Safer per-domain favicon override with debounce & preflight.
// ==UserScript==
// @name Custom Favicon Per Site
// @namespace harry297.favicon
// @version 1.3.0
// @description Safer per-domain favicon override with debounce & preflight.
// @match *://*/*
// @run-at document-start
// @grant GM_registerMenuCommand
// @grant GM_getValue
// @grant GM_setValue
// @grant GM_xmlhttpRequest
// @license MIT
// ==/UserScript==
(function () {
'use strict';
const KEY = 'custom_favicon_rules_v14';
// ---------- Rule model ----------
// { scope: 'host' | 'domain' | 'prefix', key: string, icon: string }
// host: key = full hostname (e.g. 'app.site.com')
// domain: key = registrable domain (rough heuristic: last 2 labels; allow override)
// prefix: key = URL prefix like 'https://site.com/path/'
function load(){ try{ return JSON.parse(GM_getValue(KEY, '[]')); }catch{ return []; } }
function save(list){ GM_setValue(KEY, JSON.stringify(list)); }
function getHostname(){ return location.hostname; }
function getDomainHeuristic(host){
const parts = host.split('.');
if (parts.length <= 2) return host;
// Heuristic: last 2 labels (note: .co.uk 等会不准，必要时自己改成 example.co.uk)
return parts.slice(-2).join('.');
}
function getPrefix(){
// standardize to trailing slash
const u = new URL(location.href);
let p = `${u.origin}${u.pathname}`;
if (!p.endsWith('/')) p = p.replace(/[^/]+$/, '');
return p;
}
function matchRule(rule){
if (rule.scope === 'host') return getHostname() === rule.key;
if (rule.scope === 'domain') return (getHostname() === rule.key) || getHostname().endsWith('.' + rule.key);
if (rule.scope === 'prefix') return location.href.startsWith(rule.key);
return false;
}
function bestRule(rules){
// Priority: prefix > host > domain (更具体的优先)
const candidates = rules.filter(matchRule);
const score = r => r.scope === 'prefix' ? 3 : r.scope === 'host' ? 2 : 1;
candidates.sort((a,b)=>score(b)-score(a));
return candidates[0] || null;
}
// ---------- favicon ops ----------
function isMixedContent(url){
try{
const u = new URL(url, location.href);
return location.protocol === 'https:' && u.protocol === 'http:';
}catch{ return false; }
}
function preflight(url, cb){
if (/^data:/i.test(url)) return cb(true);
if (isMixedContent(url)) return cb(false, 'Mixed content: use HTTPS icon on HTTPS pages.');
try{
GM_xmlhttpRequest({
method: 'GET',
url: new URL(url, location.href).toString(),
timeout: 4000,
onload: r => cb(r.status >= 200 && r.status < 400),
onerror: () => cb(false, 'Network error'),
ontimeout: () => cb(false, 'Timeout'),
});
}catch{ cb(false, 'Invalid URL'); }
}
function removeIcons(){
if (!document.head) return;
document.head.querySelectorAll(
"link[rel='icon'], link[rel='shortcut icon'], link[rel='apple-touch-icon']"
).forEach(n=>n.remove());
}
function addIcons(href){
if (!document.head) return;
const add = (rel, sizes) => {
const l = document.createElement('link');
l.rel = rel;
if (sizes) l.sizes = sizes;
l.href = href;
document.head.appendChild(l);
};
add('icon');
add('shortcut icon');
add('apple-touch-icon','180x180');
}
let applied = null;
const apply = (href) => {
if (!href) return;
removeIcons();
addIcons(href);
applied = href;
};
// 防抖，避免 SPA 频繁替换引发循环
let timer = null;
const debouncedApply = href => { clearTimeout(timer); timer = setTimeout(()=>apply(href), 60); };
function watch(href){
if (!document.head) return;
const mo = new MutationObserver(()=>{
// 如果站点又塞回了自己的 icon，我们再覆盖一次
const siteIcon = document.head.querySelector("link[rel*='icon']");
if (siteIcon && applied !== href) debouncedApply(href);
});
mo.observe(document.head, { childList: true, subtree: true });
}
// ---------- boot ----------
const rules = load();
const rule = bestRule(rules);
if (rule) {
const start = () => preflight(rule.icon, (ok,msg)=>{
if (!ok) { console.warn('[favicon]', msg||'preflight failed'); return; }
apply(rule.icon);
watch(rule.icon);
// 监听 pushState / popstate（单页应用内部跳转）
const _pushState = history.pushState;
history.pushState = function(){ const r = _pushState.apply(this, arguments); debouncedApply(rule.icon); return r; };
window.addEventListener('popstate', ()=>debouncedApply(rule.icon));
});
if (document.head) start(); else document.addEventListener('DOMContentLoaded', start);
}
// ---------- menus ----------
function addSetMenu(scope, labelBuilder){
GM_registerMenuCommand(labelBuilder(), ()=>{
const val = prompt(`Icon URL for scope "${scope}"\n(HTTPS SVG/PNG/ICO, or data: URL)`);
if (!val) return;
const icon = val.trim();
preflight(icon, (ok,msg)=>{
if (!ok) { alert('❌ ' + (msg||'Not usable')); return; }
const list = load();
let key = '';
if (scope==='host') key = getHostname();
if (scope==='domain') key = getDomainHeuristic(getHostname());
if (scope==='prefix') key = getPrefix();
// replace existing same-scope+key rule
const idx = list.findIndex(r=>r.scope===scope && r.key===key);
if (idx>=0) list[idx].icon = icon; else list.push({scope,key,icon});
save(list);
apply(icon);
alert(`✅ Set favicon for ${scope}: ${key}`);
});
});
}
function addRemoveMenu(scope, labelBuilder){
GM_registerMenuCommand(labelBuilder(), ()=>{
const list = load();
let key = '';
if (scope==='host') key = getHostname();
if (scope==='domain') key = getDomainHeuristic(getHostname());
if (scope==='prefix') key = getPrefix();
const idx = list.findIndex(r=>r.scope===scope && r.key===key);
if (idx>=0){ list.splice(idx,1); save(list); location.reload(); }
else alert(`No rule for ${scope}: ${key}`);
});
}
const host = getHostname();
const domain = getDomainHeuristic(host);
const prefix = getPrefix();
addSetMenu('host', ()=>`Set favicon for host: ${host}`);
addSetMenu('domain', ()=>`Set favicon for domain: *.${domain}`);
addSetMenu('prefix', ()=>`Set favicon for prefix: ${prefix}`);
addRemoveMenu('host', ()=>`Remove host rule: ${host}`);
addRemoveMenu('domain', ()=>`Remove domain rule: *.${domain}`);
addRemoveMenu('prefix', ()=>`Remove prefix rule: ${prefix}`);
GM_registerMenuCommand('Export rules (JSON)', ()=>prompt('Copy:', JSON.stringify(load(), null, 2)));
GM_registerMenuCommand('Import rules (JSON)', ()=>{
const txt = prompt('Paste JSON:'); if (!txt) return;
try{ save(JSON.parse(txt)); alert('✅ Imported. Reload to apply.'); }
catch{ alert('❌ Invalid JSON'); }
});
})();