python---django請求-響應的生命周期（FBV和CBV含義）
阿新 • • 發佈：2018-03-29
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Django請求的生命周期是指：當用戶在訪問該url路徑是，在服務器Django後臺都發生了什麽。
客戶端發送Http請求給服務端，Http請求是一堆字符串,其內容是：
訪問：http://crm.oldboy.com:8080/login.html，客戶端發送Http請求
1.路由映射，匹配路由（從上到下，匹配到就停止），對應相應views中的業務函數
url(r‘^login.html‘, views.login),
2.匹配成功後，執行views下的對應函數：（FBV）
def login(req): print(‘req.body‘,req.body) print("GETView Code",req.GET) message=‘‘ if req.method == "POST": print(req.body) print(req.POST) user = req.POST.get("username") pwd = req.POST.get("password") count = models.Administrator.objects.filter(username=user,password=pwd).count() if count: red= redirect("/index.html") timeout = datetime.datetime.now()+datetime.timedelta(seconds=3) red.set_cookie(‘username‘,user,expires=timeout) return red else: message = "用戶名或密碼錯誤" return render(req,"login.html",{‘msg‘:message})
URL --> 函數 ====> FBV(Function-based views) 基於函數的視圖
URL --> 類 ====> CBV (Class-based views) 基於類的視圖
FBV：在Django中使用較多，在其他框架中多使用CBV，例如tornado,還有PHP的多種框架等
Django中CBV使用：
首先需要設置views中的類：
from django.views import View class CBV(View):
#根據請求頭中的request method進行自動執行get和post def get(self,request): return render(request,"cbv_login.html") def post(self,request): return HttpResponse("<h1>cbv_post</h1>")
然後修改urls文件路由：
urlpatterns = [ url(r"cbv",views.CBV.as_view()) ]
模板文件：
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <form action="/cbv" method="post"> {% csrf_token %} <div> <label for="user">用戶名：</label> <input type="text" id="user" name="username"/> </div> <div> <label for="pwd">密碼：</label> <input type="password" id="pwd" name="password"/> </div> <div> <label></label> <input type="submit" value="登錄"> <label>{{ msg }}</label> </div> </form> </body> </html>cbv_login.html
使用url訪問默認是get方式，顯示cbv_login.html頁面，提交頁面，進入post頁面，顯示cbv_post數據
get還是post，是由於請求頭中的Request Method:獲取，從而找到對應方法。使用反射查找，來執行對應方法。
1.由Request URL請求去獲取路徑，與urls進行匹配，找到對應的類 2.由請求體得到：Request Method：GET 3.獲得類中方法 方法名 = getattr(對象，"GET") 方法名() #執行對應函數
源碼查看：
@classonlymethod def as_view(cls, **initkwargs): """ Main entry point for a request-response process.請求-響應的主入口點，在url解析時調用 """ for key in initkwargs: #cls.http_method_names： #[u‘get‘, u‘post‘, u‘put‘, u‘patch‘, u‘delete‘, u‘head‘, u‘options‘, u‘trace‘] 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)) #print(cls) #<class ‘app1.views.CBV‘> def view(request, *args, **kwargs): self = cls(**initkwargs) #實例化CBV對象 if hasattr(self, ‘get‘) and not hasattr(self, ‘head‘): self.head = self.get self.request = request #print(request) <WSGIRequest: GET ‘/cbv‘> #print(request.method) GET self.args = args self.kwargs = kwargs return self.dispatch(request, *args, **kwargs)#調用dispatch方法，將<WSGIRequest: GET ‘/cbv‘>傳入 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) #去調用對應的函數 else: handler = self.http_method_not_allowed return handler(request, *args, **kwargs)
推薦：介紹——基於類的視圖（class-based view）
3.業務處理
-----根據個人需求自定義
-----對於框架：基本操作是操作數據庫
---pymysql （原生）
---SQLAlchemy
---Django中orm
-----響應內容：返回給用戶的結果：響應頭和響應體
我們寫的HTTPResponse是寫在響應體中
響應頭的定制：
def post(self,request): ret = HttpResponse("<h1>post</h1>")
#下面為設置請求頭 ret[‘h1‘] =‘v1‘ ret.set_cookie(‘c1‘,‘v1‘) ret.set_cookie(‘c2‘,‘v2‘) ‘‘‘ 響應頭：h1=v1 cookies:c1=v1;c2=v2 響應體：<h1>post</h1> 請求頭信息： Content-Length:13 Content-Type:text/html; charset=utf-8 Date:Wed, 28 Mar 2018 13:54:53 GMT h1:v1 Server:WSGIServer/0.1 Python/2.7.10 Set-Cookie:c2=v2; Path=/ Set-Cookie:c1=v1; Path=/ X-Frame-Options:SAMEORIGIN ‘‘‘ return ret
python---django請求-響應的生命周期（FBV和CBV含義）