api: rework url parsing

- tlds are now parsed and validated correctly (e.g. ".co.uk" works now)
- url patterns are pre-compiled instead of being compiled for every request
- aliases are computed in a safe manner using the URL object where possible

src/modules/processing/hostOverrides.js

@@ -1,48 +1,102 @@
-export default function (inHost, inURL) {
-    let host = String(inHost);
-    let url = String(inURL);
+import { services } from "./config.js";
+import { strict as assert } from "node:assert";
+import psl from "psl";
 
-    switch(host) {
+export function aliasURL(url) {
+    assert(url instanceof URL);
+
+    const host = psl.parse(url.hostname);
+    const parts = url.pathname.split('/');
+
+    switch (host.sld) {
         case "youtube":
-            if (url.startsWith("https://youtube.com/live/") || url.startsWith("https://www.youtube.com/live/")) {
-                url = url.split("?")[0].replace("www.", "");
-                url = `https://youtube.com/watch?v=${url.replace("https://youtube.com/live/", "")}`
-            }
-            if (url.includes('youtube.com/shorts/')) {
-                url = url.split('?')[0].replace('shorts/', 'watch?v=');
+            if (url.pathname.startsWith('/live/') || url.pathname.startsWith('/shorts/')) {
+                url.pathname = '/watch';
+                // ['', 'live' || 'shorts', id, ...rest]
+                url.search = `?v=${encodeURIComponent(parts[2])}`
             }
             break;
         case "youtu":
-            if (url.startsWith("https://youtu.be/")) {
-                host = "youtube";
-                url = `https://youtube.com/watch?v=${url.replace("https://youtu.be/", "")}`
+            if (url.hostname === 'youtu.be' && parts.length === 2) {
+                /* youtu.be urls can be weird, e.g. https://youtu.be/<id>//asdasd// still works
+                ** but we only care about the 1st segment of the path */
+                url = new URL(`https://youtube.com/watch?v=${
+                    encodeURIComponent(parts[1])
+                }`)
             }
             break;
+
         case "vxtwitter":
         case "x":
-            if (url.startsWith("https://x.com/")) {
-                host = "twitter";
-                url = url.replace("https://x.com/", "https://twitter.com/")
-            }
-            if (url.startsWith("https://vxtwitter.com/")) {
-                host = "twitter";
-                url = url.replace("https://vxtwitter.com/", "https://twitter.com/")
+            if (['x.com', 'vxtwitter.com'].includes(url.hostname)) {
+                url.hostname = 'twitter.com'
             }
             break;
+
         case "tumblr":
-            if (!url.includes("blog/view")) {
-                if (url.slice(-1) === '/') url = url.slice(0, -1);
-                url = url.replace(url.split('/')[5], '')
+            if (!url.pathname.includes("/blog/view")) {
+                if (url.pathname.endsWith('/'))
+                    url.pathname = url.pathname.slice(0, -1);
+                url.pathname = url.pathname.replace(parts[5], '')
             }
             break;
+
         case "twitch":
-            if (url.includes('clips.twitch.tv')) {
-                url = url.split('?')[0].replace('clips.twitch.tv/', 'twitch.tv/_/clip/');
+            if (url.hostname === 'clips.twitch.tv' && parts.length >= 2) {
+                url = new URL(`https://twitch.tv/_/clip/${parts[1]}`);
             }
             break;
     }
-    return {
-        host: host,
-        url: url
-    }
+
+    return { url, host: host.sld }
 }
+
+export function cleanURL({ url, host }) {
+    assert(url instanceof URL);
+    let stripQuery = true;
+
+    if (host === 'pinterest') {
+        url.hostname = 'pinterest.com'
+    } else if (host === 'vk' && url.pathname.includes('/clip')) {
+        if (url.searchParams.get('z'))
+            url.search = '?z=' + encodeURIComponent(url.searchParams.get('z'));
+        stripQuery = false;
+    } else if (host === 'youtube' && url.searchParams.get('v')) {
+        url.search = '?v=' + encodeURIComponent(url.searchParams.get('v'));
+        stripQuery = false;
+    }
+
+    if (stripQuery) {
+        url.search = url.hash = ''
+    }
+
+    if (url.pathname.endsWith('/'))
+        url.pathname = url.pathname.slice(0, -1);
+
+    return url
+}
+
+export function normalizeURL(url) {
+    return cleanURL(
+        aliasURL(
+            new URL(url.replace(/^https\/\//, 'https://'))
+        )
+    );
+}
+
+export function hasValidHostname(url) {
+    const host = psl.parse(url.hostname);
+    if (host.error) return false;
+
+    const service = services[host.sld];
+    if (!service) return false;
+    
+    if ((service.tld ?? 'com') !== host.tld) return false;
+
+    const anySubdomainAllowed = service.subdomains === '*';
+    const validSubdomain = [null, 'www', ...(service.subdomains ?? [])].includes(host.subdomain);
+    if (!validSubdomain && !anySubdomainAllowed)
+        return false;
+
+    return true;
+}