add torrents directly from nyaa.si to WebUI qBittorent instance

nyaa-qbit.js

// ==UserScript==
// @name         Nyaa to qBittorrent
// @namespace    https://violentmonkey.github.io/
// @version      1.0
// @description  Add a torrent to a qBittorrent instance via WebUI API
// @match        https://nyaa.si/*
// @grant        GM_xmlhttpRequest
// @grant        GM_getValue
// @grant        GM_setValue
// ==/UserScript==

(function () {
    'use strict';

    const qBittorrent = {
        host: 'http://localhost:3000',
        username: 'admin',
        password: 'johnsmith'
    };

    refresh();

    document.addEventListener('click', async function (e) {
        if (e.target.classList.contains('fa-magnet')) {
            e.preventDefault();
            const magnet = e.target.parentNode.href;
            await addMagnet(magnet);
        }
    });

    function GM_promise(options) {
        return new Promise((resolve, reject) => {
            options.onload = resolve;
            options.onerror = reject;
            GM_xmlhttpRequest(options);
        });
    }

    async function authenticate() {
        try {
            let response = await GM_promise({
                method: 'POST',
                url: `${qBittorrent.host}/api/v2/auth/login`,
                headers: {
                    'Referer': qBittorrent.host,
                    'Content-Type': 'application/x-www-form-urlencoded'
                },
                data: `username=${qBittorrent.username}&password=${qBittorrent.password}`
            });

            let sidMatch = response.responseHeaders.match(/SID=(.*?);/);
            let sid = sidMatch ? sidMatch[1] : null;

            if (!sid) {
                console.error("Session already exists");
                debug(response);
                return null;
            }

            console.log("Authenticated with qBittorrent, SID: " + sid);
            return sid;

        } catch (error) {
            console.error(error);
            console.error("Failed to authenticate with qBittorrent");
            return;
        }
    }

    async function refresh() {

        let sid = await GM_getValue("SID");

        if (!sid) {
            sid = await authenticate();
            GM_setValue("SID", sid);

        } else {

            let isValid = await validate(sid);

            if (!isValid) {
                console.log("SID is invalid, authenticating with qBittorrent");
                sid = await authenticate();
                GM_setValue("SID", sid);
            }
        }
    }

    async function validate(SID) {

        try {
            let response = await GM_promise({
                method: 'GET',
                url: `${qBittorrent.host}/api/v2/torrents/info`,
                headers: {
                    'Cookie': `SID=${SID}`
                }
            });

            if (response.status == 200) {
                return true;
            } else {
                console.error("SID " + SID + " is invalid");
                console.error(response);
                return false;
            }
        } catch (error) {
            console.error("SID is invalid");
            console.error(error);
            return false;
        }
    }

    async function addMagnet(magnet) {
        let sid = await GM_getValue("SID");

        try {
            let response = await GM_promise({
                method: 'POST',
                url: `${qBittorrent.host}/api/v2/torrents/add`,
                headers: {
                    'Cookie': `SID=${sid}`,
                    'Content-Type': 'application/x-www-form-urlencoded'
                },
                data: `urls=${magnet}`
            });

            console.log("Added magnet to qBittorrent");
        } catch (error) {
            console.error("Failed to add magnet to qBittorrent");
        }
    }

})();