns = [
path("employee_model/", views.CustomModelViewSet.as_view({"get": "list", "post": "create"})),
re_path("employee_model/(?P<pk>\d+)/", views.CustomModelViewSet.as_view({"get": "retrieve","put":"update","delete":"destroy"})),
]
常用视图集父类 ReadOnlyModelViewSet
- 继承自GenericViewSet,同时包括了ListModelMixin、RetrieveModelMixin
视图示例
from rest_framework.viewsets import ReadOnlyModelViewSet
from myproject.models import Book
from myproject.serializer import BookSerilizer
class CustomReadOnlyModelViewSet(ReadOnlyModelViewSet):
"""
list:获取列表数据
retrieve:获取详情数据
"""
queryset = Book.objects.all()
serializer_class = BookSerilizer
路由示例
from django.urls import path, re_path
from myproject import views
urlpatterns = [
path("employee_readonly/", views.CustomReadOnlyModelViewSet.as_view({"get": "list", "post": "create"})),
re_path("employee_readonly/(?P<pk>\d+)/", views.CustomReadOnlyModelViewSet.as_view({"get": "retrieve","put":"update","delete":"destroy"})),
]
视图集中自定义附加action动作
视图示例
from rest_framework.viewsets import ModelViewSet,ReadOnlyModelViewSet
from rest_framework.response import Response
from myproject.models import Employee
from myproject.serializer import EmployeeModelSerializer
class EmployeeModelViewSet(ModelViewSet):
queryset = Employee.objects.all()
serializer_class = EmployeeModelSerializer
def login(self,request):
"""登录功能"""
return Response({"message":"登录成功"})
路由示例
from django.urls import path, re_path
from myproject import views
urlpatterns = [
path("employee_action/", views.StudentModelViewSet.as_view({"get": "list", "post": "create"})),
re_path("employee_action/(?P<pk>\d+)/", views.StudentModelViewSet.as_view({"get": "retrieve", "put": "update", "delete": "destroy"})),
path("employee_action/login/",views.StudentModelViewSet.as_view({"get":"login"}))
]
视图集中action属性
- 在视图集中,我们可以通过action对象属性来获取当前请求视图集时的action动作是哪个
视图示例
from rest_framework.viewsets import ModelViewSet
from employee.models import Employee
from .serializers import EmployeeModelSerializer
from rest_framework.response import Response
class StudentModelViewSet(ModelViewSet):
queryset = Employee.objects.all()
serializer_class = EmployeeModelSerializer
def get_top_5(self,request):
"""获取前5条信息"""
# 获取本次请求的视图方法名
print(self.action)
路由示例
from django.urls import path, re_path
from myproject import views
urlpatterns = [
path("employee/get_top5/",views.StudentModelViewSet.as_view({"get":"get_top_5"}))
]
总结
两个基类
- ViewSet: 继承ViewSetMixin和APIView
- GenericViewSet: 继承ViewSetMixin, generics.GenericAPIView
- ViewSetMixin: 重写了as_view
两个拓展类
- ModelViewSet: 继承mixins.CreateModelMixin,mixins.RetrieveModelMixin,mixins.UpdateModelMixin,mixins.DestroyModelMixin,mixins.ListModelMixin,GenericViewSet
- ReadOnlyModelViewSet:继承mixins.RetrieveModelMixin,mixins.ListModelMixin,GenericViewSet