FBV与CBV CBV源码分析
FBV(Function Based View) 基于函数的视图
基于函数的视图，我们一直在用没啥好讲的，就是导入模块调用函数执行业务
CBV(Class Based View) 基于类的视图
路由
from app01 import views url(r'^haha/',views.zx_view.as_view()),
视图
class zx_view(View):
def get(self,request):
return render(request,'edit.html')
def post(self,request):
return HttpResponse("你好我是POST")
CBV源码分析
首先我们的路由竟然是一个函数（），这样的话是直接执行的，我们找到返回值就行
url(r'^haha/',views.zx_view.as_view()),
进入源码
@classonlymethod
def as_view(cls, **initkwargs):
"""
Main entry point for a request-response process.
"""
#views.zx_view.as_view(),我们调用的时候并没有传递关键字参数，所以这个for可以跳过
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))
#这里有个函数但是并没有执行
def view(request, *args, **kwargs):
self = cls(**initkwargs)
if hasattr(self, 'get') and not hasattr(self, 'head'):
self.head = self.get
self.request = request
self.args = args
self.kwargs = kwargs
return self.dispatch(request, *args, **kwargs)
#这里在给函数对象添加属性
view.view_class = cls
view.view_initkwargs = initkwargs
#下面的代码有注释，可以知道大概的功能
#从类中获取名称和文档字符串
# take name and docstring from class
update_wrapper(view, cls, updated=())
# and possible attributes set by decorators
# like csrf_exempt from dispatch
# 设置CSRF的装饰器
update_wrapper(view, cls.dispatch, assigned=())
#最后把函数对象给返回去了
return view
路由就相当于是这个了
那么就和FBV一样了，路由触发函数的执行
url(r'^haha/',view),
触发路由查看view是怎么执行的
def view(request, *args, **kwargs):
#这个self是什么，就是我们之前创建的zx_view类对象，这里直接实例化了一个self对象
self = cls(**initkwargs)
#通过反射获取get方法并且没有head方法
if hasattr(self, 'get') and not hasattr(self, 'head'):
self.head = self.get
#给self对象添加属性
self.request = request
self.args = args
self.kwargs = kwargs
#最后执行self.dispatch(request, *args, **kwargs)
return self.dispatch(request, *args, **kwargs)
self.dispatch我们知道我们的zx_view是没有这个方法的，那么就去它的父类找dispatch这个方法，结果找到了
def dispatch(self, request, *args, **kwargs):
# Try to dispatch to the right method; if a method doesn't exist,
# defer to the error handler. Also defer to the error handler if the
# request method isn't on the approved list.
#获取请求方法并转换成小写，判断是否在http_method_names，http_method_names信息下面那段代码
if request.method.lower() in self.http_method_names:
#通过反射拿到zx_view的请求的方法
handler = getattr(self, request.method.lower(), self.http_method_not_allowed)
else:
handler = self.http_method_not_allowed
#执行zx_view的get或者post函数对象，并返回结果，结束
return handler(request, *args, **kwargs)
http_method_names = ['get', 'post', 'put', 'patch', 'delete', 'head', 'options', 'trace']