Every web page is an installable app! Generate or repair a Web Manifest for any web page.
// ==UserScript==
// @name Installability
// @description Every web page is an installable app! Generate or repair a Web Manifest for any web page.
// @namespace Itsnotlupus Industries
// @match https://*/*
// @version 1.8
// @noframes
// @author itsnotlupus
// @license MIT
// @require https://greasyfork.org/scripts/468394-itsnotlupus-tiny-utilities/code/utils.js
// @grant GM_xmlhttpRequest
// @grant GM_addElement
// @grant GM_getValue
// @grant GM_setValue
// @connect *
// ==/UserScript==
/* jshint esversion:11 */
/* eslint curly: 0 no-return-assign: 0, no-loop-func: 0 */
/* global $, $$, crel, log, logGroup, withLogs, fetchJSON, observeDOM */
/**
* Wishlist:
* - too many rules. can't deploy a worker, etc.
* - how far could a userscript go in emulating an offline worker tho?
* - fetch/xhr can be intercepted.
* - image loading could be polyfilled too.
* - page navigation is iffier. if the first page doesn't load, the userscript won't either.
* - but if we can get pasted that, network-first offline policy would probably cause the least damage (https://developer.mozilla.org/en-US/docs/Web/Progressive_web_apps/Guides/Caching)
* - [...new Set([...$$`[href],[src]`].map(a=>a.href??a.src).filter(url=>url.startsWith(location.origin)).map(url=>url.split('#')[0]))] // things one might precache in an install event handler
* - maskable icons (which involves finding the smallest rect that captures all non-transparent pixels, and shrinking them to fit within safe area.)
* - take the silliness further:
* - detecting main site navigation entrypoints and generating shortcuts would kinda kick ass.
* - look for more weird PWA features, and see if there's a generic way to leverage them.
*/
// Bits of code that might be useful later:
// 1. holding a user's hand to get installed. in case the script ever exposes a more visible mean to install an app, I guess.
//early:
// const installer = await new Promise(r => addEventListener('beforeinstallprompt', r));
//later:
// installer.prompt();
// const { outcome } = await installer.userChoice;
// const installed = await new Promise(r => addEventListener('appinstalled', r);
// a default app icon to use if no suitable icons are found in the site
const FALLBACK_ICON = 'data:image/svg+xml;base64,'+btoa`<svg xmlns="http://www.w3.org/2000/svg" width="48" height="48"><defs><linearGradient id="a" x1="-44" x2="-4" y1="-24" y2="-24" gradientUnits="userSpaceOnUse"><stop offset="0" stop-color="#009467"/><stop offset="1" stop-color="#87d770"/></linearGradient></defs><rect width="40" height="40" x="-44" y="-44" fill="url(#a)" rx="20" transform="matrix(0 -1 -1 0 0 0)"/><path d="M4 23.5v.5a20 20 0 1 0 40 0v-.5a20 20 0 0 1-40 0z" opacity=".1"/><path fill="#fff" d="M24.5 23a1.5 1.5 0 0 0 0 3 1.5 1.5 0 0 0 0-3z"/><g fill="none" stroke="#fff" stroke-linecap="round" stroke-linejoin="round"><path d="M33.5 27.5s3-1 3-3c0-3.5-9.2-5-12.5-5-7-.1-12.3 1.4-12.5 4s3 3 3 3"/><path d="M30.5 17.5s1.1-3.8-.6-4.7c-3-1.7-8.9 5.7-10.5 8.4-3.7 6-5 11.4-2.8 12.9 2.2 1.4 3.9-.6 3.9-.6"/><path d="M21.5 14.5s-2.2-2.4-3.8-1.4c-3 1.8.3 10.5 2 13.4 3.3 6.2 7.3 10 9.6 8.8 5.2-2-.8-12.8-.8-12.8"/></g></svg>`;
// keep cached bits of manifests on any given site for 24 hours before fetching/generating new ones.
const CACHE_MANIFEST_EXPIRATION = 24*3600*1000;
/** cache the result of work() into GM storage for a day. */
async function cacheInto(key, work) {
const cached = GM_getValue(key);
if (cached && cached.expires > Date.now()) return cached.data;
const data = await work();
if (data != null) GM_setValue(key, { expires: Date.now() + CACHE_MANIFEST_EXPIRATION, data });
return data;
}
/** Resolve a relative URL into an absolute URL */
const resolveURL = (url, base=location.href) => url && new URL(url, base).toString();
/**
* load an image without CSP restrictions.
*/
function getImage(src) {1
return new Promise((resolve) => {
const img = GM_addElement('img', {
src: resolveURL(src),
crossOrigin: "anonymous"
});
img.onload = () => resolve(img);
img.onerror = () => resolve(null);
img.remove();
});
}
/** test if the URL given loads correctly (not 404, etc.) */
function workingURL(src) {
return new Promise(resolve => {
const url = resolveURL(src);
GM_xmlhttpRequest({
url,
method: "HEAD",
onload(res) {
resolve(res.status<300);
},
onerror() {
resolve(false);
}
});
});
}
function cachedWorkingURL(src) {
return cacheInto('working-url:'+src, () => workingURL(src));
}
/** fetch an arbitrary URL using current browser cookies. no restrictions. */
function grabURL(src) {
return new Promise(resolve => {
const url = resolveURL(src);
GM_xmlhttpRequest({
url,
responseType: 'blob',
async onload(res) {
resolve(res.response);
},
onerror() {
log("Couldn't grab URL " + src);
resolve(null);
}
});
});
}
/**
* Grab an image and its mime-type regardless of browser sandbox limitations.
*/
async function getUntaintedImage(src) {
const blob = await grabURL(src);
const blobURL = URL.createObjectURL(blob);
const img = await getImage(blobURL);
if (!img) return null;
URL.revokeObjectURL(blobURL);
return {
src: resolveURL(src),
img,
width: img.naturalWidth,
height: img.naturalHeight,
type: blob.type
};
}
function makeBigPNG({ img }) {
// scale to at least 512x512, but keep the pixels if there are more.
const width = Math.max(512, img.width);
const height = Math.max(512, img.height);
const canvas = crel('canvas', { width, height });
const ctx = canvas.getContext('2d');
ctx.drawImage(img, 0, 0, width, height);
const url = canvas.toDataURL({ type: "image/png" });
return {
src: url,
width,
height,
type: "image/png"
};
}
function guessAppName() {
// Remember how there's this universal way to get a web site's name? Yeah, me neither.
const goodNames = [
// plausible places to find one
$`meta[name="application-name"]`?.content,
$`meta[name="apple-mobile-web-app-title"]`?.content,
$`meta[name="al:android:app_name"]`?.content,
$`meta[name="al:ios:app_name"]`?.content,
$`meta[property="og:site_name"]`?.content,
$`meta[property="og:title"]`?.content,
].filter(v=>!!v).sort((a,b)=>a.length-b.length); // short names first.
const badNames = [
// various bad ideas
$`link[rel="search]"`?.title.replace(/ search/i,''),
document.title,
$`h1`?.textContent,
[...location.hostname.replace(/^www\./,'')].map((c,i)=>i?c:c.toUpperCase()).join('') // capitalized domain name. If everything else fails, there's at least this.
].filter(v=>!!v);
const short_name = goodNames[0] ?? badNames[0];
//const app_name = goodNames.at(-1) ?? badNames[0];
return short_name;
}
function guessAppDescription() {
const descriptions = [
$`meta[property="og:description"]`?.content,
$`meta[name="description"]`?.content,
$`meta[name="description"]`?.getAttribute("value"),
$`meta[name="twitter:description"]`?.content,
].filter(v=>!!v);
return descriptions[0];
}
function guessAppColors() {
const colors = [
$`meta[name="theme-color"]`?.content,
getComputedStyle(document.body).backgroundColor
].filter(v=>!!v);
return {
theme_color: colors[0],
background_color: colors.at(-1)
};
}
async function gatherAppIcons() {
// focus on caching only the bits with network requests
return cacheInto("images:"+location.origin, async () => {
const iconURLs = [
...Array.from($$`link[rel*="icon"]`).filter(link=>link.rel!="mask-icon").map(link=>link.href),
resolveURL($`meta[itemprop="image"]`?.content),
].filter(v=>!!v);
// fetch all the icons, so we know what we're working with.
const images = (await Promise.all(iconURLs.map(getUntaintedImage))).filter(v=>!!v);
if (!images.length) {
const fallback = await getUntaintedImage("/favicon.ico"); // last resort. well known location for tiny site icons.
if (fallback) images.unshift(fallback);
}
if (!images.length) {
images.unshift(await getUntaintedImage(FALLBACK_ICON));
verb = 'generated with a fallback icon';
}
const icons = images.map(img => ({
src: img.src,
sizes: `${img.width}x${img.height}`,
type: img.type
}));
await fixAppIcons(icons);
verb = '';
return icons;
});
}
function getIconMaxSize(icon) {
// "any" is technically infinite, but 512x512 is close enough
const sizes = icon.sizes.split(/\s+/).map(size=>size=='any'?[512,512]:size.split(/x/i).map(v=>+v)).sort((a,b)=>b[0]-a[0]);
return sizes[0]; // [ width, height ]
}
function appIconsValid(icons) {
return icons.some(icon => {
const [ width, height ] = getIconMaxSize(icon);
return width >= 512 && height >= 512 && icon.type == 'image/png';
});
}
async function fixAppIcons(icons) {
icons.sort((a,b)=>getIconMaxSize(b)[0] - getIconMaxSize(a)[0]); // largest image first. suboptimal
// grab the biggest one.
const biggestImage = icons[0];
const [ width, height ] = getIconMaxSize(biggestImage);
if (width < 512 || height < 512 || biggestImage.type !== 'image/png') {
log(`We may not have a valid icon yet, scaling an image of type ${biggestImage.type} and size (${width}x${height}) into a big enough PNG.`);
// welp, we're gonna scale it.
const img = await makeBigPNG(await getUntaintedImage(biggestImage.src));
icons.unshift({
src: img.src,
sizes: `${img.width}x${img.height}`,
type: img.type
});
}
return icons;
}
async function guessRelatedApplications() {
// 1. "app links", a weird decade old half-baked half-supported spec that has the data we'd need for this.
// seen on threads.net, and probably not much elsewhere. but hey, we can parse synchronously and cheaply.
const apps = [];
const android_id = $`meta[property="al:android:package"]`?.content
if (android_id) {
const url = `https://play.google.com/store/apps/details?id=${android_id}`;
if (await cachedWorkingURL(url)) {
apps.push({
platform: "play", // XXX "chromeos_play"?
id: android_id,
url
});
}
}
const ios_id = $`meta[property="al:ios:app_store_id"]`?.content;
if (ios_id) {
const app_name = $`meta[property="al:ios:app-name"]`?.content ?? 'app';
const url = `https://apps.apple.com/app/${app_name}/${ios_id}`;
if (await cachedWorkingURL(url)) {
apps.push({
platform: "itunes",
id: ios_id,
url
});
}
}
// theoretically, there could be more here, like windows app and stuff.
// see https://developers.facebook.com/docs/applinks/metadata-reference
// 2. .well-known/assetlinks.json
// see https://github.com/google/digitalassetlinks/blob/master/well-known/details.md
const assetLinksJson = await cacheInto("assetLinksJson:"+location.origin, async () => {
try {
return await fetchJSON(resolveURL("/.well-known/assetlinks.json"));
} catch {
return [];
}
});
if (Array.isArray(assetLinksJson)) {
await Promise.all(assetLinksJson.filter(i=>i.relation.includes("delegate_permission/common.handle_all_urls")).map(async ({target}) => {
switch (target.namespace) {
case "android_app": {
const url = `https://play.google.com/store/apps/details?id=${target.package_name}`
if (await cachedWorkingURL(url)) {
apps.push({
platform: "play",
id: target.package_name,
url
});
}
break;
}
case "ios_app": { // the definition of unbridled optimism
const url = `https://apps.apple.com/app/app/${target.id}`;
if (await cachedWorkingURL(url)) {
if (target.appid) apps.push({
platform: "itunes",
id: target.appid,
url
});
}
break;
}
}
}));
}
// dedup apps right quick
const urls = new Set;
for (let i=apps.length-1;i>=0;i--) {
if (urls.has(apps[i].url)) {
apps.splice(i,1);
} else {
urls.add(apps[i].url);
}
}
return apps.length ? apps : undefined;
}
/** modify manifest in place, turn all known relative URLs into absolute URLs */
function fixManifestURLs(manifest, manifestURL) {
// a map of URLs in the manifest structure
const URL_IN_MANIFEST = {
file_handlers: [ { action: true } ],
icons: [ { src: true } ],
protocol_handlers: [ { url: true } ],
scope: true,
screenshots: [ { src: true } ],
serviceworker: { url: true },
share_target: { action: true },
shortcuts: [ {
url: true,
icons: [ { src: true } ]
} ],
start_url: true
};
// How to use a map to traverse a manifest
function recurse(obj, schema, transform) {
if (Array.isArray(schema)) return obj.forEach(item => recurse(item, schema[0], transform));
Object.keys(schema).forEach(key => { switch (true) {
case !obj[key]: return;
case typeof obj[key] == 'object': recurse(obj[key], schema[key], transform); break;
default: obj[key] = transform(obj[key]);
}});
}
recurse(manifest, URL_IN_MANIFEST, url => resolveURL(url, manifestURL));
}
async function repairManifest() {
let fixed = 0;
const manifestURL = $`link[rel="manifest"]`.href;
const manifest = await cacheInto("site_manifest:" + location.origin, async () => {
verb = '';
return JSON.parse(await (await grabURL(manifestURL)).text());
});
// since we're loading the manifest from a data: URL, get rid of all relative URLs
fixManifestURLs(manifest, manifestURL);
// fix: missing short_name
if (!manifest.short_name) {
log("Missing short_name field.");
manifest.short_name = manifest.name || guessAppName();
fixed++;
}
// fix: missing name
if (!manifest.name) {
log("Missing name field.");
manifest.name = manifest.short_name || guessAppName();
fixed++;
}
// fix: missing or insufficient icons
if (!manifest.icons) {
log("Missing icons field.");
manifest.icons = await gatherAppIcons();
fixed++;
} else if (!appIconsValid(manifest.icons)) {
log("Invalid icons field.");
await fixAppIcons(manifest.icons);
fixed++;
}
// fix: missing start_url
if (!manifest.start_url) {
log("Missing start_url field.");
manifest.start_url = location.origin;
fixed++;
}
// fix: invalid display value (typically "browser")
if (!["standalone", "fullscreen", "minimal-ui"].includes(manifest.display)) {
log("Missing or invalid display field.");
manifest.display = "minimal-ui";
fixed++;
}
if (manifest.prefer_related_applications) {
log("Obsolete prefer_related_applications field found.");
delete manifest.prefer_related_applications;
fixed++;
}
if (manifest.launch_handler) {
if (manifest.launch_handler.route_to) {
log("Obsolete launch_handler.route_to field found, renaming to client_mode");
manifest.launch_handler.client_mode = manifest.launch_handler.route_to;
delete manifest.launch_handler.route_to;
fixed++;
}
if (manifest.launch_handler.navigate_existing_client) {
log ("Obsolete launch_handler.navigate_existing_client field found.");
delete manifest.launch_handler.navigate_existing_client;
fixed++;
}
}
if (fixed) {
$$`link[rel="manifest"]`.forEach(link=>link.remove());
verb += `repaired ${fixed} issue${fixed>1?'s':''}`;
return manifest;
}
// nothing to do, let the original manifest stand.nothing.
verb += 'validated';
return null;
}
// return an array of CSP sources acceptable for a manifest URL and usable by this script. may be empty.
async function inspectCSP() {
const CSP_HEADER = 'Content-Security-Policy';
const parseCSP = csp => csp?csp.split(';').map(line=>line.trim().split(/\s+/)).reduce((o,a)=>(a.length>1&&(o[a[0]]=a.slice(1)),o),{}):{};
function checkCSP(csp, sources = []) {
if (!Object.keys(csp).length) return sources;
const allowedSources = csp['manifest-src'] ?? csp['default-src'];
if (!allowedSources) return sources;
return sources.filter(source=>allowedSources.includes(source));
}
const cspHeader = parseCSP((await fetch('', {method:'HEAD'})).headers.get(CSP_HEADER));
const cspMeta = parseCSP($(`meta[http-equiv="${CSP_HEADER}"]`)?.content);
const sources = checkCSP(cspMeta, checkCSP(cspHeader, ["data:", "blob:"]));
if (sources.length) {
// log("Acceptable manifest sources are ", sources);
} else {
log("CSP rules will probably prevent us from setting a manifest.");
}
return sources;
}
async function generateManifest(sources) {
const short_name = guessAppName();
const description = guessAppDescription();
const { theme_color, background_color } = guessAppColors();
const icons = await gatherAppIcons();
const related_applications = await guessRelatedApplications();
verb += 'generated';
// There it is, our glorious Web Manifest.
return {
name: short_name,
short_name,
description,
start_url: location.href,
scope: resolveURL("/"),
display: "standalone",
display_override: [ "window-controls-overlay" ],
theme_color,
background_color,
icons,
related_applications
};
}
let adjective;
let verb = 'grabbed from cache and ';
async function getManifest(sources) {
const start = Date.now();
let manifest;
let wasGenerated = false;
if ($`link[rel="manifest"]`) {
adjective = 'Site';
manifest = await repairManifest();
} else {
adjective = 'Custom';
manifest = await generateManifest();
wasGenerated = true;
}
if (manifest) {
// Use GM_addElement to inject the manifest.
// It doesn't succeed in bypassing Content Security Policy rules today, but maybe userscript extensions will make this work someday.
// (Note: TamperMonkey Beta has a setting to disable CSP altogether in their Advanced Settings.)
let manifestLink;
if (sources.includes('data:')) {
manifestLink = 'data:application/manifest+json;charset=utf-8,'+encodeURIComponent(JSON.stringify(manifest));
} else {
const blob = new Blob([JSON.stringify(manifest)], {type: 'application/manifest+json;charset=utf-8'});
manifestLink = URL.createObjectURL(blob);
// NOTE: no good way to revoke that URL. stick to page lifetime.
}
GM_addElement('link', {
rel: "manifest",
href: manifestLink
});
// This sets the color of the app title bar on desktop.
if (!$`meta[name="theme-color"]`) GM_addElement('meta', {
name: "theme-color",
content: manifest.theme_color
});
}
// summarize what we did.
logGroup(`${adjective} manifest ${verb} in ${Date.now()-start}ms.`,
manifest ?
JSON.stringify(manifest,null,2).replace(/"data:.{70,}?"/g, url=>`"${url.slice(0,35)}…[${url.length-45}_more_bytes]…${url.slice(-10,-1)}"`)
: $`link[rel="manifest"]`?.href ?? ''
);
return [manifest, wasGenerated];
}
// make a custom title bar from whatever header-like content we can find.
function customTitleBarJustAddWater(manifest) {
let outerDisconnect;
function findAndAdjustTitleBar(query) {
if (query.matches) {
let header = null;
let disconnect;
// 1. find a header. make it fit roughly as a titelbar, and make it draggable.
function findHeader() {
if (header && document.body.contains(header)) return;
const nodes = [...$$`body *`];
// header nodes are mostly top-most level nodes that cover the width of the page, are flush against the top of the page, and not too tall.
// (all broad generalizations are faulty, etc.)
const header_nodes = nodes.filter(n=> {
const { width, height, top } = n.getBoundingClientRect();
return document.body.clientWidth - width < 2 && top < 5 && height > 10 && height < 200;
}).filter((n,i,a)=>a.every(p=>p==n||!p.contains(n)));
if (!header_nodes.length) return;
// ok, plausible header found. Yer a titlebar, Header!
header = header_nodes[0];
Object.assign(header.style, {
// fixed or sticky position would be great here, but it's too likely to break pages that weren't expecting it.
// settle for trying not to be drawn under native titlebar elements.
WebkitAppRegion: 'drag',
appRegion: 'drag',
paddingLeft: 'env(titlebar-area-x, 0)',
paddingRight: 'calc(100% - env(titlebar-area-width, 100%))',
minHeight: 'env(titlebar-area-height, initial)',
backgroundColor: manifest.theme_color
});
// 2. look for interactive elements within the header. make those not draggable.
function findInteractiveHeaderElements() {
// this won't catch clickable divs.
$$('a,input,button,select,label,textarea', header).forEach(n=>Object.assign(n.style, {
WebkitAppRegion: 'no-drag',
appRegion: 'no-drag'
}));
}
try { disconnect?.(); } catch (e) { log(e) }
findInteractiveHeaderElements();
disconnect = observeDOM(findInteractiveHeaderElements, header);
}
try { outerDisconnect?.(); } catch(e) { log(e) }
findHeader();
outerDisconnect = observeDOM(findHeader);
} else {
try { outerDisconnect?.(); } catch(e) { log(e) }
}
}
const query = matchMedia('(display-mode: window-controls-overlay)');
findAndAdjustTitleBar(query);
query.addListener(e => findAndAdjustTitleBar(e));
}
async function main() {
const sources = await inspectCSP();
const [manifest, wasGenerated] = await getManifest(sources);
// if there was a site manifest, then trust that someone knew what they were doing, and don't try weird shenanigans.
if (wasGenerated) {
// but if we instead foisted installability upon an unuspecting web page...
await customTitleBarJustAddWater(manifest);
}
}
main();