DRF的View类视图

1.准备工作

2.APIView的使用

3.使用generics生成类视图

4.使用ViewSet生成类视图

1.准备工作

(1).做一个简单的model类

在models.py中制作一个很简单的一个图书模型类,有书名,作者和价钱

from django.db import models# Create your models here.
class Book(models.Model):name = models.CharField(max_length=12, verbose_name="书名")author = models.CharField(max_length=24, verbose_name="作者")price = models.FloatField(default=0, verbose_name="价格")create_date = models.DateField(verbose_name="创建时间", auto_now_add=True)update_date = models.DateField(verbose_name="更新时间", auto_now=True)

(2).做一个序列化器

新建一个serializer.py文件,直接使用ModelSerializer制作一个序列化器

from rest_framework.serializers import ModelSerializer
from .models import Bookclass BookSerializer(ModelSerializer):class Meta:model = Bookfields = '__all__'def create(self, validated_data):Book.objects.create(**validated_data)return validated_datadef update(self, instance, validated_data):instance["name"] = validated_data.get("name")instance["author"] = validated_data.get("author")instance["price"] = validated_data.get("price")instance.save()return instance

(3).准备

修改seting.py的数据库配置,生成迁移文件,然后开始view视图的编写

2.APIView的使用

通过APIView生成单查(一般详情页),群查(一般列表页)接口,还有增删改三个接口

from rest_framework.views import APIView
from .serializers import BookSerializer
from .models import Book
from rest_framework.response import Responseclass BookView(APIView):def get(self, request, pk=None):if pk:book = Book.objects.filter(pk=pk)else:book = Book.objects.all()ser = BookSerializer(instance=book, many=True)return Response(ser.data)def post(self, request):data = request.dataser = BookSerializer(data=data)ser.is_valid(raise_exception=True)ser.save()return Response({"msg": "ok", "data": data})def put(self, request, pk=None):data = request.databook = Book.objects.get(pk=pk)bs = BookSerializer(instance=book, data=data)bs.is_valid(raise_exception=True)bs.save()return Response({"msg": "ok"})def delete(self, request, pk):Book.objects.get(pk=pk).delete()return Response({"msg": "ok"})

3.使用generics生成类视图

上面通过APIView生成了一个具有增删改,单查,群查的功能的类视图,可以看到有很多代码都是重复代码,所以这个时候generics的类视图就出现了,可以简化开发过程

from rest_framework.generics import ListAPIView, DestroyAPIView, UpdateAPIView, CreateAPIViewclass BookView(ListAPIView, DestroyAPIView, UpdateAPIView, CreateAPIView):queryset = Book.objects.all()serializer_class = BookSerializer

只需要4行代码就可以完成增删改查的操作,因为ListAPIView和RetrieveAPIView是同时封装的get方法,所以正常情况下没有办法同时调用,这个时候需要我们可以重写get_queryset方法,实现对ListAPIView和RetrieveAPIView同时调用

class BookView(ListAPIView, DestroyAPIView, UpdateAPIView, CreateAPIView, RetrieveAPIView):queryset = Book.objects.all()serializer_class = BookSerializerdef get_queryset(self):pk = self.kwargs.get("pk")queryset = self.querysetif pk:queryset = Book.objects.filter(pk=pk)if isinstance(queryset, QuerySet):queryset = queryset.all()return queryset

4.使用ViewSet生成类视图

因为上面的两个视图,单查和群查都是get请求,写的会比较乱,所以ViewSET出现解决了这个问题,首先修改一下视图类,如下图,我们把单查单独做成了一个函数

from rest_framework.viewsets import ViewSet
from rest_framework.response import Responseclass BookView(ViewSet):def list(self, request):book = Book.objects.all()ser = BookSerializer(instance=book, many=True)return Response(ser.data)def retrieve(self, request, pk):book = Book.objects.filter(pk=pk)ser = BookSerializer(instance=book, many=True)return Response(ser.data)def create(self, request):data = request.dataser = BookSerializer(data=data)ser.is_valid(raise_exception=True)ser.save()return Response({"msg": "ok", "data": data})def update(self, request, pk):data = request.databook = Book.objects.get(pk=pk)bs = BookSerializer(instance=book, data=data)bs.is_valid(raise_exception=True)bs.save()return Response({"msg": "ok"})def destroy(self, request, pk):Book.objects.get(pk=pk).delete()return Response({"msg": "ok"})

光修改视图还是不够的,还需要修改一下路由

from django.urls import path, re_path
from .views import BookViewurlpatterns = [path("BookView/", BookView.as_view({"get": "list", "post": "create"})),re_path(r"BookView/(?P<pk>\d+)", BookView.as_view({"get": "retrieve", "put": "update", "delete": "destroy"}))
]

上面既然可以把单查单独做成一个函数了,所以我们就可以直接通过继承来完成所有的功能,甚至都不需要重写什么东西

class BookView(ModelViewSet):queryset = Book.objects.all()serializer_class = BookSerializer

顺便可以通过drf提供的路由,对urls.py进行一个简化

from .views import BookView
from rest_framework import routersrouter = routers.SimpleRouter()
router.register(r"BookView", BookView)urlpatterns = []
urlpatterns += router.urls