Django补充
Http请求的本质：
socket之间进行通信
Django程序：socket服务端
a.服务端监听IP和端口
c.接受请求
请求头之间\r\n分割
请求体之间\r\n\r\n分割
请求分为POST请求和GET请求：POST请求有请求头和请求体，GET请求只有请求头
d.服务器响应
响应头和响应体
e.断开连接
浏览器：socket客户端
b.浏览器发送请求
e.断开连接
Cookie：在请求头和响应头中存在
写浏览器cookie:{session_id: '随机字符串' }
用户认证成功后，写入用户信息到服务器session:{ '随机字符串' :{key : value,......}}
每次用户请求都在cookie中携带session_id，服务器根据session_id寻找对应的用户信息
Django的请求生命周期:
Django没有socket
1.wsgiref的socket接受数据
2.数据通过中间件到达路由系统
3.路由系统分发到相应的视图函数
4.视图函数通过ORM到数据库中取得相应的数据，并获得模板将数据进行渲染最后返回中间件，通过wsgi返回给用户
FBV
urlpatterns = [
url(r'^admin/', admin.site.urls),
url(r'^index.html$', views.index), #FBV
]
def index(request):
return HttpResponse('OK') #FBV
CBV
urlpatterns = [
url(r'^admin/', admin.site.urls),
# url(r'^index.html$', views.index), #FBV
url(r'^index.html$', views.IndexView.as_view()), #CBV
url(r'^login.html$', views.LoginView.as_view()), #CBV
]
class AuthView(View):
def dispatch(self, request, *args, **kwargs):
if not request.session['user_login']:
return redirect('/login.html')
res=super(AuthView, self).dispatch(request,*args,**kwargs)
return res
class LoginView(View):
def get(self,request):
return (request,"login.html")
def post(self,request):
user=request.POST.get('name')
pwd=request.POST.get('pwd')
if user == 'xiaobai' and pwd == 'youzi':
request.session['user_login']='xiaobai'
return redirect('/index.html')
return render(request,"login.html")
class IndexView(AuthView):
def get(self,request,*args,**kwargs):
return render(request,'index.html')
def post(self,request,*args,**kwargs):
return HttpResponse('youzi')
CBV的装饰器
1.加在get和post方法上
def test(func):
def inner(*args,**kwargs):
return func(*args,**kwargs)
return inner
class LoginView(View):
def dispatch(self, request, *args, **kwargs):
return super(LoginView,self).dispatch(request, *args, **kwargs)
@method_decorator(test)
def get(self,request):
return render(request,'login.html')
@method_decorator(test)
def post(self,request):
# request.GET
# request.POST # 请求头中的：content-type
# request.body
user = request.POST.get('user')
pwd = request.POST.get('pwd')
if user == 'alex' and pwd == "alex3714":
# 生成随机字符串
# 写浏览器cookie： session_id: 随机字符串
# 写到服务端session：
# {
# "随机字符串": {'user_info':'alex}
# }
request.session['user_info'] = "alex"
return redirect('/index.html')
return render(request, 'login.html')
2.加在dispatch上
class LoginView(View):
@method_decorator(test)
def dispatch(self, request, *args, **kwargs):
return super(LoginView,self).dispatch(request, *args, **kwargs)
def get(self,request):
return render(request,'login.html')
def post(self,request):
# request.GET
# request.POST # 请求头中的：content-type
# request.body
user = request.POST.get('user')
pwd = request.POST.get('pwd')
if user == 'alex' and pwd == "alex3714":
# 生成随机字符串
# 写浏览器cookie： session_id: 随机字符串
# 写到服务端session：
# {
# "随机字符串": {'user_info':'alex}
# }
request.session['user_info'] = "alex"
return redirect('/index.html')
return render(request, 'login.html')
3.加在类上
@method_decorator(test,name='get')
class LoginView(View):
def dispatch(self, request, *args, **kwargs):
return super(LoginView,self).dispatch(request, *args, **kwargs)
def get(self,request):
return render(request,'login.html')
def post(self,request):
# request.GET
# request.POST # 请求头中的：content-type
# request.body
user = request.POST.get('user')
pwd = request.POST.get('pwd')
if user == 'alex' and pwd == "alex3714":
# 生成随机字符串
# 写浏览器cookie： session_id: 随机字符串
# 写到服务端session：
# {
# "随机字符串": {'user_info':'alex}
# }
request.session['user_info'] = "alex"
return redirect('/index.html')
return render(request, 'login.html')
4.特殊csrf，只能加在dispatch上
全局django.middleware.csrf.CsrfViewMiddleware；下面代码为局部伪造跨站请求
from django.views.decorators.csrf import csrf_exempt,csrf_protect
class LoginView(View):
@method_decorator(csrf_exempt)
def dispatch(self, request, *args, **kwargs):
return super(LoginView,self).dispatch(request, *args, **kwargs)
def get(self,request):
return render(request,'login.html')
def post(self,request):
# request.GET
# request.POST # 请求头中的：content-type
# request.body
user = request.POST.get('user')
pwd = request.POST.get('pwd')
if user == 'alex' and pwd == "alex3714":
# 生成随机字符串
# 写浏览器cookie： session_id: 随机字符串
# 写到服务端session：
# {
# "随机字符串": {'user_info':'alex}
# }
request.session['user_info'] = "alex"
return redirect('/index.html')
return render(request, 'login.html')
中间件
from django.shortcuts import HttpResponse,redirect
class MiddlewareMixin(object):
def __init__(self, get_response=None):
self.get_response = get_response
super(MiddlewareMixin, self).__init__()
def __call__(self, request):
response = None
if hasattr(self, 'process_request'):
response = self.process_request(request)
if not response:
response = self.get_response(request)
if hasattr(self, 'process_response'):
response = self.process_response(request, response)
return response
class M1(MiddlewareMixin):
def process_request(self,request):
print('m1.process_request')
def process_view(self,request, view_func, view_func_args, view_func_kwargs):
print('m1.process_view')
def process_exception(self,request,exception):
print('m1.process_exception')
def process_response(self,request,response):
print('m1.process_response')
return response
def process_template_response(self,request,response):
print('m1.process_template_response')
return response
class M2(MiddlewareMixin):
def process_request(self, request):
print('m2.process_request')
def process_view(self, request, view_func, view_func_args, view_func_kwargs):
print('M2.process_view')
def process_exception(self,request,exception):
print('m2.process_exception')
return HttpResponse('开发的程序员已经被打死')
def process_response(self, request, response):
print('m2.process_response')
return response
def process_template_response(self,request,response):
print('m2.process_template_response')
return response
process_request和process_response
请求信息从上而下执行各个中间件的process_request，进行路由匹配执行相应的视图函数，返回值通过中间件自下而上执行process_response；如果编写的process_request有return 返回值时，会执行平行的process_response返回给用户
process_view
中间价中存在process_view时：
中间价从上而下执行process_request，全部执行完成之后会进行路由匹配，从上而下执行中间件的process_view最后执行匹配到的视图函数，返回中间件执行process_response；如果process_view有return返回值时，不会执行匹配到的视图函数，而是从下而上执行中间件的process_response
process_exception
process_exception 默认不执行，在视图函数出错时执行，有return返回值；请求发来后，中间件从上而下执行process_request，进行路由匹配，继续按照从上而下的顺序执行process_view，出错后从下而上执行捕获到的process_exception然后按照从下而下执行process_response
process_template_response
process_template_response 默认不执行，返回的对象如果有render方法时会运行，有返回值
return response
