写爬虫总是免不了被ban  ip，限制流量等问题，有个高效的ip代理池还是很重要的，这里我们就介绍如何从已有公开代理总提取有效ip组建自己高效的爬虫代理池

主要以下几个模块

1.requests爬取代理 2.更新检测可用代理

requests爬取代理，选取xici代理为例

高匿网页地址xici， 检查元素

xici

元素选择就是id为ip_list的tr为一个一个的代理，td下为详细信息，因此css选择器就可以为 content.css("#ip_list").css(“tr”) ，然后在提取1，6项即可,后续加入判断ip可用性选项，判断成功后存入json文件，以后就可以通过http形式获取到可用的代理信息。

#!/root/anaconda3/bin/python

from scrapy.selector import Selector
import redis
import requests
import json
import requests
from requests.packages.urllib3.exceptions import InsecureRequestWarning
requests.packages.urllib3.disable_warnings(InsecureRequestWarning)
import random
def get_headers():
    USER_AGENT_LIST = [
    'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; 360SE)',
    'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 Safari/537.36',
    'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET4.0C; .NET4.0E; 360SE)'
    'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.140 Safari/537.36 Edge/18.17763',
    '"Mozilla/5.0 (Linux; Android 6.0.1; Nexus 5X Build/MMB29P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.96 Mobile Safari/537.36',
    'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36 SE 2.X MetaSr 1.0',

]
    USER_AGENT = random.choice(USER_AGENT_LIST)

    return {'User-Agent':USER_AGENT}
def get_random_proxy():
    https_pro=[i for i in pro if "https" in i]
    if len(https_pro)==0:
        return None
    else:
        return https_pro[random.randint(0,len(https_pro))] 
def crawl_ip():
   
    
    for i in range(5):
        
        rand_ip = get_random_proxy()
        if rand_ip:
            r =requests.get('https://www.xicidaili.com/nn/{}'.format(str(i+1)),headers=get_headers())
        else:
            r =requests.get('https://www.xicidaili.com/nn/{}'.format(str(i+1)),headers=get_headers(),proxies=proxies_ip(rand_ip))
        content = Selector(r)
        ip_list = content.css("#ip_list").css("tr")
        for i in ip_list[1:]:
            
            info = i.css("td::text").extract()
            ip = info[0]
            protoco = info[5].strip().lower()
            if protoco=="http" or protoco=="https":
                url = protoco + '://' + ip + ':' + info[1] 
            else:
                url = 'http://' + ip + ':' + info[1]
            validate_ip(url)

def proxies_ip(url):
    if 'https' not in url:
        proxies={'http':url}
    else:
        proxies={'https':url}
    return proxies

def validate_ip(url):
    proxies = proxies_ip(url)
    if url not in pro:
        bobo_url=http_url
        if "https" in url:
            bobo_url=https_url
        try:
            r = requests.get(bobo_url, headers=get_headers(), proxies=proxies, timeout=1)
            pro.append(url)
            print('ip %s validated' % url)
        except Exception as e:
            print('cant check ip %s' % url)
def check_current_ip():# 更新检测可用代理
    curr = open(JSON_PATH).read()
    if curr!='':
        for url in json.loads(open(JSON_PATH).read()):
            validate_ip(url)
if __name__ =='__main__':
    http_url = "http://www.bobobk.com"
    https_url = "https://www.bobobk.com"
    pro = []
    TXT_PATH = '/www/wwwroot/default/daili.txt'
    JSON_PATH='/www/wwwroot/default/daili.json'
    PROXYCHAIN_CONF='/www/wwwroot/default/proxy.conf'
    check_current_ip()
    crawl_ip()

    with open(JSON_PATH,'w') as fw:
        fw.write(json.dumps(list(set(pro))))

    fw.close()
    with open(TXT_PATH,'w') as fw:
        for i in set(pro):
            fw.write(i+"\n")
    fw.close()

更新检测可用代理

程序每次抓取页面前先检测可用代理，然后自动使用可用代理来抓取新的代理，可以稳定运行。 这里设置一下定时运行，那么就可以每小时自动更新代理信息

crontab -e

调用定时任务，加入当前脚本，就可以。 本人服务器实例

0 */1 * * *  /www/service/daili.py >> /www/service/daili.log 2>&1

最后访问127.0.0.1/daili.txt就可以看到搜集到的代理了