蓝奏云获取下载链接js逆向

本期地址如下，使用base64解密获得
aHR0cHM6Ly9meGpkLmxhbnpvdXcuY29tL2l6bkxrMTdncnkyZA==

获取最终的下载链接需要经过三次请求获得，如下图

每个请求都包含下一次请求的信息，我们逐步分析请求

第一个请求直接包含了第二次请求的src

第二个请求直接包含了第三次post请求所需要传的data参数

第三个请求直接包含了文件下载的url

所以本质上，这里面没有js逆向的逻辑，只是请求的逻辑而已，python代码如下

import requests
import re
from bs4 import BeautifulSoup

session = requests.session()

headers = {
    'Accept': 'application/json, text/javascript, */*',
    'Accept-Language': 'zh-CN,zh;q=0.9',
    'Cache-Control': 'no-cache',
    'Connection': 'keep-alive',
    'Content-Type': 'application/x-www-form-urlencoded',
    # 'Cookie': 'codelen=1; Hm_lvt_fb7e760e987871d56396999d288238a4=1705051448; pc_ad1=1; uz_distinctid=18cfcfc9243e23-06f6015bb3f86a-26001951-384000-18cfcfc9244134c; STDATA82=czst_eid%3D130820850-3821-https%253A%252F%252Ffxjd.lanzouw.com%252F%26ntime%3D3821; Hm_lpvt_fb7e760e987871d56396999d288238a4=1705051547',
    'Origin': 'https://fxjd.lanzouw.com',
    'Pragma': 'no-cache',
    'Referer': 'https://fxjd.lanzouw.com/fn?VzEGbAhkD2hWNQJlC2ZVbQRnAz4FaQQgBXZTaAVoBDJVZQVnCWRQMQVhAmUEZF1qA38CcVc1ATIFJFUkV25XNFckBjgIMg81VmsCMQsmVWkEawN3BRYEPw_c_c',
    'Sec-Fetch-Dest': 'empty',
    'Sec-Fetch-Mode': 'cors',
    'Sec-Fetch-Site': 'same-origin',
    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
    'X-Requested-With': 'XMLHttpRequest',
    'sec-ch-ua': '"Not_A Brand";v="8", "Chromium";v="120", "Google Chrome";v="120"',
    'sec-ch-ua-mobile': '?0',
    'sec-ch-ua-platform': '"Windows"',
}
host = "https://fxjd.lanzouw.com"

response = session.get('https://fxjd.lanzouw.com/iW8O40no7fni', headers=headers)
print(response)
soup = BeautifulSoup(response.text, 'html.parser')
divs = soup.find('div', {'class': 'n_downlink'})
src = soup.find(class_="n_downlink").get("src")

second_src = host + src
response = session.get(second_src, headers=headers)
print(response)
pattern = r']*>(.*?)'
matches = re.findall(pattern, response.text, re.DOTALL)

dowload_js = matches[1]
aihidcms = re.search(r"var aihidcms\s*=\s*'(.*?)';", dowload_js).group(1)
action = re.search(r"'action':'(.*?)'", dowload_js).group(1)
ajaxdata = re.search(r"var ajaxdata\s*=\s*'(.*?)';", dowload_js).group(1)
sign = re.search(r"'sign':'(.*?)'", dowload_js).group(1)
ciucjdsdc = re.search(r"var ciucjdsdc\s*=\s*'(.*?)';", dowload_js).group(1)
ves = re.search(r"'ves':(\d+)", dowload_js).group(1)

print("aihidcms:", aihidcms)
print("action:", action)
print("ajaxdata:", ajaxdata)
print("sign:", sign)
print("ciucjdsdc:", ciucjdsdc)
print("ves:", ves)

data = {
    'action': action,
    'signs': ajaxdata,
    'sign': sign,
    'websign': ciucjdsdc,
    'websignkey': aihidcms,
    'ves': ves,
}

response = session.post('https://fxjd.lanzouw.com/ajaxm.php',  headers=headers, data=data)
print(response)
print(response.json())

data_src = 'https://developer-oss.lanrar.com/file/' + response.json().get('url')
response = session.get(data_src,  headers=headers)
print(response)
print(len(response.content))

拿到最后的文件content，大小也是正确