python爬虫之User-Agent用户信息

　　爬虫是自动的爬取网站信息，实质上我们也只是一段代码，并不是真正的浏览器用户，加上User-Agent（用户代理，简称UA）信息，只是让我们伪装成一个浏览器用户去访问网站，然而一个用户频繁的访问一个网站很容易被察觉，既然我们可以伪装成浏览器，那么也同样可以通过UA信息来变换我们的身份。

　　整理部分UA信息

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

淘宝浏览器
Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.11 (KHTML, like Gecko) Chrome/20.0.1132.11 TaoBrowser/2.0 Safari/536.11

猎豹浏览器
Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.71 Safari/537.1 LBBROWSER
Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; LBBROWSER)
Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; QQDownload 732; .NET4.0C; .NET4.0E; LBBROWSER)"

QQ浏览器
Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; QQBrowser/7.0.3698.400)
Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; QQDownload 732; .NET4.0C; .NET4.0E)

sogou浏览器
Mozilla/5.0 (Windows NT 5.1) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.84 Safari/535.11 SE 2.X MetaSr 1.0
Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0; SV1; QQDownload 732; .NET4.0C; .NET4.0E; SE 2.X MetaSr 1.0)

maxthon浏览器
Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Maxthon/4.4.3.4000 Chrome/30.0.1599.101 Safari/537.36

UC浏览器
Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.122 UBrowser/4.0.3214.0 Safari/537.36

------UA信息链接：https://blog.csdn.net/tao_627/article/details/42297443 ------

User-Agent的添加方法

　　UA的添加方法有三种：1.实例化Request类时添加；2.调用Request类的实例方法add_header()动态添加；3.创建opener，赋值opener.addheaders修改。

　　方法一

 import urllib.request

 def load_message():

     url = 'https://www.baidu.com'

     header = {

         'user-agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.92 \

 Safari/537.36',

         'test': ''

     }

     request = urllib.request.Request(url, headers=header)  # 添加请求头

     response = urllib.request.urlopen(request)

     response_str = response.read().decode('utf-8')

     request_header_get = request.get_header('User-agent')  # 坑：查看时必须首字母大写，其他字母均小写，否则返回None

     print(request_header_get)  # 获取请求头的指定内容方式

     # request_header_get = request.get_header('Test')

     # print(request_header_get)

     #

     # request_header_get = request.get_header('test')

     # print(request_header_get)

     return response.headers, request.headers, response_str

 response_header, request_header, response_data = load_message()

 print(response_header)

 print('------------------------------------')

 print(request_header)

 print('------------------------------------')

 print(response_data)

　　方法二

 import urllib.request

 def load_message():

     url = 'https://www.baidu.com'

     request = urllib.request.Request(url)

     request.add_header('user-agent', 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko)\

 Chrome/69.0.3497.92Safari/537.36')  # 动态添加请求头信息

     response = urllib.request.urlopen(request)

     response_str = response.read().decode('utf-8')

     request_header_get = request.get_header('User-agent')  # 坑：查看时必须首字母大写，其他字母均小写，否则返回None

     print(request_header_get)  # 获取请求头的指定内容方式

     return response.headers, request.headers, response_str

 response_header, request_header, response_data = load_message()

 print(response_header)

 print('------------------------------------')

 print(request_header)

 print('------------------------------------')

 print(response_data)

方法三

 import urllib.request

 url= "http://blog.csdn.net/weiwei_pig/article/details/51178226"

 headers=("User-Agent","Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.122 Safari/537.36 SE 2.X MetaSr 1.0")

 opener = urllib.request.build_opener()

 opener.addheaders = [headers]

 data=opener.open(url).read()

随机UA信息添加至请求头的案例

 #!/usr/bin/env python

 # -*- coding=utf-8 -*-

 # Author: Snow

 import urllib.request

 import random

 def random_agent():

     url = 'https://www.baidu.com'

     user_agent_list = [

         'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36 ',

         'Mozilla/5.0 (Windows NT 5.1; U; en; rv:1.8.1) Gecko/20061208 Firefox/2.0.0 Opera 9.50',

         'Mozilla/5.0 (Windows NT 6.1; WOW64; rv:34.0) Gecko/20100101 Firefox/34.0',

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

         '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 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko',

         'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.11 (KHTML, like Gecko) Chrome/20.0.1132.11 TaoBrow\

 ser/2.0 Safari/536.11'

     ]

     user_agent_value = random.choice(user_agent_list)

     request = urllib.request.Request(url)

     request.add_header('User-Agent', user_agent_value)

     request_user_agent = request.get_header('User-agent')

     response = urllib.request.urlopen(request)

     response_str = response.read().decode('utf-8')

     return request_user_agent, response_str

 cat_user_agent, _ = random_agent()

 print(cat_user_agent)