// ==UserScript==
// @name Jsdelivr Auto Fallback
// @namespace https://github.com/PipecraftNet/jsdelivr-auto-fallback
// @version 0.3.3
// @author PipecraftNet&DreamOfIce
// @description 修复 cdn.jsdelivr.net 无法访问的问题
// @homepage https://github.com/PipecraftNet/jsdelivr-auto-fallback
// @supportURL https://github.com/PipecraftNet/jsdelivr-auto-fallback/issues
// @license MIT
// @match *://*/*
// @run-at document-start
// @grant GM_setValue
// @grant GM_getValue
// ==/UserScript==
((document) => {
'use strict';
let fastNode;
let failed;
let isRunning;
const DEST_LIST = [
'cdn.jsdelivr.net',
'fastly.jsdelivr.net',
'testingcf.jsdelivr.net',
'test1.jsdelivr.net',
'gcore.jsdelivr.net'
];
const PREFIX = '//';
const SOURCE = DEST_LIST[0];
const starTime = Date.now();
const TIMEOUT = 2000;
const STORE_KEY = 'jsdelivr-auto-fallback';
const TEST_PATH = '/gh/PipecraftNet/jsdelivr-auto-fallback@main/empty.css?';
const shouldReplace = (text) => text && text.includes(PREFIX + SOURCE);
const replace = (text) => text.replace(PREFIX + SOURCE, PREFIX + fastNode);
const setTimeout = window.setTimeout;
const $ = document.querySelectorAll.bind(document);
const replaceElementSrc = () => {
let element;
let value;
for (element of $('link[rel="stylesheet"]')) {
value = element.href;
if (shouldReplace(value) && !value.includes(TEST_PATH)) {
element.href = replace(value);
}
}
for (element of $('script')) {
value = element.src;
if (shouldReplace(value)) {
const newNode = document.createElement('script');
newNode.src = replace(value);
element.defer = true;
element.src = '';
element.before(newNode);
element.remove();
}
}
for (element of $('img')) {
value = element.src;
if (shouldReplace(value)) {
// Used to cancel loading. Without this line it will remain pending status.
element.src = '';
element.src = replace(value);
}
}
// All elements that have a style attribute
for (element of $('*[style]')) {
value = element.getAttribute('style');
if (shouldReplace(value)) {
element.setAttribute('style', replace(value));
}
}
for (element of $('style')) {
value = element.innerHTML;
if (shouldReplace(value)) {
element.innerHTML = replace(value);
}
}
};
const tryReplace = () => {
if (!isRunning && failed && fastNode) {
console.warn(SOURCE + ' is not available. Use ' + fastNode);
isRunning = true;
setTimeout(replaceElementSrc, 0);
// Some need to wait for a while
setTimeout(replaceElementSrc, 20);
// Replace dynamically added elements
setInterval(replaceElementSrc, 500);
}
};
const checkAvailable = (url, callback) => {
let timeoutId;
const newNode = document.createElement('link');
const handleR###lt = (isSuccess) => {
if (!timeoutId) {
return;
}
clearTimeout(timeoutId);
timeoutId = 0;
// Used to cancel loading. Without this line it will remain pending status.
if (!isSuccess) newNode.href = 'data:text/plain;base64,';
newNode.remove();
callback(isSuccess);
};
timeoutId = setTimeout(handleR###lt, TIMEOUT);
newNode.addEventListener('error', () => handleR###lt(false));
newNode.addEventListener('load', () => handleR###lt(true));
newNode.rel = 'stylesheet';
newNode.text = 'text/css';
newNode.href = url + TEST_PATH + starTime;
document.head.insertAdjacentElement('afterbegin', newNode);
};
const cached = (() => {
try {
// eslint-disable-next-line new-cap
return Object.assign({}, GM_getValue(STORE_KEY));
} catch {
return {};
}
})();
const main = () => {
cached.time = starTime;
cached.failed = false;
cached.fastNode = null;
for (const url of DEST_LIST) {
checkAvailable('https://' + url, (isAvailable) => {
// console.log(url, Date.now() - starTime, Boolean(isAvailable));
if (!isAvailable && url === SOURCE) {
failed = true;
cached.failed = true;
}
if (isAvailable && !fastNode) {
fastNode = url;
}
if (isAvailable && !cached.fastNode) {
cached.fastNode = url;
}
tryReplace();
});
}
setTimeout(() => {
// If all domains are timeout
if (failed && !fastNode) {
fastNode = DEST_LIST[1];
tryReplace();
}
// eslint-disable-next-line new-cap
GM_setValue(STORE_KEY, cached);
}, TIMEOUT + 100);
};
if (
cached.time &&
starTime - cached.time < 60 * 60 * 1000 &&
cached.failed &&
cached.fastNode
) {
failed = true;
fastNode = cached.fastNode;
tryReplace();
setTimeout(main, 1000);
} else {
main();
}
})(document);