python：从零开始教你建立爬虫代理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。

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）

代码如下：

#!/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--------------------------------------------------------

# 写入文档

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)