使用爬虫抓取数据时，经常要用到多个ip代理，防止单个ip访问太过频繁被封禁。
ip代理可以从这个网站获取：http://www.xicidaili.com/nn/。
因此写一个python程序来获取ip代理，保存到本地。
python版本：3.6.3

#grab ip proxies from xicidaili
import sys, time, re, requests
from multiprocessing.dummy import Pool as ThreadPool
from lxml import etree

IP_POOL = 'ip_pool.py'
URL = 'http://www.xicidaili.com/nn/' #IP代理 高匿
#URL = 'http://www.xicidaili.com/wt/' #IP代理 http
RUN_TIME = time.strftime("%Y-%m-%d %H:%M", time.localtime()) #执行时间

#用字典存放有效ip代理
alive_ip = {'http': [], 'https': []}
#多线程
pool = ThreadPool(20)

#返回html文本
def get_html(url):
    headers = {
        "User-Agent": "Mozilla/5.0 (Windows NT 10.0; WOW64; rv:55.0) Gecko/20100101 Firefox/55.0",
        "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
        "Accept-Language": "zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3",
        "Accept-Encoding": "gzip, deflate",
        "Referer": "https://www.xicidaili.com/",
        "Connection": "keep-alive",
        "Upgrade-Insecure-Requests": "1"
    }
    r = requests.get(url, headers=headers)
    r.encoding = 'utf-8'
    return r.text

#测试ip代理是否存活
def test_alive(proxy):
    global alive_ip
    proxies = {'http': proxy}
    try:
        r = requests.get('https://www.baidu.com', proxies=proxies, timeout=3)
        if r.status_code == 200:
            if proxy.startswith('https'):
                alive_ip['https'].append(proxy)
            else:
                alive_ip['http'].append(proxy)
    except:
        print("%s无效!"%proxy)

#解析html文本，获取ip代理
def get_alive_ip_address():
    iplist = []
    html = get_html(URL)
    selector = etree.HTML(html)
    table = selector.xpath('//table[@id="ip_list"]')[0]
    lines = table.xpath('./tr')[1:]
    for line in lines:
        speed, connect_time = line.xpath('.//div/@title')
        data = line.xpath('./td')
        ip = data[1].xpath('./text()')[0]
        port = data[2].xpath('./text()')[0]
        anonymous = data[4].xpath('./text()')[0]
        ip_type = data[5].xpath('./text()')[0]
        #过滤掉速度慢和非高匿的ip代理
        if float(speed[:-1])>1 or float(connect_time[:-1])>1 or anonymous != '高匿':
            continue
        iplist.append(ip_type.lower() + '://' + ip + ':' + port)
    pool.map(test_alive, iplist)

#把抓取到的有效ip代理写入到本地
def write_txt(output_file):
    with open(output_file, 'w') as f:
        f.write('#create time: %s\n\n' % RUN_TIME)
        f.write('http_ip_pool = \\\n')
        f.write(str(alive_ip['http']).replace(',', ',\n'))
        f.write('\n\n')
    with open(output_file, 'a') as f:
        f.write('https_ip_pool = \\\n')
        f.write(str(alive_ip['https']).replace(',', ',\n'))
    print('write successful: %s' % output_file)

def main():
    get_alive_ip_address()
    write_txt(output_file)

if __name__ == '__main__':
    try:
        output_file = sys.argv[1] #第一个参数作为文件名
    except:
        output_file = IP_POOL
    main()

运行程序：

root@c:test$ python get_ip_proxies.py
write successful: ip_pool.py

查看文件：

root@c:test$ vim ip_pool.py

#create time: 2019-03-14 19:53

http_ip_pool = \
['http://183.148.152.1:9999',
 'http://112.85.165.234:9999',
 'http://112.8