本文主要是介绍DRF视图源码分析,希望对大家解决编程问题提供一定的参考价值,需要的开发者们随着小编来一起学习吧!
DRF视图源码分析
1 APIView
class GenericAPIView(APIView):pass # 10功能class GenericViewSet(xxxx.View-2个功能, GenericAPIView):pass # 5功能能class UserView(GenericViewSet):def get(self,request):pass
APIView
是drf中 “顶层” 的视图类,在他的内部主要实现drf基础的组件的使用,例如:版本、认证、权限、限流等。
# urls.pyfrom django.urls import path
from app01 import viewsurlpatterns = [path('api/users/', views.UserView.as_view()),path('api/users/<int:pk>/', views.UserDetailView.as_view()),
]
# views.pyfrom rest_framework.views import APIView
from rest_framework.response import Responseclass UserView(APIView):# 认证、权限、限流等def get(self, request):# 业务逻辑:查看列表return Response({"code": 0, 'data': "..."})def post(self, request):# 业务逻辑:新建return Response({'code': 0, 'data': "..."})class UserDetailView(APIView):# 认证、权限、限流等def get(self, request,pk):# 业务逻辑:查看某个数据的详细return Response({"code": 0, 'data': "..."})def put(self, request,pk):# 业务逻辑:全部修改return Response({'code': 0, 'data': "..."})def patch(self, request,pk):# 业务逻辑:局部修改return Response({'code': 0, 'data': "..."})def delete(self, request,pk):# 业务逻辑:删除return Response({'code': 0, 'data': "..."})
2 GenericAPIView
GenericAPIView
继承APIView,在APIView的基础上又增加了一些功能。例如:get_queryset
、get_object
等。
实际在开发中一般不会直接继承它,他更多的是担任 中间人
的角色,为子类提供公共功能。
# urls.pyfrom django.urls import path
from app01 import viewsurlpatterns = [path('api/users/', views.UserView.as_view()),path('api/users/<int:pk>/', views.UserDetailView.as_view()),
]
# views.pyfrom rest_framework.generics import GenericAPIView
from rest_framework.response import Responseclass UserView(GenericAPIView):queryset = models.UserInfo.objects.filter(status=True)serializer_class = 序列化类def get(self, request):queryset = self.get_queryset()ser = self.get_serializer(intance=queryset,many=True)print(ser.data)return Response({"code": 0, 'data': "..."})
注意:最大的意义,将数据库查询、序列化类提取到类变量中,后期再提供公共的get/post/put/delete等方法,让开发者只定义类变量,自动实现增删改查。
3 GenericViewSet
GenericViewSet
类中没有定义任何代码,他就是继承 ViewSetMixin
和 GenericAPIView
,也就说他的功能就是将继承的两个类的功能继承到一起。
GenericViewSet
在视图中的改变不大,但是在路由中写到的功能较多
GenericAPIView
,将数据库查询、序列化类的定义提取到类变量中,便于后期处理。ViewSetMixin
,将 get/post/put/delete 等方法映射到 list、create、retrieve、update、partial_update、destroy方法中,让视图不再需要两个类。
# urls.pyfrom django.urls import path, re_path, include
from app01 import viewsurlpatterns = [path('api/users/', views.UserView.as_view({"get":"list","post":"create"})),path('api/users/<int:pk>/', views.UserView.as_view({"get":"retrieve","put":"update","patch":"partial_update","delete":"destory"})),
]
# views.pyfrom rest_framework.viewsets import GenericViewSet
from rest_framework.response import Responseclass UserView(GenericViewSet):# 认证、权限、限流等queryset = models.UserInfo.objects.filter(status=True)serializer_class = 序列化类def list(self, request):# 业务逻辑:查看列表queryset = self.get_queryset()ser = self.get_serializer(intance=queryset,many=True)print(ser.data)return Response({"code": 0, 'data': "..."})def create(self, request):# 业务逻辑:新建return Response({'code': 0, 'data': "..."})def retrieve(self, request,pk):# 业务逻辑:查看某个数据的详细return Response({"code": 0, 'data': "..."})def update(self, request,pk):# 业务逻辑:全部修改return Response({'code': 0, 'data': "..."})def partial_update(self, request,pk):# 业务逻辑:局部修改return Response({'code': 0, 'data': "..."})def destory(self, request,pk):# 业务逻辑:删除return Response({'code': 0, 'data': "..."})
注意:开发中一般也很少直接去继承他,因为他也属于是 中间人
类,在原来 GenericAPIView
基础上又增加了一个映射而已。
4 五大类
在drf的为我们提供好了5个用于做 增、删、改(含局部修改)、查列表、查单个数据的5个类(需结合 GenericViewSet
使用)。
# urls.pyfrom django.urls import path, re_path, include
from app01 import viewsurlpatterns = [path('api/users/', views.UserView.as_view({"get":"list","post":"create"})),path('api/users/<int:pk>/', views.UserView.as_view({"get":"retrieve","put":"update","patch":"partial_update","delete":"destroy"})),
]
# views.pyfrom rest_framework.viewsets import GenericViewSet
from rest_framework.mixins import (ListModelMixin, CreateModelMixin, RetrieveModelMixin, UpdateModelMixin,DestroyModelMixin, ListModelMixin
)class UserView(CreateModelMixin,RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin,ListModelMixin,GenericViewSet):# 认证、权限、限流等queryset = models.UserInfo.objects.filter(status=True)serializer_class = 序列化类
在这个5个类中已帮我们写好了 list
、create
、retrieve
、update
、partial_update
、destory
方法,我们只需要在根据写 类变量:queryset、serializer_class即可。
示例1:
# urls.pyfrom django.urls import path
from app01 import viewsurlpatterns = [path('api/users/', views.UserView.as_view({"get": "list"})),path('api/users/<int:pk>/', views.UserView.as_view({"get": "retrieve"})),
]
# views.pyfrom rest_framework import serializers
from rest_framework.viewsets import GenericViewSet
from rest_framework import mixins
from app01 import modelsclass UserModelSerializer(serializers.ModelSerializer):level_text = serializers.CharField(source="get_level_display",read_only=True)extra = serializers.SerializerMethodField(read_only=True)class Meta:model = models.UserInfofields = ["username", "age", "email", "level_text", "extra"]def get_extra(self, obj):return 666class UserView(mixins.ListModelMixin, mixins.RetrieveModelMixin, GenericViewSet):queryset = models.UserInfo.objects.all()serializer_class = UserModelSerializer
示例2:
# urls.pyfrom django.urls import path
from app01 import viewsurlpatterns = [path('api/users/', views.UserView.as_view({"get": "list", "post": "create"})),path('api/users/<int:pk>/', views.UserView.as_view({"get": "retrieve"})),
]
# views.pyfrom rest_framework import serializers
from rest_framework.viewsets import GenericViewSet
from rest_framework import mixins
from app01 import modelsclass UserModelSerializer(serializers.ModelSerializer):level_text = serializers.CharField(source="get_level_display",read_only=True)extra = serializers.SerializerMethodField(read_only=True)class Meta:model = models.UserInfofields = ["username", "age", "email", "level_text", "extra"]def get_extra(self, obj):return 666class UserView(mixins.ListModelMixin, mixins.RetrieveModelMixin, mixins.CreateModelMixin, GenericViewSet):queryset = models.UserInfo.objects.all()serializer_class = UserModelSerializerdef perform_create(self, serializer):""" 序列化:对请求的数据校验成功后,执行保存。"""serializer.save(depart_id=1, password="123")
示例3:
# urls.pyfrom django.urls import path
from app01 import viewsurlpatterns = [path('api/users/', views.UserView.as_view({"get": "list", "post": "create"})),path('api/users/<int:pk>/', views.UserView.as_view({"get": "retrieve", "put": "update", "patch": "partial_update", "delete": "destroy"})),
]
# views.pyfrom rest_framework import serializers
from rest_framework.viewsets import GenericViewSet
from rest_framework import mixins
from app01 import modelsclass UserModelSerializer(serializers.ModelSerializer):level_text = serializers.CharField(source="get_level_display",read_only=True)extra = serializers.SerializerMethodField(read_only=True)class Meta:model = models.UserInfofields = ["username", "age", "email", "level_text", "extra"]def get_extra(self, obj):return 666class UserView(mixins.ListModelMixin,mixins.RetrieveModelMixin,mixins.CreateModelMixin,mixins.UpdateModelMixin,mixins.DestroyModelMixin,GenericViewSet):queryset = models.UserInfo.objects.all()serializer_class = UserModelSerializerdef perform_create(self, serializer):""" 序列化:对请求的数据校验成功后,执行保存。"""serializer.save(depart_id=1, password="123")def perform_update(self, serializer):serializer.save()def perform_destroy(self, instance):instance.delete()
示例4:
# urls.pyfrom django.urls import path
from app01 import viewsurlpatterns = [path('api/users/', views.UserView.as_view({"get": "list", "post": "create"})),path('api/users/<int:pk>/', views.UserView.as_view({"get": "retrieve", "put": "update", "patch": "partial_update", "delete": "destroy"})),
]
# views.py
from rest_framework import serializers
from rest_framework.viewsets import ModelViewSet
from app01 import modelsclass UserModelSerializer(serializers.ModelSerializer):level_text = serializers.CharField(source="get_level_display",read_only=True)extra = serializers.SerializerMethodField(read_only=True)class Meta:model = models.UserInfofields = ["username", "age", "email", "level_text", "extra"]def get_extra(self, obj):return 666class UserView(ModelViewSet):queryset = models.UserInfo.objects.all()serializer_class = UserModelSerializerdef perform_create(self, serializer):""" 序列化:对请求的数据校验成功后,执行保存。"""serializer.save(depart_id=1, password="123")
在开发过程中使用 五大类
或 ModelViewSet
是比较常见的,并且如果他们内部的某些功能不够用,还可以进行重新某些方法进行扩展。
问题:drf中提供了这么多视图,以后那个用的比较多?
-
接口与数据库操作无关,直接继承APIView
-
接口背后需要对数据库进行操作,一般:
ModelViewSet
或CreateModelMixin、ListModelMixin...
- 利用钩子自定义功能。 - 重写某个写方法,实现更加完善的功能。
-
根据自己公司的习惯,自定义 :
ModelViewSet
或CreateModelMixin、ListModelMixin...
补充:权限
在之前定义权限类时,类中可以定义两个方法:has_permission
和 has_object_permission
has_permission
,在请求进入视图之前就会执行。has_object_permission
,当视图中调用self.get_object
时就会被调用(删除、更新、查看某个对象时都会调用),一般用于检查对某个对象是否具有权限进行操作。
class PermissionA(BasePermission):message = {"code": 1003, 'data': "无权访问"}def has_permission(self, request, view):exists = request.user.roles.filter(title="员工").exists()if exists:return Truereturn Falsedef has_object_permission(self, request, view, obj):return True
所以,让我们在编写视图类时,如果是直接获取间接继承了GenericAPIView
,同时内部调用 get_object
方法,这样在权限中通过 has_object_permission
就可以进行权限的处理。
1.5 源码分析
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