fix: rewrite avatarproxy and CachedImage (#1016)

* fix: rewrite avatarproxy and CachedImage

Avatar proxy was allowing every request to be proxied, no matter the original ressource's origin or
filetype. This PR fixes it be allowing only relevant resources to be cached, i.e. Jellyfin/Emby
images and TMDB images.

fix #1012, #1013

* fix: resolve CodeQL error

* fix: resolve CodeQL error

* fix: resolve review comments

* fix: resolve review comment

* fix: resolve CodeQL error

* fix: update imageproxy path

server/routes/avatarproxy.ts

@@ -1,5 +1,8 @@
+import { MediaServerType } from '@server/constants/server';
 import ImageProxy from '@server/lib/imageproxy';
+import { getSettings } from '@server/lib/settings';
 import logger from '@server/logger';
+import { getHostname } from '@server/utils/getHostname';
 import { Router } from 'express';
 
 const router = Router();
@@ -7,9 +10,25 @@ const router = Router();
 const avatarImageProxy = new ImageProxy('avatar', '');
 // Proxy avatar images
 router.get('/*', async (req, res) => {
-  const imagePath = req.url.startsWith('/') ? req.url.slice(1) : req.url;
-
+  let imagePath = '';
   try {
+    const jellyfinAvatar = req.url.match(
+      /(\/Users\/\w+\/Images\/Primary\/?\?tag=\w+&quality=90)$/
+    )?.[1];
+    if (!jellyfinAvatar) {
+      const mediaServerType = getSettings().main.mediaServerType;
+      throw new Error(
+        `Provided URL is not ${
+          mediaServerType === MediaServerType.JELLYFIN
+            ? 'a Jellyfin'
+            : 'an Emby'
+        } avatar.`
+      );
+    }
+
+    const imageUrl = new URL(jellyfinAvatar, getHostname());
+    imagePath = imageUrl.toString();
+
     const imageData = await avatarImageProxy.getImage(imagePath);
 
     res.writeHead(200, {