StreamingResponse raise UnicodeEncodeError when filename contains special characters

[HueyBai]

When returning a StreamingResponse to return a file stream, if filename in the header contains special characters (tested Chinese, Korean, Japanese, Arabic and Russian), a UnicodeEncodeError will be thrown.

Here is a full example to reproduce:

import boto3
filename = '测试' # can also be 'テスト', 'тест', 'امتحان', '시험'
client = boto3.client(...)
s3_file = client.get_object(...)
return StreamingResponse(
    content=s3_file["Body"].iter_chunks(),
    headers={f'Content-Disposition': 'attachment; filename={}'.format(filename)},
    media_type="application/octet-stream"
)

error:

File "", line 151, in 
    return StreamingResponse(
  File "lib/python3.9/site-packages/starlette/responses.py", line 242, in __init__
    self.init_headers(headers)
  File "lib/python3.9/site-packages/starlette/responses.py", line 72, in init_headers
    raw_headers = [
  File "lib/python3.9/site-packages/starlette/responses.py", line 73, in <listcomp>
    (k.lower().encode("latin-1"), v.encode("latin-1"))
UnicodeEncodeError: 'latin-1' codec can't encode characters in position 21-23: ordinal not in range(256)

Dependencies:

fastapi 0.89.1
starlette 0.22.0

How can I return a file stream with special characters in the filename?

[alex-oleshkevich]

Quote it. See https://stackoverflow.com/questions/1361604/how-to-encode-utf8-filename-for-http-headers-python-django