drf的頻率認證

頻率認證源碼分析

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

#從新訪問這個接口的時候，都會從新調用這個方法，每次訪問都會throtttle_durations=[]置空
    def check_throttles(self, request):
        """
        Check if request should be throttled.
        Raises an appropriate exception if the request is throttled.
        """
        #好比一分鐘只能訪問三次，第一，二，三次訪問的時候都沒有限制，第四次訪問就會制
        #限次的持續時間，還有多少秒才能接着訪問這個接口
        throtttle_durations=[]
        # self.get_throttles()全局或局部配置的類
        for throttle in self.get_throttles():
            #allow_request容許請求返回True,不容許就返回False,爲false時成立，
            if not throttle.allow_request(request, self):
                #throttle.wait()等待的限次持續時間
                self.throttled(request, throttle.wait())
        # 第四次限制，有限制持續時間纔會走這部        
        if throttle_durations:
            durations = [
                duration for duration in throttle_durations
                if duration is not None
            ]
            duration = max(durations, default=None)
            self.throttled(request, duration)

這說明咱們自定義類要重寫allow_request(request, self)和wait()，由於throttle調用了
點擊 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]
 
點擊 self.throttle_classes  
throttle_classes = api_settings.DEFAULT_THROTTLE_CLASSES

throttle_classes跟以前同樣可局部配置throttle_classes=[] ,可全局配置settings文件中配置

到drf資源文件settings.py文件中的APISettings類中查看默認配置：ctrl+f鍵查找DEFAULT_THROTTLE_CLASSES
'DEFAULT_THROTTLE_CLASSES': [],#因此說任何接口均可以無限次訪問

回到def check_throttles(self, request):pass 中的allow_request方法進行思考，首先去獲取下多長時間可以訪問多少次，而後就是訪問一次就計數一次，超次了就不能訪問了，因此要去獲取時間，在必定的時間內不能超次，若是在必定的時間內超次了就調用wait，倒計時多久才能再次訪問，
allow_request其實就是先獲取到多長時間訪問多少次，每來一次請求把當前的時間和次數保存着，若是它兩的間隔時間足夠大，就重置次數爲0，若是間隔時間較小就次數累加

找到drf資源文件throttling.py (有如下類)
AnonRateThrottle(SimpleRateThrottle)
BaseThrottle(object)
ScopedRateThrottle(SimpleRateThrottle)
SimpleRateThrottle(BaseThrottle)
UserRateThrottle(SimpleRateThrottle)

咱們自定義的類有可能繼承BaseThrottle，或SimpleRateThrottle

class BaseThrottle(object):
    """
    Rate throttling of requests.
    """
    #判斷是否限次：沒有限次能夠請求True，限次就不能夠請求False
    def allow_request(self, request, view):
        """
        Return `True` if the request should be allowed, `False` otherwise.
        """
        #若是繼承 BaseThrottle，必須重寫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
    
    #限次後調用，還需等待多長時間才能再訪問
    def wait(self):
        """
        Optionally, return a recommended number of seconds to wait before
        the next request.
        """
        return None  #返回的是等待的時間秒數

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，把秒數添加到數組裏面
                self.throttled(request, throttle.wait())
           #數組就是要等待的秒時間
        if throttle_durations:
            #格式化，展現還須要等待多少秒
            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函數方法
NUM_PROXIES若是爲空走：
return ''.join(xff.split()) if xff else remote_addr

查看 SimpleRateThrottle類，繼承BaseThrottle，並無寫get_ident方法
可是寫了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
由於返回到get_throttles(self):  return[throttle() for throttle in self.throttle_classes]
throttle()對象加括號調用觸發__init__方法
#初始化沒有傳入參數，因此沒有'rate'參數
 def __init__(self):
        # 若是沒有rate就調用get_rate()進行賦值
        if not getattr(self, 'rate', None):
            self.rate = self.get_rate()
            #解析rate，用兩個變量存起來
        self.num_requests, self.duration = self.parse_rate(self.rate)

 全部繼承SimpleRateThrottle都會走__init__

返回到
 def check_throttles(self, request):
      
        throtttle_durations=[]
        #throttle初始化成功以後
        for throttle in self.get_throttles():
           #初始化成功以後調用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沒有值，就永遠也不會限制訪問
        if self.rate is None:
            return True
        #若是有值往下走
        #獲取緩存的key賦值給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:
            #頻率失敗
            return self.throttle_failure()
        #頻率成功
        return self.throttle_success()

#頻率失敗,返回false,沒有請求次數
    def throttle_failure(self):
        """
        Called when a request to the API has failed due to throttling.
        """
        return False

#頻率成功
    def throttle_success(self):
        """
        Inserts the current request's timestamp along with the key
        into the cache.
        """
        # history中加時間，再成功再加，並且是加在insert列表的第一個，history長度就會愈來愈大，因此history的長度就是訪問了幾回
        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，而後就超次了，因此就會返回False,因此就調用wait()
返回到
 def check_throttles(self, request):
      
        throtttle_durations=[]
        #throttle初始化成功以後
        for throttle in self.get_throttles():
           #初始化成功以後調用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資源文件throttling.py (有如下類)
如下是系統提供的三大頻率認證類，能夠局部或者全局配置
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'
    
    #返回一個字符串
    def get_cache_key(self, request, view):
        #有用戶而且是認證用戶
        if request.user.is_authenticated:
            #獲取到用戶的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
        }
點擊self.cache_format
cache_format = 'throttle_%(scope)s_%(ident)s'

假設個人認證類採用了UserRateThrottle(SimpleRetaThrottle),
    for throttle in self.get_throttles():pass  產生的throttle的就是UserRateThrottle產生的對象，而後UserRateThrottle中沒有__init__，因此走SimpleRetaThrottle的__init__方法
    
    def __init__(self):
        if not getattr(self, 'rate', None):
            self.rate = self.get_rate()
        self.num_requests, self.duration = self.parse_rate(self.rate)

        
點擊self.get_rate()，
    def get_rate(self):
        """
        Determine the string representation of the allowed request rate.
        """
        #若是沒有scope直接拋異常，
        #這裏的self就是UserRateThrottle產生的對象，返回到UserRateThrottle獲取到 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)

        try:
            #self.THROTTLE_RATES['user'] ,這種格式就能夠判斷THROTTLE_RATES是一個字典，點擊進入THROTTLE_RATES = api_settings.DEFAULT_THROTTLE_RATES   ，，跟以前同樣資源settings.py中ctrl+F查找DEFAULT_THROTTLE_RATES，
# 'DEFAULT_THROTTLE_RATES': {
     #   'user': None,
     #   'anon': None,
 #   },            
#而後在本身的settings.py中進行配置，就先走本身的配置，
            #因此在這裏的返回值是None
            return self.THROTTLE_RATES[self.scope]
        except KeyError:
            # 當key沒有對應的value的時候就會報錯，而這裏的user對應None因此是有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)

點擊 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>
        """
        #若是rate是None，返回None,None
        if rate is None:
            return (None, None)
        #若是rate不是None，就獲得的是字符串而且包含有一個‘/’，由於拆分後獲得得是兩個結果，而後有int強轉，因此num必定是一個數字
        num, period = rate.split('/')
        num_requests = int(num)
        #period[0]取第一位，而後做爲key到字典duration中查找，因此字母開頭必定要是s /m / h / d,發現value都是以秒來計算，因此獲得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)

爲了能rate拿到值，就能夠到本身得settings.py中配置
# drf配置
REST_FRAMEWORK = {
    # 頻率限制條件配置
    '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=[]

        for throttle in self.get_throttles():
            # 而後調用allow_request，到UserRateThrottle找，沒有走UserRateThrottle得父類SimpleRetaThrottle
            if not 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父級有這個方法，是拋異常，本身去實現這個方法
        #而後子級UserRateThrottle實現了這個方法
        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緩存
        #導包cache：from django.core.cache import cache as default_cache
        #緩存有過時時間，key,value,,,default是默認值
        #添加緩存：cache.set(key,defalut)
        #獲取緩存：cache.get(key,default) 沒有獲取到key採用默認值
        
        #獲取緩存key:'throttle_user_1'
        #初次訪問緩存爲空列表,self.history=[],
        self.history = self.cache.get(self.key, [])
        #獲取當前時間存入到self.now
        self.now = self.timer()

        
        while self.history and self.history[-1] <= self.now - self.duration:
            self.history.pop()
        #history的長度與限制次數3進行比較
        if len(self.history) >= self.num_requests:
            return self.throttle_failure()
        #history的長度未達到限制次數3，表明能夠訪問
        return self.throttle_success()

點擊self.throttle_success()
#將當前時間插入到history列表的開頭，將history列表做爲數據存到緩存中，key是'throttle_user_1'  ，過時時間60s
   def throttle_success(self):
        """
        Inserts the current request's timestamp along with the key
        into the cache.
        """
        #將當前的時間插到第一位
        self.history.insert(0, self.now)
        #設置緩存，key:'throttle_user_1' history:[self.now, self.now...]
        # duration過時時間60s:'60'
        self.cache.set(self.key, self.history, self.duration)
        return True

第二次訪問走到這個函數的時候
    
    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
        
        #第二次訪問self.history已經有值，就是第一次訪問存放的時間
        self.history = self.cache.get(self.key, [])
        #獲取當前時間存入到self.now
        self.now = self.timer()

        #也就是當前的時間減去history緩存的時間（永遠都取第一次訪問的時間，因此是-1）是否大於過時時間
        #self.now - self.history[-1] >= self.duration
        #當超出的過時時間時，也就是第四次訪問
        while self.history and self.history[-1] <= self.now - self.duration:
            #pop是將最後的時間拿出來
            self.history.pop()
        #history的長度與限制次數3進行比較
        #history長度 第一次訪問爲0， 第二次訪問爲1，第三次訪問的時間長度爲2，第四次訪問失敗
        if len(self.history) >= self.num_requests:
            #直接返回False,表明頻率限制了
            return self.throttle_failure()
        #history的長度未達到限制次數3，表明能夠訪問
        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():
            #只要頻率限制了，allow_request 返回False,纔會調用wait
            if not throttle.allow_request(request, self):
         
                self.throttled(request, throttle.wait())

調用的是SimpleRateThrottle的wait,由於UserRateThrouttle中沒有wait這個方法
    def wait(self):
        """
        Returns the recommended next request time in seconds.
        """
        #若是緩存中還有history等30s
        if self.history:
            #self.duration=60， self.now當前時間-self.history[-1]第一次訪問時間
            remaining_duration = self.duration - (self.now - self.history[-1])
        else:
            #若是緩存中沒有，直接等60s
            remaining_duration = self.duration
        #self.num_requests=3,len(self.history)=3 結果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
        #若是意外第二次訪問就被限制了就是30/2=15s
        return remaining_duration / float(available_requests)

自定義頻率類

# 1) 自定義一個繼承 SimpleRateThrottle 類 的頻率類
# 2) 設置一個 scope 類屬性，屬性值爲任意見名知意的字符串
# 3) 在settings配置文件中，配置drf的DEFAULT_THROTTLE_RATES，格式爲 {scope字符串: '次數/時間'}
# 4) 在自定義頻率類中重寫 get_cache_key 方法
    # 限制的對象返回 與限制信息有關的字符串
    # 不限制的對象返回 None (只能放回None，不能是False或是''等)

短信接口 1/min 頻率限制

頻率：api/throttles.py

from rest_framework.throttling import SimpleRateThrottle

class SMSRateThrottle(SimpleRateThrottle):
    scope = 'sms'

    # 只對提交手機號的get方法進行限制,由於get請求發送數據就是在params中傳送數據的，若是想要禁用post請發送過來的數據就要mobile = request.query_params.get('mobile') or request.data.get('mobile')
    def get_cache_key(self, request, view):
        mobile = request.query_params.get('mobile')
        # 沒有手機號，就不作頻率限制
        if not mobile:
            return None
        # 返回能夠根據手機號動態變化，且不易重複的字符串，做爲操做緩存的key
        return 'throttle_%(scope)s_%(ident)s' % {'scope': self.scope, 'ident': mobile}

配置：settings.py

# drf配置
REST_FRAMEWORK = {
    # 頻率限制條件配置
    'DEFAULT_THROTTLE_RATES': {
        'sms': '3/min'  #60s內能夠訪問三次請求
    },
}

視圖：views.py

from .throttles import SMSRateThrottle
class TestSMSAPIView(APIView):
    # 局部配置頻率認證
    throttle_classes = [SMSRateThrottle]
    def get(self, request, *args, **kwargs):
        return APIResponse(0, 'get 獲取驗證碼 OK')
    def post(self, request, *args, **kwargs):
        return APIResponse(0, 'post 獲取驗證碼  OK')

路由：api/url.py

url(r'^sms/$', views.TestSMSAPIView.as_view()),

限制的接口

# 只會對 /api/sms/?mobile=具體手機號 接口才會有頻率限制
# 1）對 /api/sms/ 或其餘接口發送無限制
# 2）對數據包提交mobile的/api/sms/接口無限制
# 3）對不是mobile（如phone）字段提交的電話接口無限制

測試