File selection button for Jupyter notebook

Question

Background

This is a feature that I have wanted to see in Jupyter notebook for quite some time. I'm sure that others have built similar things but I haven't been able to find them on SO, Github, CodeReview or the rest of the searchable internet.

Approach

I used ipywidgets.Button as a base class and added a traitlet called files. This traitlet receives a list of files as strings from tkinter.filedialog.askopenfilename. When the button is clicked the file dialog pops up the user selects files and then can access that list of strings as an attribute/traitlet on the button instance.

import traitlets
from ipywidgets import widgets
from IPython.display import display
from tkinter import Tk, filedialog


class SelectFilesButton(widgets.Button):
    """A file widget that leverages tkinter.filedialog."""

    def __init__(self):
        super(SelectFilesButton, self).__init__()
        # Add the selected_files trait
        self.add_traits(files=traitlets.traitlets.List())
        # Create the button.
        self.description = "Select Files"
        self.icon = "square-o"
        self.style.button_color = "orange"
        # Set on click behavior.
        self.on_click(self.select_files)

    @staticmethod
    def select_files(b):
        """Generate instance of tkinter.filedialog.

        Parameters
        ----------
        b : obj:
            An instance of ipywidgets.widgets.Button 
        """
        # Create Tk root
        root = Tk()
        # Hide the main window
        root.withdraw()
        # Raise the root to the top of all windows.
        root.call('wm', 'attributes', '.', '-topmost', True)
        # List of selected fileswill be set to b.value
        b.files = filedialog.askopenfilename(multiple=True)

        b.description = "Files Selected"
        b.icon = "check-square-o"
        b.style.button_color = "lightgreen"

Example Usage

Displaying the button

my_button = SelectFilesButton()
my_button # This will display the button in the context of Jupyter Notebook

Retrieving the file list from the button.

# In a different cell of the same Jupyter Notebook You can access the file list by using the following:
my_button.files

Questions

These are just some suggestions.

1) Does this work on your machine? If so throw me an upvote! If not please specify what versions you are working with so I can extend.

2) Are there any general overall improvements that can be made?

3) Is there any redundancy that I missed?

4) Does this code follow best practices?

Answer 1

It is a nice piece of code. I have tried it in both jupyter notebook and jupyter lab. It works quite well in the notebook, but it does not work that well in lab.

In jupyter lab, it shows the button, but does not execute anything when you push it. I have adapted your code to be able to run it in lab.

Code:

import traitlets
from ipywidgets import widgets
from IPython.display import display
from tkinter import Tk, filedialog


class SelectFilesButton(widgets.Button):
    """A file widget that leverages tkinter.filedialog."""

    def __init__(self):
        super(SelectFilesButton, self).__init__()
        # Add the selected_files trait
        self.add_traits(files=traitlets.traitlets.List())
        # Create the button.
        self.description = "Select Files"
        self.icon = "square-o"
        self.style.button_color = "orange"
        # Set on click behavior.
        self.on_click(self.select_files)

    @staticmethod
    def select_files(b):
        """Generate instance of tkinter.filedialog.

        Parameters
        ----------
        b : obj:
            An instance of ipywidgets.widgets.Button 
        """
        with out:
            try:
                # Create Tk root
                root = Tk()
                # Hide the main window
                root.withdraw()
                # Raise the root to the top of all windows.
                root.call('wm', 'attributes', '.', '-topmost', True)
                # List of selected fileswill be set to b.value
                b.files = filedialog.askopenfilename(multiple=True)

                b.description = "Files Selected"
                b.icon = "check-square-o"
                b.style.button_color = "lightgreen"
            except:
                pass
out = widgets.Output()
raw = SelectFilesButton()
widgets.VBox([raw, out])

Answer 2

I like your idea. This is a feature I often need. I tried this on Python 2.7.

The first problem was no tkinter module (I have Tkinter) and no filedialog present in it. I had to modify this (according to this and this):

from Tkinter import Tk
import tkFileDialog as filedialog

Then I had to remove the style changes (no style member).

I've got an error when clicked OK without selecting any file:

TraitError: The 'files' trait of a SelectFilesButton instance must be a list, but a value of type 'str' (i.e. '') was specified.