Enable pn.widgets.FileSelector() to watch for new files and update directory

[tlmille2]

Problem Statement
The general flow is a user can upload a series of images they would like to analyze or transform, select an image to do the analysis on, and then preform the analysis using Panel.

I'm using the file_input = pn.widgets.FileInput() to input files and = pn.widgets.FileSelector(nameofdir) to allow the selection of images to be analyzed using panel. However, I'm noticing the pn.widgets.FileSelector() doesn't update the available files unless you refresh the browser.

Additionally, the FileSelector() Widget has a method self._update_files() is called in response certain events, such as pressing the down arrow. You can force a refresh without reloading the browser. The only issue I have with using the UI to force the update is if you explicitly define a directory, without any children folders inside that directory, those buttons are basically disabled.

Desired Solution
Add a periodic callback to watch the directory for any changes.

Alternative Solution
A refresh button that can refresh the directory and display any new changes

[philippjfr]

Thanks @tlmille2, very reasonable suggestions. I'll implement both, one question I have though, what did you do to get that layout for the FileSelector, it should really look like this:

[tlmille2]

@philippjfr - Appending the FileSelector in a bootstrap.main template (see below). I filtered out a large chunk of variable names.

I'm going to open another ticket about FileSelector not behaving it's margins when applied to the bootstrap template. I'm trying to diagnose it's cause, but I think it's a css issue.

[philippjfr]

Thanks, I'll file a new issue.