Part 2 - Lightbulb Bot

Lightbulb is a command handler for Hikari, making it easy to create commands.

So to start using Lightbulb, let’s change our bot.py a little (new code has been highlighted):

import os
from typing import Optional

import dotenv
import hikari
import lightbulb
from hikari import Intents

dotenv.load_dotenv()

INTENTS = Intents.GUILD_MEMBERS | Intents.GUILDS

bot = lightbulb.BotApp(
    os.environ["BOT_TOKEN"],
    intents=INTENTS,
    banner=None,
)


@bot.command
@lightbulb.command("ping", description="The bot's ping.")
@lightbulb.implements(lightbulb.SlashCommand)
async def ping(ctx: lightbulb.SlashContext) -> None:
    await ctx.respond(f"Pong! Latency: {bot.heartbeat_latency * 1000:.2f}ms.")


if __name__ == "__main__":
    bot.run()

• Line 2 & 6-7 - Import Optional from typing, lightbulb, and Intents from hikari

• Line 11 - Set up the intents we want to use
  Read the docs - Intents

• Line 13-17 - Use lightbulb to create the bot now,

  • passing our bot’s token as before

  • changing the intents kwarg to use our new set of intents

  • adding a banner kwarg set to None, disabling the hikari banner shown when the bot starts

    • This isn’t necessary, but the banner can get a little annoying after a while (sorry dav >_>)

• Line 20-24 - Create a slash command with lightbulb named ping which works the same as the old ping command, responding with Pong! and the bot’s heartbeat latency

Note

The GUILD_MEMBERS intent must be enable on the developer portal for your bot to use them.

Now let’s run the bot again!

You should see a slightly different output this time:

I 2022-12-24 13:24:37,209 hikari.bot: you can start 998 sessions before the next window which starts at 2022-12-25 12:55:43.325554+00:00; planning to start 1 session... 
I 2022-12-24 13:24:37,808 hikari.gateway.0: shard is ready: 2 guilds, Hikari#1093 (1007678609466601492), session '9432e40babfaa02547b09cf16b23ac98' on v10 gateway
I 2022-12-24 13:24:38,216 lightbulb.internal: Processing guild application commands
I 2022-12-24 13:24:38,216 lightbulb.internal: Processing global application commands
I 2022-12-24 13:24:38,567 lightbulb.internal: Application command processing completed
I 2022-12-24 13:24:38,567 hikari.bot: started successfully in approx 1.78 seconds

Trying to run @bot ping will no longer work, as we’ve removed the code for that. However, you now have the slash command /ping!

Try typing /ping. A command should appear, with your bot’s avatar next to it:

Hit enter, and let’s run this new command!

We’ve just made a slash command! By passing lightbulb.SlashCommand to the @lightbulb.implements decorator, lightbulb will turn the command into a slash command.

Command Options

Slash Commands can have options, and Discord supports quite a few different options types.

Read the docs - Command Option Types

Let’s make a new slash command using some of these option types to demonstrate them!

After your ping command, add this:

@bot.command
@lightbulb.option(
    "ping", "Role to ping with announcement.", type=hikari.Role, required=False
)
@lightbulb.option(
    "image", "Announcement attachment.", type=hikari.Attachment, required=False
)
@lightbulb.option(
    "channel", "Channel to post announcement to.", type=hikari.TextableChannel
)
@lightbulb.option("message", "The message to announce.", type=str)
@lightbulb.command("announce", "Make an announcement!", pass_options=True)
@lightbulb.implements(lightbulb.SlashCommand)
async def announce(
    ctx: lightbulb.SlashContext,
    message: str,
    channel: hikari.GuildTextChannel,
    image: Optional[hikari.Attachment] = None,
    ping: Optional[hikari.Role] = None,
) -> None:
    embed = hikari.Embed(
        title="Announcement!",
        description=message,
    )
    embed.set_image(image)

    await ctx.app.rest.create_message(
        channel=channel.id,
        content=ping.mention if ping else hikari.UNDEFINED,
        embed=embed,
        role_mentions=True,
    )

    await ctx.respond(
        f"Announcement posted to <#{channel.id}>!", flags=hikari.MessageFlag.EPHEMERAL
    )

• Line 2-11 - Specify the options for our command

  • We’ve specified a type for each option, such as hikari.Role, hikari.Attachment and hikari.TextableChannel

  • Using built-in Python types such as str and int is also valid (Line 11)

• Line 16-19 - Pass the options as parameters to the command’s function.

  • You must specify pass_options=True in the command decorator (Line 12) when passing the options as function parameters, or else lightbulb will error when attempting to run your command.

  Warning

  The parameters must be named exactly as the options. You cannot, for example, name your message parameter “msg”. Lightbulb will error if you do so.

• Line 21-25 - Create an embed, setting its description and image to the message and attachment the command author provided
  We’ll look at embeds in more detail in the next part

• Line 27-32 - Send the message to the given channel, pinging the role (if provided in the command options)

  Note

  To ping everyone with the role, you must have set role_mentions to True, and the bot must have the permissions to mention the role in the guild

• Line 34-36 - Respond to the interaction with an ephemeral message, stating where the announcement has been posted

Read the docs - Commands