一、CBV流程解析
urls.py
urlpatterns = [
url(r'^admin/', admin.site.urls),
url(r'^book/', views.BookView.as_view()),
]
views.py
from django.views import View class BookView(View):
def get(self,request):
return HttpResponse("get.........")
def post(self,request):
return HttpResponse("post........")
请求走到url中，怎么执行的？
1、先找BookView中as_view方法，没有找到，找父类View，找到View中的as_view执行，返回view
2、执行View中的view，返回结果self.dispatch，self为自定义的类的对象，自定义类中无dispatch方法就执行View中的dispatch
3、执行View中的dispatch，利用反射执行对应的请求函数
二、 classbasedview的源码剖析
base.py
class View:
http_method_names = ['get', 'post', 'put', 'patch', 'delete', 'head', 'options', 'trace'] @classonlymethod
def as_view(cls, **initkwargs):
# 实例化一个对象，对象名称为self，self是cls的对象，谁调用了cls
# cls就是谁（当前调用cls的是BookView），
# 所以，此时的self就是BookView的实例化对象
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. as_view "
"only accepts arguments that are already "
"attributes of the class." % (cls.__name__, key)) def view(request, *args, **kwargs):
self = cls(**initkwargs)
if hasattr(self, 'get') and not hasattr(self, 'head'):
self.head = self.get
# 此时的request对象指向原始的request对象
# 给self这个实例化对象赋值：原始的request
self.request = request
self.args = args
self.kwargs = kwargs
# 开始执行self.dispatch()
return self.dispatch(request, *args, **kwargs)
view.view_class = cls
view.view_initkwargs = initkwargs
update_wrapper(view, cls, updated=()) update_wrapper(view, cls.dispatch, assigned=())
return view def dispatch(self, request, *args, **kwargs):
if request.method.lower() in self.http_method_names:
# 通过getattr找到的属性，已经和对象绑定了，访问的时候不需要在指明对象了
# 不需要再：self.handler
# 直接handler()
handler = getattr(self, request.method.lower(), self.http_method_not_allowed)
else:
handler = self.http_method_not_allowed
return handler(request, *args, **kwargs)