"""
views：视图
generics：工具视图
mixins：视图工具集
viewsets：视图集
"""
"""
学习曲线
APIView => GenericAPIView => mixins的五大工具类 => generics中的工具视图 => viewsets中的视图集
"""
一、GenericAPIView基类
GenericAPIView是继承APIView的，使用完全兼容APIView
重点：GenericAPIView在APIView基础上完成了哪些事
1）get_queryset()：从类属性queryset中获得model的queryset数据
2）get_object()：从类属性queryset中获得model的queryset数据，再通过有名分组pk确定唯一操作对象
3）get_serializer()：从类属性serializer_class中获得serializer的序列化类
路由层：urls.py
urlpatterns = [
url(r'^v2/books/$', views.BookGenericAPIView.as_view()),
url(r'^v2/books/(?P<pk>.*)/$', views.BookGenericAPIView.as_view()),
]
视图层：views.py
from rest_framework.generics import GenericAPIView
class BookGenericAPIView(GenericAPIView):
queryset = models.Book.objects.filter(is_delete=False)
serializer_class = serializers.BookModelSerializer
# 自定义主键的 有名分组 名
lookup_field = 'pk'
# 群取
# def get(self, request, *args, **kwargs):
# book_query = self.get_queryset()
# book_ser = self.get_serializer(book_query, many=True)
# book_data = book_ser.data
# return APIResponse(results=book_data)
# 单取
def get(self, request, *args, **kwargs):
book_query = self.get_object()
book_ser = self.get_serializer(book_query)
book_data = book_ser.data
return APIResponse(results=book_data)
二、mixins视图工具集 - 辅助GenericAPIView
1）mixins有五个工具类文件，一共提供了五个工具类，六个工具方法：单查、群查、单增、单删、单整体改、单局部改
2）继承工具类可以简化请求函数的实现体，但是必须继承GenericAPIView，需要GenericAPIView类提供的几个类属性和方法(见上方GenericAPIView基类知识点)
3）工具类的工具方法返回值都是Response类型对象，如果要格式化数据格式再返回给前台，可以通过 response.data 拿到工具方法返回的Response类型对象的响应数据
路由层：urls.py
urlpatterns = [
url(r'^v3/books/$', views.BookMixinGenericAPIView.as_view()),
url(r'^v3/books/(?P<pk>.*)/$', views.BookMixinGenericAPIView.as_view()),
]
视图层：views.py
from rest_framework.mixins import ListModelMixin, CreateModelMixin, RetrieveModelMixin, UpdateModelMixin
class BookMixinGenericAPIView(ListModelMixin, CreateModelMixin, RetrieveModelMixin, UpdateModelMixin, GenericAPIView):
queryset = models.Book.objects.filter(is_delete=False)
serializer_class = serializers.BookModelSerializer
def get(self, request, *args, **kwargs):
if 'pk' in kwargs:
response = self.retrieve(request, *args, **kwargs)
else:
# mixins提供的list方法的响应对象是Response，想将该对象格式化为APIResponse
response = self.list(request, *args, **kwargs)
# response的数据都存放在response.data中
return APIResponse(results=response.data)
def post(self, request, *args, **kwargs):
response = self.create(request, *args, **kwargs)
return APIResponse(results=response.data)
def put(self, request, *args, **kwargs):
response = self.update(request, *args, **kwargs)
return APIResponse(results=response.data)
def patch(self, request, *args, **kwargs):
response = self.partial_update(request, *args, **kwargs)
return APIResponse(results=response.data)
三、工具视图
1）工具视图都是GenericAPIView的子类，且不同的子类继承了不听的工具类，重写了请求方法
2）工具视图的功能如果直接可以满足需求，只需要继承工具视图，提供queryset与serializer_class即可
路由层：urls.py
urlpatterns = [
url(r'^v4/books/$', views.BookListCreatePIView.as_view()),
url(r'^v4/books/(?P<pk>.*)/$', views.BookListCreatePIView.as_view()),
]
视图层：views.py
from rest_framework.generics import ListCreateAPIView, UpdateAPIView
class BookListCreatePIView(ListCreateAPIView, UpdateAPIView):
queryset = models.Book.objects.filter(is_delete=False)
serializer_class = serializers.BookModelSerializer
四、视图集
1）视图集都是优先继承ViewSetMixin类，再继承一个视图类（GenericAPIView或APIView）
GenericViewSet、ViewSet
2）ViewSetMixin提供了重写的as_view()方法，继承视图集的视图类，配置路由时调用as_view()必须传入 请求名-函数名 映射关系字典
eg: url(r'^v5/books/$', views.BookGenericViewSet.as_view({'get': 'my_get_list'})),
表示get请求会交给my_get_list视图函数处理
路由层：urls.py
urlpatterns = [
# View的as_view()：将get请求映射到视图类的get方法
# ViewSet的as_view({'get': 'my_get_list'})：将get请求映射到视图类的my_get_list方法
url(r'^v5/books/$', views.BookGenericViewSet.as_view({'get': 'my_get_list'})),
url(r'^v5/books/(?P<pk>.*)/$', views.BookGenericViewSet.as_view({'get': 'my_get_obj'})),
]
视图层：views.py
from rest_framework.viewsets import GenericViewSet
from rest_framework import mixins
class BookGenericViewSet(mixins.RetrieveModelMixin, mixins.ListModelMixin, GenericViewSet):
queryset = models.Book.objects.filter(is_delete=False)
serializer_class = serializers.BookModelSerializer
def my_get_list(self, request, *args, **kwargs):
return self.list(request, *args, **kwargs)
def my_get_obj(self, request, *args, **kwargs):
return self.retrieve(request, *args, **kwargs)
五、工具视图集
路由层：urls.py
urlpatterns = [
url(r'^v6/books/$', views.BookModelViewSet.as_view({'get': 'list', 'post': 'create'})),
url(r'^v6/books/(?P<pk>.*)/$', views.BookModelViewSet.as_view({'get': 'retrieve', 'put': 'update', 'patch': 'partial_update', 'delete': 'destroy'})),
]
视图层：views.py
from rest_framework.viewsets import ModelViewSet
class BookModelViewSet(ModelViewSet):
queryset = models.Book.objects.filter(is_delete=False)
serializer_class = serializers.BookModelSerializer
# 删不是数据库，而是该记录中的删除字段
def destroy(self, request, *args, **kwargs):
instance = self.get_object() # type: models.Book
if not instance:
return APIResponse(1, '删除失败') # 实际操作，在此之前就做了判断
instance.is_delete = True
instance.save()
return APIResponse(0, '删除成功')
GenericAPIView 与 APIView 最为两大继承视图的区别
1）GenericViewSet和ViewSet都继承了ViewSetMixin，as_view都可以配置 请求-函数 映射
2）GenericViewSet继承的是GenericAPIView视图类，用来完成标准的 model 类操作接口
3）ViewSet继承的是APIView视图类，用来完成不需要 model 类参与，或是非标准的 model 类操作接口
post请求在标准的 model 类操作下就是新增接口，登陆的post不满足
post请求验证码的接口，不需要 model 类的参与
案例：登陆的post请求，并不是完成数据的新增，只是用post提交数据，得到的结果也不是登陆的用户信息，而是登陆的认证信息
路由组件（了解）
路由层：urls.py
from django.conf.urls import include
from rest_framework.routers import SimpleRouter
router = SimpleRouter()
# 所有路由与ViewSet视图类的都可以注册，会产生 '^v6/books/$' 和 '^v6/books/(?P<pk>[^/.]+)/$'
router.register('v6/books', views.BookModelViewSet)
urlpatterns = [
# 第一种添加子列表方式
url(r'^', include(router.urls)),
]
# 第二种添加子列表方式
# urlpatterns.extend(router.urls)