爬虫案例：有道翻译python逆向

pip install

pip install requests
pip install base64
pip install pycrytodome

tools

浏览器的开发者工具，重点使用断点，和调用堆栈
工具网站：https://curlconverter.com/ 简便请求发送信息

flow

在这里插入图片描述

根据网站信息，preview,response均是加密数据，或者说请求和响应我们都需要使用代码来进行模仿
由请求方式是post，所以我们需要关注payload载荷发现动态值sign,mysticTime是时间戳
对JS代码进行分析，找到动态值生成的地方，这里可以使用initiator发起程序，使用调用堆栈进行溯源，打断点进行测试，分析可知动态值是由md5摘要得出。
分析可知数据是base64变种对响应数据进行base64解码处理，分析加密算法是AES对称加密，找到对称密钥key,iv，进行解密。
最后对json数据进行反序列化，取得特定值

Code

import requests
import time
import hashlib
import base64
import json
from Crypto.Cipher import AES
from Crypto.Util.Padding import unpaddef get_md5(value, is_hex=True):"""md5 abstract algorithmparams:value: str, the value to be md5is_hex: bool, whether to return the md5 value in hex formatreturn: str, the md5 value"""md5 = hashlib.md5()md5.update(value.encode('utf-8'))if is_hex:return md5.hexdigest()else:return md5.digest()word = input("Enter the word to be translated ：")
url =  'https://dict.youdao.com/webtranslate'
mysticTime = str(int(time.time() * 1000))# (1)构建逆向动态值
d = 'fanyideskweb'
e = mysticTime
u = 'webfanyi'
t = 'fsdsogkndfokasodnaso'i = f"client={d}&mysticTime={e}&product={u}&key={t}"
sign = get_md5(i)# （2）请求模拟
cookies = {'OUTFOX_SEARCH_USER_ID': '-815609020@10.55.164.249','OUTFOX_SEARCH_USER_ID_NCOO': '1719344943.4114175','_ga': 'GA1.2.674292823.1712131832',
}headers = {'Accept': 'application/json, text/plain, */*','Accept-Language': 'zh-CN,zh;q=0.9,en;q=0.8,en-GB;q=0.7,en-US;q=0.6','Connection': 'keep-alive','Content-Type': 'application/x-www-form-urlencoded','Cookie': 'OUTFOX_SEARCH_USER_ID=-815609020@10.55.164.249; OUTFOX_SEARCH_USER_ID_NCOO=1719344943.4114175; _ga=GA1.2.674292823.1712131832','Origin': 'https://fanyi.youdao.com','Referer': 'https://fanyi.youdao.com/','Sec-Fetch-Dest': 'empty','Sec-Fetch-Mode': 'cors','Sec-Fetch-Site': 'same-site','User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36 Edg/126.0.0.0','sec-ch-ua': '"Not/A)Brand";v="8", "Chromium";v="126", "Microsoft Edge";v="126"','sec-ch-ua-mobile': '?0','sec-ch-ua-platform': '"Windows"','referer': 'https://fanyi.youdao.com/',
}data = {'i': word,'from': 'auto','to': '','useTerm': 'false','dictResult': 'true','keyid': 'webfanyi','sign': sign,'client': 'fanyideskweb','product': 'webfanyi','appVersion': '1.0.0','vendor': 'web','pointParam': 'client,mysticTime,product','mysticTime': mysticTime,'keyfrom': 'fanyi.web','mid': '1','screen': '1','model': '1','network': 'wifi','abtest': '0','yduuid': 'abcdefg',
}res = requests.post(url , cookies=cookies, headers=headers, data=data)# base64变种 --> 正常base64
res_encrypt_base64 = res.text.replace('-', '+').replace('_', '/')# （3）解码和解密数据
res_encrypt_bytes = res_encrypt_base64.encode('utf-8')# 1.解码  
res_encrypt_decode = base64.b64decode(res_encrypt_bytes)# 2.解密
t = 'ydsecret://query/key/B*RGygVywfNBwpmBaZg*WT7SIOUP2T0C9WHMZN39j^DAdaZhAnxvGcCY6VYFwnHl'
o = 'ydsecret://query/iv/C@lZe2YzHtZ2CYgaXKSVfsb7Y4QWHjITPPZ0nQp87fBeJ!Iv6v^6fvi2WN@bYpJ4'key = get_md5(t, is_hex=False)
iv = get_md5(o, is_hex=False)aes = AES.new(key, AES.MODE_CBC, iv)
source_data = aes.decrypt(res_encrypt_decode)# （4）解析数据
data = unpad(source_data, 16)  # json字符串,有base64填充，所以需要去填充
data = json.loads(data)ret = [line.get('tgt') for line in data['translateResult'][0]]
print("\n".join(ret))