Haketilo

/**

 * This file is part of Haketilo.

 *

 * Function: Serving page actions to content scripts.

 *

 * Copyright (C) 2021 Wojtek Kosior

 *

 * 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 this code in a

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

 */

/*

 * IMPORTS_START

 * IMPORT get_storage

 * IMPORT light_storage

 * IMPORT TYPE_PREFIX

 * IMPORT CONNECTION_TYPE

 * IMPORT browser

 * IMPORT listen_for_connection

 * IMPORT sha256

 * IMPORT query_best

 * IMPORT make_ajax_request

 * IMPORTS_END

 */

var storage;

var handler;

let policy_observable;

function send_actions(url, port)

{

    const [pattern, queried_settings] = query_best(storage, url);

    const settings = {allow: policy_observable && policy_observable.value};

    Object.assign(settings, queried_settings);

    if (settings.components)

	settings.allow = false;

    const repos = storage.get_all(TYPE_PREFIX.REPO);

    port.postMessage(["settings", [pattern, settings, repos]]);

    const components = settings.components;

    const processed_bags = new Set();

    if (components !== undefined)

	send_scripts([components], port, processed_bags);

}

// TODO: parallelize script fetching

async function send_scripts(components, port, processed_bags)

{

    for (let [prefix, name] of components) {

	if (prefix === TYPE_PREFIX.BAG) {

	    if (processed_bags.has(name)) {

		console.log(`preventing recursive inclusion of bag ${name}`);

		continue;

	    }

	    var bag = storage.get(TYPE_PREFIX.BAG, name);

	    if (bag === undefined) {

		console.log(`no bag in storage for key ${name}`);

		continue;

	    }

	    processed_bags.add(name);

	    await send_scripts(bag, port, processed_bags);

	    processed_bags.delete(name);

	} else {

	    let script_text = await get_script_text(name);

	    if (script_text === undefined)

		continue;

	    port.postMessage(["inject", [script_text]]);

	}

    }

}

async function get_script_text(script_name)

{

    try {

	let script_data = storage.get(TYPE_PREFIX.SCRIPT, script_name);

	if (script_data === undefined) {

	    console.log(`missing data for ${script_name}`);

	    return;

	}

	let script_text = script_data.text;

	if (!script_text)

	    script_text = await fetch_remote_script(script_data);

	return script_text;

    } catch (e) {

	console.log(e);

    }

}

async function fetch_remote_script(script_data)

{

    try {

	let xhttp = await make_ajax_request("GET", script_data.url);

	if (xhttp.status === 200) {

	    let computed_hash = sha256(xhttp.responseText);

	    if (computed_hash !== script_data.hash) {

		console.log(`Bad hash for ${script_data.url}\n    got ${computed_hash} instead of ${script_data.hash}`);

		return;

	    }

	    return xhttp.responseText;

	} else {

	    console.log("script not fetched: " + script_data.url);

	    return;

	}

    } catch (e) {

	console.log(e);

    }

}

function handle_message(port, message, handler)

{

    port.onMessage.removeListener(handler[0]);

    let url = message.url;

    console.log({url});

    send_actions(url, port);

}

function new_connection(port)

{

    console.log("new page actions connection!");

    let handler = [];

    handler.push(m => handle_message(port, m, handler));

    port.onMessage.addListener(handler[0]);

}

async function start_page_actions_server()

{

    storage = await get_storage();

    listen_for_connection(CONNECTION_TYPE.PAGE_ACTIONS, new_connection);

    policy_observable = await light_storage.observe_var("default_allow");

}

/*

 * EXPORTS_START

 * EXPORT start_page_actions_server

 * EXPORTS_END

 */