geas-bot/app/cogs/events/on_command_error.py

import yaml								# YAML parser for Bot config files
import asyncio							# Discord Py Dependency
import discord							# Main Lib
from discord.ext import commands		# Commands module
from discord_slash import SlashCommand, SlashContext, cog_ext, utils			# Slash Command Library
from discord_slash.utils.manage_commands import create_choice, create_option	# Slash Command features
import logging
# logger and handler
from bot import configFile, yaml_load, yaml_dump

#### Error Handler Event Listener
class on_command_error(commands.Cog, name='On Command Error'):
	def __init__(self, client):
		self.client = client

	@commands.Cog.listener()
	async def on_command_error(self, ctx, error):
		if isinstance(error, discord.DiscordException):
			if isinstance(error, commands.CommandNotFound):
				print(f'Error: User {ctx.author.name}#{ctx.author.discriminator} / {ctx.author.display_name} entered an invalid command <{ctx.message.clean_content}> in the guild {ctx.guild.name}.')
				await ctx.reply(f'```Error: This is not a valid command.```')
			elif isinstance(error, commands.CheckFailure):
				print(f'Error: User {ctx.author.name}#{ctx.author.discriminator} / {ctx.author.display_name} is not authorised to issue the command <{ctx.command.name}> in the guild {ctx.guild.name}.')
				await ctx.reply(f'```Error: You are not authorised to issue this command.```')
			else:
				print(f'User {ctx.author.name}#{ctx.author.discriminator} / {ctx.author.display_name} received error: "{error}" when attempting to issue command <{ctx.command.name}> in the guild {ctx.guild.name}.')
				await ctx.reply(f'```Error: {error}```')

def setup(client):
	client.add_cog(on_command_error(client))