官网：https://www.django-rest-framework.org/api-guide/viewsets/
在django rest framework 视图中一共有N个类
第一类：APIview
class IndexView(APIView):
def get(self,request,*args,**kwargs):
pk = kwargs.get('pk')
if pk:
queryset = models.UserInfo.objects.get(pk=pk)
ser = UserInfoSerializer(instance=queryset,many=False)
else:
queryset = models.UserInfo.objects.all()
ser = UserInfoSerializer(instance=queryset,many=True)
return Response(ser.data)
#
这种直接继承了APIView，是最原始的。请求方式就是那五种，get,post,put,patch,delete
第二类 GenericAPIView
class IndexView(GenericAPIView):
queryset = models.UserInfo.objects.all()
serializer_class = UserInfoSerializer
lookup_field = 'pk'
def get(self,request,*args,**kwargs):
pk = kwargs.get('pk')
if pk:
users = self.filter_queryset(queryset=models.UserInfo.objects.get(pk=pk))
ser = self.get_serializer(instance=users)
else:
users = self.get_queryset()
ser = self.get_serializer(instance=users,many=True)
return Response(ser.data)
在GenericAPIView中要重写一些字段和方法，不常用。
第三类 GenericViewSet
class IndexView(GenericViewSet):
serializer_class = UserInfoSerializer
queryset = models.UserInfo.objects.all()
def create(self,request,*args,**kwargs):
pass
def list(self,request,*args,**kwargs): # 获取列表数据
users = models.UserInfo.objects.all()
ser = UserInfoSerializer(instance=users,many=True)
return Response(ser.data)
def retrieve(self,request,*args,**kwargs): # 获取单条数据
pk = kwargs.get('pk')
users = models.UserInfo.objects.get(pk=pk)
ser = UserInfoSerializer(instance=users,many=False)
return Response(ser.data)
def destroy(self,request,*args,**kwargs):
pass
def update(self,request,*args,**kwargs):
pass
def partial_update(self,request,*args,**kwargs):
pass
这个类继承了ViewSetMixin, generics.GenericAPIView，其中在ViewSetMixin中会重写as_view()方法，因此可以将URL中的请求方式与视图函数绑定到一起，在urls.py中以键值对的方式存在：
urls.py
from django.conf.urls import url
from django.contrib import admin
from app01 import views
urlpatterns = [
# url(r'^admin/', admin.site.urls),
url(r'^hehe/', views.hehe),
url(r'^index/$', views.IndexView.as_view({'get':'list','post':'create'})),
url(r'^index/(?P<pk>d+)/$', views.IndexView.as_view({'get':'retrieve','put':'update','patch':'partial_update','delete':'destroy'})),
]
ViewSetMixin源码部分：
class ViewSetMixin(object):
"""
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'})
"""
@classonlymethod
def as_view(cls, actions=None, **initkwargs):
"""
Because of the way class based views create a closure around the
instantiated view, we need to totally reimplement `.as_view`,
and slightly modify the view function that is created and returned.
"""
# The suffix initkwarg is reserved for displaying the viewset type.
# eg. 'List' or 'Instance'.
cls.suffix = None
# Setting a basename allows a view to reverse its action urls. This
# value is provided by the router through the initkwargs.
cls.basename = None
# actions must not be empty
if not actions:
raise TypeError("The `actions` argument must be provided when "
"calling `.as_view()` on a ViewSet. For example "
"`.as_view({'get': 'list'})`")
# sanitize keyword arguments
for key in initkwargs:
if key in cls.http_method_names:
raise TypeError("You tried to pass in the %s method name as a "
"keyword argument to %s(). Don't do that."
% (key, cls.__name__))
if not hasattr(cls, key):
raise TypeError("%s() received an invalid keyword %r" % (
cls.__name__, key))
def view(request, *args, **kwargs):
self = cls(**initkwargs)
# We also store the mapping of request methods to actions,
# so that we can later set the action attribute.
# eg. `self.action = 'list'` on an incoming GET request.
self.action_map = actions
# Bind methods to actions
# This is the bit that's different to a standard view
for method, action in actions.items():
handler = getattr(self, action) # 通过反射获取请求方式
setattr(self, method, handler) # 绑定到视图函数中的方法
if hasattr(self, 'get') and not hasattr(self, 'head'):
self.head = self.get
self.request = request
self.args = args
self.kwargs = kwargs
# And continue as usual
return self.dispatch(request, *args, **kwargs)
# take name and docstring from class
update_wrapper(view, cls, updated=())
# and possible attributes set by decorators
# like csrf_exempt from dispatch
update_wrapper(view, cls.dispatch, assigned=())
# We need to set these on the view function, so that breadcrumb
# generation can pick out these bits of information from a
# resolved URL.
view.cls = cls
view.initkwargs = initkwargs
view.suffix = initkwargs.get('suffix', None)
view.actions = actions
return csrf_exempt(view)
def initialize_request(self, request, *args, **kwargs):
"""
Set the `.action` attribute on the view,
depending on the request method.
"""
request = super(ViewSetMixin, self).initialize_request(request, *args, **kwargs)
method = request.method.lower()
if method == 'options':
# This is a special case as we always provide handling for the
# options method in the base `View` class.
# Unlike the other explicitly defined actions, 'metadata' is implicit.
self.action = 'metadata'
else:
self.action = self.action_map.get(method)
return request
def reverse_action(self, url_name, *args, **kwargs):
"""
Reverse the action for the given `url_name`.
"""
url_name = '%s-%s' % (self.basename, url_name)
kwargs.setdefault('request', self.request)
return reverse(url_name, *args, **kwargs)
第四类 ModelViewSet 继承了这个类，ModelViewSet继承了四个混入类和一个泛类，
将会获得增删改查的所有方法。
class IndexView(ModelViewSet):
queryset = models.UserInfo.objects.all()
serializer_class = UserInfoSerializer
class ModelViewSet(mixins.CreateModelMixin,
mixins.RetrieveModelMixin,
mixins.UpdateModelMixin,
mixins.DestroyModelMixin,
mixins.ListModelMixin,
GenericViewSet):
"""
A viewset that provides default `create()`, `retrieve()`, `update()`,
`partial_update()`, `destroy()` and `list()` actions.
"""
pass
使用类视图的好处：
1、我们将各个HTTP请求方法之间，做了更好的分离。
2、可以很容易地，组成可重复使用的行为。