Python爬虫反爬机制解析:Headers、IP代理与Cookies实战
本文详解Python爬虫应对常见反爬策略的三种核心方法。首先介绍如何通过F12开发者工具获取并模拟User-Agent和Referer以伪装浏览器身份;其次讲解IP代理的配置及访问频率控制,防止IP被封禁;最后阐述手动与自动获取Cookie的技巧,利用Session保持登录状态,有效解决403禁止访问错误。
一、浏览器模拟(Headers)
浏览器指纹模拟是应对反爬检测的基础手段。若网站频繁接收来自同一浏览器版本的高频请求,极易触发风控机制将其判定为机器人。为规避此风险,策略在于每次请求时动态更换浏览器标识信息。
如何找到浏览器信息
启动浏览器,按下F12键(Mac系统为Option+Command+I,或右键点击页面选择“检查”)进入开发者工具。

在开发者工具顶部导航栏中,点击“Network”(网络)标签页。

按下Ctrl+R(Mac系统为Command+R)刷新页面以触发网络抓包。
刷新完成后,在右侧Name列表中的任意请求项上点击,即可展开详情面板。红框标注区域即为当前浏览器向服务器发送的关键头部信息。

注意:部分网站会校验Referer字段,用于识别请求来源页面。类似某些特定站点会严格检查此信息,因此需通过上述相同步骤提取Referer值。如红框所示位置。

经由上述步骤,即可成功提取浏览器版本及相关头部信息。若能获取多组不同版本的标识数据,即可实现模拟不同浏览器的访问行为。
在Python代码中应用User-Agent的方法如下:
headers = {
'Referer': '具体的Referer',
'User-Agent': '具体的user-agent'
}
requests.get(url,headers=headers)
常用的模拟浏览器请求头(Headers)配置列表如下:
User_Agent = [
"Mozilla/5.0 (iPod; U; CPU iPhone OS 4_3_2 like Mac OS X; zh-cn) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8H7 Safari/6533.18.5",
"Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_3_2 like Mac OS X; zh-cn) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8H7 Safari/6533.18.5",
"MQQBrowser/25 (Linux; U; 2.3.3; zh-cn; HTC Desire S Build/GRI40;480*800)",
"Mozilla/5.0 (Linux; U; Android 2.3.3; zh-cn; HTC_DesireS_S510e Build/GRI40) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1",
"Mozilla/5.0 (SymbianOS/9.3; U; Series60/3.2 NokiaE75-1 /110.48.125 Profile/MIDP-2.1 Configuration/CLDC-1.1 ) AppleWebKit/413 (KHTML, like Gecko) Safari/413",
"Mozilla/5.0 (iPad; U; CPU OS 4_3_3 like Mac OS X; zh-cn) AppleWebKit/533.17.9 (KHTML, like Gecko) Mobile/8J2",
"Mozilla/5.0 (Windows NT 5.2) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.122 Safari/534.30",
"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_2) AppleWebKit/535.1 (KHTML, like Gecko) Chrome/14.0.835.202 Safari/535.1",
"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_2) AppleWebKit/534.51.22 (KHTML, like Gecko) Version/5.1.1 Safari/534.51.22",
"Mozilla/5.0 (iPhone; CPU iPhone OS 5_0 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A5313e Safari/7534.48.3",
"Mozilla/5.0 (iPhone; CPU iPhone OS 5_0 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A5313e Safari/7534.48.3",
"Mozilla/5.0 (iPhone; CPU iPhone OS 5_0 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A5313e Safari/7534.48.3",
"Mozilla/5.0 (Windows NT 6.1) AppleWebKit/535.1 (KHTML, like Gecko) Chrome/14.0.835.202 Safari/535.1",
"Mozilla/5.0 (compatible; MSIE 9.0; Windows Phone OS 7.5; Trident/5.0; IEMobile/9.0; SAMSUNG; OMNIA7)",
"Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0; XBLWP7; ZuneWP7)",
"Mozilla/5.0 (Windows NT 5.2) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.122 Safari/534.30",
"Mozilla/5.0 (Windows NT 5.1; rv:5.0) Gecko/20100101 Firefox/5.0",
"Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.2; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET4.0E; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; .NET4.0C)",
"Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.2; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET4.0E; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; .NET4.0C)",
"Mozilla/4.0 (compatible; MSIE 60; Windows NT 5.1; SV1; .NET CLR 2.0.50727)",
"Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; 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)",
"Opera/9.80 (Windows NT 5.1; U; zh-cn) Presto/2.9.168 Version/11.50",
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)",
"Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 2.0.50727; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022; .NET4.0E; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; .NET4.0C)",
"Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN) AppleWebKit/533.21.1 (KHTML, like Gecko) Version/5.0.5 Safari/533.21.1",
"Mozilla/5.0 (Windows; U; Windows NT 5.1; ) AppleWebKit/534.12 (KHTML, like Gecko) Maxthon/3.0 Safari/534.12",
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 2.0.50727; TheWorld)",
"Opera/9.80 (X11; Linux i686; Ubuntu/14.10) Presto/2.12.388 Version/12.16",
"Opera/9.80 (Windows NT 6.0) Presto/2.12.388 Version/12.14",
"Mozilla/5.0 (Windows NT 6.0; rv:2.0) Gecko/20100101 Firefox/4.0 Opera 12.14",
"Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.0) Opera 12.14",
"Opera/12.80 (Windows NT 5.1; U; en) Presto/2.10.289 Version/12.02",
"Opera/9.80 (Windows NT 6.1; U; es-ES) Presto/2.9.181 Version/12.00",
"Opera/9.80 (Windows NT 5.1; U; zh-sg) Presto/2.9.181 Version/12.00",
"Opera/12.0(Windows NT 5.2;U;en)Presto/22.9.168 Version/12.00",
"Opera/12.0(Windows NT 5.1;U;en)Presto/22.9.168 Version/12.00",
"Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.1",
"Mozilla/5.0 (Windows NT 6.3; rv:36.0) Gecko/20100101 Firefox/36.0",
"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10; rv:33.0) Gecko/20100101 Firefox/33.0",
"Mozilla/5.0 (X11; Linux i586; rv:31.0) Gecko/20100101 Firefox/31.0",
"Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20130401 Firefox/31.0",
"Mozilla/5.0 (Windows NT 5.1; rv:31.0) Gecko/20100101 Firefox/31.0",
"Mozilla/5.0 (Windows NT 6.1; WOW64; rv:29.0) Gecko/20120101 Firefox/29.0",
"Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:25.0) Gecko/20100101 Firefox/29.0",
"Mozilla/5.0 (X11; OpenBSD amd64; rv:28.0) Gecko/20100101 Firefox/28.0",
"Mozilla/5.0 (X11; Linux x86_64; rv:28.0) Gecko/20100101 Firefox/28.0",
"Mozilla/5.0 (Windows NT 6.1; rv:27.3) Gecko/20130101 Firefox/27.3",
"Mozilla/5.0 (Windows NT 6.2; Win64; x64; rv:27.0) Gecko/20121011 Firefox/27.0",
"Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:25.0) Gecko/20100101 Firefox/25.0",
"Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:25.0) Gecko/20100101 Firefox/25.0",
"Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:24.0) Gecko/20100101 Firefox/24.0",
"Mozilla/5.0 (Windows NT 6.0; WOW64; rv:24.0) Gecko/20100101 Firefox/24.0",
"Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:24.0) Gecko/20100101 Firefox/24.0"
]
二、IP代理
除浏览器指纹外,单一IP地址的高频访问同样会导致封禁风险。个人IP被封尚可接受,若企业出口IP被封锁,将严重影响业务访问。
针对IP策略,除需定期更换代理IP地址外,还需严格控制请求发送速度,避免程序高速运行导致瞬间流量激增。
Python中配置IP代理的代码示例如下:
import requests
proxies = {"http": 'IP地址'}
requests.get(url, headers=headers, proxies=proxies)
注:关于代理IP的来源,网络上存在大量免费或付费代理服务,可根据需求选择使用。
通过Python内置的time模块控制请求间隔:
import time
time.sleep(5)
三、Cookies模拟
访问某些网站时若返回403 Forbidden错误,通常意味着权限不足。这往往发生在未设置Cookie或Cookie配置错误的情况下。Cookie相当于网站的通行证,登录前后其值会发生显著变化。
手动获取cookie
获取Cookie的方式与提取User-Agent类似,可通过开发者工具直接查看:

自动获取cookie
利用requests库的Session对象可实现Cookie的自动管理与持久化。
具体示例代码如下:
import requests
session = requests.session()
session.cookies = LWPCookieJar(filename='Cookies.txt')
def login():
name = input("输入账户:")
password = input("输入密码:")
url = "url"
data = {
"ck": "",
"name": name,
"password": password,
"remember": "True",
"ticket": "",
}
response = session.post(url, data=data)
print(response.text)
session.cookies.save() # 保存 cookie
执行上述代码后,Cookie信息将自动保存至本地文件。
通过Session加载已保存Cookie的方法如下:
session.cookies = LWPCookieJar(filename='Cookies.txt')
session.cookies.load(ignore_discard=True)
使用cookies
获取Cookie后,使用方式与加载User-Agent类似,直接将其加入请求头即可。
headers = {
'Referer': '具体的Referer',
'User-Agent': '具体的user-agent',
'Cookie': 'cookie'
}
requests.get(url,headers=headers)
以上介绍了Python爬虫应对反爬机制的基础操作,更多相关技术资料请关注本站其他文章。
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