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rest-framework之頻率控制

key meta ava timestamp fail ase 所有 urn ip限制

  • 一 頻率簡介
  • 二 自定義頻率類,自定義頻率規則
  • 三 內置頻率類及局部使用
  • 四 內置頻率類及全局使用
  • 五 源碼分析
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一 頻率簡介

為了控制用戶對某個url請求的頻率,比如,一分鐘以內,只能訪問三次

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二 自定義頻率類,自定義頻率規則

自定義的邏輯

#(1)取出訪問者ip
# (2)判斷當前ip不在訪問字典裏,添加進去,並且直接返回True,表示第一次訪問,在字典裏,繼續往下走
# (3)循環判斷當前ip的列表,有值,並且當前時間減去列表的最後一個時間大於60s,把這種數據pop掉,這樣列表中只有60s以內的訪問時間,
# (4)判斷,當列表小於3,說明一分鐘以內訪問不足三次,把當前時間插入到列表第一個位置,返回True,順利通過
# (5)當大於等於3,說明一分鐘內訪問超過三次,返回False驗證失敗

代碼實現:

技術分享圖片
class MyThrottles():
    VISIT_RECORD = {}
    def __init__(self):
        self.history=None
    def allow_request(self,request, view):
        #(1)取出訪問者ip
        # print(request.META)
        ip=request.META.get(REMOTE_ADDR)
        import time
        ctime
=time.time() # (2)判斷當前ip不在訪問字典裏,添加進去,並且直接返回True,表示第一次訪問 if ip not in self.VISIT_RECORD: self.VISIT_RECORD[ip]=[ctime,] return True self.history=self.VISIT_RECORD.get(ip) # (3)循環判斷當前ip的列表,有值,並且當前時間減去列表的最後一個時間大於60s,把這種數據pop掉,這樣列表中只有60s以內的訪問時間, while
self.history and ctime-self.history[-1]>60: self.history.pop() # (4)判斷,當列表小於3,說明一分鐘以內訪問不足三次,把當前時間插入到列表第一個位置,返回True,順利通過 # (5)當大於等於3,說明一分鐘內訪問超過三次,返回False驗證失敗 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])
View Code 回到目錄

三 內置頻率類及局部使用

寫一個類,繼承自SimpleRateThrottle,(根據ip限制)問:要根據用戶現在怎麽寫

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裏配置:(一分鐘訪問三次)

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

在視圖類裏使用

throttle_classes = [MyThrottles,]

錯誤信息的中文提示:

技術分享圖片
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 = 還有 {wait} second.
            extra_detail_plural = 出了 {wait} seconds.
        raise MyThrottled(wait)
View Code

內置頻率限制類:

技術分享圖片

BaseThrottle是所有類的基類:方法:def get_ident(self, request)獲取標識,其實就是獲取ip,自定義的需要繼承它

AnonRateThrottle:未登錄用戶ip限制,需要配合auth模塊用

SimpleRateThrottle:重寫此方法,可以實現頻率現在,不需要咱們手寫上面自定義的邏輯

UserRateThrottle:登錄用戶頻率限制,這個得配合auth模塊來用

ScopedRateThrottle:應用在局部視圖上的(忽略)

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四 內置頻率類及全局使用

REST_FRAMEWORK = {
    DEFAULT_THROTTLE_CLASSES:[app01.utils.VisitThrottle,],
    DEFAULT_THROTTLE_RATES:{
        luffy:3/m
    }
}
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五 源碼分析

技術分享圖片
    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):
        #拋異常,可以自定義異常,實現錯誤信息的中文顯示
        raise exceptions.Throttled(wait)
View Code 技術分享圖片
class SimpleRateThrottle(BaseThrottle):
    # 咱自己寫的放在了全局變量,他的在django的緩存中
    cache = default_cache
    # 獲取當前時間,跟咱寫的一樣
    timer = time.time
    # 做了一個字符串格式化,
    cache_format = throttle_%(scope)s_%(ident)s
    scope = None
    # 從配置文件中取DEFAULT_THROTTLE_RATES,所以咱配置文件中應該配置,否則報錯
    THROTTLE_RATES = api_settings.DEFAULT_THROTTLE_RATES

    def __init__(self):
        if not getattr(self, rate, None):
            # 從配置文件中找出scope配置的名字對應的值,比如咱寫的‘3/m’,他取出來
            self.rate = self.get_rate()
        #     解析‘3/m‘,解析成 3      m
        self.num_requests, self.duration = self.parse_rate(self.rate)
    # 這個方法需要重寫
    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:
            # 獲取在setting裏配置的字典中的之,self.scope是 咱寫的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這種傳參
    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也是代表一分鐘
        duration = {s: 1, m: 60, h: 3600, d: 86400}[period[0]]
        return (num_requests, duration)
    # 邏輯跟咱自定義的相同
    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,並且插入到緩存中
    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
    # 失敗返回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)
SimpleRateThrottle源碼分析

rest-framework之頻率控制