Project

General

Profile

Download (3.07 KB) Statistics
| Branch: | Tag: | Revision:

haketilo / content / repo_query_cacher.js @ e6fca496

1
/**
2
 * This file is part of Haketilo.
3
 *
4
 * Function: Caching responses from remote repositories and serving them to
5
 *           popup pages.
6
 *
7
 * Copyright (C) 2022 Wojtek Kosior
8
 *
9
 * This program is free software: you can redistribute it and/or modify
10
 * it under the terms of the GNU General Public License as published by
11
 * the Free Software Foundation, either version 3 of the License, or
12
 * (at your option) any later version.
13
 *
14
 * This program is distributed in the hope that it will be useful,
15
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17
 * GNU General Public License for more details.
18
 *
19
 * As additional permission under GNU GPL version 3 section 7, you
20
 * may distribute forms of that code without the copy of the GNU
21
 * GPL normally required by section 4, provided you include this
22
 * license notice and, in case of non-source distribution, a URL
23
 * through which recipients can access the Corresponding Source.
24
 * If you modify file(s) with this exception, you may extend this
25
 * exception to your version of the file(s), but you are not
26
 * obligated to do so. If you do not wish to do so, delete this
27
 * exception statement from your version.
28
 *
29
 * As a special exception to the GPL, any HTML file which merely
30
 * makes function calls to this code, and for that purpose
31
 * includes it by reference shall be deemed a separate work for
32
 * copyright law purposes. If you modify this code, you may extend
33
 * this exception to your version of the code, but you are not
34
 * obligated to do so. If you do not wish to do so, delete this
35
 * exception statement from your version.
36
 *
37
 * You should have received a copy of the GNU General Public License
38
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
39
 *
40
 * I, Wojtek Kosior, thereby promise not to sue for violation of this file's
41
 * license. Although I request that you do not make use of this code in a
42
 * proprietary program, I am not going to enforce this in court.
43
 */
44

    
45
#FROM common/browser.js IMPORT browser
46
#FROM common/misc.js    IMPORT error_data_jsonifiable
47

    
48
/*
49
 * Map URLs to objects containing parsed responses, error info or promises
50
 * resolving to those. The use of promises helps us prevent multiple requests
51
 * for the same resource from starting concurrently.
52
 */
53
const cache = new Map();
54

    
55
async function perform_download(url) {
56
    if (cache.has(url))
57
	return cache.get(url);
58

    
59
    let resolve_cb;
60
    cache.set(url, new Promise(cb => resolve_cb = cb));
61

    
62
    try {
63
	var result = await browser.runtime.sendMessage(["CORS_bypass", {url}]);
64
	if (result === undefined)
65
	    throw new Error("Couldn't communicate with background script.");
66
    } catch(e) {
67
	return {error: error_data_jsonifiable(e)};
68
    }
69

    
70
    cache.set(url, result);
71
    resolve_cb(result);
72

    
73
    return result;
74
}
75

    
76
function on_repo_query_request([type, url], sender, respond_cb) {
77
    if (type !== "repo_query")
78
	return;
79

    
80
    perform_download(url).then(respond_cb);
81

    
82
    return true;
83
}
84

    
85
function start() {
86
    browser.runtime.onMessage.addListener(on_repo_query_request);
87
}
88
#EXPORT start
(4-4/4)