feat: add endpoint to serve embedded cover art from audio files

src/server/routes/audio.js

@@ -1,9 +1,13 @@
 import fs from 'fs';
 import path from 'path';
 import mime from 'mime';
+import { parseFile as mmParseFile } from 'music-metadata';
 import { DATA_DIR } from '../config.js';
 
 export function registerAudioRoutes(app) {
+  // Simple in-memory cover cache: name -> { mime, buf }
+  const coverCache = new Map();
+
   app.head('/audio/:name', (req, res) => {
     const name = req.params.name;
     const filePath = path.join(DATA_DIR, name);
@@ -55,4 +59,36 @@ export function registerAudioRoutes(app) {
       fs.createReadStream(filePath).pipe(res);
     }
   });
+
+  // Serve embedded cover art from audio files, if present
+  app.get('/cover/:name', async (req, res) => {
+    try {
+      const name = req.params.name;
+      const filePath = path.join(DATA_DIR, name);
+      const resolved = path.resolve(filePath);
+      if (!resolved.startsWith(DATA_DIR)) return res.status(400).send('Invalid path');
+      if (!fs.existsSync(resolved)) return res.status(404).send('Not found');
+
+      if (coverCache.has(resolved)) {
+        const c = coverCache.get(resolved);
+        res.setHeader('Content-Type', c.mime || 'image/jpeg');
+        res.setHeader('Cache-Control', 'no-store');
+        return res.status(200).end(c.buf);
+      }
+
+      const meta = await mmParseFile(resolved, { duration: false });
+      const pic = meta.common?.picture?.[0];
+      if (!pic || !pic.data || !pic.data.length) {
+        return res.status(404).send('No cover');
+      }
+      const mimeType = pic.format || 'image/jpeg';
+      const buf = Buffer.from(pic.data);
+      coverCache.set(resolved, { mime: mimeType, buf });
+      res.setHeader('Content-Type', mimeType);
+      res.setHeader('Cache-Control', 'no-store');
+      return res.status(200).end(buf);
+    } catch (e) {
+      return res.status(500).send('Error reading cover');
+    }
+  });
 }