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Python - fake_useragent

楔子

在爬虫中进行request请求,很多时候,都需要添加请求头,不然服务器会认为是非法的请求,从而拒绝你的访问。

import requests
url = 'https://www.zhihu.com/question/315387406/answer/812734512'
response = requests.get(url=url)
print(response.status_code)  # 400

在添加请求头中最常用的就是添加user-agent来讲本次请求伪装成浏览器。

User Agent 中文名为用户代理,简称 UA,它是一个特殊字符串头,使得服务器能够识别客户使用的操作系统及版本、CPU 类型、浏览器及版本、浏览器渲染引擎、浏览器语言、浏览器插件等。

那么个人怎么搞这个user-agent呢,没错?八仙过海各显神通,但一般都是用手来解决个人问题!

import requests

url = 'https://www.zhihu.com/question/315387406/answer/812734512'
headers = {
    "user-agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.132 Safari/537.36"
}
response = requests.get(url=url, headers=headers)
print(response.status_code)  # 200

但,自从有了fake_useragent,妈妈再也不用担心......

from fake_useragent import UserAgent
# 实例化 user-agent 对象
ua = UserAgent()

url = 'https://www.zhihu.com/question/315387406/answer/812734512'
headers = {"user-agent": ua.chrome}  # 指定浏览器 user-agent
# 或者可以这样写
# headers = {"user-agent": UserAgent().random}  # 一步到位,随机生成一个 user-agent
response = requests.get(url=url, headers=headers)
print(response.status_code)  # 200

About

什么是fake_useragent?

简单来说,fake_useragent就像你的女朋友,能灵活的帮助我们生成user-agent,从而解放双手。

install

pip install fake_useragent

update

pip install -U fake-useragent

查看版本

import fake_useragent
print(fake_useragent.VERSION)  # 0.1.11

Usage

生成指定浏览器的user-agent

import fake_useragent

# 实例化 user-agent 对象
ua = fake_useragent.UserAgent()

# ua.ie
print(ua.ie)  # Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0; chromeframe/13.0.782.215)

# ua.msie
print(ua['Internet Explorer'])  # Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; InfoPath.2; SLCC1; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; .NET CLR 2.0.50727)

# ua.opera
print(ua.opera)  # Opera/9.80 (Windows NT 6.1; U; en-US) Presto/2.7.62 Version/11.01

# ua.chrome
print(ua.chrome)  # Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.16 Safari/537.36

# ua.google
print(ua['google chrome'])  # Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2227.0 Safari/537.36

# ua.firefox
print(ua.firefox)  # Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:16.0.1) Gecko/20121011 Firefox/21.0.1

# ua.ff
print(ua.ff)  # Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:25.0) Gecko/20100101 Firefox/29.0

# ua.safari
print(ua.safari)  # Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-TW) AppleWebKit/533.19.4 (KHTML, like Gecko) Version/5.0.2 Safari/533.18.5

随机生成user-agent

import fake_useragent

# 实例化 user-agent 对象
ua = fake_useragent.UserAgent()
print(ua.random)  # Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.67 Safari/537.36
print(ua.random)  # Mozilla/5.0 (compatible; MSIE 10.0; Macintosh; Intel Mac OS X 10_7_3; Trident/6.0)
print(ua.random)  # Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/537.36

每次都能随机生成一个UA表示,大大增强了爬虫的真实性。

其他用法

将远程user agent json文件下载到本地

由于fake_useragent库维护的user-agent json文件是在线的:

import fake_useragent
print(fake_useragent.settings.CACHE_SERVER)
'''
# 网址,其实是个json文件
https://fake-useragent.herokuapp.com/browsers/0.1.11
'''

既然是在线的json文件,那么我们就可将之下载到本地:

from fake_useragent import UserAgent, VERSION

location = './fake_useragent%s.json' % fake_useragent.VERSION
ua = UserAgent(path=location)

如果报错fake_useragent.errors.FakeUserAgentError: Maximum amount of retries reached,重新运行代码就好。

完事你就会发现在与脚本文件的同级目录有了一个json文件。

如果仅是想跟新本地已保存的json文件

from fake_useragent import UserAgent
ua = UserAgent()
ua.update()

如果你不想缓存数据库或没有可写文件系统

from fake_useragent import UserAgent
ua = UserAgent(cache=False)

如果不想使用托管的缓存服务器

from fake_useragent import UserAgent
ua = UserAgent(use_cache_server=False)

处理异常

fake_useragent.errors.FakeUserAgentError: Maximum amount of retries

from fake_useragent import UserAgent
# 禁用服务器缓存: use_cache_server=False
headers = {"User-Agent": UserAgent(use_cache_server=False).chrome}
response = requests.get(url=url, headers=headers)
print(response.status_code)  # 200

FakeUserAgentError(‘Maximum amount of retries reached’

from fake_useragent import UserAgent
# 法1 禁用服务器缓存: use_cache_server=False
headers = {"User-Agent": UserAgent(use_cache_server=False).chrome}
# 法2 忽略ssl验证
headers = {"User-Agent": UserAgent(verify_ssl=False).chrome}
# 法3 不缓存数据
headers = {"User-Agent": UserAgent(cache=False).chrome}
response = requests.get(url=url, headers=headers)
print(response.status_code)  # 200

fake_useragent.errors.FakeUserAgentError: Maximum amount of retries reached

from fake_useragent import UserAgent, VERSION

location = './fake_useragent%s.json' % fake_useragent.VERSION
ua = UserAgent(path=location)

我在将在线的json文件写入到本地时,由urllib.error.URLError: <urlopen error timed out>引起的报错,重新运行就好,本地文件也下载完成。


欢迎斧正,that's all see also:[fake_useragent-github](https://github.com/hellysmile/fake-useragent) | [fake_user_agent-pypi]() | [Python爬虫小技巧之伪造随机的User-Agent]() | [Python 使用 fake-useragent 库时报错的解决方法]()
posted @ 2019-09-16 09:29  听雨危楼  阅读(2723)  评论(0编辑  收藏  举报