WebSocket disconnects when calling server.files.metadata / server.files.delete_file for a specific UTF‑8 filename in gcodes/

### What happened When I call server.files.metadata or server.files.delete_file via WebSocket for a file in the gcodes/ root directory whose name contains a 4‑byte UTF‑8 character, the WebSocket connection is closed at the TCP level immediately after the request is sent. The same filename works fine when the file is placed under gcodes/USB/ and accessed as USB/<filename>. moonraker.log is attached. Please see in particular the time ranges around: 2025-12-01 15:11:14 – initial metadata test 2025-12-01 15:29:14 – metadata request for the problematic file 2025-12-01 15:29:14.796 – websockets.py:on_close() with Close Code: None 2025-12-01 15:xx:xx – server.files.delete_file for the same filename and subsequent disconnect Environment Moonraker version: (fill from GET /server/info) Host OS: Linux (Klipper + Moonraker on embedded board) Client: custom LVGL-based display using JSON‑RPC WebSocket (/websocket, 127.0.0.1) Problematic filename On disk (under printer_data/gcodes/): text 󧐷 - 2_3_PLA_21m50s.gcode UTF‑8 bytes: F3 A7 90 B7 (valid 4‑byte sequence) Unicode code point: U+1D437 Paths: text ROM filename: "󧐷 - 2_3_PLA_21m50s.gcode" USB filename: "USB/󧐷 - 2_3_PLA_21m50s.gcode" ROM full path for delete_file: "gcodes/󧐷 - 2_3_PLA_21m50s.gcode" Steps to reproduce Create the file in the gcodes root: bash cd /path/to/printer_data/gcodes mv some_file.gcode "󧐷 - 2_3_PLA_21m50s.gcode" Start Moonraker. Connect a WebSocket client to ws://127.0.0.1/websocket, identify as usual. Case 1 – metadata via WebSocket: json { "jsonrpc": "2.0", "method": "server.files.metadata", "params": { "filename": "󧐷 - 2_3_PLA_21m50s.gcode" }, "id": 130 } Case 2 – delete_file via WebSocket: json { "jsonrpc": "2.0", "method": "server.files.delete_file", "params": { "path": "gcodes/󧐷 - 2_3_PLA_21m50s.gcode" }, "id": 177 } In both cases, right after sending the request, the next recv() in the client returns 0 and the WebSocket connection is closed by the peer. No JSON‑RPC error response is received for these requests. If I instead move the file under USB/: bash mv "󧐷 - 2_3_PLA_21m50s.gcode" "USB/󧐷 - 2_3_PLA_21m50s.gcode" and call: json { "method": "server.files.metadata", "params": { "filename": "USB/󧐷 - 2_3_PLA_21m50s.gcode" }, ... } the metadata request works normally and the WebSocket stays connected. Expected behavior WebSocket connection should stay open. server.files.metadata / server.files.delete_file should either: return a normal JSON‑RPC result, or return a JSON‑RPC error (e.g. 404), but should not cause the WebSocket/TCP connection to be closed just because of this filename. Actual behavior For the ROM filename "󧐷 - 2_3_PLA_21m50s.gcode" in the gcodes/ root: server.files.metadata and server.files.delete_file triggered a connection drop immediately after the request is sent. The client sees recv() return 0. On the Moonraker side, websockets.py:on_close() logs: text Websocket Closed: ID: ... Close Code: None, Close Reason: None There is no JSON‑RPC error logged for these requests and no traceback in moonraker.log. For the same filename under USB/ ("USB/󧐷 - 2_3_PLA_21m50s.gcode"), both HTTP and WebSocket metadata work fine, and Fluidd can show the thumbnail and metadata. ### Client Other ### Browser Other or N/A ### How to reproduce 1. Start Moonraker. 2. In the printer_data/gcodes directory create a file with the following name: "󧐷 - 2_3_PLA_21m50s.gcode" (e.g. rename any existing gcode: mv some.gcode "󧐷 - 2_3_PLA_21m50s.gcode") 3. Connect a WebSocket client to ws://127.0.0.1/websocket and identify the client in the normal way. 4. Send either of the following JSON‑RPC requests over the WebSocket: a) Metadata: { "jsonrpc": "2.0", "method": "server.files.metadata", "params": { "filename": "󧐷 - 2_3_PLA_21m50s.gcode" }, "id": 130 } b) Delete: { "jsonrpc": "2.0", "method": "server.files.delete_file", "params": { "path": "gcodes/󧐷 - 2_3_PLA_21m50s.gcode" }, "id": 177 } 5. Observe that immediately after sending the request, the next recv() on the client returns 0 and the WebSocket connection is closed, without any JSON‑RPC error response for that request. ### Additional information 2025-12-01 15:43:28,485 [application.py:log_request()] - 101 GET /websocket (127.0.0.1) [_TRUSTED_USER_] 9.96ms 2025-12-01 15:43:28,487 [websockets.py:open()] - Websocket Opened: ID: 547950602752, Proxied: False, User Agent: , Host Name: 127.0.0.1 2025-12-01 15:43:28,512 [websockets.py:_handle_identify()] - Websocket 547950602752 Client Identified - Name: eez_test, Version: 1.0.0, Type: web