设置User-Agent和IP代理

设置User-Agent作用是隐藏爬虫身份，IP代理则可以避免频繁访问网站资源导致的封禁

一、常见的User-Agent

Opera
Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36 OPR/26.0.1656.60
Opera/8.0 (Windows NT 5.1; U; en)
Mozilla/5.0 (Windows NT 5.1; U; en; rv:1.8.1) Gecko/20061208 Firefox/2.0.0 Opera 9.50
Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; en) Opera 9.50

Firefox
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:34.0) Gecko/20100101 Firefox/34.0
Mozilla/5.0 (X11; U; Linux x86_64; zh-CN; rv:1.9.2.10) Gecko/20100922 Ubuntu/10.10 (maverick) Firefox/3.6.10

Safari
Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/534.57.2 (KHTML, like Gecko) Version/5.1.7 Safari/534.57.2

chrome
Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.71 Safari/537.36
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11
Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.133 Safari/534.16

360
Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/30.0.1599.101 Safari/537.36
Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko

二、设置User-Agent

1. 创建Request对象时指定headers

 url = 'http://www.csdn.net/'
 head = {}
 head['User-Agent'] = 'Mozilla/5.0 (Linux; Android 4.1.1; Nexus 7 Build/JRO03D) AppleWebKit/535.19 (KHTML,  like Gecko) Chrome/18.0.1025.166  Safari/535.19'
 req = request.Request(url, headers=head)
 #传入创建好的Request对象
 response = request.urlopen(req)
 html = response.read().decode('utf-8')
 print(html)

1. 创建Request对象后使用add_header

 req.add_header('User-Agent', 'Mozilla/5.0 (Linux; Android 4.1.1; Nexus 7 Build/JRO03D) AppleWebKit/535.19 (KHTML, like Gecko) Chrome/18.0.1025.166  Safari/535.19')
 # 参数为 (key, value) 

三、IP代理

找合适的IP地址进行伪装
URL：http://www.xicidaili.com/
使用install_opener方法之后，会将程序默认的urlopen方法替换掉。也就是说，如果使用install_opener之后，在该文件中，再次调用urlopen会使用自己创建好的opener。如果不想替换掉，只是想临时使用一下，可以使用opener.open(url)，这样就不会对程序默认的urlopen有影响。

from urllib import request

if __name__ == "__main__":
    url = 'http://www.whatismyip.com.tw/'
    #这是代理IP
    proxy = {'http':'106.46.136.112:808'}
    #创建ProxyHandler
    proxy_support = request.ProxyHandler(proxy)
    #创建Opener
    opener = request.build_opener(proxy_support)
    #添加User Angent
    opener.addheaders = [('User-Agent','Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36')]
    #安装OPener
    request.install_opener(opener)
    #使用自己安装好的Opener
    response = request.urlopen(url)
    html = response.read().decode("utf-8")
    print(html)

参考链接：https://blog.csdn.net/c406495762/article/details/60137956