浅谈Django的生命周期和CBF和FBC

Django的生命周期和CBF和FBC

对于所有的web框架来说本质就是一个socket服务端&＃xff0c;浏览器是socket客户端&＃xff0c;客户端和服务端通信&＃xff0c;字符串&＃xff08;Http协议&＃xff09;&＃xff1a;请求头和请求体
响应头&＃43;响应体

而对于Django这个web框架其整个请求的生命周期如上图所示

需要提别提醒的是大部分人以为Django内部封装了socket&＃xff0c;其实不然&＃xff0c;Django的socket是没有封装的&＃xff0c;而是外部插件。

路由系统(FBV&CBV)

一、FBV(function base view)

在Django的url中我们可以根据一个URL对应一个函数名来定义路由规则如下&＃xff1a;

urlpatterns &＃61; [url(r&＃39;^admin/$&＃39;, admin.site.urls),url(r&＃39;^index/$&＃39;, views.index),url(r&＃39;^ajaxHandel/$&＃39;, views.ajaxHandel),url(r&＃39;^login/$&＃39;, views.login),url(r&＃39;^ajaxlogin/$&＃39;, views.ajaxlogin),url(r&＃39;^reg/$&＃39;, views.reg),url(r&＃39;^set_password/$&＃39;, views.set_password),
]

这里需要注意的是&＃xff1a;当客户访问过来请求的时候&＃xff0c;到达路由系统后是根据正则来匹配的&＃xff0c;如果上面的匹配成功了&＃xff0c;后面的路由规则将不会继续匹配&＃xff0c;需要注意&＃xff01;&＃xff01;&＃xff01;&＃xff01;所以我们在后面都加一个$来做结尾.

二、CBV(class base view)

除可以使用常规的函数去设置Django的视图函数&＃xff0c;我们也可以使用类去定义视图如&＃xff1a;

url

urlpatterns &＃61; [url(r&＃39;^admin/$&＃39;, admin.site.urls),url(r&＃39;^index.html$&＃39;,views.IndexView.as_view()),
]

这里需要注意当我们使用class去定义视图时需要在url中继承一个as_view()的类

views

对应的视图&＃xff1a;

from django.shortcuts import render,HttpResponse
from django.views import View #class视图需要导入Viewclass IndexView(View): #继承Viewdef get(self,request,*args,**kwargs):return render(request,&＃39;index.html&＃39;)def post(self,request,*args,**kwargs)return HttpResponse("whatmini")

通过class定义的视图&＃xff0c;可以清楚的界定出client端的请求时get请求还是post请求&＃xff0c;并执行相应的操作。

View

我们会有疑问在执行get和post的函数之前class IndexView(View)这个类发生了什么&＃xff1f;

所以我们需要进入到它继承的View类中去看看如下&＃xff1a;

在View这个类中我们看到有一个dispatch的函数&＃xff0c;不难看出我们知道了
这是一个反射函数的执行&＃xff0c;这个反射的列表http_method_allowed
如下图所示&＃xff1a;

dispatch设置验证

通过上面的View的源码我们知道了在用类定义视图时首先需要执行的是dispatch函数&＃xff0c;所以现在我们可以使用dispatch设置用户登录的关卡&＃xff1a;

from django.shortcuts import render,HttpResponse,redirect
from django.views import View
from django.utils.decorators import method_decorator
from django.views.decorators.csrf import csrf_exempt,csrf_protectclass LoginView(View):def dispatch(self,request,*args,**kwargs):return super(LoginView,self).dispatch(request, *args, **kwargs)def get(self,request):return render(request,&＃39;login.html&＃39;)def post(self,request):# request.GET# request.POST # 请求头中的&＃xff1a;content-type# request.bodyuser &＃61; request.POST.get(&＃39;user&＃39;)pwd &＃61; request.POST.get(&＃39;pwd&＃39;)if user &＃61;&＃61; &＃39;whatmini&＃39; and pwd &＃61;&＃61; "4324225":# 生成随机字符串# 写浏览器COOKIE&＃xff1a; session_id: 随机字符串# 写到服务端session&＃xff1a;# {# "随机字符串": {&＃39;user_info&＃39;:&＃39;whatmini}# }request.session[&＃39;user_info&＃39;] &＃61; "whatmini"return redirect(&＃39;/index.html&＃39;)return render(request, &＃39;login.html&＃39;)class AuthView(View):def dispatch(self, request, *args, **kwargs):if not request.session.get(&＃39;user_info&＃39;): return redirect(&＃39;/login.html&＃39;)res &＃61; super(AuthView,self).dispatch(request, *args, **kwargs) return res #在源码中反射的函数有return值所以这里同样要将res的只return出来class IndexView(AuthView):def get(self,request,*args,**kwargs):"""获取数据:param request::param args::param kwargs::return:"""return render(request,&＃39;index.html&＃39;)def post(self,request,*args,**kwargs):"""提交数据:param request::param args::param kwargs::return:"""return HttpResponse(&＃39;999&＃39;)class OrderView(AuthView,View):def get(self,request,*args,**kwargs):"""获取数据:param request::param args::param kwargs::return:"""return render(request,&＃39;index.html&＃39;)def post(self,request,*args,**kwargs):"""提交数据:param request::param args::param kwargs::return:"""return HttpResponse(&＃39;999&＃39;)

整个执行的过程如下图所示&＃xff1a;

同时需要提醒的是在form表单提交&＃xff08;只支持两种&＃xff09;&＃xff1a;GET,POST

Ajax提交数据&＃xff08;提交方式都支持&＃xff09;&＃xff1a;[&＃39;get&＃39;获取, &＃39;post&＃39;创建, &＃39;put&＃39;更新, &＃39;patch&＃39;局部更新, &＃39;delete&＃39;删除, &＃39;head&＃39;, &＃39;options&＃39;, &＃39;trace&＃39;] -> restful规范

装饰器

Django中使用装饰器必须的继承method_decorator&＃xff1a;

from django.utils.decorators import method_decorator

get,post方法上

class LoginView(View):def dispatch(self, request, *args, **kwargs):return super(LoginView,self).dispatch(request, *args, **kwargs)def get(self,request):return render(request,&＃39;login.html&＃39;)&＃64;method_decorator(test)def post(self,request):# request.GET# request.POST # 请求头中的&＃xff1a;content-type# request.bodyuser &＃61; request.POST.get(&＃39;user&＃39;)pwd &＃61; request.POST.get(&＃39;pwd&＃39;)if user &＃61;&＃61; &＃39;alex&＃39; and pwd &＃61;&＃61; "alex3714":# 生成随机字符串# 写浏览器COOKIE&＃xff1a; session_id: 随机字符串# 写到服务端session&＃xff1a;# {# "随机字符串": {&＃39;user_info&＃39;:&＃39;alex}# }request.session[&＃39;user_info&＃39;] &＃61; "alex"return redirect(&＃39;/index.html&＃39;)return render(request, &＃39;login.html&＃39;)

dispatch方法上

class LoginView(View):&＃64;method_decorator(test) #表示给get和post同时装上装饰器def dispatch(self, request, *args, **kwargs):return super(LoginView,self).dispatch(request, *args, **kwargs)def get(self,request):return render(request,&＃39;login.html&＃39;)def post(self,request):# request.GET# request.POST # 请求头中的&＃xff1a;content-type# request.bodyuser &＃61; request.POST.get(&＃39;user&＃39;)pwd &＃61; request.POST.get(&＃39;pwd&＃39;)if user &＃61;&＃61; &＃39;alex&＃39; and pwd &＃61;&＃61; "alex3714":# 生成随机字符串# 写浏览器COOKIE&＃xff1a; session_id: 随机字符串# 写到服务端session&＃xff1a;# {# "随机字符串": {&＃39;user_info&＃39;:&＃39;alex}# }request.session[&＃39;user_info&＃39;] &＃61; "alex"return redirect(&＃39;/index.html&＃39;)return render(request, &＃39;login.html&＃39;)

类上

&＃64;method_decorator(test,name&＃61;&＃39;get&＃39;) #加上name&＃61;get表示只给get装上装饰器class LoginView(View):def dispatch(self, request, *args, **kwargs):return super(LoginView,self).dispatch(request, *args, **kwargs)def get(self,request):return render(request,&＃39;login.html&＃39;)def post(self,request):# request.GET# request.POST # 请求头中的&＃xff1a;content-type# request.bodyuser &＃61; request.POST.get(&＃39;user&＃39;)pwd &＃61; request.POST.get(&＃39;pwd&＃39;)if user &＃61;&＃61; &＃39;alex&＃39; and pwd &＃61;&＃61; "alex3714":# 生成随机字符串# 写浏览器COOKIE&＃xff1a; session_id: 随机字符串# 写到服务端session&＃xff1a;# {# "随机字符串": {&＃39;user_info&＃39;:&＃39;alex}# }request.session[&＃39;user_info&＃39;] &＃61; "alex"return redirect(&＃39;/index.html&＃39;)return render(request, &＃39;login.html&＃39;)

特殊&＃xff1a;CSRF Token只能加到dispatch

from django.views.decorators.csrf import csrf_exempt,csrf_protectclass LoginView(View):&＃64;method_decorator(csrf_exempt) #表示在post请求时不需要COOKIE验证def dispatch(self, request, *args, **kwargs):return super(LoginView,self).dispatch(request, *args, **kwargs)def get(self,request):return render(request,&＃39;login.html&＃39;)def post(self,request):# request.GET# request.POST # 请求头中的&＃xff1a;content-type# request.bodyuser &＃61; request.POST.get(&＃39;user&＃39;)pwd &＃61; request.POST.get(&＃39;pwd&＃39;)if user &＃61;&＃61; &＃39;alex&＃39; and pwd &＃61;&＃61; "alex3714":# 生成随机字符串# 写浏览器COOKIE&＃xff1a; session_id: 随机字符串# 写到服务端session&＃xff1a;# {# "随机字符串": {&＃39;user_info&＃39;:&＃39;alex}# }request.session[&＃39;user_info&＃39;] &＃61; "alex"return redirect(&＃39;/index.html&＃39;)return render(request, &＃39;login.html&＃39;)