commandErrorHandlerFile.py

import traceback
import sys
from discord.ext import commands

""" http://discordpy.readthedocs.io/en/rewrite/ext/commands/api.html#errors for a list of exceptions"""


class CommandErrorHandler:
    def __init__(self, client):
        self.client = client

    async def on_command_error(self, ctx, error):
        """Triggers when an error is raised while calling/invoking any command."""

        # Tuple of ignored errors
        ignored = (commands.CommandNotFound, commands.CommandOnCooldown, commands.UserInputError)

        # Check for original exceptions raised and sent to CommandInvokeError.
        # Otherwise, keep the exception passed to on_command_error.
        error = getattr(error, 'original', error)

        # If the error is ignored, return and nothing happens.
        if isinstance(error, ignored):
            return

        # If a disabled command has been called by a user.
        elif isinstance(error, commands.DisabledCommand):
            return await ctx.send(f'{ctx.command} has been disabled.')

        # If the command can only be used in server channels (and not Direct Messages)
        elif isinstance(error, commands.NoPrivateMessage):
            try:
                return await ctx.author.send(f'{ctx.command} can not be used in Private Messages.')
            except:
                pass

        # If user mentioned does not exist (for the >user command)
        elif isinstance(error, commands.BadArgument):
            if ctx.command.qualified_name == 'user':
                return await ctx.send('I could not find that member. Please try again.')

        # If the error hasn't been returned yet, print the traceback
        print('Ignoring exception in command {}:'.format(ctx.command), file=sys.stderr)
        traceback.print_exception(type(error), error, error.__traceback__, file=sys.stderr)


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