feat: refactor audio token management and implement cover art retrieval

src/server/routes/audio/pathUtils.js

@@ -0,0 +1,33 @@
+import fs from 'fs';
+import path from 'path';
+import mime from 'mime';
+import { DATA_DIR as RAW_DATA_DIR } from '../../config.js';
+
+// Resolve DATA_DIR once, ensure absolute path and normalized with trailing separator for prefix checks
+const DATA_DIR = path.resolve(RAW_DATA_DIR);
+const DATA_DIR_WITH_SEP = DATA_DIR.endsWith(path.sep) ? DATA_DIR : DATA_DIR + path.sep;
+
+export function resolveSafePath(name) {
+  if (!name || typeof name !== 'string') return null;
+  // Prevent path traversal and normalize input
+  const joined = path.join(DATA_DIR, name);
+  const resolved = path.resolve(joined);
+  if (resolved === DATA_DIR || resolved.startsWith(DATA_DIR_WITH_SEP)) return resolved;
+  return null;
+}
+
+export function fileExists(p) {
+  try {
+    return fs.existsSync(p);
+  } catch {
+    return false;
+  }
+}
+
+export function statFile(p) {
+  return fs.statSync(p);
+}
+
+export function getMimeType(p, fallback = 'audio/mpeg') {
+  return mime.getType(p) || fallback;
+}