Fix truncated responses from compressed upstreams

fetch() decompresses transparently, but the proxies forwarded the upstream
content-length, so browsers cut compressed Plex/Seafile responses short and
JSON.parse failed. Ask Plex for identity encoding and drop the stale length
whenever the upstream response was encoded.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

server.js

@@ -38,6 +38,7 @@ async function proxySeafile(req, res) {
     const out = {};
     for (const h of ['content-type', 'content-length', 'content-disposition', 'content-range', 'accept-ranges']) {
       if (inline && h === 'content-disposition') continue;
+      if (h === 'content-length' && upstream.headers.get('content-encoding')) continue; // decompressed by fetch, so the length changed
       const v = upstream.headers.get(h);
       if (v) out[h] = v;
     }
@@ -245,14 +246,16 @@ async function plexApi(req, res) {
 async function plexProxy(req, res) {
   const ck = parseCookies(req), base = unsigned(ck.plex_srv), tok = ck.plex_stk;
   if (!base || !tok) { res.writeHead(401); return res.end(); }
-  const headers = { ...PLEX_HEADERS, 'X-Plex-Token': tok, Accept: req.headers.accept || 'application/json' };
+  const headers = { ...PLEX_HEADERS, 'X-Plex-Token': tok, Accept: req.headers.accept || 'application/json', 'Accept-Encoding': 'identity' };
   if (req.headers.range) headers.range = req.headers.range;
   const ac = new AbortController();
   res.on('close', () => ac.abort());
   try {
     const up = await fetch(base + req.url.slice('/plex'.length), { headers, signal: ac.signal });
     const out = {};
-    for (const h of ['content-type', 'content-length', 'content-range', 'accept-ranges']) { const v = up.headers.get(h); if (v) out[h] = v; }
+    // fetch() transparently decompresses, so an upstream content-length would no longer match the bytes we send.
+    const encoded = !!up.headers.get('content-encoding');
+    for (const h of ['content-type', 'content-length', 'content-range', 'accept-ranges']) { if (encoded && h === 'content-length') continue; const v = up.headers.get(h); if (v) out[h] = v; }
     if (req.url.startsWith('/plex/photo/')) out['cache-control'] = 'private, max-age=86400';
     res.writeHead(up.status, out);
     if (up.body) Readable.fromWeb(up.body).on('error', () => res.destroy()).pipe(res); else res.end();