dgg-chat-bot 0.1.10a0

Build chat bots for the destiny.gg chat

DGG Chat Bot

A framework for building chat bots for the destiny.gg chat. It allows you to register commands for when a user whispers you, so you can then reply with something useful. Built with the dgg-chat package.

In case you want a more in-depth example, check out the remind me bot.

Installing

This package is available via pip!

pip install dgg-chat-bot

A (very) minimal working example (more details below):

from dgg_chat_bot import DGGChatBot

bot = DGGChatBot("<dgg auth token>")

@bot.on_command('helloworld')
def hello_world():
    bot.reply('Hello World!')

bot.run_forever()

How To Use

The DGGChatBot class runs the main event loop. It parses messages users sent to you for a command and invokes any functions registered. Registering a function to a command can be done with the DGGChatBot().on_command() decorator.

As it is with the dgg-chat package, all handlers are called synchronously, that is, a handler will only be called after the previous one finished its work. If you want to do time intensive tasks, the asynchronous aspect has to be done manually. Native asynchronous support might be implemented in the future.

A more complete example can be found in the example.py file.

Registering Commands

When using the on_command() decorator, the first argument will be the keyword associated with that command, followed by any number of aliases. There's also override and optional_args, arguments explained later on.

It is enforced that the same alias cannot be used for multiple commands. Unless you set override to True, keywords also cannot be reused. override is specially useful to define your own help command, in case you don't like the default one.

@bot.on_command('command', 'alias1', 'alias2')
def on_command():
    ...

@bot.on_command('help', 'h', override=True)
def custom_on_help():
    ...

Defining A Command Handler

Command handlers can have any number of arguments. Arguments are defined as each word that follows the command keyword in the message received, separated by spaces. If the handler defines no arguments, everything after the keyword is ignored. Example:

@bot.on_command('command')
def on_command(arg1, arg2):
    # user invokes "!command abc 123"
    # arg1 = 'abc', arg2 = '123'

In case the command is invoked with more arguments than defined, all exceeding words are grouped as the last argument.

In case arguments received are less than expected, and optional_args is True (default value), missing arguments are received as empty ('' or 0 for numeric arguments, as explained later).

If optional_args is set to False, InvalidCommandArgumentsError exception is raised, and the on_invalid_arguments() special handler is called instead, which is explained further on.

Examples:

@bot.on_command('command')
def on_command(arg1, arg2, multi_word_arg):
    # user invokes "!command arg1"
    # arg1 = 'arg1', other args equal to ''
    #
    # user invokes "!command 1 2 3 4 5 6"
    # arg1 = '1', arg2 = '2', and multi_word_arg = '3 4 5 6'

@bot.on_other_command('othercommand', optional_args=False)
def on_other_command(arg1, arg2):
    # user invokes "!othercommand"
    # `InvalidCommandArgumentsError` is raised, and `on_invalid_arguments()` is called instead

Typed Arguments

Arguments can be set to expect specific types using annotations, specially useful when you want an argument to be an int or float (arguments are str by default).

If the command is invoked using arguments of wrong type, InvalidCommandArgumentsError is raised and on_invalid_arguments() is called.

The Optional annotation from the typing package can be used in conjunction with optional_args to selectively enforce certain arguments. Default values can also be set as you'd expect.

Examples:

@bot.on_command('typedcommand')
def typed_command(str_arg, int_arg: int, float_arg: float):
    # user invokes "!typedcommand 123 123 123.0"
    # str_arg = '123', int_arg = 123, and float_arg = 123.0
    #
    # user invokes "!typedcommand a b c"
    # `InvalidCommandArgumentsError` is raised, and `on_invalid_arguments()` is called instead

from typing import Optional

@bot.on_command('optionalcommand', optional_args=False)
def optional_command(required, optional: Optional[int] = 5):
    # user invoked "!optionalcommand abc 123
    # required = 'abc', optional = 123
    #
    # user invoked "!optionalcommand abc
    # required = 'abc', optional = 5 (would be 0 if no default were set)
    #
    # user invoked "!optionalcommand
    # `InvalidCommandArgumentsError` is raised, and `on_invalid_arguments()` is called instead

The raw message received can also be retrieved by annotating the last argument with the Message type. This message will be of type Whisper as defined in the dgg-chat package. The available attributes are:

• user: Of type ChatUser, contains the user's nick and their chat features.
• message_id: Message id as defined in the chat backend, rarely useful.
• timestamp: Unix timestamp for when the message was sent.
• content: The raw message content the user originally sent.

Example:

from dgg_chat_bot import Message

@bot.on_command('command')
def command(arg1, arg2, message: Message):
    print(message.user.nick)

Obs.: If used, the Message argument HAS to be set as the last one.

Command Description

One other very important aspect of implementing a command handler is the description. The default help command implementation uses it to describe to the user what the command does and how it's supposed to be used, so don't forget to write it! To do so, use the standard way of documenting functions, the docstrings. Example:

@bot.on_command('hello')
def say_hello(message: Message):
    """
    Replies hello to you!
    Example: "!hello".
    """
    bot.reply(f"Hi {message.user.nick}!")

Try to keep the description below 400 characters, since by default it is sent in one message along with other information, and messages have a size limit of 512 characters.

Special Handlers

There are a few special scenarios worth mentioning:

• The help command.
• A command with invalid arguments was invoked.
• An unknown command was invoked.
• A message which didn't start with the command prefix ("!" by default) was received.
• An unhandled exception was raised while processing the command.

All of them have default implementations (which can be reviewed here), so implementing them is not necessary.

As described before, use the override option of the on_command() decorator to implement a custom help command.

As for the other handlers, use the respective decorators: on_invalid_arguments(), on_unknown_command(), on_generic_message(), and on_fail().

Also, you can user the before_every_command() and after_every_command() to define handlers that are called before and after every command. The expected signature for these functions can be seen in the example.py file.

Replying To Messages

As shown in the previous examples, the reply() function can be used to reply to the user who sent the command being processed. There's also reply_multine(), which does what the name suggests. Expect a small delay (~200-500 ms) between messages, since they'd get throttled otherwise.

Replying will be disabled by default. Follow down the source code to figure out how to enable it. This is just to make sure you know what you're doing before allowing message sending.

Authentication

Check the authentication section in the dgg-chat package description.

Extra Features

This framework being built on top of the dgg-chat package, its functionality is exposed through the chat attribute of the DGGChatBot class. So you can also use decorators to handle different events in chat, like with chat.on_chat_message() and chat.on_user_joined().

The chat.send_whisper() method is also available, which is specially useful when you need to send a whisper not as an immediate reply (e.g.: a command that does something for a longer amount of time and sends a message when it is done).

For more details, go check out the dgg-chat documentation.