teachable-downloader.user.js

// ==UserScript==
// @name         Teachable video downloader
// @downloadURL  https://github.com/Lambik/wistia-downloader/raw/master/teachable-downloader.user.js
// @namespace    https://github.com/Lambik/
// @version      0.3
// @description  Make all wistia videos downloadable on teachable courses
// @author       You
// @match        *://*.teachable.com/*
// @match        *://courses.coursecreatorpro.com/*
// @match        *://courses.fulltimefilmmaker.com/*
// @match        *://courses.52kards.com/*
// @match        *://howtofreedive.com/*
// @connect      fast.wistia.net
// @grant        GM_xmlhttpRequest
// @run-at       document-end
// ==/UserScript==

(function () {
	'use strict';

	function parseVideos() {
		let viddivs = document.getElementsByClassName('attachment-wistia-player');

		for (let viddiv of viddivs) {
			let wistiaId = viddiv.dataset.wistiaId;

			GM_xmlhttpRequest(
				{
					method : 'GET',
					url    : 'https://fast.wistia.net/embed/iframe/' + wistiaId,
					onerror: function (result) {
						console.error('xmlrequest error', result);
					},
					onabort: function (result) {
						console.error('xmlrequest abort', result);
					},
					onload : function (result) {
						let body = result.responseText;
						let assets = body.match(/"assets":(\[.*?\])/);
						if (assets.length) {
							let allvids = JSON.parse(assets[1]);
							console.log(allvids);
							let newNode = document.createElement('div');
							let str = "<h4>Download options:</h4><ul>";
							for (let vid of allvids) {
								if (vid.type != 'hls_video' && vid.public) {
									str += '<li>' + vid.display_name + ' (' + vid.width + 'x' + vid.height + ', ' + vid.ext + '): <a href="' + vid.url + '" target="_blank">' + formatBytes(vid.size) + '</a></li>';
								}
							}
							str += "</ul>";
							newNode.innerHTML = str;
							viddiv.parentNode.parentNode.parentNode.appendChild(newNode)
						}
						else {
							console.error('wista returned invalid data', body);
						}
					}
				}
			);
		}
	}

	// thanks to https://stackoverflow.com/a/18650828/102720
	function formatBytes(bytes, decimals = 2) {
		if (bytes === 0) {
			return '0 Bytes';
		}

		const k = 1024;
		const dm = decimals < 0 ? 0 : decimals;
		const sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];

		const i = Math.floor(Math.log(bytes) / Math.log(k));

		return parseFloat((bytes / Math.pow(k, i)).toFixed(dm)) + ' ' + sizes[i];
	}

	parseVideos();

	window.addEventListener('lecture:ajax_success', parseVideos);
})();