fix export case download with non-ascii names (#24100)

frigate/api/export.py

@@ -9,6 +9,7 @@ import zipfile
 from collections import deque
 from collections.abc import Iterator
 from pathlib import Path
+from urllib.parse import quote
 
 import psutil
 from fastapi import APIRouter, Depends, Query, Request
@@ -453,6 +454,22 @@ def _stream_case_archive(exports: list[Export]) -> Iterator[bytes]:
     yield from buffer.drain()
 
 
+def _content_disposition(filename: str, ascii_fallback: str) -> str:
+    """Build an attachment Content-Disposition that survives non-ASCII names.
+
+    Header values are encoded as latin-1, so a name outside that range cannot
+    go in filename at all. RFC 6266 handles this with a pair: a plain ASCII
+    filename for old clients, plus a percent-encoded UTF-8 filename* that
+    every current browser prefers.
+    """
+    ascii_name = filename if filename.isascii() else ascii_fallback
+
+    return (
+        f'attachment; filename="{ascii_name}"; '
+        f"filename*=UTF-8''{quote(filename, safe='')}"
+    )
+
+
 @router.get(
     "/cases/{case_id}/download",
     dependencies=[Depends(allow_any_authenticated())],
@@ -495,7 +512,9 @@ def download_export_case(
         _stream_case_archive(exports),
         media_type="application/zip",
         headers={
-            "Content-Disposition": f'attachment; filename="{archive_base}.zip"',
+            "Content-Disposition": _content_disposition(
+                f"{archive_base}.zip", f"{case_id}.zip"
+            ),
         },
     )