ratelimit (#21)

Author: elisiei

cmd/bot/register.go

@@ -3,5 +3,6 @@ package main
 import (
 	_ "first.fm/internal/commands/fm"
 	_ "first.fm/internal/commands/profile"
+	_ "first.fm/internal/commands/register"
 	_ "first.fm/internal/commands/stats"
 )

go.mod

@@ -5,13 +5,14 @@ go 1.25.0
 require (
 	github.com/disgoorg/disgo v0.19.0-rc.6.0.20250924005456-3274c76733fc
 	github.com/disgoorg/snowflake/v2 v2.0.3
+	github.com/mattn/go-sqlite3 v1.14.32
+	golang.org/x/time v0.13.0
 )
 
 require (
 	github.com/disgoorg/json/v2 v2.0.0 // indirect
 	github.com/disgoorg/omit v1.0.0 // indirect
 	github.com/gorilla/websocket v1.5.3 // indirect
-	github.com/mattn/go-sqlite3 v1.14.32 // indirect
 	github.com/sasha-s/go-csync v0.0.0-20240107134140-fcbab37b09ad // indirect
 	golang.org/x/crypto v0.39.0 // indirect
 	golang.org/x/sys v0.33.0 // indirect

go.sum

@@ -22,5 +22,7 @@ golang.org/x/crypto v0.39.0 h1:SHs+kF4LP+f+p14esP5jAoDpHU8Gu/v9lFRK6IT5imM=
 golang.org/x/crypto v0.39.0/go.mod h1:L+Xg3Wf6HoL4Bn4238Z6ft6KfEpN0tJGo53AAPC632U=
 golang.org/x/sys v0.33.0 h1:q3i8TbbEz+JRD9ywIRlyRAQbM0qF7hu24q3teo2hbuw=
 golang.org/x/sys v0.33.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
+golang.org/x/time v0.13.0 h1:eUlYslOIt32DgYD6utsuUeHs4d7AsEYLuIAdg7FlYgI=
+golang.org/x/time v0.13.0/go.mod h1:eL/Oa2bBBK0TkX57Fyni+NgnyQQN4LitPmob2Hjnqw4=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal/bot/commands.go

@@ -3,8 +3,10 @@ package bot
 import (
 	"context"
 	"strings"
+	"sync"
 	"time"
 
+	"first.fm/internal/emojis"
 	"first.fm/internal/lastfm"
 	"first.fm/internal/logger"
 	"github.com/disgoorg/disgo/discord"
@@ -23,9 +25,15 @@ type CommandHandler func(*CommandContext) error
 var (
 	allCommands []discord.ApplicationCommandCreate
 	registry    = map[string]CommandHandler{}
+	initOnce    sync.Once
 )
 
 func Register(meta discord.ApplicationCommandCreate, handler CommandHandler) {
+	initOnce.Do(func() {
+		allCommands = []discord.ApplicationCommandCreate{}
+		registry = map[string]CommandHandler{}
+	})
+
 	logger.Infow("registered command", logger.F{"name": meta.CommandName()})
 	allCommands = append(allCommands, meta)
 	registry[meta.CommandName()] = handler
@@ -58,9 +66,9 @@ func Dispatcher(bot *Bot) func(*events.ApplicationCommandInteractionCreate) {
 		}
 
 		if err := handler(ctx); err != nil {
-			logger.Errorw("command failed", logger.F{"name": data.CommandName(), "err": err.Error()})
-			_ = event.CreateMessage(discord.NewMessageCreateBuilder().
-				SetContent("error: " + err.Error()).
+			logger.Warnw("command failed", logger.F{"name": data.CommandName(), "err": err.Error()})
+			_ = ctx.CreateMessage(discord.NewMessageCreateBuilder().
+				SetContentf("%s %v", emojis.EmojiCross, err).
 				SetEphemeral(true).
 				Build())
 		}

internal/bot/events.go

@@ -10,5 +10,10 @@ import (
 
 func onReady(event *events.Ready) {
 	logger.Info("started client")
-	event.Client().SetPresence(context.Background(), gateway.WithCustomActivity("gwa gwa"))
+	event.
+		Client().
+		SetPresence(
+			context.Background(),
+			gateway.WithCustomActivity("listen to crystal castles!"),
+		)
 }

internal/commands/register/register.go

@@ -0,0 +1,51 @@
+package register
+
+import (
+	"errors"
+	"strings"
+
+	"first.fm/internal/bot"
+	"first.fm/internal/persistence/sqlc"
+	"github.com/disgoorg/disgo/discord"
+)
+
+func init() {
+	bot.Register(data, handle)
+}
+
+var data = discord.SlashCommandCreate{
+	Name:        "register",
+	Description: "link your last.fm username",
+	Options: []discord.ApplicationCommandOption{
+		discord.ApplicationCommandOptionString{
+			Name:        "username",
+			Description: "your last.fm username",
+			Required:    true,
+		},
+	},
+}
+
+func handle(ctx *bot.CommandContext) error {
+	username := ctx.SlashCommandInteractionData().String("username")
+
+	_, err := ctx.LastFM.User.Info(username)
+	if err != nil {
+		return errors.New("last.fm user not found")
+	}
+
+	err = ctx.Queries.UpsertUser(ctx.Ctx, sqlc.UpsertUserParams{
+		UserID:         ctx.User().ID,
+		LastfmUsername: username,
+	})
+	if err != nil {
+		if strings.Contains(err.Error(), "UNIQUE constraint failed") {
+			return errors.New("another discord user already uses this username")
+		}
+
+		return err
+	}
+
+	return ctx.CreateMessage(discord.NewMessageCreateBuilder().
+		SetContentf("successfully linked your account to **%s**", username).
+		Build())
+}

internal/lastfm/api/api.go

@@ -1,6 +1,7 @@
 package api
 
 import (
+	"context"
 	"encoding/xml"
 	"errors"
 	"fmt"
@@ -11,6 +12,7 @@ import (
 	"time"
 
 	"first.fm/internal/lastfm"
+	"golang.org/x/time/rate"
 )
 
 var (
@@ -37,10 +39,11 @@ type HTTPClient interface {
 }
 
 type API struct {
-	APIKey    string
-	UserAgent string
-	Retries   uint
-	Client    HTTPClient
+	APIKey      string
+	UserAgent   string
+	Retries     uint
+	Client      HTTPClient
+	rateLimiter *rate.Limiter
 }
 
 func New(apiKey string) *API {
@@ -50,10 +53,11 @@ func New(apiKey string) *API {
 func NewWithTimeout(apiKey string, timeout int) *API {
 	t := time.Duration(timeout) * time.Second
 	return &API{
-		APIKey:    apiKey,
-		UserAgent: DefaultUserAgent,
-		Retries:   DefaultRetries,
-		Client:    &http.Client{Timeout: t},
+		APIKey:      apiKey,
+		UserAgent:   DefaultUserAgent,
+		Retries:     DefaultRetries,
+		Client:      &http.Client{Timeout: t},
+		rateLimiter: rate.NewLimiter(rate.Every(time.Second), 5),
 	}
 }
 
@@ -110,6 +114,10 @@ func (a API) PostBody(dest any, url, body string) error {
 }
 
 func (a API) tryRequest(dest any, method, url, body string) error {
+	if err := a.rateLimiter.Wait(context.Background()); err != nil {
+		return err
+	}
+
 	var (
 		res   *http.Response
 		lfm   LFMWrapper