频率认证源码分析

APIView ---》dispatch方法---》self.initial(request, *args, **kwargs)---》 self.check_throttles(request)

  #重新访问这个接口的时候，都会重新调用这个方法，每次访问都会throtttle_durations=[]置空
    def check_throttles(self, request):
        """
        Check if request should be throttled.
        Raises an appropriate exception if the request is throttled.
        """
        #比如一分钟只能访问三次，第一，二，三次访问的时候都没有限制，第四次访问就会制
        #限次的持续时间，还有多少秒才能接着访问这个接口
        throtttle_durations=[]
        # self.get_throttles()全局或局部配置的类
        for throttle in self.get_throttles():
            #allow_request允许请求返回True,不允许就返回False,为false时成立，
            if not throttle.allow_request(request, self):
                #throttle.wait()等待的限次持续时间
                self.throttled(request, throttle.wait())
        # 第四次限制，有限制持续时间才会走这部        
        if throttle_durations:
            durations = [
                duration for duration in throttle_durations
                if duration is not None
            ]
            duration = max(durations, default=None)
            self.throttled(request, duration)

这说明我们自定义类要重写allow_request(request, self)和wait()，因为throttle调用了
点击 self.get_throttles()查看
    def get_throttles(self):
        """
        Instantiates and returns the list of throttles that this view uses.
        """
        return [throttle() for throttle in self.throttle_classes]
点击 self.throttle_classes

throttle_classes = api_settings.DEFAULT_THROTTLE_CLASSES
throttle_classes跟之前一样可局部配置throttle_classes=[] ,可全局配置settings文件中配置
到drf资源文件settings.py文件中的APISettings类中查看默认配置：ctrl+f键查找DEFAULT_THROTTLE_CLASSES
\'DEFAULT_THROTTLE_CLASSES\': [],#所以说任何接口都可以无限次访问
回到def check_throttles(self, request):pass 中的allow_request方法进行思考，首先去获取下多长时间能够访问多少次，然后就是访问一次就计数一次，超次了就不能访问了，所以要去获取时间，在一定的时间内不能超次，如果在一定的时间内超次了就调用wait，倒计时多久才能再次访问，

allow_request其实就是先获取到多长时间访问多少次，每来一次请求把当前的时间和次数保存着，如果它两的间隔时间足够大，就重置次数为0，如果间隔时间较小就次数累加

找到drf资源文件throttling.py (有以下类)
AnonRateThrottle(SimpleRateThrottle)
BaseThrottle(object)
ScopedRateThrottle(SimpleRateThrottle)
SimpleRateThrottle(BaseThrottle)
UserRateThrottle(SimpleRateThrottle)

我们自定义的类有可能继承BaseThrottle，或SimpleRateThrottle

class BaseThrottle(object):
    """
    Rate throttling of requests.
    """
    #判断是否限次：没有限次可以请求True，限次就不可以请求False
    def allow_request(self, request, view):
        """
        Return `True` if the request should be allowed, `False` otherwise.
        """
        #如果继承 BaseThrottle，必须重写allow_request
        raise NotImplementedError(\'.allow_request() must be overridden\')

    def get_ident(self, request):
        """
        Identify the machine making the request by parsing HTTP_X_FORWARDED_FOR
        if present and number of proxies is > 0. If not use all of
        HTTP_X_FORWARDED_FOR if it is available, if not use REMOTE_ADDR.
        """
        xff = request.META.get(\'HTTP_X_FORWARDED_FOR\')
        remote_addr = request.META.get(\'REMOTE_ADDR\')
        num_proxies = api_settings.NUM_PROXIES
    
        if num_proxies is not None:
            if num_proxies == 0 or xff is None:
                return remote_addr
            addrs = xff.split(\',\')
            client_addr = addrs[-min(num_proxies, len(addrs))]
            return client_addr.strip()
    
        return \'\'.join(xff.split()) if xff else remote_addr
    
    #限次后调用，还需等待多长时间才能再访问
    def wait(self):
        """
        Optionally, return a recommended number of seconds to wait before
        the next request.
        """
        return None  #返回的是等待的时间秒数

返回到 def check_throttles(self, request):

        throtttle_durations=[]
        
        for throttle in self.get_throttles():
            
            if not throttle.allow_request(request, self):
                #wait()的返回值就是要等待的多少秒，把秒数添加到数组里面
                self.throttled(request, throttle.wait())
           #数组就是要等待的秒时间
        if throttle_durations:
            #格式化，展示还需要等待多少秒
            durations = [
                duration for duration in throttle_durations
                if duration is not None
            ]
            duration = max(durations, default=None)
            self.throttled(request, duration)

分析def get_ident(self, request):pass
查看：
num_proxies = api_settings.NUM_PROXIES

到APISettings中ctrl+F查找NUM_PROXIES  
\'NUM_PROXIES\'=None

返回到def get_ident(self, request):pass函数方法
NUM_PROXIES如果为空走：
return \'\'.join(xff.split()) if xff else remote_addr

查看 SimpleRateThrottle类，继承BaseThrottle，并没有写get_ident方法
但是写了allow_request，和wait
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)

分析SimpleRateThrottle中的__init__方法
因为返回到get_throttles(self):  return[throttle() for throttle in self.throttle_classes]
throttle()对象加括号调用触发__init__方法
#初始化没有传入参数，所以没有\'rate\'参数
 def __init__(self):
        # 如果没有rate就调用get_rate()进行赋值
        if not getattr(self, \'rate\', None):
            self.rate = self.get_rate()
            #解析rate，用两个变量存起来
        self.num_requests, self.duration = self.parse_rate(self.rate)

 所有继承SimpleRateThrottle都会走__init__

返回到
 def check_throttles(self, request):

        throtttle_durations=[]
        #throttle初始化成功之后
        for throttle in self.get_throttles():
           #初始化成功之后调用allow_request方法，也就是SimpleRateThrottle中的allow_request
            if not throttle.allow_request(request, self):
               
                self.throttled(request, throttle.wait())

分析SimpleRateThrottle中的allow_request方法
  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`.
        """
        #rate没有值，就永远也不会限制访问
        if self.rate is None:
            return True
        #如果有值往下走
        #获取缓存的key赋值给self.key
        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:
            #频率失败
            return self.throttle_failure()
        #频率成功
        return self.throttle_success()

  #频率失败,返回false,没有请求次数
    def throttle_failure(self):
        """
        Called when a request to the API has failed due to throttling.
        """
        return False

    #频率成功
    def throttle_success(self):
        """
        Inserts the current request\'s timestamp along with the key
        into the cache.
        """
        # history中加时间，再成功再加，而且是加在insert列表的第一个，history长度就会越来越大，所以history的长度就是访问了几次
        self.history.insert(0, self.now)
        self.cache.set(self.key, self.history, self.duration)
        return True

#一直成功一直成功，然后就超次了，所以就会返回False,所以就调用wait()
返回到
 def check_throttles(self, request):

        throtttle_durations=[]
        #throttle初始化成功之后
        for throttle in self.get_throttles():
           #初始化成功之后调用allow_request方法，也就是SimpleRateThrottle中的allow_request
            if not throttle.allow_request(request, self):
               
                self.throttled(request, throttle.wait())

找到drf资源文件throttling.py (有以下类)
以下是系统提供的三大频率认证类，可以局部或者全局配置
ScopedRateThrottle(SimpleRateThrottle)
SimpleRateThrottle(BaseThrottle)
UserRateThrottle(SimpleRateThrottle)

分析UserRateThrottle(SimpleRateThrottle)
class UserRateThrottle(SimpleRateThrottle):
    """
    Limits the rate of API calls that may be made by a given user.

    The user id will be used as a unique cache key if the user is
    authenticated.  For anonymous requests, the IP address of the request will
    be used.
    """
    scope = \'user\'
    
    #返回一个字符串
    def get_cache_key(self, request, view):
        #有用户并且是认证用户
        if request.user.is_authenticated:
            #获取到用户的id
            ident = request.user.pk
        else:
            ident = self.get_ident(request)
        #\'throttle_%(user)s_%(request.user.pk)s\'
        return self.cache_format % {
            \'scope\': self.scope,
            \'ident\': ident
        }
点击self.cache_format
cache_format = \'throttle_%(scope)s_%(ident)s\'
    

   假设我的认证类采用了UserRateThrottle(SimpleRetaThrottle),
    for throttle in self.get_throttles():pass  产生的throttle的就是UserRateThrottle产生的对象，然后UserRateThrottle中没有__init__，所以走SimpleRetaThrottle的__init__方法
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">__init__</span><span class="hljs-params">(self)</span>:</span>
    <span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> getattr(self, <span class="hljs-string">\'rate\'</span>, <span class="hljs-keyword">None</span>):
        self.rate = self.get_rate()
    self.num_requests, self.duration = self.parse_rate(self.rate)

​

点击self.get_rate()，

​    def get_rate(self):

​        """

​        Determine the string representation of the allowed request rate.

​        """

​        #如果没有scope直接抛异常，

​        #这里的self就是UserRateThrottle产生的对象，返回到UserRateThrottle获取到 scope = \'user\'

​        if not getattr(self, \'scope\', None):

​            msg = ("You must set either .scope or .rate for \'%s\' throttle" %

​                   self.class.name)

​            raise ImproperlyConfigured(msg)
    <span class="hljs-keyword">try</span>:
        <span class="hljs-comment">#self.THROTTLE_RATES[\'user\'] ,这种格式就可以判断THROTTLE_RATES是一个字典，点击进入THROTTLE_RATES = api_settings.DEFAULT_THROTTLE_RATES   ，，跟之前一样资源settings.py中ctrl+F查找DEFAULT_THROTTLE_RATES，</span>


# \'DEFAULT_THROTTLE_RATES\': {
#   \'user\': None,
#   \'anon\': None,
#   },            
#然后在自己的settings.py中进行配置，就先走自己的配置，
#所以在这里的返回值是None
return self.THROTTLE_RATES[self.scope]
except KeyError:
# 当key没有对应的value的时候就会报错，而这里的user对应None所以是有value的

msg = "No default throttle rate set for \'%s\' scope" % self.scope
raise ImproperlyConfigured(msg)


返回到SimpleRetaThrottle

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

点击 self.parse_rate(self.rate)

   def parse_rate(self, rate):
        """
        Given the request rate string, return a two tuple of:
        <allowed number of requests>, <period of time in seconds>
        """
        #如果rate是None，返回None,None
        if rate is None:
            return (None, None)
        #如果rate不是None，就得到的是字符串并且包含有一个‘/’，因为拆分后得到得是两个结果，然后有int强转，所以num一定是一个数字
        num, period = rate.split(\'/\')
        num_requests = int(num)
        #period[0]取第一位，然后作为key到字典duration中查找，所以字母开头一定要是s /m / h / d,发现value都是以秒来计算，所以得到rate得格式是\'3/min\' 也就是\'3/60\'
        duration = {\'s\': 1, \'m\': 60, \'h\': 3600, \'d\': 86400}[period[0]]
        return (num_requests, duration)


返回到SimpleRetaThrottle
    
    def __init__(self):
        if not getattr(self, \'rate\', None):
            #self.rate=None
            self.rate = self.get_rate()
            #self.num_requests, self.duration =None,None
        self.num_requests, self.duration = self.parse_rate(self.rate)

为了能rate拿到值，就可以到自己得settings.py中配置
# drf配置
REST_FRAMEWORK = {
    # 频率限制条件配置
    \'DEFAULT_THROTTLE_RATES\': {
        \'user\': \'3/min\',  
        \'anon\': None,
    },
}

返回
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:
            #return \'3/min\'
            return self.THROTTLE_RATES[self.scope]
        except KeyError:
            msg = "No default throttle rate set for \'%s\' scope" % self.scope
            raise ImproperlyConfigured(msg)


返回到SimpleRetaThrottle
    
    def __init__(self):
        if not getattr(self, \'rate\', None):
            self.rate = self.get_rate()
            #self.num_requests:3, self.duration:60
        self.num_requests, self.duration = self.parse_rate(self.rate)

返回到
 def check_throttles(self, request):
    throtttle_durations=[]

    <span class="hljs-keyword">for</span> throttle <span class="hljs-keyword">in</span> self.get_throttles():
        <span class="hljs-comment"># 然后调用allow_request，到UserRateThrottle找，没有走UserRateThrottle得父类SimpleRetaThrottle</span>
        <span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> throttle.allow_request(request, self):
           
            self.throttled(request, throttle.wait())




    
    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
        
        #rate有值rate = \'3/60\'
        # self.get_cache_key父级有这个方法，是抛异常，自己去实现这个方法
        #然后子级UserRateThrottle实现了这个方法
        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()
UserRateThrottle中得get_cache_key方法
class UserRateThrottle(SimpleRateThrottle):
    """
    Limits the rate of API calls that may be made by a given user.

    The user id will be used as a unique cache key if the user is
    authenticated.  For anonymous requests, the IP address of the request will
    be used.
    """
    scope = \'user\'
    
    def get_cache_key(self, request, view):
        if request.user.is_authenticated:
            ident = request.user.pk
        else:
            ident = self.get_ident(request)
        #\'throttle_%(scope)s_%(ident)s\' =》\'throttle_user_1\'
        return self.cache_format % {
            \'scope\': self.scope,
            \'ident\': ident
        }
    
    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 = \'throttle_user_1\'
        self.key = self.get_cache_key(request, view)
        if self.key is None:
            return True
        
        #django缓存
        #导包cache：from django.core.cache import cache as default_cache
        #缓存有过期时间，key,value,,,default是默认值
        #添加缓存：cache.set(key,defalut)
        #获取缓存：cache.get(key,default) 没有获取到key采用默认值
        
        #获取缓存key:\'throttle_user_1\'
        #初次访问缓存为空列表,self.history=[],
        self.history = self.cache.get(self.key, [])
        #获取当前时间存入到self.now
        self.now = self.timer()


​        
        while self.history and self.history[-1] <= self.now - self.duration:
            self.history.pop()
        #history的长度与限制次数3进行比较
        if len(self.history) >= self.num_requests:
            return self.throttle_failure()
        #history的长度未达到限制次数3，代表可以访问
        return self.throttle_success()
点击self.throttle_success()
#将当前时间插入到history列表的开头，将history列表作为数据存到缓存中，key是\'throttle_user_1\'  ，过期时间60s
   def throttle_success(self):
        """
        Inserts the current request\'s timestamp along with the key
        into the cache.
        """
        #将当前的时间插到第一位
        self.history.insert(0, self.now)
        #设置缓存，key:\'throttle_user_1\' history:[self.now, self.now...]
        # duration过期时间60s:\'60\'
        self.cache.set(self.key, self.history, self.duration)
        return True
 第二次访问走到这个函数的时候

    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 = \'throttle_user_1\'
        self.key = self.get_cache_key(request, view)
        if self.key is None:
            return True
        
        #第二次访问self.history已经有值，就是第一次访问存放的时间
        self.history = self.cache.get(self.key, [])
        #获取当前时间存入到self.now
        self.now = self.timer()
    
        #也就是当前的时间减去history缓存的时间（永远都取第一次访问的时间，所以是-1）是否大于过期时间
        #self.now - self.history[-1] >= self.duration
        #当超出的过期时间时，也就是第四次访问
        while self.history and self.history[-1] <= self.now - self.duration:
            #pop是将最后的时间拿出来
            self.history.pop()
        #history的长度与限制次数3进行比较
        #history长度 第一次访问为0， 第二次访问为1，第三次访问的时间长度为2，第四次访问失败
        if len(self.history) >= self.num_requests:
            #直接返回False,代表频率限制了
            return self.throttle_failure()
        #history的长度未达到限制次数3，代表可以访问
        return self.throttle_success()
def throttle_failure(self):
    return False
返回到
  def check_throttles(self, request):

        throtttle_durations=[]
      
        for throttle in self.get_throttles():
            #只要频率限制了，allow_request 返回False,才会调用wait
            if not throttle.allow_request(request, self):
         
                self.throttled(request, throttle.wait())
调用的是SimpleRateThrottle的wait,因为UserRateThrouttle中没有wait这个方法
    def wait(self):
        """
        Returns the recommended next request time in seconds.
        """
        #如果缓存中还有history等30s
        if self.history:
            #self.duration=60， self.now当前时间-self.history[-1]第一次访问时间
            remaining_duration = self.duration - (self.now - self.history[-1])
        else:
            #如果缓存中没有，直接等60s
            remaining_duration = self.duration
        #self.num_requests=3,len(self.history)=3 结果3-3+1=1
        available_requests = self.num_requests - len(self.history) + 1
        if available_requests <= 0:
            return None
        # 30/1=30 返回的就是30s
        #如果意外第二次访问就被限制了就是30/2=15s
        return remaining_duration / float(available_requests)
自定义频率类
# 1) 自定义一个继承 SimpleRateThrottle 类 的频率类
# 2) 设置一个 scope 类属性，属性值为任意见名知意的字符串
# 3) 在settings配置文件中，配置drf的DEFAULT_THROTTLE_RATES，格式为 {scope字符串: \'次数/时间\'}
# 4) 在自定义频率类中重写 get_cache_key 方法
    # 限制的对象返回 与限制信息有关的字符串
    # 不限制的对象返回 None (只能放回None，不能是False或是\'\'等)
短信接口 1/min 频率限制
频率：api/throttles.py
from rest_framework.throttling import SimpleRateThrottle
class SMSRateThrottle(SimpleRateThrottle):

scope = \'sms\'
<span class="hljs-comment"># 只对提交手机号的get方法进行限制,因为get请求发送数据就是在params中传送数据的，如果想要禁用post请发送过来的数据就要mobile = request.query_params.get(\'mobile\') or request.data.get(\'mobile\')</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">get_cache_key</span><span class="hljs-params">(self, request, view)</span>:</span>
    mobile = request.query_params.get(<span class="hljs-string">\'mobile\'</span>)
    <span class="hljs-comment"># 没有手机号，就不做频率限制</span>
    <span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> mobile:
        <span class="hljs-keyword">return</span> <span class="hljs-keyword">None</span>
    <span class="hljs-comment"># 返回可以根据手机号动态变化，且不易重复的字符串，作为操作缓存的key</span>
    <span class="hljs-keyword">return</span> <span class="hljs-string">\'throttle_%(scope)s_%(ident)s\'</span> % {<span class="hljs-string">\'scope\'</span>: self.scope, <span class="hljs-string">\'ident\'</span>: mobile}</code></pre>

配置：settings.py
# drf配置
REST_FRAMEWORK = {
    # 频率限制条件配置
    \'DEFAULT_THROTTLE_RATES\': {
        \'sms\': \'3/min\'  #60s内可以访问三次请求
    },
}
视图：views.py
from .throttles import SMSRateThrottle
class TestSMSAPIView(APIView):
    # 局部配置频率认证
    throttle_classes = [SMSRateThrottle]
    def get(self, request, *args, **kwargs):
        return APIResponse(0, \'get 获取验证码 OK\')
    def post(self, request, *args, **kwargs):
        return APIResponse(0, \'post 获取验证码  OK\')
路由：api/url.py
url(r\'^sms/$\', views.TestSMSAPIView.as_view()),
限制的接口
# 只会对 /api/sms/?mobile=具体手机号 接口才会有频率限制
# 1）对 /api/sms/ 或其他接口发送无限制
# 2）对数据包提交mobile的/api/sms/接口无限制
# 3）对不是mobile（如phone）字段提交的电话接口无限制
测试