python script to apply dark theme to the latest Slack Chat app

PythonicSlack.py

import requests 
import os

class PythonicSlack():
    """Identified latest version of Slack App and applies dark theme to it.
    
    Raises:
        Exception: Exception raised in the event that the Slack Root directory is not found
        Exception: Exception is raised in event that the Slack App directory is not found in the Slack Root direcotry
        ValueError: Exception is raised in the event that the slack theme is blank
    """

    def __init__(self):
        """Applies core Slack and Theme variables
        """

        self.SLACK_ROOT = '{}/slack'.format(os.environ.get('localappdata'))
        self.THEME_URL = 'https://raw.githubusercontent.com/cryocaustik/Slack-Windows-Theme/master/slack_theme.js'

        self.slack_app_dir = self._get_slack_dir()
        self.slack_js_file = self._get_slack_js_file()
        self.theme_js = self._get_theme_js()

    def __call__(self):
        """Apply Slack Theme.
        """

        theme_line_break = "\n\n\n{br}\n//\tslack theme applied by {author}\n{br}\n\n\n".format(br='//'*30, author='python')

        with open(self.slack_js_file, 'a') as _f:
            _f.write(theme_line_break)
            _f.write(self.theme_js)
            _f.close()
        
        print("success! theme applied to {}".format(self.slack_js_file))

    def _get_slack_dir(self, root_dir=None):
        """get the directory for the latest slack app version within the slack root directory
            root_dir (str, optional): Defaults to None. Path to root directory of Slack
        
        Raises:
            Exception: Exception raised when Slack directory is not found
        
        Returns:
            str: Path to Slack root directory
        """

        if not root_dir:
            root_dir = self.SLACK_ROOT
        
        dir_list = list()
        for _d in os.listdir(root_dir):
            _p = os.path.join(root_dir, _d)
            if os.path.isdir(_p) and 'app-' in _p:
                dir_list.append(_d)
        
        if not dir_list:
            raise Exception('no app directories found')

        return os.path.join(root_dir, dir_list[-1])


    def _get_slack_js_file(self, target_file='ssb-interop.js'):
        """Locates and returns the path to the Slack JS files used to apply the theme
            target_file (str, optional): Defaults to 'ssb-interop.js'. Slack JS file name to be found
        
        Raises:
            Exception: Exception raisd when target file is not found
        
        Returns:
            str: Path to Target file
        """

        slack_app_dir = self.slack_app_dir
        for p, d, f in os.walk(slack_app_dir):
            for _f in f:
                if _f.lower() == target_file:
                    return os.path.join(p, _f)
        else:
            raise Exception('target file not found')


    def _get_theme_js(self, theme_url=None):
        """Pulls (http) and returns the Slack Theme JS Code
            theme_url (str, optional): Defaults to None. URL to Slack Theme JS
        
        Raises:
            ValueError: Exception raised when theme js is blank
        
        Returns:
            str: Slack Theme JS
        """


        if not theme_url:
            theme_url = self.THEME_URL
        
        response = requests.get(theme_url)

        if response.status_code != 200:
            response.raise_for_status
        
        response_text = response.text
        if not response_text:
            raise ValueError('response_test is blank')
        
        return response_text


if __name__ == '__main__':
    t = PythonicSlack()()