Restful framework【第八篇】频率组件

目录

• 基本使用
• 自定义频率类，自定义频率规则
  • 自定义的逻辑
• 内置频率类及局部使用
• 内置频率类及全局使用
• 源码分析

 

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基本使用#

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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?

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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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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)

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）

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内置频率类及全局使用#

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

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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)

 SimpleRateThrottle源码分析

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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)