drf第一天笔记

内容回顾：

	1. 开发模式
		- 普通开发方式（前后端放在一起写）
		- 前后端分离
	
	2. 后端开发
		为前端提供URL（API/接口的开发）
		注：永远返回HttpResponse
		
	3. Django FBV、CBV
		FBV,function base view
			def users(request):
				user_list = ['alex','oldboy']
				return HttpResponse(json.dumps((user_list)))
				
		CBV,class base view 
			路由：
				url(r'^students/', views.StudentsView.as_view()),
			
			视图：
				from django.views import View

				class StudentsView(View):

					def get(self,request,*args,**kwargs):
						return HttpResponse('GET')

					def post(self, request, *args, **kwargs):
						return HttpResponse('POST')

					def put(self, request, *args, **kwargs):
						return HttpResponse('PUT')

					def delete(self, request, *args, **kwargs):
						return HttpResponse('DELETE')
	4. 列表生成时
	
		class Foo:
			pass
			
		class Bar:
			pass
		
		v = []
		for i in [Foo,Bar]:
			obj = i()
			v.append(obj)
		
		
		v = [item() for item in [Foo,Bar]]
		
		v对象列表
		
	5. 面向对象
		- 封装
			- 对同一类方法封装到类中
				class File:
					文件增删改查方法
					
				Class DB:
					数据库的方法
					
			- 将数据封装到对象中
				class File:
					def __init__(self,a1,a2):
						self.a1 = a1 
						self.xxx = a2
					def get:...
					def delete:...
					def update:...
					def add:...
					
				obj1 = File(123,666)
				obj2 = File(456,999)
		
		    PS: 扩展 
				class Request(object):

					def __init__(self,obj):
						self.obj = obj

					@property
					def user(self):
						return self.obj.authticate()

				class Auth(object):
					def __init__(self,name,age):
						self.name = name
						self.age = age

					def authticate(self):
						return self.name


				class APIView(object):

					def dispatch(self):
						self.f2()

					def f2(self):
						a = Auth('alex',18)
						b = Auth('oldboy',18)
						req = Request(b)
						print(req.user)

				obj = APIView()
				obj.dispatch()
	
	
	
	
今日概要：
	1. restful 规范（建议）
	
	2. django rest framework框架
	
内容详细：
	0. FBV、CBV
		CBV，基于反射实现根据请求方式不同，执行不同的方法。
		原理：
			url -> view方法 -> dispatch方法（反射执行其他：GET/POST/DELETE/PUT）
			
		流程：
			class StudentsView(View):
				def dispatch(self, request, *args, **kwargs):
					print('before')
					ret = super(StudentsView,self).dispatch(request, *args, **kwargs)
					print('after')
					return ret

				def get(self,request,*args,**kwargs):
					return HttpResponse('GET')

				def post(self, request, *args, **kwargs):
					return HttpResponse('POST')

				def put(self, request, *args, **kwargs):
					return HttpResponse('PUT')

				def delete(self, request, *args, **kwargs):
					return HttpResponse('DELETE')
	
		继承（多个类共用的功能，为了避免重复编写）：
			from django.views import View


			class MyBaseView(object):
				def dispatch(self, request, *args, **kwargs):
					print('before')
					ret = super(MyBaseView,self).dispatch(request, *args, **kwargs)
					print('after')
					return ret

			class StudentsView(MyBaseView,View):

				def get(self,request,*args,**kwargs):
					print('get方法')
					return HttpResponse('GET')

				def post(self, request, *args, **kwargs):
					return HttpResponse('POST')

				def put(self, request, *args, **kwargs):
					return HttpResponse('PUT')

				def delete(self, request, *args, **kwargs):
					return HttpResponse('DELETE')

			class TeachersView(MyBaseView,View):

				def get(self,request,*args,**kwargs):
					return HttpResponse('GET')

				def post(self, request, *args, **kwargs):
					return HttpResponse('POST')

				def put(self, request, *args, **kwargs):
					return HttpResponse('PUT')

				def delete(self, request, *args, **kwargs):
					return HttpResponse('DELETE')
	
		面试题：
			1. django中间件
				- process_request
				- process_view
				- process_response
				- process_exception
				- process_render_template
			2. 使用中间件做过什么？
				- 权限
				- 用户登录验证
				- django的csrf是如何实现？
					process_view方法
						- 检查视图是否被 @csrf_exempt （免除csrf认证）
						- 去请求体或cookie中获取token
			3. 
				情况一：
					MIDDLEWARE = [
						'django.middleware.security.SecurityMiddleware',
						'django.contrib.sessions.middleware.SessionMiddleware',
						'django.middleware.common.CommonMiddleware',
						'django.middleware.csrf.CsrfViewMiddleware', # 全站使用csrf认证
						'django.contrib.auth.middleware.AuthenticationMiddleware',
						'django.contrib.messages.middleware.MessageMiddleware',
						'django.middleware.clickjacking.XFrameOptionsMiddleware',
					]
					
					
					from django.views.decorators.csrf import csrf_exempt
					@csrf_exempt # 该函数无需认证
					def users(request):
						user_list = ['alex','oldboy']
						return HttpResponse(json.dumps((user_list)))
				
				情况二：
					MIDDLEWARE = [
						'django.middleware.security.SecurityMiddleware',
						'django.contrib.sessions.middleware.SessionMiddleware',
						'django.middleware.common.CommonMiddleware',
						#'django.middleware.csrf.CsrfViewMiddleware', # 全站不使用csrf认证
						'django.contrib.auth.middleware.AuthenticationMiddleware',
						'django.contrib.messages.middleware.MessageMiddleware',
						'django.middleware.clickjacking.XFrameOptionsMiddleware',
					]
					
					
					from django.views.decorators.csrf import csrf_exempt
					@csrf_protect # 该函数需认证
					def users(request):
						user_list = ['alex','oldboy']
						return HttpResponse(json.dumps((user_list)))
					
			
		CBV小知识,csrf时需要使用
			- @method_decorator(csrf_exempt)
			- 在dispatch方法中（单独方法无效）
			
			方式一：
				from django.views.decorators.csrf import csrf_exempt,csrf_protect
				from django.utils.decorators import method_decorator
				class StudentsView(View):
					
					@method_decorator(csrf_exempt)
					def dispatch(self, request, *args, **kwargs):
						return super(StudentsView,self).dispatch(request, *args, **kwargs)

					def get(self,request,*args,**kwargs):
						print('get方法')
						return HttpResponse('GET')

					def post(self, request, *args, **kwargs):
						return HttpResponse('POST')

					def put(self, request, *args, **kwargs):
						return HttpResponse('PUT')

					def delete(self, request, *args, **kwargs):
						return HttpResponse('DELETE')
			方式二：
				from django.views.decorators.csrf import csrf_exempt,csrf_protect
				from django.utils.decorators import method_decorator

				@method_decorator(csrf_exempt,name='dispatch')
				class StudentsView(View):

					def get(self,request,*args,**kwargs):
						print('get方法')
						return HttpResponse('GET')

					def post(self, request, *args, **kwargs):
						return HttpResponse('POST')

					def put(self, request, *args, **kwargs):
						return HttpResponse('PUT')

					def delete(self, request, *args, **kwargs):
						return HttpResponse('DELETE')

		总结：
			- 本质，基于反射来实现
			- 流程：路由，view，dispatch(反射)
			- 取消csrf认证（装饰器要加到dispatch方法上且method_decorator装饰）
				
			扩展：
				- csrf 
					- 基于中间件的process_view方法
					- 装饰器给单独函数进行设置（认证或无需认证）
					
				
	1. restful 规范（建议）
		a. 接口开发
			
			urlpatterns = [
				# url(r'^admin/', admin.site.urls),
				url(r'^get_order/', views.get_order),
				url(r'^add_order/', views.add_order),
				url(r'^del_order/', views.del_order),
				url(r'^update_order/', views.update_order),
			]
			
				
			def get_order(request):
				return HttpResponse('')


			def add_order(request):
				return HttpResponse('')


			def del_order(request):
				return HttpResponse('')


			def update_order(request):
				return HttpResponse('')
				
		b. restful 规范（建议）
			
			1. 根据method不同做不同的操作，示例：
			
				基于FBV:
					urlpatterns = [
						url(r'^order/', views.order),
					]

					def order(request):
						if request.method == 'GET':
							return HttpResponse('获取订单')
						elif request.method == 'POST':
							return HttpResponse('创建订单')
						elif request.method == 'PUT':
							return HttpResponse('更新订单')
						elif request.method == 'DELETE':
							return HttpResponse('删除订单')
				基于CBV:
					urlpatterns = [
						url(r'^order/', views.OrderView.as_view()),
					]
			
					class OrderView(View):
						def get(self,request,*args,**kwargs):
							return HttpResponse('获取订单')

						def post(self,request,*args,**kwargs):
							return HttpResponse('创建订单')

						def put(self,request,*args,**kwargs):
							return HttpResponse('更新订单')

						def delete(self,request,*args,**kwargs):
							return HttpResponse('删除订单')

			
		c. 谈谈自己对restful api 规范的认识
			
			10个规则
		
			
		注意：推荐使用CBV
			
			
			
	2. django rest framework框架
		pip3 install djangorestframework
	
		a. 认证 
			- 仅使用：
					from django.views import View
					from rest_framework.views import APIView
					from rest_framework.authentication import BasicAuthentication
					from rest_framework import exceptions
					from rest_framework.request import Request

					class MyAuthentication(object):
						def authenticate(self,request):
							token = request._request.GET.get('token')
							# 获取用户名和密码，去数据校验
							if not token:
								raise exceptions.AuthenticationFailed('用户认证失败')
							return ("alex",None)

						def authenticate_header(self,val):
							pass

					class DogView(APIView):
						authentication_classes = [MyAuthentication,]

						def get(self,request,*args,**kwargs):
							print(request)
							print(request.user)
							ret  = {
								'code':1000,
								'msg':'xxx'
							}
							return HttpResponse(json.dumps(ret),status=201)

						def post(self,request,*args,**kwargs):
							return HttpResponse('创建Dog')

						def put(self,request,*args,**kwargs):
							return HttpResponse('更新Dog')

						def delete(self,request,*args,**kwargs):
							return HttpResponse('删除Dog')

			- 源码流程：
				dispatch...
					
作业：
	1. 中间件
	2. csrf 
	3. CBV 
	4. 规范 
		- 10条规范
		- 认识 
	5. djangorestframework
		- 如何验证（基于数据库实现用户认证）
		- 源码流程（面向对象回顾流程）
	
	预习：
		版本
		权限
		控制访问频率