fix: proxy suit les redirects côté serveur (302 → CORS bypass)

backend/src/routes/audioRoutes.ts

@@ -1,10 +1,10 @@
 import { Router, Request, Response } from 'express';
 import https from 'https';
 import http from 'http';
+import { IncomingMessage } from 'http';
 
 const router = Router();
 
-// Block private/loopback ranges to prevent SSRF
 const BLOCKED = [
   /^127\./,
   /^10\./,
@@ -18,6 +18,69 @@ function isBlocked(hostname: string): boolean {
   return BLOCKED.some(r => r.test(hostname));
 }
 
+const REDIRECT_CODES = new Set([301, 302, 303, 307, 308]);
+
+function fetchAudio(
+  url: string,
+  headers: Record<string, string>,
+  res: Response,
+  depth: number,
+): void {
+  if (depth > 8) {
+    if (!res.headersSent) res.status(502).json({ message: 'Too many redirects' });
+    return;
+  }
+
+  let parsed: URL;
+  try {
+    parsed = new URL(url);
+  } catch {
+    if (!res.headersSent) res.status(400).json({ message: 'Invalid redirect URL' });
+    return;
+  }
+
+  if (!['http:', 'https:'].includes(parsed.protocol)) {
+    if (!res.headersSent) res.status(400).json({ message: 'Protocol not allowed' });
+    return;
+  }
+  if (isBlocked(parsed.hostname)) {
+    if (!res.headersSent) res.status(403).json({ message: 'Forbidden' });
+    return;
+  }
+
+  const lib = parsed.protocol === 'https:' ? https : http;
+
+  const proxyReq = lib.request(url, { headers }, (proxyRes: IncomingMessage) => {
+    const status = proxyRes.statusCode ?? 200;
+
+    // Follow redirects server-side so browser never sees non-CORS domains
+    if (REDIRECT_CODES.has(status) && proxyRes.headers.location) {
+      const next = new URL(proxyRes.headers.location, url).toString();
+      proxyRes.resume(); // drain to free socket
+      fetchAudio(next, headers, res, depth + 1);
+      return;
+    }
+
+    res.setHeader('Access-Control-Allow-Origin', '*');
+    res.setHeader('Access-Control-Expose-Headers', 'Content-Length, Content-Range, Content-Type, Accept-Ranges');
+
+    const forward = ['content-type', 'content-length', 'content-range', 'accept-ranges'];
+    for (const h of forward) {
+      const v = proxyRes.headers[h];
+      if (v) res.setHeader(h, v as string);
+    }
+
+    res.status(status);
+    proxyRes.pipe(res);
+  });
+
+  proxyReq.on('error', () => {
+    if (!res.headersSent) res.status(502).json({ message: 'Proxy error' });
+  });
+
+  proxyReq.end();
+}
+
 router.get('/proxy', (req: Request, res: Response) => {
   const raw = req.query.url as string;
   if (!raw) { res.status(400).json({ message: 'url required' }); return; }
@@ -40,30 +103,11 @@ router.get('/proxy', (req: Request, res: Response) => {
     'User-Agent': 'Mozilla/5.0 (compatible; Podcastic/1.0)',
     'Accept': '*/*',
   };
-  if (req.headers.range) upstream['Range'] = req.headers.range;
+  if (req.headers.range) upstream['Range'] = req.headers.range as string;
 
-  const lib = parsed.protocol === 'https:' ? https : http;
+  req.on('close', () => res.destroy());
 
-  const proxyReq = lib.request(raw, { headers: upstream }, (proxyRes) => {
-    res.setHeader('Access-Control-Allow-Origin', '*');
-    res.setHeader('Access-Control-Expose-Headers', 'Content-Length, Content-Range, Content-Type, Accept-Ranges');
-
-    const forward = ['content-type', 'content-length', 'content-range', 'accept-ranges'];
-    for (const h of forward) {
-      const v = proxyRes.headers[h];
-      if (v) res.setHeader(h, v);
-    }
-
-    res.status(proxyRes.statusCode ?? 200);
-    proxyRes.pipe(res);
-  });
-
-  proxyReq.on('error', () => {
-    if (!res.headersSent) res.status(502).json({ message: 'Proxy error' });
-  });
-
-  req.on('close', () => proxyReq.destroy());
-  proxyReq.end();
+  fetchAudio(raw, upstream, res, 0);
 });
 
 export default router;