telegram-click

Click inspired command-line interface creation toolkit for python-telegram-bot.

Try the latest version of the example.py out for yourself: @PythonTelegramClickBot

If you are looking for asyncio and aiogram support, head over to telegram-click-aio!

Features

• POSIX style argument parsing
  • Quoted arguments (/command "Hello World")
  • Named arguments (/command --text "Hello World")
  • Value Separator (/command --text=myvalue )
  • Flags (/command --yes)
  • Multiple combined Flags (/command -Syu)
  • Optional arguments
  • Type conversion including support for custom types
  • Argument input validation
• Automatic help messages
  • Show help messages when a command was used with invalid arguments
  • List all available commands with a single method
• Permission handling
  • Set up permissions for each command separately
  • Limit command execution to private chats or group admins
  • Combine permissions using logical operators
  • Create custom permission handlers
• Error handling
  • Automatically send error and help messages if something goes wrong
  • Write custom error handlers

telegram-click is used by

• InfiniteWisdom
• DeineMudda
• keel-telegram-bot
• grocy-telegram-bot
• FrundenBot

and hopefully many others :)

How to use

Install this library as a dependency to use it in your project.

pip install telegram-click

Then annotate your command handler functions with the @command decorator of this library:

from telegram import Update
from telegram.ext import ContextTypes
from telegram_click.decorator import command
from telegram_click.argument import Argument

class MyBot:

    [...]
    
    @command(name='start', description='Start bot interaction')
    async def _start_command_callback(self, update: Update, context: ContextTypes.DEFAULT_TYPE):
        # do something
        pass
        
    @command(name='age', 
             description='Set age',
             arguments=[
                 Argument(name='age',
                          description='The new age',
                          type=int,
                          validator=lambda x: x > 0,
                          example='25')
             ])
    async def _age_command_callback(self, update: Update, context: ContextTypes.DEFAULT_TYPE, age: int):
        context.bot.send_message(update.effective_chat.id, "New age: {}".format(age))

Arguments

telegram-click parses arguments using a custom tokenizer:

• space acts as an argument delimiter, except when quoted (supporting both " and ')
• argument keys are prefixed with --, — (long dash) or - (for single character keys)
• quoted arguments are never considered as argument keys, even when prefixed with -- or —
• flags can be combined in a single argument (f.ex. -AxZ)

The behaviour should be pretty intuitive. If it's not, let's discuss and improve it!

Naming

Arguments can have multiple names to allow for abbreviated names. The first name you specify for an argument will be used for the callback parameter name (normalized to snake-case). Because of this it is advisable to specify a full word argument name as the first one.

Types

Since all user input initially is of type str there needs to be a type conversion if the expected type is not a str. For basic types like bool, int, float and str converters are built in to this library. If you want to use other types you have to specify how to convert the str input to your type using the converter attribute of the Argument constructor:

from telegram_click.argument import Argument

Argument(name='age',
         description='The new age',
         type=MyType,
         converter=lambda x: MyType(x),
         validator=lambda x: x > 0,
         example='25')

Flags

Technically you can use the Argument class to specify a flag, but since many of its parameters are implicit for a flag the Flag class can be used instead:

from telegram_click.argument import Flag

Flag(name='flag',
     description='My boolean flag')

Permission handling

If a command should only be executable when a specific criteria is met you can specify those criteria using the permissions parameter:

from telegram import Update
from telegram.ext import ContextTypes
from telegram_click.decorator import command
from telegram_click.permission import GROUP_ADMIN

@command(name='permission', 
         description='Needs permission',
         permissions=GROUP_ADMIN)
async def _permission_command_callback(self, update: Update, context: ContextTypes.DEFAULT_TYPE):

Multiple permissions can be combined using &, | and ~ (not) operators.

If a user does not have permission to use a command it will not be displayed when this user generate a list of commands.

Integrated permission handlers

Custom permissions

If none of the integrated permissions suit your needs you can simply write your own permission handler by extending the Permission base class and pass an instance of the MyPermission class to the list of permissions:

from telegram import Update
from telegram.ext import ContextTypes
from telegram_click.decorator import command
from telegram_click.permission.base import Permission
from telegram_click.permission import GROUP_ADMIN

class MyPermission(Permission):
    async def evaluate(self, update: Update, context: ContextTypes.DEFAULT_TYPE) -> bool:
        from_user = update.effective_message.from_user
        return from_user.id in [12345, 32435]
        
@command(name='permission', description='Needs permission',
         permissions=MyPermission() & GROUP_ADMIN)
async def _permission_command_callback(self, update: Update, context: ContextTypes.DEFAULT_TYPE):

Show "Permission denied" message

This behaviour is defined by the error handler. The DefaultErrorHandler silently ignores command messages from users without permission. To change this simply define your own, customized ErrorHandler class as shown in the example.py.

Targeted commands

Telegram supports the @ notation to target commands at specific bot usernames:

/start               # unspecified
/start@myAwesomeBot  # targeted at self
/start@someOtherBot  # targeted at other bot

When using a MessageHandler instead of a CommandHandler it is possible to catch even commands that are targeted at other bots. By default only messages without a target, and messages that are targeted directly at your bot are processed.

To control this behaviour specify the command_target parameter:

from telegram import Update
from telegram.ext import ContextTypes
from telegram_click.decorator import command
from telegram_click import CommandTarget
from telegram_click.permission import NOBODY

@command(name="commands",
         description="List commands supported by this bot.",
         permissions=NOBODY,
         command_target=CommandTarget.UNSPECIFIED | CommandTarget.SELF)
async def _unknown_command_callback(self, update: Update, context: ContextTypes.DEFAULT_TYPE):

You can combine CommandTarget's using logical operators like in the example above.

Hidden commands

In rare cases it can be useful to hide a command from the help output. To do this you can use the hidden parameter on the @command decorator by either passing True or False, or a callable like f.ex. this one:

async def hide_whois_if_admin(update: Update, context: ContextTypes.DEFAULT_TYPE):
    user_id = update.effective_user.id
    return user_id not in [123456]

This function is evaluated on each message and therefore provides the update and context object from python-telegram-bot, which allows you to make decisions based on chat and user properties among other things.

Error handling

telegram-click automatically handles errors in most situations.

Errors are divided into three categories:

• Permission errors
• Input validation errors
• Command execution errors

The DefaultErrorHandler will handle these categories in the following way:

• Permission errors will be silently ignored.

• Input validation errors like

  • an argument can not be parsed correctly
  • an invalid value is passed for an argument

  will send the exception message, as well as a help message of the command the user was trying to use.

• On command execution errors the user will be notified that his command has crashed, without any specific error message.

To modify the behaviour for each of those categories, define an ErrorHandler and pass an instance of it to the error_handler parameter of the @command decorator, like shown in the example.py.

Contributing

GitHub is for social coding: if you want to write code, I encourage contributions through pull requests from forks of this repository. Create GitHub tickets for bugs and new features and comment on the ones that you are interested in.

License

telegram-click
Copyright (c) 2019 Markus Ressel

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.