Django请求的生命周期是指：当用户在访问该url路径是，在服务器Django后台都发生了什么。
客户端发送Http请求给服务端，Http请求是一堆字符串,其内容是：
访问：http://crm.oldboy.com:8080/login.html，客户端发送Http请求
1.路由映射，匹配路由（从上到下，匹配到就停止），对应相应views中的业务函数
url(r‘^login.html‘, views.login),
2.匹配成功后，执行views下的对应函数：（FBV）
def login(req):
print(‘req.body‘,req.body)
print("GET",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 = "用户名或密码错误"
return render(req,"login.html",{‘msg‘:message})
URL --> 函数 ====> FBV(Function-based views) 基于函数的视图
URL --> 类 ====> CBV (Class-based views) 基于类的视图
FBV：在Django中使用较多，在其他框架中多使用CBV，例如tornado,还有PHP的多种框架等
Django中CBV使用：
首先需要设置views中的类：
from django.views import View
class CBV(View): #根据请求头中的request method进行自动执行get和post
def get(self,request):
return render(request,"cbv_login.html")
def post(self,request):
return HttpResponse("<h1>cbv_post</h1>")
然后修改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">用户名：</label>
<input type="text" id="user" name="username"/>
</div>
<div>
<label for="pwd">密码：</label>
<input type="password" id="pwd" name="password"/>
</div>
<div>
<label></label>
<input type="submit" value="登录">
<label>{{ msg }}</label>
</div>
</form>
</body>
</html>
cbv_login.html
使用url访问默认是get方式，显示cbv_login.html页面，提交页面，进入post页面，显示cbv_post数据
get还是post，是由于请求头中的Request Method:获取，从而找到对应方法。使用反射查找，来执行对应方法。
1.由Request URL请求去获取路径，与urls进行匹配，找到对应的类 2.由请求体得到：Request Method：GET 3.获得类中方法 方法名 = getattr(对象，"GET") 方法名() #执行对应函数
源码查看：
@classonlymethod
def as_view(cls, **initkwargs):
"""
Main entry point for a request-response process.请求-响应的主入口点，在url解析时调用
"""
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) #实例化CBV对象
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)#调用dispatch方法，将<WSGIRequest: GET ‘/cbv‘>传入
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) #去调用对应的函数
else:
handler = self.http_method_not_allowed
return handler(request, *args, **kwargs)
推荐：介绍——基于类的视图（class-based view）
3.业务处理
-----根据个人需求自定义
-----对于框架：基本操作是操作数据库
---pymysql （原生）
---SQLAlchemy
---Django中orm
-----响应内容：返回给用户的结果：响应头和响应体
我们写的HTTPResponse是写在响应体中
响应头的定制：
def post(self,request):
ret = HttpResponse("<h1>post</h1>") #下面为设置请求头
ret[‘h1‘] =‘v1‘
ret.set_cookie(‘c1‘,‘v1‘)
ret.set_cookie(‘c2‘,‘v2‘)
‘‘‘
响应头：h1=v1
cookies:c1=v1;c2=v2
响应体：<h1>post</h1>
请求头信息：
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
原文地址：https://www.cnblogs.com/ssyfj/p/8666664.html
时间： 2024-12-30 12:10:06