django_rest framework 接口开发（二）

1 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')

    梳理：
        1. 使用
            - 创建类:继承BaseAuthentication； 实现：authenticate方法
            - 返回值：
                - None,我不管了，下一认证来执行。
                - raise exceptions.AuthenticationFailed('用户认证失败') # from rest_framework import exceptions
                - (元素1，元素2)  # 元素1赋值给request.user; 元素2赋值给request.auth 

            - 局部使用
                from rest_framework.authentication import BaseAuthentication,BasicAuthentication
                class UserInfoView(APIView):
                    """
                    订单相关业务
                    """
                    authentication_classes = [BasicAuthentication,]
                    def get(self,request,*args,**kwargs):
                        print(request.user)
                        return HttpResponse('用户信息')
            - 全局使用：
                REST_FRAMEWORK = {
                    # 全局使用的认证类
                    "DEFAULT_AUTHENTICATION_CLASSES":['api.utils.auth.FirstAuthtication','api.utils.auth.Authtication', ],
                    # "UNAUTHENTICATED_USER":lambda :"匿名用户"
                    "UNAUTHENTICATED_USER":None, # 匿名，request.user = None
                    "UNAUTHENTICATED_TOKEN":None,# 匿名，request.auth = None
                }
        2. 源码流程
            - dispatch
                - 封装request
                    - 获取定义的认证类（全局/局部），通过列表生成时创建对象。
                - initial
                    - perform_authentication
                        request.user(内部循环....)

2. 权限
    问题：不用视图不用权限可以访问

    基本使用：

        class MyPermission(object):

            def has_permission(self,request,view):
                if request.user.user_type != 3:
                    return False
                return True

            class OrderView(APIView):
                """
                订单相关业务(只有SVIP用户有权限)
                """
                permission_classes = [MyPermission,]

                def get(self,request,*args,**kwargs):
                    # request.user
                    # request.auth
                    self.dispatch
                    ret = {'code':1000,'msg':None,'data':None}
                    try:
                        ret['data'] = ORDER_DICT
                    except Exception as e:
                        pass
                    return JsonResponse(ret)

    源码流程：
        - ...

    梳理：
        1. 使用
            - 类，必须继承：BasePermission，必须实现：has_permission方法
                from rest_framework.permissions import BasePermission

                class SVIPPermission(BasePermission):
                    message = "必须是SVIP才能访问"
                    def has_permission(self,request,view):
                        if request.user.user_type != 3:
                            return False
                        return True
            - 返回值：
                - True, 有权访问
                - False，无权访问
            - 局部
                class UserInfoView(APIView):
                    """
                    订单相关业务（普通用户、VIP）
                    """
                    permission_classes = [MyPermission1, ]

                    def get(self,request,*args,**kwargs):
                        return HttpResponse('用户信息')

            - 全局
                REST_FRAMEWORK = {
                    "DEFAULT_PERMISSION_CLASSES":['api.utils.permission.SVIPPermission']
                }

        2. 源码流程 

3. 访问频率控制（节流）
    问题：控制访问频率
        import time
        VISIT_RECORD = {}

        class VisitThrottle(object):
            """60s内只能访问3次"""

            def __init__(self):
                self.history = None

            def allow_request(self,request,view):
                # 1. 获取用户IP
                remote_addr = request.META.get('REMOTE_ADDR')
                ctime = time.time()
                if remote_addr not in VISIT_RECORD:
                    VISIT_RECORD[remote_addr] = [ctime,]
                    return True
                history = VISIT_RECORD.get(remote_addr)
                self.history = history

                while history and history[-1] < ctime - 60:
                    history.pop()

                if len(history) < 3:
                    history.insert(0,ctime)
                    return True

                # return True    # 表示可以继续访问
                # return False # 表示访问频率太高，被限制

            def wait(self):
                """
                还需要等多少秒才能访问
                :return:
                """
                ctime = time.time()
                return 60 - (ctime - self.history[-1])

        class AuthView(APIView):
            """
            用于用户登录认证
            """
            authentication_classes = []
            permission_classes = []
            throttle_classes = [VisitThrottle,]

            def post(self,request,*args,**kwargs):

                ret = {'code':1000,'msg':None}
                try:
                    user = request._request.POST.get('username')
                    pwd = request._request.POST.get('password')
                    obj = models.UserInfo.objects.filter(username=user,password=pwd).first()
                    if not obj:
                        ret['code'] = 1001
                        ret['msg'] = "用户名或密码错误"
                    # 为登录用户创建token
                    token = md5(user)
                    # 存在就更新，不存在就创建
                    models.UserToken.objects.update_or_create(user=obj,defaults={'token':token})
                    ret['token'] = token
                except Exception as e:
                    ret['code'] = 1002
                    ret['msg'] = '请求异常'

                return JsonResponse(ret)

    源码流程：
        ...

    内置控制频率类：
        from rest_framework.throttling import BaseThrottle,SimpleRateThrottle
        class VisitThrottle(SimpleRateThrottle):
            scope = "Luffy"

            def get_cache_key(self, request, view):
                return self.get_ident(request)

        class UserThrottle(SimpleRateThrottle):
            scope = "LuffyUser"

            def get_cache_key(self, request, view):
                return request.user.username

        REST_FRAMEWORK = {
            # 全局使用的认证类
            "DEFAULT_AUTHENTICATION_CLASSES":['api.utils.auth.FirstAuthtication','api.utils.auth.Authtication', ],
            # "DEFAULT_AUTHENTICATION_CLASSES":['api.utils.auth.FirstAuthtication', ],
            # "UNAUTHENTICATED_USER":lambda :"匿名用户"
            "UNAUTHENTICATED_USER":None, # 匿名，request.user = None
            "UNAUTHENTICATED_TOKEN":None,# 匿名，request.auth = None
            "DEFAULT_PERMISSION_CLASSES":['api.utils.permission.SVIPPermission'],
            "DEFAULT_THROTTLE_CLASSES":["api.utils.throttle.UserThrottle"],
            "DEFAULT_THROTTLE_RATES":{
                "Luffy":'3/m',
                "LuffyUser":'10/m',
            }
        }

    梳理：
        a. 基本使用
            - 类， 继承：BaseThrottle，实现：allow_request、wait
            - 类， 继承：SimpleRateThrottle，实现：get_cache_key、scope = "Luffy"（配置文件中的key）

        b. 局部
            class AuthView(APIView):
                """
                用于用户登录认证
                """
                authentication_classes = []
                permission_classes = []
                throttle_classes = [VisitThrottle,] # *******************

                def post(self,request,*args,**kwargs):

                    ret = {'code':1000,'msg':None}
                    try:
                        user = request._request.POST.get('username')
                        pwd = request._request.POST.get('password')
                        obj = models.UserInfo.objects.filter(username=user,password=pwd).first()
                        if not obj:
                            ret['code'] = 1001
                            ret['msg'] = "用户名或密码错误"
                        # 为登录用户创建token
                        token = md5(user)
                        # 存在就更新，不存在就创建
                        models.UserToken.objects.update_or_create(user=obj,defaults={'token':token})
                        ret['token'] = token
                    except Exception as e:
                        ret['code'] = 1002
                        ret['msg'] = '请求异常'

                    return JsonResponse(ret)

        c. 全局
            REST_FRAMEWORK = {
                # 全局使用的认证类
                "DEFAULT_AUTHENTICATION_CLASSES":['api.utils.auth.FirstAuthtication','api.utils.auth.Authtication', ],
                # "DEFAULT_AUTHENTICATION_CLASSES":['api.utils.auth.FirstAuthtication', ],
                # "UNAUTHENTICATED_USER":lambda :"匿名用户"
                "UNAUTHENTICATED_USER":None, # 匿名，request.user = None
                "UNAUTHENTICATED_TOKEN":None,# 匿名，request.auth = None
                "DEFAULT_PERMISSION_CLASSES":['api.utils.permission.SVIPPermission'],

                "DEFAULT_THROTTLE_CLASSES":["api.utils.throttle.UserThrottle"],
                "DEFAULT_THROTTLE_RATES":{
                    "Luffy":'3/m',
                    "LuffyUser":'10/m',
                }
            }