Hydrilla

/**

 * SPDX-License-Identifier: LicenseRef-GPL-3.0-or-later-WITH-js-exceptions

 *

 * Make files on drive.google.com downloadable without nonfree js

 *

 * Copyright (C) 2021 Wojtek Kosior <koszko@koszko.org>

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * As additional permission under GNU GPL version 3 section 7, you

 * may distribute forms of that code without the copy of the GNU

 * GPL normally required by section 4, provided you include this

 * license notice and, in case of non-source distribution, a URL

 * through which recipients can access the Corresponding Source.

 * If you modify file(s) with this exception, you may extend this

 * exception to your version of the file(s), but you are not

 * obligated to do so. If you do not wish to do so, delete this

 * exception statement from your version.

 *

 * As a special exception to the GPL, any HTML file which merely

 * makes function calls to this code, and for that purpose

 * includes it by reference shall be deemed a separate work for

 * copyright law purposes. If you modify this code, you may extend

 * this exception to your version of the code, but you are not

 * obligated to do so. If you do not wish to do so, delete this

 * exception statement from your version.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <https://www.gnu.org/licenses/>.

 *

 * I, Wojtek Kosior, thereby promise not to sue for violation of this file's

 * license. Although I request that you do not make use of this code in a

 * proprietary program, I am not going to enforce this in court.

 */

/* Use with: https://drive.google.com/file/d/** */

const og = {};

for (const node of document.head.childNodes) {

    if (node.tagName === "STYLE") {

	document.head.removeChild(node);

	continue;

    }

    if (node.tagName !== "META")

	continue;

    const match = /^og:(.+)/.exec(node.getAttribute("property"));

    if (!match)

	continue;

    og[match[1]] = node.getAttribute("content");

}

const match = new RegExp("/file/d/([^/]+)").exec(document.URL);

const file_id = match && match[1];

/* Extract file's mime type from script. */

let mime_type;

for (const script of document.scripts) {

    const match = /itemJson\s*:\s*(\[.*\])\s*}\s*;$/.exec(script.textContent);

    if (!match)

	continue;

    let data;

    try {

	data = JSON.parse(match[1]);

    } catch(e) {

	console.log(e);

	continue;

    }

    if (/^[^\/]+\/[^\/]+$/.test(data[11]))

	mime_type = data[11];

}

/* If file is folder, redirect to its page. */

const redirect = file_id &&

      /^application\/vnd.google-apps.(folder|shortcut)$/.test(mime_type);

if (redirect)

    window.location.href = `https://drive.google.com/drive/folders/${file_id}`;

const download_link =

      file_id && `https://drive.google.com/uc?export=download&id=${file_id}`;

const body = document.createElement("body");

const name_div = document.createElement("div");

const download_div = document.createElement("div");

const download_button = document.createElement("a");

const type_div = document.createElement("div");

const type_span = document.createElement("span");

const show_image_div = document.createElement("div");

const show_image_button = document.createElement("button");

const image = document.createElement("img");

let button_text = "download";

if (!og.title)

    button_text += " file";

else

    name_div.textContent = og.title;

name_div.setAttribute("style", "font-weight: bold; display:inline-block;");

if (download_link)

    download_button.setAttribute("href", download_link);

else

    button_text += " (unavailable)";

download_button.textContent = button_text;

download_button.setAttribute("style", "border-radius: 5px; padding: 10px; color: black; background-color: lightgreen; text-decoration: none; box-shadow: -4px 8px 8px #888;");

download_div.appendChild(download_button);

download_div.setAttribute("style", "padding: 10px; display: inline-block; margin: 0 0 10px;");

type_span.textContent = "type: ";

type_span.setAttribute("style", "font-weight: bold; display:inline-block; white-space: pre;");

type_div.setAttribute("style", "margin: 0 0 10px;");

type_div.appendChild(type_span);

if (mime_type || og.type)

    type_div.append(mime_type || og.type);

function show_image()

{

    const image = document.createElement("img");

    image.setAttribute("src", og.image);

    image.setAttribute("width", og["image:width"]);

    image.setAttribute("height", og["image:height"]);

    image.setAttribute("style", "border: 1px solid #eee;");

    document.body.replaceChild(image, show_image_div);

}

show_image_button.setAttribute("style", "border-radius: 5px; padding: 10px; color: black; background-color: lightgreen; box-shadow: -4px 8px 8px #888; font-family: inherit; font-size: inherit; border: none;");

show_image_button.textContent = "show image";

show_image_button.addEventListener("click", show_image);

show_image_div.appendChild(show_image_button);

body.setAttribute("style", "margin: 20px;");

if (og.title)

    body.appendChild(name_div);

body.appendChild(download_div);

if (og.type)

    body.appendChild(type_div);

if (og.image && og["image:width"] && og["image:height"])

    body.appendChild(show_image_div);

if (!redirect)

    document.documentElement.replaceChild(body, document.body);