SingleFile/lib/single-file/processors/hooks/content/content-hooks-web.js

/*
 * Copyright 2010-2020 Gildas Lormeau
 * contact : gildas.lormeau <at> gmail.com
 * 
 * This file is part of SingleFile.
 *
 *   The code in this file is free software: you can redistribute it and/or 
 *   modify it under the terms of the GNU Affero General Public License 
 *   (GNU AGPL) as published by the Free Software Foundation, either version 3
 *   of the License, or (at your option) any later version.
 * 
 *   The code in this file 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 Affero 
 *   General Public License for more details.
 *
 *   As additional permission under GNU AGPL version 3 section 7, you may 
 *   distribute UNMODIFIED VERSIONS OF THIS file without the copy of the GNU 
 *   AGPL normally required by section 4, provided you include this license 
 *   notice and a URL through which recipients can access the Corresponding 
 *   Source.
 */

/* global window, globalThis, Headers */

(globalThis => {

	const FETCH_REQUEST_EVENT = "single-file-request-fetch";
	const FETCH_RESPONSE_EVENT = "single-file-response-fetch";
	const ACCEPT_HEADER = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";

	const CustomEvent = globalThis.CustomEvent;
	const fetch = globalThis.fetch;
	const addEventListener = (type, listener, options) => globalThis.addEventListener(type, listener, options);
	const dispatchEvent = event => globalThis.dispatchEvent(event);

	addEventListener(FETCH_REQUEST_EVENT, async event => {
		const url = event.detail;
		let detail;
		try {
			const response = await fetch(url, { cache: "force-cache", headers: new Headers({ accept: ACCEPT_HEADER }) });
			detail = { url, response: await response.arrayBuffer(), headers: [...response.headers], status: response.status };
		} catch (error) {
			detail = { url, error: error && error.toString() };
		}
		dispatchEvent(new CustomEvent(FETCH_RESPONSE_EVENT, { detail }));
	});

})(typeof globalThis == "object" ? globalThis : window);