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
1.AnonRateThrottle：未登录用户ip限制，需要配合auth模块用
2.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
3.UserRateThrottle:登录用户频率限制，这个得配合auth模块来用
4.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)