DRF 视图组件

DRF框架提供了很多通用的视图基类与扩展类，上篇使用的APIView是比较偏Base的，视图的使用更加简化了代码，这里介绍一下其他视图的用法

Django REST framwork 提供的视图的主要作用：

控制序列化器的执行（检验、保存、转换数据）
控制数据库查询的执行

先来看看这其中的人情世故：两个视图基本类，五个扩展类，九个视图子类，视图集方法，视图集··

视图组件大纲

两个视图基本类

导入：

from rest_framework.views import APIView

from rest_framework.generics import GenericAPIView

APIView：DRF最顶层视图类
GenericAPIView：DRF通用视图类

五个扩展类

扩展类不是视图类，没有集成APIView，需要配合GenericAPIView使用，因为五个扩展类的实现需要调用GenericAPIView提供的序列化器与数据库查询的方法

主要是用来对数据进行增删改查

导入

from rest_framework.mixins import CreateModelMixin,ListModelMixin,DestroyModelMixin,RetrieveModelMixin,UpdateModelMixin

CreateModelMixin
ListModelMixin
DestroyModelMixin
RetrieveModelMixin
UpdateModelMixin

九个子类视图

导入

from rest_framework.generics import  CreateAPIView,ListAPIView,DestroyAPIView,RetrieveAPIView,UpdateAPIView,ListCreateAPIView,RetrieveUpdateAPIView,RetrieveUpdateDestroyAPIView,RetrieveDestroyAPIView

视图子类其实可以理解为GenericAPIView通用视图类和Mixin扩展类的排列组合组成的，底层事通过封装和继承来写

CreateAPIView

提供 post 方法

继承自： GenericAPIView、CreateModelMixin

ListAPIView

提供 get 方法

继承自：GenericAPIView、ListModelMixin

DestroyAPIView

提供 delete 方法

继承自：GenericAPIView、DestoryModelMixin

RetrieveAPIView

提供 get 方法

继承自: GenericAPIView、RetrieveModelMixin

UpdateAPIView

提供 put 和 patch 方法

继承自：GenericAPIView、UpdateModelMixin

ListCreateAPIView

提供get 和 post方法

继承自：ListModelMixin、CreateModelMixin、GenericAPIView

RetrieveUpdateAPIView

提供 get、put、patch方法

继承自： GenericAPIView、RetrieveModelMixin、UpdateModelMixin

RetrieveDestroyAPIView

提供：get、delete方法

继承自：RetrieveModelMixin、DestroyModelMixin、GenericAPIView

RetrieveUpdateDestroyAPIView

提供 get、put、patch、delete方法

继承自：GenericAPIView、RetrieveModelMixin、UpdateModelMixin、DestoryModelMixin

视图集

导入

from rest_framework.viewsets import ModelViewSet,ReadOnlyModelViewSet,ViewSet,GenericViewSet,ViewSetMixin

常用视图集父类

ModelViewSet：继承自GenericViewSet，同时包括了ListModelMixin、RetrieveModelMixin、CreateModelMixin、UpdateModelMixin、DestoryModelMixin。
ReadOnlyModelViewSet：继承自GenericViewSet，同时包括了ListModelMixin、RetrieveModelMixin。
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（{'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。
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。

魔法类

ViewSetMixin：控制自动生成路由

一览表

DRF中视图的“七十二变”

第一层是继承APIView写，第二层基于基于GenericAPIView写，第三层基于GenericAPIView+五个扩展类写，第四层通过九个视图子类来写，第五层是通过ViewSet写

ps：第几层是我意淫出来的词不要介意~，一层更比一层牛，欲练此功必先自宫！！！

第一层：基于APIview的五个接口

class BookView(APIView):

    def get(self, requets):

        # 序列化

        book_list = models.Book.objects.all()

        # 序列化多条数据many=True

        ser = serializer.BookSerializer(instance=book_list, many=True)

        return Response(ser.data)

    def post(self, request):

        # 获取反序列化数据

        ser = serializer.BookSerializer(data=request.data)

        if ser.is_valid():

            # 校验通过存入数据库，不需要重写create方法了

            ser.save()

            return Response({'code': 100, 'msg': '新增成功', 'data': ser.data})

        # 校验失败

        return Response({'code': 101, 'msg': '校验未通过', 'error': ser.errors})

class BookViewDetail(APIView):

    def get(self, request, pk):

        book = models.Book.objects.filter(pk=pk).first()

        ser = serializer.BookSerializer(instance=book)

        return Response(ser.data)

    def put(self, request, pk):

        book = models.Book.objects.filter(pk=pk).first()

        # 修改，instance和data都要传

        ser = serializer.BookSerializer(instance=book, data=request.data)

        if ser.is_valid():

            # 校验通过修改，不需要重写update

            ser.save()

            return Response({'code:': 100, 'msg': '修改成功', 'data': ser.data})

        # 校验不通过

        return Response({'code:': 102, 'msg': '校验未通过，修改失败', 'error': ser.errors})

    def delete(self, request, pk):

        models.Book.objects.filter(pk=pk).delete()

        return Response({'code': 100, 'msg': '删除成功'})

第一层五个接口demo

ModelSerializer序列化器实战 - HammerZe - 博客园 (cnblogs.com)

第二层：基于GenericAPIView的五个接口

常用类属性：

-GenericAPIView   继承了APIView，封装了一些属性和方法，跟数据库打交道

  	-queryset = None # 指定序列化集

    -serializer_class = None  # 指定序列化类

    -lookup_field = 'pk'  # 查询单条，分组分出来的参数，转换器对象参数的名字

    -filter_backends   # 过滤排序功能会用它

    -pagination_class  # 分页功能

    -get_queryset()  # 获取要序列化的数据,后期可能会重写

    -get_object()    # 通过lookup_field查询的

    -get_serializer()  # 使用它序列化

    -get_serializer_class() # 返回序列化类 ，后期可能重写

demo：

# 指定序列化集

queryset = models.Book.objects.all()

# 指定序列化类

serializer_class = serializer.BookSerializer

第二层五个接口demo

from rest_framework.response import Response

from app01 import models

from app01 import serializer

from rest_framework.generics import GenericAPIView

# 书视图类

class BookView(GenericAPIView):

    # 指定序列化集

    queryset = models.Book.objects.all()

    # 指定序列化类

    serializer_class = serializer.BookSerializer

    def get(self, requets):

        # obj = self.queryset()

        obj = self.get_queryset() # 等同于上面

        # ser = self.get_serializer_class()(instance=obj,many=True)

        ser = self.get_serializer(instance=obj,many=True) # 等同于上面

        return Response(ser.data)

    def post(self, request):

        # 获取反序列化数据

        # ser = serializer.BookSerializer(data=request.data)

        ser = self.get_serializer(data = request.data)

        if ser.is_valid():

            # 校验通过存入数据库，不需要重写create方法了

            ser.save()

            return Response({'code': 100, 'msg': '新增成功', 'data': ser.data})

        # 校验失败

        return Response({'code': 101, 'msg': '校验未通过', 'error': ser.errors})

class BookViewDetail(GenericAPIView):

    # 指定序列化集

    queryset = models.Book.objects.all()

    # 指定序列化类

    serializer_class = serializer.BookSerializer

    def get(self, request, pk):

        # book = models.Book.objects.filter(pk=pk).first()

        book = self.get_object() # 根据pk拿到单个对象

        # ser = serializer.BookSerializer(instance=book)

        ser = self.get_serializer(instance=book)

        return Response(ser.data)

    def put(self, request, pk):

        # book = models.Book.objects.filter(pk=pk).first()

        book = self.get_object()

        # 修改，instance和data都要传

        # ser = serializer.BookSerializer(instance=book, data=request.data)

        ser = self.get_serializer(instance=book,data=request.data)

        if ser.is_valid():

            # 校验通过修改，不需要重写update

            ser.save()

            return Response({'code:': 100, 'msg': '修改成功', 'data': ser.data})

        # 校验不通过

        return Response({'code:': 102, 'msg': '校验未通过，修改失败', 'error': ser.errors})

    def delete(self, request, pk):

        # models.Book.objects.filter(pk=pk).delete()

        self.get_object().delete()

        return Response({'code': 100, 'msg': '删除成功'})

路由

path('books/', views.BookView.as_view()),

path('books/<int:pk>', views.BookViewDetail.as_view())

总结：到第二层只需修改queryset和serializer_class类属性即可，其余都不需要修改

注意：虽然pk没有在orm语句中过滤使用，但是路由分组要用，所以不能删，或者写成*args **kwargs接收多余的参数，且路由转换器必须写成pk

# 源码

lookup_field = 'pk'

lookup_url_kwarg = None

get_queryset()方法可以重写，如果我们需要在一个视图类内操作另外表模型，来指定序列化的数据

class BookViewDetail(GenericAPIView):

    queryset = models.Book.objects.all()

    ···

    '''

    指定序列化数据的格式：

    self.queryset()

    self.get_queryset() # 等同于上面

    queryset = models.Book.objects.all()

    '''

	# 可以重写get_queryset方法在book视图类里操作作者模型

    def get_queryset(self,request):

        if self.request.path == '/user'

        return Author.objects.all()

    ···

    # 这样序列化的数据就不一样了，根据不同的条件序列化不同的数据

    '''当然还可以通过重写get_serializer_class来返回其他序列化器类'''

第三层：基于GenericAPIView+五个视图扩展类写

五个视图扩展类：from rest_framework.mixins import CreateModelMixin,ListModelMixin,DestroyModelMixin,RetrieveModelMixin,UpdateModelMixin

通过GenericAPIView+视图扩展类来使得代码更简单，一个接口对应一个扩展类，注意扩展类不是视图类

ListModelMixin：获取所有API，对应list()方法
CreateModelMixin：新增一条API，对应create()方法
UpdateModelMixin：修改一条API，对应update()方法
RetrieveModelMixin：获取一条API，对应retrieve()方法
DestroyModelMixin：删除一条API，对应destroy()方法

注意：CreateModelMixin扩展类提供了更高级的方法，可以通过重写来校验数据存入

    def perform_create(self, serializer):

        serializer.save()

第三层五个接口demo

from app01 import models

from app01 import serializer

from rest_framework.generics import GenericAPIView

from rest_framework.mixins import CreateModelMixin,ListModelMixin,DestroyModelMixin,RetrieveModelMixin,UpdateModelMixin

# 获取所有和新增API

class BookView(ListModelMixin,CreateModelMixin,GenericAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

    def get(self, request):

       return super().list(request)

    def post(self, request):

        return super().create(request)

# 获取删除修改单个API

class BookViewDetail(UpdateModelMixin,RetrieveModelMixin,DestroyModelMixin,GenericAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

    def get(self, request, *args,**kwargs):

        return super().retrieve(request, *args,**kwargs)

    def put(self, request, *args,**kwargs):

        return super().update(request, *args,**kwargs)

    def delete(self, request, *args,**kwargs):

        return super().destroy(request, *args,**kwargs)

总结

通过进一次封装+继承代码也变得越来越少了

GenericAPIView速写五个接口demo

模型

from django.db import models

# Create your models here.

# build four model tables

class Book(models.Model):

    name = models.CharField(max_length=32)

    price = models.DecimalField(decimal_places=2, max_digits=5)

    publish = models.ForeignKey(to='Publish', on_delete=models.CASCADE)

    authors = models.ManyToManyField(to='Author')

    def __str__(self):

        return self.name

    # 自定制字段

    @property

    def publish_detail(self):

        return {'name': self.publish.name, 'addr': self.publish.city}

    @property

    def author_list(self):

        l = []

        print(self.authors.all()) # <QuerySet [<Author: Author object (1)>, <Author: Author object (2)>]>

        for author in self.authors.all():

            print(author.author_detail) # AuthorDetail object (1)

            l.append({'name': author.name, 'age': author.age, 'addr': author.author_detail.addr})

        return l

class Author(models.Model):

    name = models.CharField(max_length=32)

    age = models.IntegerField()

    author_detail = models.OneToOneField(to='AuthorDetail', on_delete=models.CASCADE)

    def __str__(self):

        return self.name

    @property

    def authordetail_info(self):

        return {'phone':self.author_detail.telephone,'addr':self.author_detail.addr}

class AuthorDetail(models.Model):

    telephone = models.BigIntegerField()

    addr = models.CharField(max_length=64)

class Publish(models.Model):

    name = models.CharField(max_length=32)

    city = models.CharField(max_length=32)

    email = models.EmailField()

序列化器

from django.db import models

# Create your models here.

# build four model tables

class Book(models.Model):

    name = models.CharField(max_length=32)

    price = models.DecimalField(decimal_places=2, max_digits=5)

    publish = models.ForeignKey(to='Publish', on_delete=models.CASCADE)

    authors = models.ManyToManyField(to='Author')

    def __str__(self):

        return self.name

    # 自定制字段

    @property

    def publish_detail(self):

        return {'name': self.publish.name, 'addr': self.publish.city}

    @property

    def author_list(self):

        l = []

        print(self.authors.all()) # <QuerySet [<Author: Author object (1)>, <Author: Author object (2)>]>

        for author in self.authors.all():

            print(author.author_detail) # AuthorDetail object (1)

            l.append({'name': author.name, 'age': author.age, 'addr': author.author_detail.addr})

        return l

class Author(models.Model):

    name = models.CharField(max_length=32)

    age = models.IntegerField()

    author_detail = models.OneToOneField(to='AuthorDetail', on_delete=models.CASCADE)

    def __str__(self):

        return self.name

    @property

    def authordetail_info(self):

        return {'phone':self.author_detail.telephone,'addr':self.author_detail.addr}

class AuthorDetail(models.Model):

    telephone = models.BigIntegerField()

    addr = models.CharField(max_length=64)

class Publish(models.Model):

    name = models.CharField(max_length=32)

    city = models.CharField(max_length=32)

    email = models.EmailField()

视图

from rest_framework.generics import GenericAPIView

from rest_framework.mixins import ListModelMixin, CreateModelMixin, DestroyModelMixin, RetrieveModelMixin, \

    UpdateModelMixin

from app01 import models

from app01 import serializer

# 书视图类

class BookView(ListModelMixin, CreateModelMixin, GenericAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

    def get(self, request):

        return super().list(request)

    def post(self, request):

        return super().create(request)

class BookViewDetail(RetrieveModelMixin, DestroyModelMixin, UpdateModelMixin, GenericAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

    def get(self, request, *args, **kwargs):

        return super().retrieve(request, *args, **kwargs)

    def put(self, request, *args, **kwargs):

        return super().update(request, *args, **kwargs)

    def delete(self, request, *args, **kwargs):

        return super().destroy(request, *args, **kwargs)

# 作者

class AuthorView(ListModelMixin, CreateModelMixin, GenericAPIView):

    queryset = models.Author.objects.all()

    serializer_class = serializer.AuthorSerializer

    def get(self, request):

        return super().list(request)

    def post(self, request):

        return super().create(request)

class AuthorViewDetail(RetrieveModelMixin, DestroyModelMixin, UpdateModelMixin, GenericAPIView):

    queryset = models.Author.objects.all()

    serializer_class = serializer.AuthorSerializer

    def get(self, request, *args, **kwargs):

        return super().retrieve(request, *args, **kwargs)

    def put(self, request, *args, **kwargs):

        return super().update(request, *args, **kwargs)

    def delete(self, request, *args, **kwargs):

        return super().destroy(request, *args, **kwargs)

# 作者详情

class AuthorDetailView(ListModelMixin, CreateModelMixin, GenericAPIView):

    queryset = models.AuthorDetail.objects.all()

    serializer_class = serializer.AuthorDetailSerializer

    def get(self, request):

        return super().list(request)

    def post(self, request):

        return super().create(request)

class OneAuthorViewDetail(RetrieveModelMixin, DestroyModelMixin, UpdateModelMixin, GenericAPIView):

    queryset = models.AuthorDetail.objects.all()

    serializer_class = serializer.AuthorDetailSerializer

    def get(self, request, *args, **kwargs):

        return super().retrieve(request, *args, **kwargs)

    def put(self, request, *args, **kwargs):

        return super().update(request, *args, **kwargs)

    def delete(self, request, *args, **kwargs):

        return super().destroy(request, *args, **kwargs)

# 出版社

class PublishView(ListModelMixin, CreateModelMixin, GenericAPIView):

    queryset = models.Publish.objects.all()

    serializer_class = serializer.PublishSerializer

    def get(self, request):

        return super().list(request)

    def post(self, request):

        return super().create(request)

class PublishViewDetail(RetrieveModelMixin, DestroyModelMixin, UpdateModelMixin, GenericAPIView):

    queryset = models.Publish.objects.all()

    serializer_class = serializer.PublishSerializer

    def get(self, request, *args, **kwargs):

        return super().retrieve(request, *args, **kwargs)

    def put(self, request, *args, **kwargs):

        return super().update(request, *args, **kwargs)

    def delete(self, request, *args, **kwargs):

        return super().destroy(request, *args, **kwargs)

路由

from django.contrib import admin

from django.urls import path

from app01 import views

urlpatterns = [

    path('admin/', admin.site.urls),

    # 书

    path('books/', views.BookView.as_view()),

    path('books/<int:pk>', views.BookViewDetail.as_view()),

    # 作者

    path('authors/', views.AuthorView.as_view()),

    path('authors/<int:pk>', views.AuthorViewDetail.as_view()),

    # 作者详情

    path('authorsdetail/', views.AuthorDetailView.as_view()),

    path('authorsdetail/<int:pk>', views.OneAuthorViewDetail.as_view()),

    # 出版社

    path('publish/', views.PublishView.as_view()),

    path('publish/<int:pk>', views.PublishViewDetail.as_view()),

]

Postman以及测完，请放心使用~

第四层：GenericAPIView+九个视图子类写五个接口

导入视图子类：from rest_framework.generics import CreateAPIView,ListAPIView,DestroyAPIView,RetrieveAPIView,UpdateAPIView,ListCreateAPIView,RetrieveUpdateAPIView,RetrieveUpdateDestroyAPIView,RetrieveDestroyAPIView

使用哪个继承哪个就可以了，具体可以看继承的父类里有什么方法不需要刻意去记

from rest_framework.generics import  CreateAPIView,ListAPIView,DestroyAPIView,RetrieveAPIView,UpdateAPIView,ListCreateAPIView,RetrieveUpdateAPIView,RetrieveUpdateDestroyAPIView,RetrieveDestroyAPIView

# 1、查询所有,新增API

class BookView(ListCreateAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

# 2、新增接口

class BookView(CreateAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

# 3、查询接口

class BookView(ListAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

# 4、查询单个，修改一个，删除一个接口

class BookViewDetail(RetrieveUpdateDestroyAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

# 5、查询单个接口

class BookViewDetail(RetrieveAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

# 6、修改单个接口

class BookViewDetail(UpdateAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

# 7、删除单个接口

class BookViewDetail(DestroyAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

# 8、查询单个、修改接口

class BookViewDetail(RetrieveUpdateAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

# 9、查询单个、删除接口

class BookViewDetail(RetrieveDestroyAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

'''上述共九个视图子类，九九归一剑诀~'''

# 更新和删除接口自己整合

class BookViewDetail(UpdateAPIView,DestroyAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

第四层快速写五个接口demo

from rest_framework.generics import ListCreateAPIView, RetrieveUpdateDestroyAPIView

from app01 import models

from app01 import serializer

class BookView(ListCreateAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

class BookViewDetail(RetrieveUpdateDestroyAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

'''其余的和第三层一样'''

第五层：基于ViewSet写五个接口

视图集导入：from rest_framework.viewsets import ModelViewSet,ReadOnlyModelViewSet,ViewSet,GenericViewSet,ViewSetMixin

路由导入：from rest_framework.routers import SimpleRouter,DefaultRouter

基于ViewSet视图集写，需要我们配置路由

方法一

from django.urls import path, include

from rest_framework.routers import SimpleRouter

from app01 import views

router = SimpleRouter()

router.register('books', views.BookView, 'books')

urlpatterns = [

    ...

]

urlpatterns += router.urls

'''

register(self, prefix, viewset, basename=None)

prefix：路由url前缀

viewset：处理请求的viewset类

basename：路由名称的前缀，一般和prefix写成一样就行

'''

# 等同于

path('books/'),include(router.urls)

path('books/<int:pk>'),include(router.urls)

方法二

router = SimpleRouter()

router.register('books', views.BookView, 'books')

urlpatterns = [

    ...

    url(r'^', include(router.urls))

]

# 生成两种路由

path('/api/v1'),include(router.urls)

# [<URLPattern '^books/$' [name='books-list']>, <URLPattern '^books/(?P<pk>[^/.]+)/$' [name='books-detail']>]

# 等同于自己配的

path('/api/v1/books/'),include(router.urls)

path('/api/v1/books/<int:pk>'),include(router.urls)

异同：

同：方法一和方法二都可以自动生成路由，代替了下面的路由

path('books/', views.BookView.as_view()),

path('books/<int:pk>', views.BookViewDetail.as_view()),

异：方法二可以拼接路径，如果不拼接是和方法一一样的

两种不同的路由

第五层基于ModelViewSet视图集写五个接口demo

views.py

from rest_framework.viewsets import ModelViewSet,ReadOnlyModelViewSet,ViewSet,GenericViewSet,ViewSetMixin

class BookView(ModelViewSet):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

urls.py

from django.contrib import admin

from django.urls import path, include

from rest_framework.routers import SimpleRouter

from app01 import views

router = SimpleRouter()

router.register('books', views.BookView, 'books')

urlpatterns = [

    path('admin/', admin.site.urls),

    path('api/v1/',include(router.urls)),

]

ps：剩下的都一样~

ReadOnlyModelViewSet视图集

继承该ReadOnlyModelViewSet视图集的作用是只读，只做查询，修改删除等操作不允许

from rest_framework.viewsets import ModelViewSet,ReadOnlyModelViewSet,ViewSet,GenericViewSet,ViewSetMixin

class BookView(ReadOnlyModelViewSet):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

两个视图集总结：

ModelViewSet可以写五个接口，而ReadOnlyModelViewSet只能写两个接口

本质

ModelViewSet继承了五个视图扩展类+GenericViewSet，GenericViewSet继承了ViewSetMixin+GenericAPIView

PS：ViewSetMixin控制了路由写法
ReadOnlyModelViewSet继承了RetrieveModelMixin+ListModelMixin+GenericViewSet

其他视图集

ViewSet

ViewSet = ViewSetMixin+APIView



class ViewSet(ViewSetMixin, views.APIView):

    """

    The base ViewSet class does not provide any actions by default.

    """

    pass

GenericViewSet

GenericViewSet = ViewSetMixin+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

ViewSetMixin

魔术视图类，控制自动生成路由，可以通过组合继承，以前的写法可以继续使用，但是如果要自动生成路由必须得继承ViewSetMixin及其子类；或者选择继承ViewSet、GenericViewSet

class ViewSetMixin:

    """

    This is the magic.

    Overrides `.as_view()` so that it takes an `actions` keyword that performs

    the binding of HTTP methods to actions on the Resource.

    For example, to create a concrete view binding the 'GET' and 'POST' methods

    to the 'list' and 'create' actions...

    view = MyViewSet.as_view({'get': 'list', 'post': 'create'})

    """

这就是魔法。  

重写' .as_view() '，以便它接受一个' actions '关键字执行

将HTTP方法绑定到资源上的动作。  

例如，创建绑定'GET'和'POST'方法的具体视图

到“列表”和“创建”动作…  

= MyViewSet视图。 As_view ({'get': 'list'， 'post': 'create'})

总结

第一层：基于APIView写视图，get、post、put、delete都需要自己写，序列化的数据和序列化类需要获取后指定

class BookView(APIView):

    def get(self, requets):

        book_list = models.Book.objects.all()

        ser = serializer.BookSerializer(instance=book_list, many=True)

        return Response(ser.data)

第二层：基于GenericAPIView写视图，优化了视图类内序列化数据和序列化类的代码冗余问题，通过queryset和serializer_class指定序列化集和序列化器即可，一个视图类内写一次即可，最后通过get_queryset和get_serializer方法处理

class BookView(GenericAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

    def get(self, requets):

        obj = self.get_queryset()

        ser = self.get_serializer(instance=obj,many=True)

        return Response(ser.data)

第三层：基于GenericAPIView+5个视图扩展类写视图，每个扩展类对应一个接口，更加细化，通过继承父类(扩展类)减少了代码的冗余

class BookView(ListModelMixin,CreateModelMixin,GenericAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

    def get(self, request):

       return super().list(request)

第四层，基于九个视图子类写，视图子类将扩展类和GenericAPIView封装到一块，使得我们要写的代码更少了，总之就是牛逼~
```
class BookView(ListCreateAPIView):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer
```

第五层，基于ViewSet写视图，这样以来5个接口就都在一个视图类内，代码更少了，但是可扩展性低了，路由也是问题，get所有和get一条路由冲突需要修改

class BookView(ModelViewSet):

    queryset = models.Book.objects.all()

    serializer_class = serializer.BookSerializer

'''路由'''

router = SimpleRouter()

router.register('books', views.BookView, 'books')

urlpatterns = [

    path('admin/', admin.site.urls),

    path('api/v1/',include(router.urls)),

]

累死，有错误请指正~感谢