Panel - Dynamically Viewing the file in File Selector

Panel
1

Hi All,

I am new to Panel and new help with File Selector.

I have defined a save_template_button to save templates and a FileSelector. When I click on save_templte_button it saves a template to the location from where File Selector should pick it.

self.save_template_button = pn.widgets.Button(name="\u21bb Save Template", button_type="primary", height=50, width=200)
self.files = pn.widgets.FileSelector('/Vineet/Saved_Files')
def callback(target, event):
   if len(target.value) > 1:
        target.value = [target.val[-1]]
        target._update_files(target)

self.files.link(
    self.files,
    callbacks = {"value":callback}
)
self.files

However, when I add a new file using the save_template_button, I am not able to see the new file it in the FileSelector unless I restart the server.
How can we dynamically update the files in File Selector?

2

It is easier to help if the minimal running code is complete, you can copy,paste and run it. I completed it according to what I believed. Sure there is a public method, but the ._refresh method works.

import panel as pn 

class Files():
  def get_files(self):
    self.save_template_button = pn.widgets.Button(name="\u21bb Save Template", 
        button_type="primary", height=50, width=200)
    self.files = pn.widgets.FileSelector('../Desktop')
    def callback(event):
        self.files._refresh()
    self.save_template_button.on_click(callback)
    return pn.Column(self.save_template_button, self.files)

f = Files()
pn.Row(f.get_files()).servable()
1 Like
3

Hi @nghenzi,

Apologies for the missing code. The detail for the problem are defined below-
I have a directory ‘/Users/Shaheen/Desktop/Vineet/MS_SE_Spring2019/Panel/Files’.

Our batch job will dumb files to this folder, now we should be able to select files from this folder and be able to upload further, I have implemented the part for uploading. The challenge I am facing is to dynamically refresh the files in the ‘Files’ folder.

I used the code you shared-
import panel as pn

class Files():

def get_files(self):

    def callback(event):
        self.files._refresh()

    self.refresh_template_button = pn.widgets.Button(name="\u21bb Refresh Template", 
        button_type="primary", height=50, width=200)
    self.files = pn.widgets.FileSelector('/Users/Shaheen/Desktop/Vineet/MS_SE_Spring2019/Panel/Files')

    self.refresh_template_button.on_click(callback)
    return pn.Column(self.refresh_template_button, self.files)

f = Files()
pn.Row(f.get_files()).servable()

Currently I have two files at the location-
‘/Users/Shaheen/Desktop/Vineet/MS_SE_Spring2019/Panel/Files’

Now if I any batch adds one or more files and we click on ‘Refresh Template’ button, we are not able to see the new files added in the ‘File Selector’ panel.
Hopefully, I am able to explain the issue I am facing here. Please feel free if you need any additional information. Thanks a lot!

Screen Shot 2021-04-12 at 10.47.20 PM
Screen Shot 2021-04-12 at 10.47.20 PM1912×1338 240 KB

4

maybe it is related to panel version. Try to upgrade to latest panel

dynfl

1 Like
5

.Thanks @nghenzi.
I am getting the error when I click on ‘Save Template’ button.

File “/Users/Shaheen/Desktop/Vineet/MS_SE_Spring2019/Panel/file.py”, line 13, in callback
self.files._refresh()
AttributeError: ‘FileSelector’ object has no attribute ‘_refresh’.

Attached is the file I am using for running the code. The panel version in my machine is- ‘0.10.3’

Ifile.py (637 Bytes)

6

-UPDATE

I updated my panel to ‘0.11.2’ and it works on Jupyter notebook now. However, when I run the file from command line - ‘panel serve file.py’, I get bokeh issue-

Failed to load Bokeh session veIIFdF9NuGVgkeBpPT76gncc4s6ihdvdtc4GSZP7F9w: Error: Lost websocket connection, 1005

Thanks a lot @nghenzi. I will try to fix the bokeh issue. Panel issue seems to work fine now.