12.DRF-節流

Django rest framework源碼分析(3)—-節流

添加節流

自定義節流的方法

  • 限制60s內只能訪問3次

(1)API文件夾下面新建throttle.py,代碼如下:

# utils/throttle.py

from rest_framework.throttling import BaseThrottle
import time
VISIT_RECORD = {}   #保存訪問記錄

class VisitThrottle(BaseThrottle):
    '''60s內只能訪問3次'''
    def __init__(self):
        self.history = None   #初始化訪問記錄

    def allow_request(self,request,view):
        #獲取用戶ip (get_ident)
        remote_addr = self.get_ident(request)
        ctime = time.time()
        #如果當前IP不在訪問記錄裏面,就添加到記錄
        if remote_addr not in VISIT_RECORD:
            VISIT_RECORD[remote_addr] = [ctime,]     #鍵值對的形式保存
            return True    #True表示可以訪問
        #獲取當前ip的歷史訪問記錄
        history = VISIT_RECORD.get(remote_addr)
        #初始化訪問記錄
        self.history = history

        #如果有歷史訪問記錄,並且最早一次的訪問記錄離當前時間超過60s,就刪除最早的那個訪問記錄,
        #只要為True,就一直循環刪除最早的一次訪問記錄
        while history and history[-1] < ctime - 60:
            history.pop()
        #如果訪問記錄不超過三次,就把當前的訪問記錄插到第一個位置(pop刪除最後一個)
        if len(history) < 3:
            history.insert(0,ctime)
            return True

    def wait(self):
        '''還需要等多久才能訪問'''
        ctime = time.time()
        return 60 - (ctime - self.history[-1])

(2)settings中全局配置節流

#全局
REST_FRAMEWORK = {
    #節流
    "DEFAULT_THROTTLE_CLASSES":['API.utils.throttle.VisitThrottle'],
}

(3)現在訪問auth看看結果:

  • 60s內訪問次數超過三次,會限制訪問
  • 提示剩餘多少時間可以訪問

接着訪問

節流源碼分析

(1)dispatch

def dispatch(self, request, *args, **kwargs):
    """
    `.dispatch()` is pretty much the same as Django's regular dispatch,
    but with extra hooks for startup, finalize, and exception handling.
    """
    self.args = args
    self.kwargs = kwargs
    #對原始request進行加工,豐富了一些功能
    #Request(
    #     request,
    #     parsers=self.get_parsers(),
    #     authenticators=self.get_authenticators(),
    #     negotiator=self.get_content_negotiator(),
    #     parser_context=parser_context
    # )
    #request(原始request,[BasicAuthentications對象,])
    #獲取原生request,request._request
    #獲取認證類的對象,request.authticators
    #1.封裝request
    request = self.initialize_request(request, *args, **kwargs)
    self.request = request
    self.headers = self.default_response_headers  # deprecate?

    try:
        #2.認證
        self.initial(request, *args, **kwargs)

        # Get the appropriate handler method
        if request.method.lower() in self.http_method_names:
            handler = getattr(self, request.method.lower(),
                                  self.http_method_not_allowed)
        else:
            handler = self.http_method_not_allowed

        response = handler(request, *args, **kwargs)

    except Exception as exc:
        response = self.handle_exception(exc)

    self.response = self.finalize_response(request, response, *args, **kwargs)
    return self.response

(2)initial

def initial(self, request, *args, **kwargs):
    """
    Runs anything that needs to occur prior to calling the method handler.
    """
    self.format_kwarg = self.get_format_suffix(**kwargs)

    # Perform content negotiation and store the accepted info on the request
    neg = self.perform_content_negotiation(request)
    request.accepted_renderer, request.accepted_media_type = neg

    # Determine the API version, if versioning is in use.
    version, scheme = self.determine_version(request, *args, **kwargs)
    request.version, request.versioning_scheme = version, scheme

    # Ensure that the incoming request is permitted
    #4.實現認證
    self.perform_authentication(request)
    #5.權限判斷
    self.check_permissions(request)
    #6.控制訪問頻率
    self.check_throttles(request)

(3)check_throttles

裏面有個allow_request

def check_throttles(self, request):
    """
    Check if request should be throttled.
    Raises an appropriate exception if the request is throttled.
    """
    for throttle in self.get_throttles():
        if not throttle.allow_request(request, self):
            self.throttled(request, throttle.wait())

(4)get_throttles

def get_throttles(self):
    """
    Instantiates and returns the list of throttles that this view uses.
    """
    return [throttle() for throttle in self.throttle_classes]

(5)thtottle_classes

內置節流類

上面是寫的自定義節流,drf內置了很多節流的類,用起來比較方便。

(1)BaseThrottle

  • 自己要寫allow_request和wait方法
  • get_ident就是獲取ip
class BaseThrottle(object):
    """
    Rate throttling of requests.
    """

    def allow_request(self, request, view):
        """
        Return `True` if the request should be allowed, `False` otherwise.
        """
        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

    def wait(self):
        """
        Optionally, return a recommended number of seconds to wait before
        the next request.
        """
        return None

(2)SimpleRateThrottle

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   #這個值自定義,寫什麼都可以
    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)

我們可以通過繼承SimpleRateThrottle類,來實現節流,會更加的簡單,因為SimpleRateThrottle裏面都幫我們寫好了

(1)throttle.py

from rest_framework.throttling import SimpleRateThrottle

class VisitThrottle(SimpleRateThrottle):
    '''匿名用戶60s只能訪問三次(根據ip)'''
    scope = 'NBA'   #這裏面的值,自己隨便定義,settings裏面根據這個值配置Rate

    def get_cache_key(self, request, view):
        #通過ip限制節流
        return self.get_ident(request)

class UserThrottle(SimpleRateThrottle):
    '''登錄用戶60s可以訪問10次'''
    scope = 'NBAUser'    #這裏面的值,自己隨便定義,settings裏面根據這個值配置Rate

    def get_cache_key(self, request, view):
        return request.user.username

(2)settings.py

#全局
REST_FRAMEWORK = {
    #節流
    "DEFAULT_THROTTLE_CLASSES":['API.utils.throttle.UserThrottle'],   #全局配置,登錄用戶節流限制(10/m)
    "DEFAULT_THROTTLE_RATES":{
        'NBA':'3/m',         #沒登錄用戶3/m,NBA就是scope定義的值
        'NBAUser':'10/m',    #登錄用戶10/m,NBAUser就是scope定義的值
    }
}

(3)views.py

局部配置方法

class AuthView(APIView):
    .
    .    
    .
    # 默認的節流是登錄用戶(10/m),AuthView不需要登錄,這裏用匿名用戶的節流(3/m)
    throttle_classes = [VisitThrottle,]   .    .
# views.py
from django.shortcuts import render,HttpResponse
from django.http import JsonResponse
from rest_framework.views import APIView
from API import models
from rest_framework.request import Request
from rest_framework import exceptions
from rest_framework.authentication import BaseAuthentication
from API.utils.permission import SVIPPremission,MyPremission
from API.utils.throttle import  VisitThrottle

ORDER_DICT = {
    1:{
        'name':'apple',
        'price':15
    },
    2:{
        'name':'dog',
        'price':100
    }
}

def md5(user):
    import hashlib
    import time
    #當前時間,相當於生成一個隨機的字符串
    ctime = str(time.time())
    m = hashlib.md5(bytes(user,encoding='utf-8'))
    m.update(bytes(ctime,encoding='utf-8'))
    return m.hexdigest()


class AuthView(APIView):
    '''用於用戶登錄驗證'''

    authentication_classes = []      #裏面為空,代表不需要認證
    permission_classes = []          #不裏面為空,代表不需要權限
    # 默認的節流是登錄用戶(10/m),AuthView不需要登錄,這裏用匿名用戶的節流(3/m)
    throttle_classes = [VisitThrottle,]

    def post(self,request,*args,**kwargs):
        ret = {'code':1000,'msg':None}
        try:
            user = request._request.POST.get('username')
            pwd = request._request.POST.get('password')
            obj = models.UserInfo.objects.filter(username=user,password=pwd).first()
            if not obj:
                ret['code'] = 1001
                ret['msg'] = '用戶名或密碼錯誤'
            #為用戶創建token
            token = md5(user)
            #存在就更新,不存在就創建
            models.UserToken.objects.update_or_create(user=obj,defaults={'token':token})
            ret['token'] = token
        except Exception as e:
            ret['code'] = 1002
            ret['msg'] = '請求異常'
        return JsonResponse(ret)


class OrderView(APIView):
    '''
    訂單相關業務(只有SVIP用戶才能看)
    '''

    def get(self,request,*args,**kwargs):
        self.dispatch
        #request.user
        #request.auth
        ret = {'code':1000,'msg':None,'data':None}
        try:
            ret['data'] = ORDER_DICT
        except Exception as e:
            pass
        return JsonResponse(ret)


class UserInfoView(APIView):
    '''
       訂單相關業務(普通用戶和VIP用戶可以看)
       '''
    permission_classes = [MyPremission,]    #不用全局的權限配置的話,這裏就要寫自己的局部權限
    def get(self,request,*args,**kwargs):

        print(request.user)
        return HttpResponse('用戶信息')

說明:

  • API.utils.throttle.UserThrottle 這個是全局配置(根據ip限制,10/m)
  • DEFAULT_THROTTLE_RATES —>>>設置訪問頻率的
  • throttle_classes = [VisitThrottle,] —>>>局部配置(不適用settings裏面默認的全局配置)

總結

基本使用

  • 創建類,繼承BaseThrottle, 實現:allow_request ,wait
  • 創建類,繼承SimpleRateThrottle, 實現: get_cache_key, scope=’NBA’ (配置文件中的key)

全局

   #節流
    "DEFAULT_THROTTLE_CLASSES":['API.utils.throttle.UserThrottle'],   #全局配置,登錄用戶節流限制(10/m)
    "DEFAULT_THROTTLE_RATES":{
        'NBA':'3/m',         #沒登錄用戶3/m,NBA就是scope定義的值
        'NBAUser':'10/m',    #登錄用戶10/m,NBAUser就是scope定義的值
    }
}

局部

throttle_classes = [VisitThrottle,]

所有代碼

認證、權限和節流

# MyProject/urls.py

from django.contrib import admin
from django.urls import path
from API.views import AuthView,OrderView,UserInfoView

urlpatterns = [
    path('admin/', admin.site.urls),
    path('api/v1/auth/',AuthView.as_view()),
    path('api/v1/order/',OrderView.as_view()),
    path('api/v1/info/',UserInfoView.as_view()),
]
#全局 settings.py
REST_FRAMEWORK = {
    #認證
    "DEFAULT_AUTHENTICATION_CLASSES":['API.utils.auth.Authentication',],
    #權限
    "DEFAULT_PERMISSION_CLASSES":['API.utils.permission.SVIPPermission'],
    #節流
    "DEFAULT_THROTTLE_CLASSES":['API.utils.throttle.UserThrottle'],   #全局配置,登錄用戶節流限制(10/m)
    "DEFAULT_THROTTLE_RATES":{
        'NBA':'3/m',         #沒登錄用戶3/m,NBA就是scope定義的值
        'NBAUser':'10/m',    #登錄用戶10/m,NBAUser就是scope定義的值
    }
}
# API/models.py


from django.db import models

class UserInfo(models.Model):
    USER_TYPE = (
        (1,'普通用戶'),
        (2,'VIP'),
        (3,'SVIP')
    )

    user_type = models.IntegerField(choices=USER_TYPE)
    username = models.CharField(max_length=32)
    password = models.CharField(max_length=64)

class UserToken(models.Model):
    user = models.OneToOneField(UserInfo,on_delete=models.CASCADE)
    token = models.CharField(max_length=64)
# API/views.py

from django.shortcuts import render,HttpResponse
from django.http import JsonResponse
from rest_framework.views import APIView
from API import models
from rest_framework.request import Request
from rest_framework import exceptions
from rest_framework.authentication import BaseAuthentication
from API.utils.permission import SVIPPermission,MyPermission
from API.utils.throttle import  VisitThrottle

ORDER_DICT = {
    1:{
        'name':'apple',
        'price':15
    },
    2:{
        'name':'dog',
        'price':100
    }
}

def md5(user):
    import hashlib
    import time
    #當前時間,相當於生成一個隨機的字符串
    ctime = str(time.time())
    m = hashlib.md5(bytes(user,encoding='utf-8'))
    m.update(bytes(ctime,encoding='utf-8'))
    return m.hexdigest()


class AuthView(APIView):
    '''用於用戶登錄驗證'''

    authentication_classes = []      #裏面為空,代表不需要認證
    permission_classes = []          #不裏面為空,代表不需要權限
    # 默認的節流是登錄用戶(10/m),AuthView不需要登錄,這裏用匿名用戶的節流(3/m)
    throttle_classes = [VisitThrottle,]

    def post(self,request,*args,**kwargs):
        ret = {'code':1000,'msg':None}
        try:
            user = request._request.POST.get('username')
            pwd = request._request.POST.get('password')
            obj = models.UserInfo.objects.filter(username=user,password=pwd).first()
            if not obj:
                ret['code'] = 1001
                ret['msg'] = '用戶名或密碼錯誤'
            #為用戶創建token
            token = md5(user)
            #存在就更新,不存在就創建
            models.UserToken.objects.update_or_create(user=obj,defaults={'token':token})
            ret['token'] = token
        except Exception as e:
            ret['code'] = 1002
            ret['msg'] = '請求異常'
        return JsonResponse(ret)


class OrderView(APIView):
    '''
    訂單相關業務(只有SVIP用戶才能看)
    '''

    def get(self,request,*args,**kwargs):
        self.dispatch
        #request.user
        #request.auth
        ret = {'code':1000,'msg':None,'data':None}
        try:
            ret['data'] = ORDER_DICT
        except Exception as e:
            pass
        return JsonResponse(ret)


class UserInfoView(APIView):
    '''
       訂單相關業務(普通用戶和VIP用戶可以看)
       '''
    permission_classes = [MyPermission,]    #不用全局的權限配置的話,這裏就要寫自己的局部權限
    def get(self,request,*args,**kwargs):

        print(request.user)
        return HttpResponse('用戶信息')
# API/utils/auth/py

from rest_framework import exceptions
from API import models
from rest_framework.authentication import BaseAuthentication


class Authentication(BaseAuthentication):
    '''用於用戶登錄驗證'''
    def authenticate(self,request):
        token = request._request.GET.get('token')
        token_obj = models.UserToken.objects.filter(token=token).first()
        if not token_obj:
            raise exceptions.AuthenticationFailed('用戶認證失敗')
        #在rest framework內部會將這兩個字段賦值給request,以供後續操作使用
        return (token_obj.user,token_obj)

    def authenticate_header(self, request):
        pass
# utils/permission.py

from rest_framework.permissions import BasePermission

class SVIPPermission(BasePermission):
    message = "必須是SVIP才能訪問"
    def has_permission(self,request,view):
        if request.user.user_type != 3:
            return False
        return True


class MyPermission(BasePermission):
    def has_permission(self,request,view):
        if request.user.user_type == 3:
            return False
        return True
# utils/throttle.py
#
# from rest_framework.throttling import BaseThrottle
# import time
# VISIT_RECORD = {}   #保存訪問記錄
#
# class VisitThrottle(BaseThrottle):
#     '''60s內只能訪問3次'''
#     def __init__(self):
#         self.history = None   #初始化訪問記錄
#
#     def allow_request(self,request,view):
#         #獲取用戶ip (get_ident)
#         remote_addr = self.get_ident(request)
#         ctime = time.time()
#         #如果當前IP不在訪問記錄裏面,就添加到記錄
#         if remote_addr not in VISIT_RECORD:
#             VISIT_RECORD[remote_addr] = [ctime,]     #鍵值對的形式保存
#             return True    #True表示可以訪問
#         #獲取當前ip的歷史訪問記錄
#         history = VISIT_RECORD.get(remote_addr)
#         #初始化訪問記錄
#         self.history = history
#
#         #如果有歷史訪問記錄,並且最早一次的訪問記錄離當前時間超過60s,就刪除最早的那個訪問記錄,
#         #只要為True,就一直循環刪除最早的一次訪問記錄
#         while history and history[-1] < ctime - 60:
#             history.pop()
#         #如果訪問記錄不超過三次,就把當前的訪問記錄插到第一個位置(pop刪除最後一個)
#         if len(history) < 3:
#             history.insert(0,ctime)
#             return True
#
#     def wait(self):
#         '''還需要等多久才能訪問'''
#         ctime = time.time()
#         return 60 - (ctime - self.history[-1])

from rest_framework.throttling import SimpleRateThrottle

class VisitThrottle(SimpleRateThrottle):
    '''匿名用戶60s只能訪問三次(根據ip)'''
    scope = 'NBA'   #這裏面的值,自己隨便定義,settings裏面根據這個值配置Rate

    def get_cache_key(self, request, view):
        #通過ip限制節流
        return self.get_ident(request)

class UserThrottle(SimpleRateThrottle):
    '''登錄用戶60s可以訪問10次'''
    scope = 'NBAUser'    #這裏面的值,自己隨便定義,settings裏面根據這個值配置Rate

    def get_cache_key(self, request, view):
        return request.user.username

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