From 01937dc9d5215ef96ce756e3ccda51bf29032f58 Mon Sep 17 00:00:00 2001
From: Wojtek Kosior <wk@koszkonutek-tmp.pl.eu.org>
Date: Mon, 10 May 2021 18:07:05 +0200
Subject: initial commit

---
 background/page_actions_server.mjs | 145 +++++++++++++++++++++++++++++++++++++
 1 file changed, 145 insertions(+)
 create mode 100644 background/page_actions_server.mjs

(limited to 'background/page_actions_server.mjs')

diff --git a/background/page_actions_server.mjs b/background/page_actions_server.mjs
new file mode 100644
index 0000000..5fb4924
--- /dev/null
+++ b/background/page_actions_server.mjs
@@ -0,0 +1,145 @@
+/**
+* Myext serving of page actions to content scripts
+*
+* Copyright (C) 2021 Wojtek Kosior
+*
+* Dual-licensed under:
+*   - 0BSD license
+*   - GPLv3 or (at your option) any later version
+*/
+
+import get_storage from './storage.mjs';
+import {TYPE_PREFIX} from '/common/stored_types.mjs';
+import CONNECTION_TYPE from '/common/connection_types.mjs';
+import browser from '/common/browser.mjs';
+import listen_for_connection from './message_server.mjs';
+import url_item from './url_item.mjs';
+import sha256 from './sha256.mjs';
+
+"use strict";
+
+var storage;
+var handler;
+
+function send_scripts(url, port)
+{
+    let settings = storage.get(TYPE_PREFIX.PAGE, url_item(url));
+    if (settings === undefined)
+	return;
+
+    let components = settings.components;
+    let processed_bundles = new Set();
+
+    send_scripts_rec(components, port, processed_bundles);
+}
+
+// TODO: parallelize script fetching
+async function send_scripts_rec(components, port, processed_bundles)
+{
+    for (let [prefix, name] of components) {
+	if (prefix === TYPE_PREFIX.BUNDLE) {
+	    if (processed_bundles.has(name)) {
+		console.log(`preventing recursive inclusion of bundle ${name}`);
+		continue;
+	    }
+
+	    var bundle = storage.get(TYPE_PREFIX.BUNDLE, name);
+
+	    if (bundle === undefined) {
+		console.log(`no bundle in storage for key ${name}`);
+		continue;
+	    }
+
+	    processed_bundles.add(name);
+	    await send_scripts_rec(bundle, port, processed_bundles);
+	    processed_bundles.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);
+    }
+}
+
+function ajax_callback()
+{
+    if (this.readyState == 4)
+	this.resolve_callback(this);
+}
+
+function initiate_ajax_request(resolve, method, url)
+{
+    var xhttp = new XMLHttpRequest();
+    xhttp.resolve_callback = resolve;
+    xhttp.onreadystatechange = ajax_callback;
+    xhttp.open(method, url, true);
+    xhttp.send();
+}
+
+function make_ajax_request(method, url)
+{
+    return new Promise((resolve, reject) =>
+	initiate_ajax_request(resolve, method, url));
+}
+
+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_scripts(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]);
+}
+
+export default async function start()
+{
+    storage = await get_storage();
+
+    listen_for_connection(CONNECTION_TYPE.PAGE_ACTIONS, new_connection);
+}
-- 
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