在Scrapy中使用IP池或用户代理更新版（python3）

middlewares.py

 # -*- coding: utf-8 -*-
 # 导入随机模块
 import random
 # 导入有关IP池有关的模块
 from scrapy.downloadermiddlewares.httpproxy import HttpProxyMiddleware
 # 导入有关用户代理有关的模块
 from scrapy.downloadermiddlewares.useragent import UserAgentMiddleware

 # IP池
 class HTTPPROXY(HttpProxyMiddleware):
     # 初始化 注意一定是 ip=''
     def __init__(self, ip=''):
         self.ip = ip

     def process_request(self, request, spider):
         item = random.choice(IPPOOL)
         try:
             print("当前的IP是："+item["ipaddr"])
             request.meta["proxy"] = "http://"+item["ipaddr"]
         except Exception as e:
             print(e)
             pass

 # 设置IP池
 IPPOOL = [
     {"ipaddr": "182.117.102.10:8118"},
     {"ipaddr": "121.31.102.215:8123"},
     {"ipaddr": "1222.94.128.49:8118"}
 ]

 # 用户代理
 class USERAGENT(UserAgentMiddleware):
     #初始化 注意一定是 user_agent=''
     def __init__(self, user_agent=''):
         self.user_agent = user_agent

     def process_request(self, request, spider):
         item = random.choice(UPPOOL)
         try:
             print("当前的User-Agent是："+item)
             request.headers.setdefault('User-Agent', item)
         except Exception as e:
             print(e)
             pass

 # 设置用户代理池
 UPPOOL = [
     "Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.79 Safari/537.36 Edge/14.14393"
 ]

settngs.py中添加一下代码（注意根据项目名修改指向，如这里的工程名是“的demo3”）

 DOWNLOADER_MIDDLEWARES = {
     # 'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware':123,
     # 'demo3.middlewares.HTTPPROXY' : 125,
     'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware': 2,
     'demo3.middlewares.USERAGENT': 1
 }