DjangoCBV与FBV原理及实例详解

from django.http import HttpResponse
def my_view(request):
   if request.method == 'GET':
      return HttpResponse('OK')

from django.http import HttpResponse
from django.views import View
class MyView(View):
   def get(self, request):
      return HttpResponse('OK')

# urls.py
from django.conf.urls import url
from myapp.views import MyView
urlpatterns = [
   url(r'^index/$', MyView.as_view()),
]

from django.http import HttpResponse
from django.views import View
class GreetingView(View):
  name = "yuan"
  def get(self, request):
     return HttpResponse(self.name)  
# You can override that in a subclass  
class MorningGreetingView(GreetingView):
  name= "alex"

urlpatterns = [
  url(r'^index/$', GreetingView.as_view(name="egon")),
]

########### urls.py
from django.contrib import admin
from django.urls import path
from app01 import views
 
urlpatterns = [
  path('admin/', admin.site.urls),
  path('login/', views.LoginView.as_view()),
] 
############views.py
from django.shortcuts import render, HttpResponse
from django.views import View
class LoginView(View):
  def get(self, request):
    return render(request, "login.html")
 
  def post(self, request):
    return HttpResponse("post...")
 
  def put(self, request):
    pass

  
  



  {% csrf_token %}
  

path('login/', views.LoginView.as_view()),

class View:
  """
  get:查 post:提交，添加 put:所有内容都更新  patch:只更新一部分  delete:删除
  """
  http_method_names = ['get', 'post', 'put', 'patch', 'delete', 'head', 'options', 'trace']

  def __init__(self, **kwargs):
    """
    Constructor. Called in the URLconf; can contain helpful extra
    keyword arguments, and other things.
    """
    # Go through keyword arguments, and either save their values to our
    # instance, or raise an error.
    for key, value in kwargs.items():
      setattr(self, key, value)

  @classonlymethod
  def as_view(cls, **initkwargs):
    """Main entry point for a request-response process."""
    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
      self.request = request
      self.args = args
      self.kwargs = kwargs
      return self.dispatch(request, *args, **kwargs)
    view.view_class = cls
    view.view_initkwargs = initkwargs

    # 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=())
    return view

  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.
    if request.method.lower() in self.http_method_names:
      handler = getattr(self, request.method.lower(), self.http_method_not_allowed)
    else:
      handler = self.http_method_not_allowed
    return handler(request, *args, **kwargs)

  def http_method_not_allowed(self, request, *args, **kwargs):
    logger.warning(
      'Method Not Allowed (%s): %s', request.method, request.path,
      extra={'status_code': 405, 'request': request}
    )
    return HttpResponseNotAllowed(self._allowed_methods())

  def options(self, request, *args, **kwargs):
    """Handle responding to requests for the OPTIONS HTTP verb."""
    respOnse= HttpResponse()
    response['Allow'] = ', '.join(self._allowed_methods())
    response['Content-Length'] = '0'
    return response

  def _allowed_methods(self):
    return [m.upper() for m in self.http_method_names if hasattr(self, m)]

return self.dispatch(request, *args, **kwargs)

from django.shortcuts import render, HttpResponse
from django.views import View
class LoginView(View):
  def dispatch(self, request, *args, **kwargs):
    print("dispath...")
    # return HttpResponse("自定义")
 
    # 两种写法
    # ret = super(LoginView, self).dispatch(request, *args, **kwargs)
    # ret = super().dispatch(request, *args, **kwargs)
    # return ret
 
  def get(self, request):
    print("get.....")
    return render(request, "login.html")
 
  def post(self, request):
    print("post....")
    return HttpResponse("post...")
 
  def put(self, request):
    pass

ret = super(LoginView, self).dispatch(request, *args, **kwargs)
ret = super().dispatch(request, *args, **kwargs)