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如何建立爬虫代理ip池?

  一、为什么需要建立爬虫代理ip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的,在某段时间内,当某个ip的访问量达到一定的阀值时, 该ip会被拉黑、在一段时间内被禁止访问这种时候,可以通过降低爬虫的频率,或者更改ip来应对。后者就需要有一个可 用的代理ip池,以供爬虫工作时切换。这个就是更换ip软件。


如何建立爬虫代理ip池?


  二、如何建立一个爬虫代理ip池


  思路:


  1、找到一个免费的ip代理网站(如:西刺代理)


  2、爬取ip(常规爬取requests+BeautifulSoup)


  3、验证ip有效性(携带爬取到的ip,去访问指定的url,看返回的状态码是不是200)


  4、记录ip (写到文档)


  #!/usr/bin/env python3


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


  import requests,threading,datetime


  from bs4 import BeautifulSoup


  import random


  1、抓取西刺代理网站的代理ip


  2、并根据指定的目标url,对抓取到ip的有效性进行验证


  3、最后存到指定的path


  文档处理


  def write(path,text):


  with open(path,'a', encoding='utf-8') as f:


  f.writelines(text)


  f.write('\n')


  清空文档


  def truncatefile(path):


  with open(path, 'w', encoding='utf-8') as f:


  f.truncate()


  读取文档


  def read(path):


  with open(path, 'r', encoding='utf-8') as f:


  txt = []


  for s in f.readlines():


  txt.append(s.strip())


  return txt


  计算时间差,格式: 时分秒


  def gettimediff(start,end):


  seconds = (end - start).seconds


  m, s = divmod(seconds, 60)


  h, m = divmod(m, 60)


  diff = ("%02d:%02d:%02d" % (h, m, s))


  return diff


  返回一个随机的请求头 headers


  def getheaders():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"


  ]


  UserAgent=random.choice(user_agent_list)


  headers = {'User-Agent': UserAgent}


  return headers


  检查ip是否可用


  def checkip(targeturl,ip):


  headers =getheaders()  # 定制请求头


  proxies = {"http": "http://"+ip, "https": "http://"+ip}  # 代理ip


  try:


  response=requests.get(url=targeturl,proxies=proxies,headers=headers,timeout=5).status_code


  if response == 200 :


  return True


  else:


  return False


  except:


  return False


  获取代理方法 免费代理 XiciDaili


  def findip(type,pagenum,targeturl,path): # ip类型,页码,目标url,存放ip的路径


  list={'1': 'http://www.xicidaili.com/nt/', # xicidaili国内普通代理


  '2': 'http://www.xicidaili.com/nn/', # xicidaili国内高匿代理


  '3': 'http://www.xicidaili.com/wn/', # xicidaili国内https代理


  '4': 'http://www.xicidaili.com/wt/'} # xicidaili国外http代理


  url=list[str(type)]+str(pagenum) # 配置url


  headers = getheaders() # 定制请求头


  html=requests.get(url=url,headers=headers,timeout = 5).text


  soup=BeautifulSoup(html,'lxml')


  all=soup.find_all('tr',class_='odd')


  for i in all:


  t=i.find_all('td')


  ip=t[1].text+':'+t[2].text


  is_avail = checkip(targeturl,ip)


  if is_avail == True:


  write(path=path,text=ip)


  print(ip)


  多线程抓取ip入口


  def getip(targeturl,path):


  truncatefile(path) # 爬取前清空文档


  start = datetime.datetime.now() # 开始时间


  threads=[]


  for type in range(4):   # 四种类型ip,每种类型取前三页,共12条线程


  for pagenum in range(3):


  t=threading.Thread(target=findip,args=(type+1,pagenum+1,targeturl,path))


  threads.append(t)


  print('开始爬取代理ip')


  for s in threads: # 开启多线程爬取


  s.start()


  for e in threads: # 等待所有线程结束


  e.join()


  print('爬取完成')


  end = datetime.datetime.now() # 结束时间


  diff = gettimediff(start, end)  # 计算耗时


  ips = read(path)  # 读取爬到的ip数量


  print('一共爬取代理ip: %s 个,共耗时: %s \n' % (len(ips), diff))


  启动


  if __name__ == '__main__':


  path = 'ip.txt' # 存放爬取ip的文档path


  targeturl = 'http://www.cnblogs.com/TurboWay/' # 验证ip有效性的指定url


  getip(targeturl,path)  http网页在线代理