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 reimport scrapyfrom proxy_pool.settings import PROXY_URL_FORMATTERschema_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 reimport timeimport scrapyfrom proxy_pool.utils import strip, loggerfrom proxy_pool.items import ProxyPoolItemclass KuaiProxySpider(scrapy.Spider): name = 'kuai_proxy' allowed_domains = ['kuaidaili.com'] start_urls = ['https://' + next_page yield scrapy.Request(next_url)

middlewares.py

# -*- coding: utf-8 -*-import randomfrom 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 jsonimport redisfrom proxy_pool.settings import REDIS_HOST,REDIS_PORT,REDIS_PARAMS,PROXIES_UNCHECKED_LIST,PROXIES_UNCHECKED_SETserver = 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 keyPROXIES_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 delayUSER_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 rulesROBOTSTXT_OBEY = False# Enable or disable downloader middlewares# See https://doc.scrapy.org/en/latest/topics/downloader-middleware.htmlDOWNLOADER_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 = 6379REDIS_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 blanksdef strip(data): if data is not None: return data.strip() return data

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