1. GenericAPIView 使用
在使用GenericAPIView中，需要注意定义的属性，分别是：
- queryset 指定queryset
serializer_class 指定serializer
- pagination_class 指定分页类
filter_backends 指定过滤类
- lookup_field 查询单一数据库对象时使用的条件字段，默认为’pk’
- lookup_url_kwarg 查询单一数据时URL中的参数关键字名称，默认与look_field相同
1.1. url.py
from django.urls import re_path
from . import views
urlpatterns = [
re_path(r'^v1/book/$', views.BookAPIView.as_view()), # 继承APIView
re_path(r'^v2/book/$', views.BookGenericAPIView.as_view()),
re_path(r'v2/book/(?P<pk>.*)/$', views.BookGenericAPIView.as_view())
]
1.2. views.py
from rest_framework.generics import GenericAPIView
from rest_framework.views import APIView
from . import models, serializers
from utils.response import APIResponse
# Create your views here.
class BookAPIView(APIView):
def get(self, request, *args, **kwargs):
queryset = models.Book.objects.filter(is_active=True)
ser = serializers.BookModelSerializer(instance=queryset, many=True)
return APIResponse(results=ser.data)
"""
class GenericAPIView(views.APIView):
GenericAPIView 只继承 APIView ，在其内部实现了三个方法(其他内部方法是作为这三个方法的子方法使用)
1. 对多条数据 get_queryset
def get_queryset(self):
# 判断是否有 queryset 这个类属性 ,默认为空，在继承后，需要赋值
assert self.queryset is not None, (
"'%s' should either include a `queryset` attribute, "
"or override the `get_queryset()` method."
% self.__class__.__name__
)
# 类型判断，如果通过返回 queryset.all()
queryset = self.queryset
if isinstance(queryset, QuerySet):
# Ensure queryset is re-evaluated on each request.
queryset = queryset.all()
return queryset
2. get_object() # 对单独数据
def get_object(self):
# 过滤queryset
queryset = self.filter_queryset(self.get_queryset())
# Perform the lookup filtering.
lookup_url_kwarg = self.lookup_url_kwarg or self.lookup_field
assert lookup_url_kwarg in self.kwargs, (
'Expected view %s to be called with a URL keyword argument '
'named "%s". Fix your URL conf, or set the `.lookup_field` '
'attribute on the view correctly.' %
(self.__class__.__name__, lookup_url_kwarg)
)
filter_kwargs = {self.lookup_field: self.kwargs[lookup_url_kwarg]}
obj = get_object_or_404(queryset, **filter_kwargs)
# May raise a permission denied
self.check_object_permissions(self.request, obj)
return obj
3. get_serializer()
# 返回 serializer_class(*args, **kwargs)
def get_serializer(self, *args, **kwargs):
serializer_class = self.get_serializer_class()
kwargs['context'] = self.get_serializer_context()
return serializer_class(*args, **kwargs)
def get_serializer_class(self):
# 判断是否指定 serializer_class
assert self.serializer_class is not None, (
"'%s' should either include a `serializer_class` attribute, "
"or override the `get_serializer_class()` method."
% self.__class__.__name__
)
return self.serializer_class
"""
class BookGenericAPIView(GenericAPIView):
queryset = models.Book.objects.filter(is_active=True)
serializer_class = serializers.BookModelSerializer
# 指定索引字段,与 url.py 中的值对应
lookup_field = 'pk'
# 多查
# def get(self, request, *args, **kwargs):
# queryset = self.get_queryset()
# ser = self.get_serializer(queryset, many=True)
# return APIResponse(results=ser.data)
# 单查
def get(self, request, *args, **kwargs):
queryset = self.get_object()
ser = self.get_serializer(queryset)
return APIResponse(results=ser.data)
2. mixins 使用
mixins中只有五个类，分别为：
mixins 作用 对应方法 ListModelMixin 定义list方法，返回一个queryset的列表 GET RetrieveModelMixin 定义retrieve方法，返回一个具体实例 GET UpdateModelMixin 定义update方法，对某个实例进行更新 PUT/PATCH DestroyModelMixin 定义delete方法，删除某个实例 DELETE CreateModelMixin 定义create方法，创建一个实例 POST
2.1. mixins类介绍
2.1.1. CreateModelMixin
# 源码
class CreateModelMixin(object):
"""
Create a model instance ==>创建一个实例
"""
def create(self, request, *args, **kwargs):
# 1. 获取相关serializer
serializer = self.get_serializer(data=request.data)
# 2. 进行serializer的验证
# 3. raise_exception=True,一旦验证不通过，不再往下执行，直接引发异常
serializer.is_valid(raise_exception=True)
# 调用perform_create()方法，保存实例
self.perform_create(serializer)
headers = self.get_success_headers(serializer.data)
# 5. 返回 Response
return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
def perform_create(self, serializer):
# 4. 保存实例
serializer.save()
def get_success_headers(self, data):
try:
return {'Location': str(data[api_settings.URL_FIELD_NAME])}
except (TypeError, KeyError):
return {}
流程：
post -> 获取相关serializer -> 进行数据验证 (成功)-- > 保存实例 -> Response
(失败)|--->Exception->Response
2.1.2. ListModelMixin
# 源码
class ListModelMixin(object):
"""
List a queryset.==> 列表页获取
"""
def list(self, request, *args, **kwargs):
queryset = self.filter_queryset(self.get_queryset())
# 这是一个分页功能，如果在viewset中设置了pagination_class，那么这里就会起作用
# 获取当前页的queryset，如果不存在分页，返回None
page = self.paginate_queryset(queryset)
if page is not None:
# 分页不为空，那么不能简单的执行Response(serializer.data)
# 还需要将相关的page信息序列化在进行响应
serializer = self.get_serializer(page, many=True)
return self.get_paginated_response(serializer.data)
serializer = self.get_serializer(queryset, many=True)
return Response(serializer.data)
ListModelMixin一般用来获取列表页，大多数情况下比较简单，不需要重写相关的方法。
2.1.3. RetrieveModelMixin
# 源码
class RetrieveModelMixin(object):
"""
Retrieve a model instance.==> 获取某一个对象的具体信息
"""
def retrieve(self, request, *args, **kwargs):
# 一般访问的url都为/obj/id/这种新式
# get_object()可以获取到这个id的对象
# 注意在viewset中设置lookup_field获取重写get_object()方法可以指定id具体对象是什么~！
instance = self.get_object()
serializer = self.get_serializer(instance)
return Response(serializer.data)
对retrieve这个方法的重写几率比较高，例如我们在增加点击数的时候，经常要对其进行一个重写。
2.1.4. UpdateModelMixin
# 源码
class UpdateModelMixin(object):
"""
Update a model instance.==> 更新某个具体对象的内容
"""
def update(self, request, *args, **kwargs):
partial = kwargs.pop('partial', False)
instance = self.get_object()
serializer = self.get_serializer(instance, data=request.data, partial=partial)
serializer.is_valid(raise_exception=True)
self.perform_update(serializer)
if getattr(instance, '_prefetched_objects_cache', None):
# If 'prefetch_related' has been applied to a queryset, we need to
# forcibly invalidate the prefetch cache on the instance.
instance._prefetched_objects_cache = {}
return Response(serializer.data)
def perform_update(self, serializer):
serializer.save()
# patch方法调用
def partial_update(self, request, *args, **kwargs):
kwargs['partial'] = True
return self.update(request, *args, **kwargs)
RetrieveModelMixin的实现逻辑基本整合了Create以及Retrieve，先得到具体的实例，再对其进行验证以及保存，如果需要对更新这个逻辑进行自定义，那么需要重写perform_update( )方法，而尽量少去重写update( )
2.1.5. DestroyModelMixin
# 源码
class DestroyModelMixin(object):
"""
Destroy a model instance.
"""
def destroy(self, request, *args, **kwargs):
instance = self.get_object()
self.perform_destroy(instance)
return Response(status=status.HTTP_204_NO_CONTENT)
def perform_destroy(self, instance):
instance.delete()
DestroyModelMixin的逻辑也相对比较简单，我们取CreateModelMixin下面的例子，当我们取消收藏，那么我们的DestroyModelMixin就发挥作用了。同理
2.2. 举个栗子
view.py:
class BookGenericAPIView(ListModelMixin, CreateModelMixin, UpdateModelMixin, RetrieveModelMixin, GenericAPIView):
queryset = models.Book.objects.filter(is_active=True)
serializer_class = serializers.BookModelSerializer
# 指定索引字段,与 url.py 中的值对应
lookup_field = 'pk'
# def get(self, request, *args, **kwargs):
# return self.list(request, *args, **kwargs)
# 调用ListModelMixin中的 list 方法
def get(self, request, *args, **kwargs):
if "pk" in kwargs: # 单条查询
return APIResponse(results=self.retrieve(request, *args, **kwargs).data)
# 获取self.list() 返回的 response对象
response = self.list(request, *args, **kwargs)
return APIResponse(results=response.data)
# 调用 CreateModelMixin 中的create方法
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)
3. generic 其他类使用
在 generic模块中 对mixins进行了封装，在日常使用中只需要继承相关类即可
3.1. 类介绍
3.1.1. ListAPIView
class ListAPIView(mixins.ListModelMixin,
GenericAPIView):
"""
Concrete view for listing a queryset.
"""
def get(self, request, *args, **kwargs):
return self.list(request, *args, **kwargs)
3.1.2. ListCreateAPIView
class ListCreateAPIView(mixins.ListModelMixin,
mixins.CreateModelMixin,
GenericAPIView):
"""
Concrete view for listing a queryset or creating a model instance.
"""
def get(self, request, *args, **kwargs):
return self.list(request, *args, **kwargs)
def post(self, request, *args, **kwargs):
return self.create(request, *args, **kwargs)
3.1.3. RetrieveAPIVew
class RetrieveAPIView(mixins.RetrieveModelMixin,
GenericAPIView):
"""
Concrete view for retrieving a model instance.
"""
def get(self, request, *args, **kwargs):
return self.retrieve(request, *args, **kwargs)
3.1.4. RetrieveUpdateAPIView
class RetrieveUpdateAPIView(mixins.RetrieveModelMixin,
mixins.UpdateModelMixin,
GenericAPIView):
"""
Concrete view for retrieving, updating a model instance.
"""
def get(self, request, *args, **kwargs):
return self.retrieve(request, *args, **kwargs)
def put(self, request, *args, **kwargs):
return self.update(request, *args, **kwargs)
def patch(self, request, *args, **kwargs):
return self.partial_update(request, *args, **kwargs)
3.1.5. UpdateAPIView
class UpdateAPIView(mixins.UpdateModelMixin,
GenericAPIView):
"""
Concrete view for updating a model instance.
"""
def put(self, request, *args, **kwargs):
return self.update(request, *args, **kwargs)
def patch(self, request, *args, **kwargs):
return self.partial_update(request, *args, **kwargs)
3.2. 举个栗子
在继承ListCreateAPIView 类后不需要在写 get()或 post() 方法
继承UpdateAPIView 后实现了 update()或 patch()方法
from rest_framework.generics import ListCreateAPIView, UpdateAPIView
class BookGenericAPIView(ListCreateAPIView, UpdateAPIView):
queryset = models.Book.objects.filter(is_active=True)
serializer_class = serializers.BookModelSerializer
# 指定索引字段,与 url.py 中的值对应
lookup_field = 'pk'