django之訪問頻率

頻率組件

-使用：
　　-第一步，寫一個頻率類，繼承SimpleRateThrottle
　　　　#重寫get_cache_key，返回self.get_ident(request)
　　　　#必定要記住配置一個scop=字符串

class Throttle(SimpleRateThrottle):
　　scope = 'lxx'
　　def get_cache_key(self, request, view):
　　return self.get_ident(request)

 

　　-第二步：在setting中配置
　　　　

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

 

-局部使用
　　-在視圖類中配置：
　　-throttle_classes=[Throttle,]
-全局使用
　　-在setting中配置
　　'DEFAULT_THROTTLE_CLASSES':['本身定義的頻率類'],
-局部禁用
　　throttle_classes=[]
頻率組件分析：
-核心源代碼：

def check_throttles(self, request):
　　for throttle in self.get_throttles():
　　　　if not throttle.allow_request(request, self):
　　　　　　self.throttled(request, throttle.wait())

 

-自定義的頻率類：詳解代碼views.py 25行開始

#自定義頻率類
class MyThrottle(BaseThrottle):
    VISIT_RECORD = {}
    def __init__(self):
        self.history=None
    def allow_request(self,request,view):  # 校驗是否能夠訪問 #自定義控制每分鐘訪問多少次，運行訪問返回true，不容許訪問返回false
        # （1）取出訪問者ip{ip1:[第二次訪問時間，第一次訪問時間],ip2:[]}
        # （2）判斷當前ip不在訪問字典裏，若是不在添加進去，而且直接返回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，而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之內的訪問時間，
        # （4）判斷，當列表小於3，說明一分鐘之內訪問不足三次，把當前時間插入到列表第一個位置，返回True，順利經過
        # （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
        # （1）取出訪問者ip
        # print(request.META)
        #取出訪問者ip
        ip = request.META.get('REMOTE_ADDR')
        import time
        #拿到當前時間
        ctime = time.time()
        # （2）判斷當前ip不在訪問字典裏，添加進去，而且直接返回True,表示第一次訪問
        if ip not in self.VISIT_RECORD:
            self.VISIT_RECORD[ip] = [ctime, ]
            return True
        #是個當前訪問者ip對應的時間列表 [第一次訪問的時間，]
        self.history = self.VISIT_RECORD.get(ip)
        # （3）循環判斷當前ip的列表，有值，而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之內的訪問時間，
        while self.history and ctime - self.history[-1] > 60:
            self.history.pop()
        # （4）判斷，當列表小於3，說明一分鐘之內訪問不足三次，把當前時間插入到列表第一個位置，返回True，順利經過
        # （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()
　　　　 # 返回多少秒以後能夠再次訪問　　
        return 60 - (ctime - self.history[-1])

class Books(APIView):
    # throttle_classes=[Throttle,]
    throttle_classes=[MyThrottle,]
    def get(self,request):
        return Response('')

 

-SimpleRateThrottle源碼

class SimpleRateThrottle(BaseThrottle):
    """
    A simple cache implementation, that only requires `.get_cache_key()`
    to be overridden.

    The rate (requests / seconds) is set by a `rate` attribute on the View
    class.  The attribute is a string of the form 'number_of_requests/period'.

    Period should be one of: ('s', 'sec', 'm', 'min', 'h', 'hour', 'd', 'day')

    Previous request information used for throttling is stored in the cache.
    """
    cache = default_cache
    timer = time.time
    cache_format = 'throttle_%(scope)s_%(ident)s'
    scope = None
    THROTTLE_RATES = api_settings.DEFAULT_THROTTLE_RATES

    def __init__(self):
        if not getattr(self, 'rate', None):
            self.rate = self.get_rate()
        self.num_requests, self.duration = self.parse_rate(self.rate)

    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):
        """
        Determine the string representation of the allowed request rate.
        """
        if not getattr(self, 'scope', None):
            msg = ("You must set either `.scope` or `.rate` for '%s' throttle" %
                   self.__class__.__name__)
            raise ImproperlyConfigured(msg)

        try:
            return self.THROTTLE_RATES[self.scope]
        except KeyError:
            msg = "No default throttle rate set for '%s' scope" % self.scope
            raise ImproperlyConfigured(msg)

    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)
        duration = {'s': 1, 'm': 60, 'h': 3600, 'd': 86400}[period[0]]
        return (num_requests, duration)

    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()

    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

    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)