Simple interactive IPython- or Jupyter Notebook widget-based file selection dialog

IPyFileSelectionWidget.py

'''
A simple interactive file selection class based on IPython "Selection" widget.
Navigates through directories and displays all files that match the "file_pattern"
parameter.
'''
import ipywidgets as widgets
import glob
import os

class FileSelection:
    '''
    Initialize a selection object, optionally taking the start
    directory and the file pattern as parameters.
    '''
    def __init__(self, start_directory=None, caption='Select File', file_pattern='*'):
        self._path = start_directory
        self._caption = caption
        self._file_pattern  = file_pattern
        self._widget = None
        
        if not self._path or not os.path.isdir(self._path):
            self._path = os.path.abspath(os.path.curdir)
        
    def select_file(self, success):
        '''
        Start the actual selection. "success" is a callback/handler that gets called
        when a file has been selected. The only parameter of the "success" handler is
        the selected filepath.
        '''
        self._success = success
        self._widget = widgets.Select(disabled=False)
        self._update_widget()
        display(self._widget)
            
    def _update_widget(self):
        self._widget.options = self._collect_dir_entries()
        self._widget.index = None
        self._widget.description = f"{self._caption} {os.path.abspath(self._path)}"
        self._widget.observe(self._file_selection_change)
    
    def _collect_dir_entries(self):
        all_entries = glob.glob(os.path.join(self._path, '*'))
        dir_entries =[entry for entry in all_entries if os.path.isdir(entry)]
        dir_entries.extend(glob.glob(f'{self._path}/{self._file_pattern}'))
        dir_entries = [os.path.basename(os.path.normpath(entry)) for entry in dir_entries]
        dir_entries.insert(0, '..')
        return dir_entries

    def _file_selection_change(self, change):
        if not change.owner.value:
            return
        if not isinstance(change.new, str):
            return
        change.owner.unobserve(self._file_selection_change)
        self._path = os.path.abspath(os.path.join(self._path, change.owner.value))

        if os.path.isdir(self._path):
            self._update_widget()
        else:
            change.owner.close()
            self._widget = None
            self._success(self._path)

if __name__ == '__main__':
  # Demo:
  fs = FileSelection(file_pattern='*.py')
  fs.select_file(lambda p: print('selected file:', p))