Allow non latin-1 filename in FileResponse

starlette/responses.py

@@ -7,7 +7,7 @@
 import typing
 from email.utils import formatdate
 from mimetypes import guess_type
-from urllib.parse import quote_plus
+from urllib.parse import quote, quote_plus
 
 from starlette.background import BackgroundTask
 from starlette.concurrency import iterate_in_threadpool
@@ -229,7 +229,13 @@ def __init__(
         self.background = background
         self.init_headers(headers)
         if self.filename is not None:
-            content_disposition = 'attachment; filename="{}"'.format(self.filename)
+            content_disposition_filename = quote(self.filename)
+            if content_disposition_filename != self.filename:
+                content_disposition = "attachment; filename*=utf-8''{}".format(
+                    content_disposition_filename
+                )
+            else:
+                content_disposition = 'attachment; filename="{}"'.format(self.filename)
             self.headers.setdefault("content-disposition", content_disposition)
         self.stat_result = stat_result
         if stat_result is not None:

tests/test_responses.py

@@ -202,6 +202,21 @@ def test_file_response_with_missing_file_raises_error(tmpdir):
     assert "does not exist" in str(exc_info.value)
 
 
+def test_file_response_with_chinese_filename(tmpdir):
+    content = b"file content"
+    filename = "你好.txt"  # probably "Hello.txt" in Chinese
+    path = os.path.join(tmpdir, filename)
+    with open(path, "wb") as f:
+        f.write(content)
+    app = FileResponse(path=path, filename=filename)
+    client = TestClient(app)
+    response = client.get("/")
+    expected_disposition = "attachment; filename*=utf-8''%E4%BD%A0%E5%A5%BD.txt"
+    assert response.status_code == status.HTTP_200_OK
+    assert response.content == content
+    assert response.headers["content-disposition"] == expected_disposition
+
+
 def test_set_cookie():
     async def app(scope, receive, send):
         response = Response("Hello, world!", media_type="text/plain")