sis_force_auth.user.js

// ==UserScript==
// @name         SIS force auth
// @namespace    http://grsc.cz/
// @version      2024-08-28
// @description  SIS force auth from cookie
// @author       Greenscreener
// @match        https://is.cuni.cz/studium/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=cuni.cz
// @grant        none
// ==/UserScript==

(function() {
    'use strict';
    const id = new URLSearchParams(window.location.search).get("id")
    const matches = document.cookie.match(/sis_url_auth_because_this_is_stoopid=([a-f0-9]{32})/)
    if (id !== null && id.match(/^[a-f0-9]{32}$/g)) {
        document.cookie = "sis_url_auth_because_this_is_stoopid=" + id + ";path=/"
    } else if (matches) {
        const search = (new URLSearchParams(window.location.search))
        search.set("id",matches[1])
        search.set("tid","")
        window.location.search = search
        console.log("redirecting")
    }
})();