Extracts and decrypt a list of adf.ly links from a forum's post

downloader.py

# -*- coding: utf-8 -*-

import base64, requests, os, re, sys
from bs4 import BeautifulSoup

def _crack(code):

        zeros = ''
        ones = ''
        for n,letter in enumerate(code):
            if n % 2 == 0:
                zeros += code[n]
            else:
                ones = code[n] + ones

        key = zeros + ones
        key = list(key)
        i = 0

        while i < len(key):
            if key[i].isdigit():
                for j in range(i+1,len(key)):
                    if key[j].isdigit():
                        u = int(key[i])^int(key[j])
                        if u < 10: 
                            key[i] = str(u)
                        i = j					
                        break
            i+=1
        
        key = ''.join(key)
        url = base64.b64decode(key)[16:-16].decode('utf-8')

        return url

def _decrypt(url):
    adfly = requests.get(url).text
    ysmm = re.findall(r"var ysmm = '(.*?)';", adfly)[0]
    decrypted_url = _crack(ysmm)

    return decrypted_url

def main():
    with open('links2.txt', 'r') as target, open('output.txt', 'w') as output:

        soup    = BeautifulSoup(target, 'html.parser')
        items   = soup.select('a')
        links   = []

        for item in items:
            url = item.get('href')
            try:
                output.write("{} \n".format(_decrypt(url)))
            except Exception as e:
                print("Ocurrió un error: {}".format(e))
        
    print("¡Finalizado! Resultados guardados en output/output.txt")

if __name__ == "__main__":
    main()