FilePickerUploadFile Fails When Filename Is Modified

[amgartendev]

Question

I'm experiencing an issue with FilePickerUploadFile. When I use file.name as the filename, everything works perfectly. However, if I modify the filename, even with a simple name like "hey.jpg", the upload fails. It does nothing.

I didn't find anything in the documentation regarding this issue or how the filename should be passed. I assume the filename must be exactly the same as on the user's computer.

The problem with this is that I'm creating a web app where users can upload multiple images, and I'm trying to rename the file using a format like DATETIME_USER-ID.EXTENSION to avoid conflicts with other images that may have the same name, even if I separate each user's files into individual folders in the uploads directory.

For example:
Original Filename: image.jpg
Renamed Filename: 20250304_123.jpg

I tried uploading the image first, regardless of its filename, and then modifying it later. However, once the image is uploaded, it automatically replaces the previous version.

Code sample

def handle_file_selection(e: ft.FilePickerResultEvent) -> None:
    if e.files:
        file = e.files[0]
        
        upload_datetime = datetime.now().strftime('%Y%m%d%H%M%S')
        ext = file.name.split(".")[-1] if "." in file.name else "bin"
        filename = f"{upload_datetime}_{self.user_uid}.{ext}"
        
        upload_url = self.page.get_upload_url(filename, 60)
        uploader = [
            ft.FilePickerUploadFile(
                name=filename,
                upload_url=upload_url
            )
        ]

        file_picker.upload(uploader)

Error message

No error message

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• I have searched for answers to my question both in the issues and in previous discussions.

[ndonkoHenri]

I assume the filename must be exactly the same as on the user's computer.

Yeah, that's the current implementation.

Opened an issue to support your usecase: #5037