Recipe: Discord Bot

A common pattern: your bot already owns an aiohttp.ClientSession (or you want one shared connector pool for everything), so PokeLance should reuse it rather than opening its own.

Full example

Python

import os
import asyncio

import aiohttp
import discord
from discord.ext import commands
from dotenv import load_dotenv
from pokelance import PokeLance


class Bot(commands.Bot):
    def __init__(self, *, web_client: aiohttp.ClientSession, pokemon_db: PokeLance) -> None:
        super().__init__(command_prefix="!", intents=discord.Intents.all(), case_insensitive=True)
        self.web_client = web_client
        self.pokemon_db = pokemon_db

    async def on_ready(self) -> None:
        print(f"Logged in as {self.user} ({self.user.id})")


async def main() -> None:
    load_dotenv()
    async with aiohttp.ClientSession() as session, PokeLance(session=session) as pokemon_db:
        async with Bot(web_client=session, pokemon_db=pokemon_db) as bot:
            await bot.start(os.getenv("TOKEN"))


asyncio.run(main())

Both aiohttp.ClientSession and PokeLance are entered as async context managers around the bot's own lifetime, so everything tears down cleanly together on shutdown (Ctrl+C, a crash, or a graceful bot.close()).

A /pokedex slash command

Putting Fetching Data and Error Handling together into an actual command:

Python

from discord import app_commands, Interaction
from pokelance.exceptions import ResourceNotFound


@bot.tree.command(name="pokedex", description="Look up a Pokémon by name or id")
@app_commands.describe(name="Pokémon name or Pokédex number")
async def pokedex(interaction: Interaction, name: str) -> None:
    await interaction.response.defer()
    try:
        pokemon = await bot.pokemon_db.pokemon.fetch_pokemon(name.lower())
    except ResourceNotFound as exc:
        suggestions = ", ".join(exc.suggestions or []) or "no close matches"
        await interaction.followup.send(f"Couldn't find `{name}`. Did you mean: {suggestions}?")
        return

    sprite = pokemon.sprites.front_default
    embed = (
        discord.Embed(title=pokemon.name.title(), description=f"#{pokemon.id:04d}")
        .add_field(name="Types", value=", ".join(t.type.name for t in pokemon.types))
        .add_field(name="Height", value=f"{pokemon.height / 10} m")
        .add_field(name="Weight", value=f"{pokemon.weight / 10} kg")
        .set_thumbnail(url=sprite)
    )
    await interaction.followup.send(embed=embed)

Because client.pokemon.fetch_pokemon checks the cache first, running /pokedex pikachu twice only hits the network once subsequent lookups (from this or any other command sharing the same client) are served from memory.

Autocomplete using all_pokemons

Once the endpoint registry is loaded (await bot.pokemon_db.wait_until_ready() during startup), you get free autocomplete data:

Python

@pokedex.autocomplete("name")
async def pokedex_autocomplete(interaction: Interaction, current: str):
    names = bot.pokemon_db.pokemon.all_pokemons or []
    matches = [n for n in names if current.lower() in n][:25]
    return [app_commands.Choice(name=n, value=n) for n in matches]

Warm the cache before the bot starts accepting commands

Call await pokemon_db.wait_until_ready() right after entering the PokeLance context manager and before bot.start(...), so all_pokemons and friends are populated by the time users can invoke commands.

Comments