------类视图
1、类视图引入
def register(request):
"""处理注册"""
# 获取请求方法，判断是GET/POST请求
if request.method == 'GET':
# 处理GET请求，返回注册页面
return render(request, 'register.html')
else:
# 处理POST请求，实现注册逻辑
return HttpResponse('这里实现注册逻辑')
from django.views.generic import View
class RegisterView(View):
"""类视图：处理注册"""
def get(self, request):
"""处理GET请求，返回注册页面"""
return render(request, 'register.html')
def post(self, request):
"""处理POST请求，实现注册逻辑"""
return HttpResponse('这里实现注册逻辑')
类视图的好处：
* 代码可读性好
* 类视图相对于函数视图有更高的复用性， 如果其他地方需要用到某个类视图的某个特定逻辑，直接继承该类视图即可
2、类视图使用
from django.views.generic import View
urlpatterns = [
# 视图函数：注册
# url(r'^register/$', views.register, name='register'),
# 类视图：注册
url(r'^register/$', views.RegisterView.as_view(), name='register'),
]
3、类视图原理
@classonlymethod
def as_view(cls, **initkwargs):
"""
Main entry point for a request-response process.
"""
...省略代码...
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
# 调用dispatch方法，按照不同请求方式调用不同请求方法
return self.dispatch(request, *args, **kwargs)
...省略代码...
# 返回真正的函数视图
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)
4、类视图使用装饰器
def my_decorator(func):
def wrapper(request, *args, **kwargs):
print('自定义装饰器被调用了')
print('请求路径%s' % request.path)
return func(request, *args, **kwargs)
return wrapper
class DemoView(View):
def get(self, request):
print('get方法')
return HttpResponse('ok')
def post(self, request):
print('post方法')
return HttpResponse('ok')
4-1、在URL配置中装饰
urlpatterns = [
url(r'^demo/$', my_decorate(DemoView.as_view()))
]
4-2、 在类视图中装饰
from django.utils.decorators import method_decorator
# 为全部请求方法添加装饰器class DemoView(View):
@method_decorator(my_decorator)
def dispatch(self, *args, **kwargs):
return super().dispatch(*args, **kwargs)
def get(self, request):
print('get方法')
return HttpResponse('ok')
def post(self, request):
print('post方法')
return HttpResponse('ok')
# 为特定请求方法添加装饰器class DemoView(View):
@method_decorator(my_decorator)
def get(self, request):
print('get方法')
return HttpResponse('ok')
def post(self, request):
print('post方法')
return HttpResponse('ok')
4-3 构造Mixin扩展类
class MyDecoratorMixin(object): @classmethod
def as_view(cls, *args, **kwargs):
view = super().as_view(*args, **kwargs)
view = my_decorator(view)
return view
class DemoView(MyDecoratorMixin, View):
def get(self, request):
print('get方法')
return HttpResponse('ok')
def post(self, request):
print('post方法')
return HttpResponse('ok')
-----中间件
Django中的中间件是一个轻量级、底层的插件系统，可以介入Django的请求和响应处理过程，修改Django的输入或输出。中间件的设计为开发者提供了一种无侵入式的开发方式，增强了Django框架的健壮性。
我们可以使用中间件，在Django处理视图的不同阶段对输入或输出进行干预。
1、中间件的定义方法
def simple_middleware(get_response):
# 此处编写的代码仅在Django第一次配置和初始化的时候执行一次。
def middleware(request):
# 此处编写的代码会在每个请求处理视图前被调用。
response = get_response(request)
# 此处编写的代码会在每个请求处理视图之后被调用。
return response
return middleware
def my_middleware(get_response):
print('init 被调用')
def middleware(request):
print('before request 被调用')
response = get_response(request)
print('after response 被调用')
return response
return middleware
# 定义好中间件后，需要在settings.py文件中添加注册中间件
MIDDLEWARE = [
'django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
# 'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware',
'users.middleware.my_middleware', # 添加中间件
]
2、多个中间件的执行顺序
* 在请求视图被处理前，中间件由上至下依次执行
* 在请求视图被处理后，中间件由下至上依次执行