• Restful framework【第八篇】频率组件


    基本使用

    频率:
    	-限制每个ip地址一分钟访问10次
    	-写一个类
    	from rest_framework.throttling import SimpleRateThrottle
    	class VisitThrottle(SimpleRateThrottle):
    		scope = 'xx' #一定要写它
    		# 必须重写这个方法,返回什么,就以什么作为访问频率限制的东西,
    		def get_cache_key(self, request, view):
    			# return self.get_ident(request)
    			return request.META.get('REMOTE_ADDR')
    	-在setting中配置:
    		'DEFAULT_THROTTLE_RATES': {
    			#这个key跟scope对应,value值3/m  3/h    4/d
    			'xx': '3/m'
    		}
    	-使用:
    		-局部使用:
    				throttle_classes = [VisitThrottle]
    		-全局使用:
    				"DEFAULT_THROTTLE_CLASSES":["app01.auth.VisitThrottle"],
    		-问题?如果网站所有的接口都是一分钟访问10次,但是单独有一个接口要一分钟访问2次,如何做?

    自定义频率类,自定义频率规则

    自定义的逻辑

    (1)取出访问者ip
    (2)判断当前ip不在访问字典里,添加进去,并且直接返回True,表示第一次访问,在字典里,继续往下走
    (3)循环判断当前ip的列表,有值,并且当前时间减去列表的最后一个时间大于60s,把这种数据pop掉,这样列表中只有60s以内的访问时间,
    (4)判断,当列表小于3,说明一分钟以内访问不足三次,把当前时间插入到列表第一个位置,返回True,顺利通过
    (5)当大于等于3,说明一分钟内访问超过三次,返回False验证失败

    代码实现

    class MyThrottles():
        VISIT_RECORD = {}
        def __init__(self):
            self.history=None
        def allow_request(self,request, view):
            #(1)取出访问者ip
            # print(request.META)
            ip=request.META.get('REMOTE_ADDR')
            import time
            ctime=time.time()
            # (2)判断当前ip不在访问字典里,添加进去,并且直接返回True,表示第一次访问
            if ip not in self.VISIT_RECORD:
                self.VISIT_RECORD[ip]=[ctime,]
                return True
            self.history=self.VISIT_RECORD.get(ip)
            # (3)循环判断当前ip的列表,有值,并且当前时间减去列表的最后一个时间大于60s,把这种数据pop掉,这样列表中只有60s以内的访问时间,
            while self.history and ctime-self.history[-1]>60:
                self.history.pop()
            # (4)判断,当列表小于3,说明一分钟以内访问不足三次,把当前时间插入到列表第一个位置,返回True,顺利通过
            # (5)当大于等于3,说明一分钟内访问超过三次,返回False验证失败
            if len(self.history)<3:
                self.history.insert(0,ctime)
                return True
            else:
                return False
        def wait(self):
            import time
            ctime=time.time()
            return 60-(ctime-self.history[-1])

    内置频率类及局部使用

    写一个类,继承自SimpleRateThrottle,(根据ip限制)问:要根据用户现在怎么写

    from rest_framework.throttling import SimpleRateThrottle
    class VisitThrottle(SimpleRateThrottle):
        scope = 'luffy'
        def get_cache_key(self, request, view):
            return self.get_ident(request)

    在setting里配置:(一分钟访问三次)

    REST_FRAMEWORK = {
        'DEFAULT_THROTTLE_RATES':{
            'luffy':'3/m'
        }
    }

    在视图类里使用

    throttle_classes = [MyThrottles,]

    错误信息的中文提示

    class Course(APIView):
        authentication_classes = [TokenAuth, ]
        permission_classes = [UserPermission, ]
        throttle_classes = [MyThrottles,]
    
        def get(self, request):
            return HttpResponse('get')
    
        def post(self, request):
            return HttpResponse('post')
        def throttled(self, request, wait):
            from rest_framework.exceptions import Throttled
            class MyThrottled(Throttled):
                default_detail = '傻逼啊'
                extra_detail_singular = '还有 {wait} second.'
                extra_detail_plural = '出了 {wait} seconds.'
            raise MyThrottled(wait)

    内置频率限制类:

    BaseThrottle是所有类的基类:方法:def get_ident(self, request)获取标识,其实就是获取ip,自定义的需要继承它

    AnonRateThrottle:未登录用户ip限制,需要配合auth模块用

    SimpleRateThrottle:重写此方法,可以实现频率现在,不需要咱们手写上面自定义的逻辑

    UserRateThrottle:登录用户频率限制,这个得配合auth模块来用

    ScopedRateThrottle:应用在局部视图上的(忽略)

    内置频率类及全局使用

    REST_FRAMEWORK = {
        'DEFAULT_THROTTLE_CLASSES':['app01.utils.VisitThrottle',],
        'DEFAULT_THROTTLE_RATES':{
            'luffy':'3/m'
        }
    }

    源码分析

    def check_throttles(self, request):
            for throttle in self.get_throttles():
                if not throttle.allow_request(request, self):
                    self.throttled(request, throttle.wait())
    def throttled(self, request, wait):
            #抛异常,可以自定义异常,实现错误信息的中文显示
            raise exceptions.Throttled(wait)

     SimpleRateThrottle源码分析

    class SimpleRateThrottle(BaseThrottle):
        # 咱自己写的放在了全局变量,他的在django的缓存中
        cache = default_cache
        # 获取当前时间,跟咱写的一样
        timer = time.time
        # 做了一个字符串格式化,
        cache_format = 'throttle_%(scope)s_%(ident)s'
        scope = None
        # 从配置文件中取DEFAULT_THROTTLE_RATES,所以咱配置文件中应该配置,否则报错
        THROTTLE_RATES = api_settings.DEFAULT_THROTTLE_RATES
    
        def __init__(self):
            if not getattr(self, 'rate', None):
                # 从配置文件中找出scope配置的名字对应的值,比如咱写的‘3/m’,他取出来
                self.rate = self.get_rate()
            #     解析'3/m',解析成 3      m
            self.num_requests, self.duration = self.parse_rate(self.rate)
        # 这个方法需要重写
        def get_cache_key(self, request, view):
            """
            Should return a unique cache-key which can be used for throttling.
            Must be overridden.
    
            May return `None` if the request should not be throttled.
            """
            raise NotImplementedError('.get_cache_key() must be overridden')
        
        def get_rate(self):
            if not getattr(self, 'scope', None):
                msg = ("You must set either `.scope` or `.rate` for '%s' throttle" %
                       self.__class__.__name__)
                raise ImproperlyConfigured(msg)
    
            try:
                # 获取在setting里配置的字典中的之,self.scope是 咱写的luffy
                return self.THROTTLE_RATES[self.scope]
            except KeyError:
                msg = "No default throttle rate set for '%s' scope" % self.scope
                raise ImproperlyConfigured(msg)
        # 解析 3/m这种传参
        def parse_rate(self, rate):
            """
            Given the request rate string, return a two tuple of:
            <allowed number of requests>, <period of time in seconds>
            """
            if rate is None:
                return (None, None)
            num, period = rate.split('/')
            num_requests = int(num)
            # 只取了第一位,也就是 3/mimmmmmmm也是代表一分钟
            duration = {'s': 1, 'm': 60, 'h': 3600, 'd': 86400}[period[0]]
            return (num_requests, duration)
        # 逻辑跟咱自定义的相同
        def allow_request(self, request, view):
            """
            Implement the check to see if the request should be throttled.
    
            On success calls `throttle_success`.
            On failure calls `throttle_failure`.
            """
            if self.rate is None:
                return True
    
            self.key = self.get_cache_key(request, view)
            if self.key is None:
                return True
    
            self.history = self.cache.get(self.key, [])
            self.now = self.timer()
    
            # Drop any requests from the history which have now passed the
            # throttle duration
            while self.history and self.history[-1] <= self.now - self.duration:
                self.history.pop()
            if len(self.history) >= self.num_requests:
                return self.throttle_failure()
            return self.throttle_success()
        # 成功返回true,并且插入到缓存中
        def throttle_success(self):
            """
            Inserts the current request's timestamp along with the key
            into the cache.
            """
            self.history.insert(0, self.now)
            self.cache.set(self.key, self.history, self.duration)
            return True
        # 失败返回false
        def throttle_failure(self):
            """
            Called when a request to the API has failed due to throttling.
            """
            return False
    
        def wait(self):
            """
            Returns the recommended next request time in seconds.
            """
            if self.history:
                remaining_duration = self.duration - (self.now - self.history[-1])
            else:
                remaining_duration = self.duration
    
            available_requests = self.num_requests - len(self.history) + 1
            if available_requests <= 0:
                return None
    
            return remaining_duration / float(available_requests)
    

      

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  • 原文地址:https://www.cnblogs.com/596014054-yangdongsheng/p/10402999.html
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