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rest-framework之频率控制

作者:互联网

rest-framework之频率控制

一 频率简介

为了控制用户对某个url请求的频率,比如,一分钟以内,只能访问三次

二 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:

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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])

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三 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:

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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)

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内置频率限制类:

img

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)

四 内置频率类及全局使用

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

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五 源码分析

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    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)

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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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标签:return,self,request,rest,framework,频率,throttle,def,history
来源: https://www.cnblogs.com/thaimj1314520/p/15823987.html