大师兄的Python学习笔记(二十六）: 爬虫（七）

大师兄的Python学习笔记(二十五）: 爬虫（六）
大师兄的Python学习笔记(二十七）: 爬虫（八）

八、使用Cookies模拟登录状态

• 通常，为了爬取数据，我们需要先登录网站。
• 为此，我们可以通过获取登录Cookies,并使用Cookies模拟登录状态。
• 以微博为例，思路如下:

1) 观察页面，了解到需要通过请求获取预登陆数据

2 ) 输入密码后，观察登录表单，获取预登陆数据格式。

3) 使用预登陆数据登录微博,并获取cookies。

4) 使用session + cookies访问页面保持登陆状态

>>>import requests
>>>import json
>>>import urllib
>>>import base64
>>>import rsa
>>>import binascii
>>>import re
>>>import time

>>>class Login:
>>>    def __init__(self,username,password):
>>>        self.login_url = "https://login.sina.com.cn/sso/login.php"
>>>        self.prelogin_url = r'https://login.sina.com.cn/sso/prelogin.php?entry=weibo&callback=sinaSSOController.preloginCallBack&su=&rsakt=mod&client=ssologin.js(v1.4.15)'  # 
>>>        self.username = username
>>>        self.password = password
>>>        self.session = requests.Session()

>>>    def Prelogin(self):
>>>        # 请求prelogin并获取参数
>>>        su_url = urllib.parse.quote_plus(self.username)  # 用户名先用url加密
>>>        su_encoded = su_url.encode('utf-8')
>>>        su = base64.b64encode(su_encoded)  # 再用base64加密
>>>        su = su.decode('utf-8')

>>>        per_login_params = {
>>>            'entry': "account",
>>>            'callback': "sinaSSOController.preloginCallBack",
>>>            'su': su,
>>>            'rsakt': "mod",
>>>            'client': "ssologin.js(v1.4.15)",
>>>            '_': int(time.time() * 1000),
>>>        }
>>>        try:
>>>            response = self.session.get(self.prelogin_url, params=per_login_params)
>>>            # 响应异常时，抛出异常信息
>>>            response.raise_for_status()
>>>        except Exception as error:
>>>            print('failed to prelogin:')
>>>            raise error

>>>        data_dict = json.loads(response.text.strip('sinaSSOController.preloginCallBack(').strip(')'))
>>>        pubkey = data_dict.get('pubkey')
>>>        servertime = data_dict.get('servertime')
>>>        nonce = data_dict.get('nonce')
>>>        rsakv = data_dict.get('rsakv')
>>>        return (su,pubkey, servertime, nonce, rsakv)

>>>    def RSAEncoder(self,pubkey, servertime, nonce):
>>>        # 增加密码
>>>        rsaPublickey = int(pubkey, 16)
>>>        e = int('10001', 16)
>>>        key = rsa.PublicKey(rsaPublickey, e)
>>>        message = str(servertime) + '\t' + str(nonce) + '\n' + str(self.password)
>>>        password = rsa.encrypt(message.encode('utf-8'), key)         # 加密密码
>>>        sp = binascii.b2a_hex(password).decode('utf-8')
>>>        return sp

>>>    def PostData(self,su,pubkey, servertime, nonce, rsakv):
>>>        # 模拟ssologin.js发送请求并获得cookies

>>>        sp = self.RSAEncoder(pubkey, servertime, nonce)

>>>        post_data = {
>>>            'entry': "account",
>>>            'gateway': "1",
>>>            'from': "null",
>>>            'savestate': "30",
>>>            'useticket': "0",
>>>            'vsnf': "1",
>>>            'su': su,
>>>            'service': "account",
>>>            'servertime': servertime,
>>>            'nonce': nonce,
>>>            'pwencode': "rsa2",
>>>            'rsakv': rsakv,
>>>            'sp': sp,
>>>            'sr': "1280*720",
>>>            'encoding': "UTF-8",
>>>            'cdult': "3",
>>>            'domain': "sina.com.cn",
>>>            'prelt': "170",
>>>            'returntype': "TEXT",
>>>        }

>>>        return post_data

>>>    def login(self):
>>>        login_params = {
>>>            'client': "ssologin.js(v1.4.15)",
>>>            '_': int(time.time() * 1000),
>>>        }

>>>        su,pubkey, servertime, nonce, rsakv = self.Prelogin()
>>>        post_data = self.PostData(su,pubkey,servertime,nonce,rsakv)

>>>        try:
>>>            response = self.session.post(self.login_url, params=login_params, data=post_data)
>>>            response.raise_for_status()
>>>        except Exception as error:
>>>            print("failed to login:")
>>>            raise error

>>>        cross_url = re.search(r'"(https:.*?)"', response.text).group(1)
>>>        cross_url = re.sub(r'\\', '', re.sub(r'\\', '', cross_url))

>>>        if cross_url:
>>>            print(f"redirecting to {cross_url}")
>>>            response = self.session.get(cross_url)
>>>            print(response.text)
>>>        else:
>>>            print(f"failed to login.")

>>>if __name__ == '__main__':
>>>    l = Login("yourusername","yourpassword")
>>>    l.login()
redirecting to https://passport.weibo.com/wbsso/login?ticket=ST-MTE4ODA5MTk3MQ%3D%3D-1597372265-tc-8B866F78C8DDA0E122A23B69D585454D-1&ssosavestate=1628908265
({"result":true,"userinfo":{"uniqueid":"xxxxxx","displayname":"xxxxxx"}});

参考资料

• https://blog.csdn.net/u010138758/article/details/80152151 J-Ombudsman
• https://www.cnblogs.com/zhuluqing/p/8832205.html moisiet
• https://www.runoob.com 菜鸟教程
• http://www.tulingxueyuan.com/ 北京图灵学院
• http://www.imooc.com/article/19184?block_id=tuijian_wz#child_5_1 两点水
• https://blog.csdn.net/weixin_44213550/article/details/91346411 python老菜鸟
• https://realpython.com/python-string-formatting/ Dan Bader
• https://www.liaoxuefeng.com/ 廖雪峰
• https://blog.csdn.net/Gnewocean/article/details/85319590 新海说
• https://www.cnblogs.com/Nicholas0707/p/9021672.html Nicholas
• https://www.cnblogs.com/dalaoban/p/9331113.html 超天大圣
• https://blog.csdn.net/zhubao124/article/details/81662775 zhubao124
• https://blog.csdn.net/z59d8m6e40/article/details/72871485 z59d8m6e40
• https://www.jianshu.com/p/2b04f5eb5785 MR_ChanHwang
• 《Python学习手册》Mark Lutz
• 《Python编程 从入门到实践》Eric Matthes
• 《Python3网络爬虫开发实战》崔庆才

本文作者：大师兄(superkmi)