File_upload is uploading the file but the value is always None

File_upload widget is not printing the value and always None.

Hi can you share an minimal example?

I hope this helps you get an idea about the bug!

How big is the file?

If it’s a large file: FileInput — Panel v1.4.3

file size is 208.3 Mb

Likely too big, or at least it hasn’t finished uploading so value is None.

I encountered this myself:

  --websocket-max-message-size BYTES
                        Set the Tornado websocket_max_message_size value (default: 20MB)

If it’s above 20 MBs the websocket will disconnect:

2024-06-14 11:39:36,766 WebSocket connection closed: code=None, reason=None

So, you have to panel serve --websocket-max-message-size 157286400 (this is for 150 MBs)