stemserve: stay quiet on dropped client connections

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

server/stemserve.py

@@ -490,6 +490,15 @@ def _format(query):
     return "opus", min(OPUS_RATES, key=lambda r: abs(r - br))
 
 
+class QuietServer(ThreadingHTTPServer):
+    """Browsers and proxies drop connections all the time; don't print a traceback for each."""
+
+    def handle_error(self, request, client_address):
+        if isinstance(sys.exc_info()[1], (ConnectionError, TimeoutError)):
+            return
+        super().handle_error(request, client_address)
+
+
 def main():
     if not os.path.isdir(STEMS_DIR):
         sys.exit(f"STEMS_DIR not found: {STEMS_DIR}")
@@ -497,7 +506,7 @@ def main():
     INDEX.refresh()
     log(f"stemserve on :{PORT}, {INDEX.count} tracks in {STEMS_DIR}, ffmpeg={'yes' if FFMPEG else 'no'}, "
         f"token={'on' if TOKEN else 'off'}")
-    server = ThreadingHTTPServer(("0.0.0.0", PORT), Handler)
+    server = QuietServer(("0.0.0.0", PORT), Handler)
     server.daemon_threads = True
     # As PID 1 in a container, SIGTERM is ignored unless handled; docker stop would hang.
     signal.signal(signal.SIGTERM, lambda *_: sys.exit(0))