Interactions: the Buttons (#933)

* Interactions: buttons

* Doc fix

* Gofmt fix

* Fix typo

* Remaking interaction data into interface

* Godoc fix

* Gofmt fix

* Godoc fix

* InteractionData helper functions and some fixes in slash commands example

* Fix components example

* Yet another fix of components example

* Fix interaction unmarshaling

* Gofmt fix

* Godoc fix

* Gofmt fix

* Corrected naming and docs

* Rolled back API version

* Requested fixes

* Added support of components to webhook and regular messages

* Fix components unmarshaling

* Godoc fix

* Requested fixes

* Fixed unmarshaling issues

* Components example: cleanup

* Added components tracking to state

* Requested fixes

* Renaming fix

* Remove more named returns

* Minor English fixes

Co-authored-by: Carson Hoffman <c@rsonhoffman.com>

components.go

@@ -0,0 +1,149 @@
+package discordgo
+
+import (
+	"encoding/json"
+)
+
+// ComponentType is type of component.
+type ComponentType uint
+
+// MessageComponent types.
+const (
+	ActionsRowComponent ComponentType = 1
+	ButtonComponent     ComponentType = 2
+)
+
+// MessageComponent is a base interface for all message components.
+type MessageComponent interface {
+	json.Marshaler
+	Type() ComponentType
+}
+
+type unmarshalableMessageComponent struct {
+	MessageComponent
+}
+
+// UnmarshalJSON is a helper function to unmarshal MessageComponent object.
+func (umc *unmarshalableMessageComponent) UnmarshalJSON(src []byte) error {
+	var v struct {
+		Type ComponentType `json:"type"`
+	}
+	err := json.Unmarshal(src, &v)
+	if err != nil {
+		return err
+	}
+
+	var data MessageComponent
+	switch v.Type {
+	case ActionsRowComponent:
+		v := ActionsRow{}
+		err = json.Unmarshal(src, &v)
+		data = v
+	case ButtonComponent:
+		v := Button{}
+		err = json.Unmarshal(src, &v)
+		data = v
+	}
+	if err != nil {
+		return err
+	}
+	umc.MessageComponent = data
+	return err
+}
+
+// ActionsRow is a container for components within one row.
+type ActionsRow struct {
+	Components []MessageComponent `json:"components"`
+}
+
+// MarshalJSON is a method for marshaling ActionsRow to a JSON object.
+func (r ActionsRow) MarshalJSON() ([]byte, error) {
+	type actionsRow ActionsRow
+
+	return json.Marshal(struct {
+		actionsRow
+		Type ComponentType `json:"type"`
+	}{
+		actionsRow: actionsRow(r),
+		Type:       r.Type(),
+	})
+}
+
+// UnmarshalJSON is a helper function to unmarshal Actions Row.
+func (r *ActionsRow) UnmarshalJSON(data []byte) error {
+	var v struct {
+		RawComponents []unmarshalableMessageComponent `json:"components"`
+	}
+	err := json.Unmarshal(data, &v)
+	if err != nil {
+		return err
+	}
+	r.Components = make([]MessageComponent, len(v.RawComponents))
+	for i, v := range v.RawComponents {
+		r.Components[i] = v.MessageComponent
+	}
+	return err
+}
+
+// Type is a method to get the type of a component.
+func (r ActionsRow) Type() ComponentType {
+	return ActionsRowComponent
+}
+
+// ButtonStyle is style of button.
+type ButtonStyle uint
+
+// Button styles.
+const (
+	// PrimaryButton is a button with blurple color.
+	PrimaryButton ButtonStyle = 1
+	// SecondaryButton is a button with grey color.
+	SecondaryButton ButtonStyle = 2
+	// SuccessButton is a button with green color.
+	SuccessButton ButtonStyle = 3
+	// DangerButton is a button with red color.
+	DangerButton ButtonStyle = 4
+	// LinkButton is a special type of button which navigates to a URL. Has grey color.
+	LinkButton ButtonStyle = 5
+)
+
+// ButtonEmoji represents button emoji, if it does have one.
+type ButtonEmoji struct {
+	Name     string `json:"name,omitempty"`
+	ID       string `json:"id,omitempty"`
+	Animated bool   `json:"animated,omitempty"`
+}
+
+// Button represents button component.
+type Button struct {
+	Label    string      `json:"label"`
+	Style    ButtonStyle `json:"style"`
+	Disabled bool        `json:"disabled"`
+	Emoji    ButtonEmoji `json:"emoji"`
+
+	// NOTE: Only button with LinkButton style can have link. Also, URL is mutually exclusive with CustomID.
+	URL      string `json:"url,omitempty"`
+	CustomID string `json:"custom_id,omitempty"`
+}
+
+// MarshalJSON is a method for marshaling Button to a JSON object.
+func (b Button) MarshalJSON() ([]byte, error) {
+	type button Button
+
+	if b.Style == 0 {
+		b.Style = PrimaryButton
+	}
+
+	return json.Marshal(struct {
+		button
+		Type ComponentType `json:"type"`
+	}{
+		button: button(b),
+		Type:   b.Type(),
+	})
+}
+
+// Type is a method to get the type of a component.
+func (b Button) Type() ComponentType {
+	return ButtonComponent
+}

events.go

@@ -162,19 +162,34 @@ type MessageCreate struct {
 	*Message
 }
 
+// UnmarshalJSON is a helper function to unmarshal MessageCreate object.
+func (m *MessageCreate) UnmarshalJSON(b []byte) error {
+	return json.Unmarshal(b, &m.Message)
+}
+
 // MessageUpdate is the data for a MessageUpdate event.
 type MessageUpdate struct {
 	*Message
 	// BeforeUpdate will be nil if the Message was not previously cached in the state cache.
 	BeforeUpdate *Message `json:"-"`
 }
 
+// UnmarshalJSON is a helper function to unmarshal MessageUpdate object.
+func (m *MessageUpdate) UnmarshalJSON(b []byte) error {
+	return json.Unmarshal(b, &m.Message)
+}
+
 // MessageDelete is the data for a MessageDelete event.
 type MessageDelete struct {
 	*Message
 	BeforeDelete *Message `json:"-"`
 }
 
+// UnmarshalJSON is a helper function to unmarshal MessageDelete object.
+func (m *MessageDelete) UnmarshalJSON(b []byte) error {
+	return json.Unmarshal(b, &m.Message)
+}
+
 // MessageReactionAdd is the data for a MessageReactionAdd event.
 type MessageReactionAdd struct {
 	*MessageReaction
@@ -272,3 +287,8 @@ type WebhooksUpdate struct {
 type InteractionCreate struct {
 	*Interaction
 }
+
+// UnmarshalJSON is a helper function to unmarshal Interaction object.
+func (i *InteractionCreate) UnmarshalJSON(b []byte) error {
+	return json.Unmarshal(b, &i.Interaction)
+}

examples/components/main.go

@@ -0,0 +1,151 @@
+package main
+
+import (
+	"flag"
+	"log"
+	"os"
+	"os/signal"
+
+	"github.com/bwmarrin/discordgo"
+)
+
+// Bot parameters
+var (
+	GuildID  = flag.String("guild", "", "Test guild ID")
+	BotToken = flag.String("token", "", "Bot access token")
+	AppID    = flag.String("app", "", "Application ID")
+)
+
+var s *discordgo.Session
+
+func init() { flag.Parse() }
+
+func init() {
+	var err error
+	s, err = discordgo.New("Bot " + *BotToken)
+	if err != nil {
+		log.Fatalf("Invalid bot parameters: %v", err)
+	}
+}
+
+func main() {
+	s.AddHandler(func(s *discordgo.Session, r *discordgo.Ready) {
+		log.Println("Bot is up!")
+	})
+	// Buttons are part of interactions, so we register InteractionCreate handler
+	s.AddHandler(func(s *discordgo.Session, i *discordgo.InteractionCreate) {
+		if i.Type == discordgo.InteractionApplicationCommand {
+			if i.ApplicationCommandData().Name == "feedback" {
+				err := s.InteractionRespond(i.Interaction, &discordgo.InteractionResponse{
+					Type: discordgo.InteractionResponseChannelMessageWithSource,
+					Data: &discordgo.InteractionResponseData{
+						Content: "Are you satisfied with Buttons?",
+						// Buttons and other components are specified in Components field.
+						Components: []discordgo.MessageComponent{
+							// ActionRow is a container of all buttons within the same row.
+							discordgo.ActionsRow{
+								Components: []discordgo.MessageComponent{
+									discordgo.Button{
+										Label:    "Yes",
+										Style:    discordgo.SuccessButton,
+										Disabled: false,
+										CustomID: "yes_btn",
+									},
+									discordgo.Button{
+										Label:    "No",
+										Style:    discordgo.DangerButton,
+										Disabled: false,
+										CustomID: "no_btn",
+									},
+									discordgo.Button{
+										Label:    "I don't know",
+										Style:    discordgo.LinkButton,
+										Disabled: false,
+										// Link buttons don't require CustomID and do not trigger the gateway/HTTP event
+										URL: "https://www.youtube.com/watch?v=dQw4w9WgXcQ",
+										Emoji: discordgo.ButtonEmoji{
+											Name: "🤷",
+										},
+									},
+								},
+							},
+							// The message may have multiple actions rows.
+							discordgo.ActionsRow{
+								Components: []discordgo.MessageComponent{
+									discordgo.Button{
+										Label:    "Discord Developers server",
+										Style:    discordgo.LinkButton,
+										Disabled: false,
+										URL:      "https://discord.gg/discord-developers",
+									},
+								},
+							},
+						},
+					},
+				})
+				if err != nil {
+					panic(err)
+				}
+			}
+			return
+		}
+		// Type for button press will be always InteractionButton (3)
+		if i.Type != discordgo.InteractionMessageComponent {
+			return
+		}
+
+		content := "Thanks for your feedback "
+
+		// CustomID field contains the same id as when was sent. It's used to identify the which button was clicked.
+		switch i.MessageComponentData().CustomID {
+		case "yes_btn":
+			content += "(yes)"
+		case "no_btn":
+			content += "(no)"
+		}
+
+		s.InteractionRespond(i.Interaction, &discordgo.InteractionResponse{
+			// Buttons also may update the message which to which they are attached.
+			// Or may just acknowledge (InteractionResponseDeferredMessageUpdate) that the event was received and not update the message.
+			// To update it later you need to use interaction response edit endpoint.
+			Type: discordgo.InteractionResponseUpdateMessage,
+			Data: &discordgo.InteractionResponseData{
+				Content: content,
+				Components: []discordgo.MessageComponent{
+					discordgo.ActionsRow{
+						Components: []discordgo.MessageComponent{
+							discordgo.Button{
+								Label:    "Our sponsor",
+								Style:    discordgo.LinkButton,
+								Disabled: false,
+								URL:      "https://www.youtube.com/watch?v=dQw4w9WgXcQ",
+								Emoji: discordgo.ButtonEmoji{
+									Name: "💠",
+								},
+							},
+						},
+					},
+				},
+			},
+		})
+	})
+	_, err := s.ApplicationCommandCreate(*AppID, *GuildID, &discordgo.ApplicationCommand{
+		Name:        "feedback",
+		Description: "Give your feedback",
+	})
+
+	if err != nil {
+		log.Fatalf("Cannot create slash command: %v", err)
+	}
+
+	err = s.Open()
+	if err != nil {
+		log.Fatalf("Cannot open the session: %v", err)
+	}
+	defer s.Close()
+
+	stop := make(chan os.Signal, 1)
+	signal.Notify(stop, os.Interrupt)
+	<-stop
+	log.Println("Graceful shutdown")
+}