详解基于Scrapy的IP代理池搭建

一、为什么要搭建爬虫代理池

在众多的网站防爬措施中，有一种是根据ip的访问频率进行限制，即在某一时间段内，当某个ip的访问次数达到一定的阀值时，该ip就会被拉黑、在一段时间内禁止访问。

应对的方法有两种：

1. 降低爬虫的爬取频率，避免IP被限制访问，缺点显而易见：会大大降低爬取的效率。

2. 搭建一个IP代理池，使用不同的IP轮流进行爬取。

二、搭建思路

1、从代理网站(如：西刺代理、快代理、云代理、无忧代理)爬取代理IP；

2、验证代理IP的可用性（使用代理IP去请求指定URL，根据响应验证代理IP是否生效）；

3、将可用的代理IP保存到数据库；

在《Python爬虫代理池搭建》一文中我们已经使用Python的 requests 模块简单实现了一个IP代理池搭建，但是爬取速度较慢。由于西刺代理、快代理和云代理等网站需要爬取的IP代理列表页多达上千页，使用此种方法来爬取其实并不适合。

本文将以快代理网站的IP代理爬取为例，示例如何使用 Scrapy-Redis 来爬取代理IP。

三、搭建代理池

scrapy 项目的目录结构如下：

items.py

# -*- coding: utf-8 -*-
import re
import scrapy
from proxy_pool.settings import PROXY_URL_FORMATTER

schema_pattern = re.compile(r'http|https$', re.I)
ip_pattern = re.compile(r'^([0-9]{1,3}.){3}[0-9]{1,3}$', re.I)
port_pattern = re.compile(r'^[0-9]{2,5}$', re.I)


class ProxyPoolItem(scrapy.Item):
  # define the fields for your item here like:
  # name = scrapy.Field()
  '''
    {
      "schema": "http", # 代理的类型
      "ip": "127.0.0.1", # 代理的IP地址
      "port": "8050", # 代理的端口号
      "original":"西刺代理",
      "used_total": 11, # 代理的使用次数
      "success_times": 5, # 代理请求成功的次数
      "continuous_failed": 3, # 使用代理发送请求，连续失败的次数
      "created_time": "2018-05-02" # 代理的爬取时间
    }
  '''
  schema = scrapy.Field()
  ip = scrapy.Field()
  port = scrapy.Field()
  original = scrapy.Field()
  used_total = scrapy.Field()
  success_times = scrapy.Field()
  continuous_failed = scrapy.Field()
  created_time = scrapy.Field()

  # 检查IP代理的格式是否正确
  def _check_format(self):
    if self['schema'] is not None and self['ip'] is not None and self['port'] is not None:
      if schema_pattern.match(self['schema']) and ip_pattern.match(self['ip']) and port_pattern.match(
          self['port']):
        return True
    return False

  # 获取IP代理的url
  def _get_url(self):
    return PROXY_URL_FORMATTER % {'schema': self['schema'], 'ip': self['ip'], 'port': self['port']}

kuai_proxy.py

# -*- coding: utf-8 -*-
import re
import time
import scrapy
from proxy_pool.utils import strip, logger
from proxy_pool.items import ProxyPoolItem


class KuaiProxySpider(scrapy.Spider):
  name = 'kuai_proxy'
  allowed_domains = ['kuaidaili.com']
  start_urls = ['https://www.kuaidaili.com/free/inha/1/', 'https://www.kuaidaili.com/free/intr/1/']

  def parse(self, response):
    logger.info('正在爬取：< ' + response.request.url + ' >')
    tr_list = response.css("div#list>table>tbody tr")
    for tr in tr_list:
      ip = tr.css("td[data-title='IP']::text").get()
      port = tr.css("td[data-title='PORT']::text").get()
      schema = tr.css("td[data-title='类型']::text").get()
      if schema.lower() == "http" or schema.lower() == "https":
        item = ProxyPoolItem()
        item['schema'] = strip(schema).lower()
        item['ip'] = strip(ip)
        item['port'] = strip(port)
        item['original'] = '快代理'
        item['created_time'] = time.strftime('%Y-%m-%d', time.localtime(time.time()))
        if item._check_format():
          yield item
    next_page = response.xpath("//a[@class='active']/../following-sibling::li/a/@href").get()
    if next_page is not None:
      next_url = 'https://www.kuaidaili.com' + next_page
      yield scrapy.Request(next_url)

middlewares.py

# -*- coding: utf-8 -*-

import random
from proxy_pool.utils import logger


# 随机选择 IP 代理下载器中间件
class RandomProxyMiddleware(object):

  # 从 settings 的 PROXIES 列表中随机选择一个作为代理
  def process_request(self, request, spider):
    proxy = random.choice(spider.settings['PROXIES'])
    request.meta['proxy'] = proxy
    return None


# 随机选择 User-Agent 的下载器中间件
class RandomUserAgentMiddleware(object):
  def process_request(self, request, spider):
    # 从 settings 的 USER_AGENTS 列表中随机选择一个作为 User-Agent
    user_agent = random.choice(spider.settings['USER_AGENT_LIST'])
    request.headers['User-Agent'] = user_agent
    return None

  def process_response(self, request, response, spider):
    # 验证 User-Agent 设置是否生效
    logger.info("headers ::> User-Agent = " + str(request.headers['User-Agent'], encoding="utf8"))
    return response

pipelines.py

# -*- coding: utf-8 -*-

import json
import redis
from proxy_pool.settings import REDIS_HOST,REDIS_PORT,REDIS_PARAMS,PROXIES_UNCHECKED_LIST,PROXIES_UNCHECKED_SET

server = redis.StrictRedis(host=REDIS_HOST, port=REDIS_PORT,password=REDIS_PARAMS['password'])

class ProxyPoolPipeline(object):

  # 将可用的IP代理添加到代理池队列
  def process_item(self, item, spider):
    if not self._is_existed(item):
      server.rpush(PROXIES_UNCHECKED_LIST, json.dumps(dict(item),ensure_ascii=False))

  # 检查IP代理是否已经存在
  def _is_existed(self,item):
    added = server.sadd(PROXIES_UNCHECKED_SET, item._get_url())
    return added == 0

settings.py

# -*- coding: utf-8 -*-
BOT_NAME = 'proxy_pool'

SPIDER_MODULES = ['proxy_pool.spiders']
NEWSPIDER_MODULE = 'proxy_pool.spiders'

# 保存未检验代理的Redis key
PROXIES_UNCHECKED_LIST = 'proxies:unchecked:list'

# 已经存在的未检验HTTP代理和HTTPS代理集合
PROXIES_UNCHECKED_SET = 'proxies:unchecked:set'

# 代理地址的格式化字符串
PROXY_URL_FORMATTER = '%(schema)s://%(ip)s:%(port)s'

# 通用请求头字段
DEFAULT_REQUEST_HEADERS = {
  'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8',
  'Accept-Encoding': 'gzip, deflate, br',
  'Accept-Language': 'zh-CN,zh;q=0.9,en;q=0.8,zh-TW;q=0.7',
  'Connection': 'keep-alive'
}

# 请求太频繁会导致 503 ,在此设置 5 秒请求一次
DOWNLOAD_DELAY = 5 # 250 ms of delay

USER_AGENT_LIST = [
  "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/22.0.1207.1 Safari/537.1",
  "Mozilla/5.0 (X11; CrOS i686 2268.111.0) AppleWebKit/536.11 (KHTML, like Gecko) Chrome/20.0.1132.57 Safari/536.11",
  "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.6 (KHTML, like Gecko) Chrome/20.0.1092.0 Safari/536.6",
  "Mozilla/5.0 (Windows NT 6.2) AppleWebKit/536.6 (KHTML, like Gecko) Chrome/20.0.1090.0 Safari/536.6",
  "Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/19.77.34.5 Safari/537.1",
  "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.9 Safari/536.5",
  "Mozilla/5.0 (Windows NT 6.0) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.36 Safari/536.5",
  "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.3 (KHTML, like Gecko) Chrome/19.0.1063.0 Safari/536.3",
  "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.3 (KHTML, like Gecko) Chrome/19.0.1063.0 Safari/536.3",
  "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_0) AppleWebKit/536.3 (KHTML, like Gecko) Chrome/19.0.1063.0 Safari/536.3",
  "Mozilla/5.0 (Windows NT 6.2) AppleWebKit/536.3 (KHTML, like Gecko) Chrome/19.0.1062.0 Safari/536.3",
  "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.3 (KHTML, like Gecko) Chrome/19.0.1062.0 Safari/536.3",
  "Mozilla/5.0 (Windows NT 6.2) AppleWebKit/536.3 (KHTML, like Gecko) Chrome/19.0.1061.1 Safari/536.3",
  "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.3 (KHTML, like Gecko) Chrome/19.0.1061.1 Safari/536.3",
  "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/536.3 (KHTML, like Gecko) Chrome/19.0.1061.1 Safari/536.3",
  "Mozilla/5.0 (Windows NT 6.2) AppleWebKit/536.3 (KHTML, like Gecko) Chrome/19.0.1061.0 Safari/536.3",
  "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/535.24 (KHTML, like Gecko) Chrome/19.0.1055.1 Safari/535.24",
  "Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/535.24 (KHTML, like Gecko) Chrome/19.0.1055.1 Safari/535.24"
]

# Obey robots.txt rules
ROBOTSTXT_OBEY = False

# Enable or disable downloader middlewares
# See https://doc.scrapy.org/en/latest/topics/downloader-middleware.html
DOWNLOADER_MIDDLEWARES = {
  'proxy_pool.middlewares.RandomUserAgentMiddleware': 543,
  #  'proxy_pool.middlewares.RandomProxyMiddleware': 544,
}

ITEM_PIPELINES = {
  'proxy_pool.pipelines.ProxyPoolPipeline': 300,
}

PROXIES = [
  "https://171.13.92.212:9797",
  "https://164.163.234.210:8080",
  "https://143.202.73.219:8080",
  "https://103.75.166.15:8080"
]

######################################################
##############下面是Scrapy-Redis相关配置################
######################################################

# 指定Redis的主机名和端口
REDIS_HOST = '172.16.250.238'
REDIS_PORT = 6379
REDIS_PARAMS = {'password': '123456'}

# 调度器启用Redis存储Requests队列
SCHEDULER = "scrapy_redis.scheduler.Scheduler"

# 确保所有的爬虫实例使用Redis进行重复过滤
DUPEFILTER_CLASS = "scrapy_redis.dupefilter.RFPDupeFilter"

# 将Requests队列持久化到Redis，可支持暂停或重启爬虫
SCHEDULER_PERSIST = True

# Requests的调度策略，默认优先级队列
SCHEDULER_QUEUE_CLASS = 'scrapy_redis.queue.PriorityQueue'

utils.py

# -*- coding: utf-8 -*-
import logging

# 设置日志输出格式
logging.basicConfig(level=logging.INFO,
          format='[%(asctime)-15s] [%(levelname)8s] [%(name)10s ] - %(message)s (%(filename)s:%(lineno)s)',
          datefmt='%Y-%m-%d %T'
          )
logger = logging.getLogger(__name__)

# Truncate header and tailer blanks
def strip(data):
  if data is not None:
    return data.strip()
  return data

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