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