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：
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])
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：
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）
四 内置频率类及全局使用
REST_FRAMEWORK = { 'DEFAULT_THROTTLE_CLASSES':['app01.utils.VisitThrottle',], 'DEFAULT_THROTTLE_RATES':{ 'luffy':'3/m' } }
五 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)
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)
