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很多时候，如果要多线程的爬取网页，或者是单纯的反爬，我们需要通过代理IP来进行访问。下面看看一个基本的实现方法。
代理IP的提取，网上有很多网站都提供这个服务。基本上可靠性和银子是成正比的。国内提供的免费IP基本上都是没法用的，如果要可靠的代理只能付费；国外稍微好些，有些免费IP还是比较靠谱的。
网上随便搜索了一下，找了个网页，本来还想手动爬一些对应的IP，结果发现可以直接下载现成的txt文件
下载之后，试试看用不同的代理去爬百度首页
#！/usr/bin/env python#! -*- coding:utf-8 -*-# Author: Yuan Liimport re,urllib.requestfp=open("c:\\temp\\thebigproxylist-17-12-20.txt",'r')lines=fp.readlines()for ip in lines: try: print("当前代理IP "+ip) proxy=urllib.request.ProxyHandler({ "http":ip}) opener=urllib.request.build_opener(proxy,urllib.request.HTTPHandler) urllib.request.install_opener(opener) url="http://www.baidu.com" data=urllib.request.urlopen(url).read().decode('utf-8','ignore') print("通过") print("-----------------------------") except Exception as err: print(err) print("-----------------------------")fp.close() 结果如下：
C:\Python36\python.exe C:/Users/yuan.li/Documents/GitHub/Python/Misc/爬虫/proxy.py当前代理IP 137.74.168.174:80通过-----------------------------当前代理IP 103.28.161.68:8080通过-----------------------------当前代理IP 91.151.106.127:53281HTTP Error 503: Service Unavailable-----------------------------当前代理IP 177.136.252.7:3128-----------------------------当前代理IP 47.89.22.200:80通过-----------------------------当前代理IP 118.69.61.57:8888HTTP Error 503: Service Unavailable-----------------------------当前代理IP 192.241.190.167:8080通过-----------------------------当前代理IP 185.124.112.130:80通过-----------------------------当前代理IP 83.65.246.181:3128通过-----------------------------当前代理IP 79.137.42.124:3128通过-----------------------------当前代理IP 95.0.217.32:8080 -----------------------------当前代理IP 104.131.94.221:8080通过
不过上面这种方式只适合比较稳定的IP源，如果IP不稳定的话，可能很快对应的文本就失效了，最好可以动态地去获取最新的IP地址。很多网站都提供API可以实时地去查询
还是用刚才的网站，这次我们用API去调用，这里需要浏览器伪装一下才能爬取#！/usr/bin/env python#! -*- coding:utf-8 -*-# Author: Yuan Liimport re,urllib.requestheaders=("User-Agent","Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.22 Safari/537.36 SE 2.X MetaSr 1.0")opener=urllib.request.build_opener()opener.addheaders=[headers]#安装为全局urllib.request.install_opener(opener)data=urllib.request.urlopen("http://www.thebigproxylist.com/members/proxy-api.php?output=all&user=list&pass=8a544b2637e7a45d1536e34680e11adf").read().decode('utf8')ippool=data.split('\n')for ip in ippool: ip=ip.split(',')[0] try: print("当前代理IP "+ip) proxy=urllib.request.ProxyHandler({ "http":ip}) opener=urllib.request.build_opener(proxy,urllib.request.HTTPHandler) urllib.request.install_opener(opener) url="http://www.baidu.com" data=urllib.request.urlopen(url).read().decode('utf-8','ignore') print("通过") print("-----------------------------") except Exception as err: print(err) print("-----------------------------")fp.close() 结果如下：
C:\Python36\python.exe C:/Users/yuan.li/Documents/GitHub/Python/Misc/爬虫/proxy.py当前代理IP 213.233.57.134:80HTTP Error 403: Forbidden-----------------------------当前代理IP 144.76.81.79:3128通过-----------------------------当前代理IP 45.55.132.29:53281HTTP Error 503: Service Unavailable-----------------------------当前代理IP 180.254.133.124:8080通过-----------------------------当前代理IP 5.196.215.231:3128HTTP Error 503: Service Unavailable-----------------------------当前代理IP 177.99.175.195:53281HTTP Error 503: Service Unavailable
因为直接for循环来按顺序读取文本实在是太慢了，我试着改成多线程来读取，这样速度就快多了
#！/usr/bin/env python#! -*- coding:utf-8 -*-# Author: Yuan Liimport threadingimport queueimport re,urllib.request#Number of threadsn_thread = 10#Create queuequeue = queue.Queue()class ThreadClass(threading.Thread): def __init__(self, queue): threading.Thread.__init__(self) super(ThreadClass, self).__init__() #Assign thread working with queue self.queue = queue def run(self): while True: #Get from queue job host = self.queue.get() print (self.getName() + ":" + host) try: # print("当前代理IP " + host) proxy = urllib.request.ProxyHandler({ "http": host}) opener = urllib.request.build_opener(proxy, urllib.request.HTTPHandler) urllib.request.install_opener(opener) url = "http://www.baidu.com" data = urllib.request.urlopen(url).read().decode('utf-8', 'ignore') print("通过") print("-----------------------------") except Exception as err: print(err) print("-----------------------------") #signals to queue job is done self.queue.task_done()#Create number processfor i in range(n_thread): t = ThreadClass(queue) t.setDaemon(True) #Start thread t.start()#Read file line by linehostfile = open("c:\\temp\\thebigproxylist-17-12-20.txt","r")for line in hostfile: #Put line to queue queue.put(line)#wait on the queue until everything has been processedqueue.join()