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arikawa/README.md
diamondburned 17b9c73ce3
gateway: Refactor for a better concurrent API
This commit refactors the whole package gateway as well as utils/ws
(formerly utils/wsutil) and voice/voicegateway. The new refactor
utilizes a design pattern involving a concurrent loop and an arriving
event channel.

An additional change was made to the way gateway events are typed.
Before, pretty much any type will satisfy a gateway event type, since
the actual type was just interface{}. The new refactor defines a
concrete interface that events can implement:

    type Event interface {
        Op() OpCode
        EventType() EventType
    }

Using this interface, the user can easily add custom gateway events
independently of the library without relying on string maps. This adds a
lot of type safety into the library and makes type-switching on Event
types much more reasonable.

Gateway error callbacks are also almost entirely removed in favor of
custom gateway events. A catch-all can easily be added like this:

    s.AddHandler(func(err error) {
        log.Println("gateway error:, err")
    })
2021-11-25 14:46:41 -08:00

5.5 KiB

arikawa

 Pipeline Status  Report Card      Godoc Reference  Examples         Discord Gophers  Hime Arikawa

A Golang library for the Discord API.

Examples

Simple

Simple bot example without any state. All it does is logging messages sent into the console. Run with BOT_TOKEN="TOKEN" go run .. This example only demonstrates the most simple needs; in most cases, bots should use the state or the bot router.

Undeleter

A slightly more complicated example. This bot uses a local state to cache everything, including messages. It detects when someone deletes a message, logging the content into the console.

This example demonstrates the PreHandler feature of the state library. PreHandler calls all handlers that are registered (separately from the session), calling them before the state is updated.

Bare Minimum Print Example

The least amount of code recommended to have a bot that logs all messages to console.

package main

import (
	"context"
	"log"
	"os"
	"os/signal"

	"github.com/diamondburned/arikawa/v3/gateway"
	"github.com/diamondburned/arikawa/v3/state"
)

func main() {
	s := state.New("Bot " + os.Getenv("DISCORD_TOKEN"))
	s.AddIntents(gateway.IntentGuilds | gateway.IntentGuildMessages)
	s.AddHandler(func(m *gateway.MessageCreateEvent) {
		log.Printf("%s: %s", m.Author.Username, m.Content)
	})

	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
	defer cancel()

	if err := s.Open(ctx); err != nil {
		log.Println("cannot open:", err)
	}

	<-ctx.Done() // block until Ctrl+C

	if err := s.Close(); err != nil {
		log.Println("cannot close:", err)
	}
}

Bare Minimum Bot

The least amount of code for a basic ping-pong bot. It's similar to Serenity's Discord bot example in the README.

package main

import (
	"os"

	"github.com/diamondburned/arikawa/v3/gateway"
	"github.com/diamondburned/arikawa/v3/utils/bot"
)

func main() {
	bot.Run(os.Getenv("DISCORD_TOKEN"), &Bot{},
		func(ctx *bot.Context) error {
			ctx.HasPrefix = bot.NewPrefix("!")
			return nil
		},
	)
}

type Bot struct {
	Ctx *bot.Context
}

func (b *Bot) Ping(*gateway.MessageCreateEvent) (string, error) {
	return "Pong!", nil
}

Where is package bot?

Package bot has now been deprecated after Discord's decision to eventually deprecate regular message events as means of commanding bots. We've decided to move the old bot package into utils/ to signify that it should no longer be used.

Moving bot into utils/ will allow us to eventually rewrite the whole package to use slash commands without worrying about breaking the old (v2) API, which is great, because almost nothing translates well from the previous design to slash commands.

Comparison: Why not discordgo?

Discordgo is great. It's the first library that I used when I was learning Go. Though there are some things that I disagree on. Here are some ways that this library is different:

  • Better package structure: this library divides the Discord library up into smaller packages.
  • Cleaner API/Gateway structure separation: this library separates fields that would only appear in Gateway events, so to not cause confusion.
  • Automatic un-pagination: this library automatically un-paginates endpoints that would otherwise not return everything fully.
  • Flexible underlying abstractions: this library allows plugging in different JSON and Websocket implementations, as well as direct access to the HTTP client.
  • Flexible API abstractions: because packages are separated, the developer could choose to use a lower level package (such as gateway) or a higher level package (such as state).
  • Pre-handlers in the state: this allows the developers to access items from the state storage before they're removed.
  • Pluggable state storages: although only having a default state storage in the library, it is abstracted with an interface, making it possible to implement a custom remote or local state storage.
  • REST-updated state: this library will call the REST API if it can't find things in the state, which is useful for keeping it updated.
  • No code generation: just so the library is a lot easier to maintain.

Testing

The package includes integration tests that require $BOT_TOKEN. To run these tests, do:

export BOT_TOKEN="<BOT_TOKEN>"
go test -tags integration -race ./...