Django自定义中间件开发指南：从原理到频率限制实战

django.utils.deprecation.py

class MiddlewareMixin(object):
 def __init__(self, get_response=None):
  self.get_response = get_response
  super(MiddlewareMixin, self).__init__()

 def __call__(self, request):
  response = None
  if hasattr(self, 'process_request'):
   response = self.process_request(request)
  if not response:
   response = self.get_response(request)
  if hasattr(self, 'process_response'):
   response = self.process_response(request, response)
  return response

def __init__(self, get_response=None):
 self.get_response = get_response
 super(MiddlewareMixin, self).__init__()

def __call__(self, request):
  response = None
  if hasattr(self, 'process_request'):
    response = self.process_request(request)
  if not response:
    response = self.get_response(request)
  if hasattr(self, 'process_response'):
    response = self.process_response(request, response)
  return response

from django.utils.deprecation import MiddlewareMixin

class PermissionMiddlewareMixin(MiddlewareMixin):
  """
  django 中间件
  """

  def process_request(self, request):
    pass

  def process_response(self, request, response):
    return response

# coding:utf-8

__author__ = 'carey@akhack.com'

from django.utils.deprecation import MiddlewareMixin
from django.http.response import HttpResponse
from django_redis import get_redis_connection
from hashlib import md5


class RequestBlockMiddlewareMixin(MiddlewareMixin):
  """
  django中间件客户端请求频率限制
  """

  limit = 4 # 单位时间内允许请求次数
  expire = 1 # 限制时间
  cache = "default" # 获取django cache

  def process_request(self, request):
    num = self.set_key(request)
    if num > self.limit:
      return HttpResponse("请求频率过快，请稍后重试", status=503)

  @staticmethod
  def get_ident(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.
    """
    NUM_PROXIES = 1
    xff = request.META.get('HTTP_X_FORWARDED_FOR')
    remote_addr = request.META.get('REMOTE_ADDR')
    num_proxies = 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 get_md5(self, request):
    """
    获取IP md5值
    :param request:
    :return:
    """
    ip_str = self.get_ident(request)
    ip_md5 = md5()
    ip_md5.update(ip_str.encode("utf-8"))
    return ip_md5.hexdigest()

  def set_key(self, request):
    """
    通过redis lua脚本设置请求请求次数和限制时间
    :param request:
    :return: 限制时间内请求次数
    """
    lua = """
      local current
      current = redis.call("incr",KEYS[1])
      if tonumber(current) == 1 then
        redis.call("expire",KEYS[1],ARGV[1])
      end
      return tonumber(redis.call("get", KEYS[1]))
      """
    key = self.get_md5(request)
    redis_cli = get_redis_connection(self.cache)
    data = redis_cli.eval(lua, 1, key, self.expire, self.limit)
    return data