How to change downloading name in flask?

Question

I have a small project which has to response some files. I know that using nginx will be better decision but that files a really small.

Part of my program:

Answer 1

In my case, setting the as_attachment and attachment_filename did not work because the Content-Disposition: attachment does not appear in the client-side copy of the response.

If you have Flask-CORS enabled, you can initialize it with expose_headers set to a custom header that specifies the filename (ex. "x-suggested-filename"). Then add that header to the response.

# In file where the Flask app instance is initialized
app = Flask(__name__)
CORS(app, expose_headers=["x-suggested-filename"])

# In file with the download endpoint
result = send_file("/full/path/to/some/file",
                   mimetype="text/plain", # use appropriate type based on file
                   as_attachment=True,
                   conditional=False)
result.headers["x-suggested-filename"] = "use_this_filename.txt"
return result

Then, in the client-side download code, you can inspect the response headers to get the filename from the same custom header:

# Using axios and FileSaver
let response = await axios.get(downloadUrl, downloadConfig);
let filename = response.headers["x-suggested-filename"];
FileSaver.saveAs(response.data, filename);