refactor: Discord RPC struct to encapsulate WebSocket logic

Signed-off-by: Deluan <deluan@navidrome.org>

plugins/examples/discord-rich-presence/go.mod

@@ -7,4 +7,15 @@ require (
 	github.com/navidrome/navidrome/plugins/pdk/go v0.0.0
 )
 
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/kr/pretty v0.3.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/rogpeppe/go-internal v1.13.1 // indirect
+	github.com/stretchr/objx v0.5.2 // indirect
+	github.com/stretchr/testify v1.11.1 // indirect
+	gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
+
 replace github.com/navidrome/navidrome/plugins/pdk/go => ../../pdk/go

plugins/examples/discord-rich-presence/go.sum

@@ -1,2 +1,24 @@
+github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/extism/go-pdk v1.1.3 h1:hfViMPWrqjN6u67cIYRALZTZLk/enSPpNKa+rZ9X2SQ=
 github.com/extism/go-pdk v1.1.3/go.mod h1:Gz+LIU/YCKnKXhgge8yo5Yu1F/lbv7KtKFkiCSzW/P4=
+github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
+github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
+github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
+github.com/rogpeppe/go-internal v1.13.1 h1:KvO1DLK/DRN07sQ1LQKScxyZJuNnedQ5/wKSR38lUII=
+github.com/rogpeppe/go-internal v1.13.1/go.mod h1:uMEvuHeurkdAXX61udpOXGD/AzZDWNMNyH2VO9fmH0o=
+github.com/stretchr/objx v0.5.2 h1:xuMeJ0Sdp5ZMRXx/aWO6RZxdr3beISkG5/G/aIRr3pY=
+github.com/stretchr/objx v0.5.2/go.mod h1:FRsXN1f5AsAjCGJKqEizvkpNtU+EGNCLh3NxZ/8L+MA=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
+gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

plugins/examples/discord-rich-presence/main.go

@@ -28,26 +28,19 @@ const (
 	usersKey    = "users"
 )
 
-// discordPlugin implements the scrobbler, scheduler, and websocket interfaces.
+// discordPlugin implements the scrobbler and scheduler interfaces.
 type discordPlugin struct{}
 
+// rpc handles Discord gateway communication (via websockets).
+var rpc = &discordRPC{}
+
 // init registers the plugin capabilities
 func init() {
 	scrobbler.Register(&discordPlugin{})
 	scheduler.Register(&discordPlugin{})
-	websocket.Register(&discordPlugin{})
+	websocket.Register(rpc)
 }
 
-// Ensure discordPlugin implements the required provider interfaces
-var (
-	_ scrobbler.Scrobbler             = (*discordPlugin)(nil)
-	_ scheduler.CallbackProvider      = (*discordPlugin)(nil)
-	_ websocket.TextMessageProvider   = (*discordPlugin)(nil)
-	_ websocket.BinaryMessageProvider = (*discordPlugin)(nil)
-	_ websocket.ErrorProvider         = (*discordPlugin)(nil)
-	_ websocket.CloseProvider         = (*discordPlugin)(nil)
-)
-
 // getConfig loads the plugin configuration.
 func getConfig() (clientID string, users map[string]string, err error) {
 	clientID, ok := pdk.GetConfig(clientIDKey)
@@ -121,7 +114,7 @@ func (p *discordPlugin) NowPlaying(input scrobbler.NowPlayingRequest) error {
 	}
 
 	// Connect to Discord
-	if err := connect(input.Username, userToken); err != nil {
+	if err := rpc.connect(input.Username, userToken); err != nil {
 		return fmt.Errorf("%w: failed to connect to Discord: %v", scrobbler.ScrobblerErrorRetryLater, err)
 	}
 
@@ -134,7 +127,7 @@ func (p *discordPlugin) NowPlaying(input scrobbler.NowPlayingRequest) error {
 	endTime := startTime + int64(input.Track.Duration)*1000
 
 	// Send activity update
-	if err := sendActivity(clientID, input.Username, userToken, activity{
+	if err := rpc.sendActivity(clientID, input.Username, userToken, activity{
 		Application: clientID,
 		Name:        "Navidrome",
 		Type:        2, // Listening
@@ -180,14 +173,14 @@ func (p *discordPlugin) OnCallback(input scheduler.SchedulerCallbackRequest) err
 	switch input.Payload {
 	case payloadHeartbeat:
 		// Heartbeat callback - scheduleId is the username
-		if err := handleHeartbeatCallback(input.ScheduleID); err != nil {
+		if err := rpc.handleHeartbeatCallback(input.ScheduleID); err != nil {
 			return err
 		}
 
 	case payloadClearActivity:
 		// Clear activity callback - scheduleId is "username-clear"
 		username := strings.TrimSuffix(input.ScheduleID, "-clear")
-		if err := handleClearActivityCallback(username); err != nil {
+		if err := rpc.handleClearActivityCallback(username); err != nil {
 			return err
 		}
 
@@ -198,31 +191,4 @@ func (p *discordPlugin) OnCallback(input scheduler.SchedulerCallbackRequest) err
 	return nil
 }
 
-// ============================================================================
-// WebSocket Callback Implementation
-// ============================================================================
-
-// OnTextMessage handles incoming WebSocket text messages.
-func (p *discordPlugin) OnTextMessage(input websocket.OnTextMessageRequest) error {
-	return handleWebSocketMessage(input.ConnectionID, input.Message)
-}
-
-// OnBinaryMessage handles incoming WebSocket binary messages.
-func (p *discordPlugin) OnBinaryMessage(input websocket.OnBinaryMessageRequest) error {
-	pdk.Log(pdk.LogDebug, fmt.Sprintf("Received unexpected binary message for connection '%s'", input.ConnectionID))
-	return nil
-}
-
-// OnError handles WebSocket errors.
-func (p *discordPlugin) OnError(input websocket.OnErrorRequest) error {
-	pdk.Log(pdk.LogWarn, fmt.Sprintf("WebSocket error for connection '%s': %s", input.ConnectionID, input.Error))
-	return nil
-}
-
-// OnClose handles WebSocket connection closure.
-func (p *discordPlugin) OnClose(input websocket.OnCloseRequest) error {
-	pdk.Log(pdk.LogInfo, fmt.Sprintf("WebSocket connection '%s' closed with code %d: %s", input.ConnectionID, input.Code, input.Reason))
-	return nil
-}
-
 func main() {}

plugins/examples/discord-rich-presence/rpc.go

@@ -1,17 +1,18 @@
 // Discord Rich Presence Plugin - RPC Communication
 //
 // This file handles all Discord gateway communication including WebSocket connections,
-// presence updates, and heartbeat management.
+// presence updates, and heartbeat management. The discordRPC struct implements WebSocket
+// callback interfaces and encapsulates all Discord communication logic.
 package main
 
 import (
 	"encoding/json"
 	"fmt"
 	"strings"
-	"time"
 
 	"github.com/extism/go-pdk"
 	host "github.com/navidrome/navidrome/plugins/pdk/go/host"
+	"github.com/navidrome/navidrome/plugins/pdk/go/websocket"
 )
 
 // Discord WebSocket Gateway constants
@@ -32,6 +33,36 @@ const (
 	payloadClearActivity = "clear-activity"
 )
 
+// discordRPC handles Discord gateway communication and implements WebSocket callbacks.
+type discordRPC struct{}
+
+// ============================================================================
+// WebSocket Callback Implementation
+// ============================================================================
+
+// OnTextMessage handles incoming WebSocket text messages.
+func (r *discordRPC) OnTextMessage(input websocket.OnTextMessageRequest) error {
+	return r.handleWebSocketMessage(input.ConnectionID, input.Message)
+}
+
+// OnBinaryMessage handles incoming WebSocket binary messages.
+func (r *discordRPC) OnBinaryMessage(input websocket.OnBinaryMessageRequest) error {
+	pdk.Log(pdk.LogDebug, fmt.Sprintf("Received unexpected binary message for connection '%s'", input.ConnectionID))
+	return nil
+}
+
+// OnError handles WebSocket errors.
+func (r *discordRPC) OnError(input websocket.OnErrorRequest) error {
+	pdk.Log(pdk.LogWarn, fmt.Sprintf("WebSocket error for connection '%s': %s", input.ConnectionID, input.Error))
+	return nil
+}
+
+// OnClose handles WebSocket connection closure.
+func (r *discordRPC) OnClose(input websocket.OnCloseRequest) error {
+	pdk.Log(pdk.LogInfo, fmt.Sprintf("WebSocket connection '%s' closed with code %d: %s", input.ConnectionID, input.Code, input.Reason))
+	return nil
+}
+
 // activity represents a Discord activity.
 type activity struct {
 	Name        string             `json:"name"`
@@ -74,13 +105,17 @@ type identifyProperties struct {
 	Device  string `json:"device"`
 }
 
+// ============================================================================
+// Image Processing
+// ============================================================================
+
 // processImage processes an image URL for Discord, with fallback to default image.
-func processImage(imageURL, clientID, token string, isDefaultImage bool) (string, error) {
+func (r *discordRPC) processImage(imageURL, clientID, token string, isDefaultImage bool) (string, error) {
 	if imageURL == "" {
 		if isDefaultImage {
 			return "", fmt.Errorf("default image URL is empty")
 		}
-		return processImage(defaultImage, clientID, token, true)
+		return r.processImage(defaultImage, clientID, token, true)
 	}
 
 	if strings.HasPrefix(imageURL, "mp:") {
@@ -107,7 +142,7 @@ func processImage(imageURL, clientID, token string, isDefaultImage bool) (string
 		if isDefaultImage {
 			return "", fmt.Errorf("failed to process default image: HTTP %d", resp.Status())
 		}
-		return processImage(defaultImage, clientID, token, true)
+		return r.processImage(defaultImage, clientID, token, true)
 	}
 
 	var data []map[string]string
@@ -115,14 +150,14 @@ func processImage(imageURL, clientID, token string, isDefaultImage bool) (string
 		if isDefaultImage {
 			return "", fmt.Errorf("failed to unmarshal default image response: %w", err)
 		}
-		return processImage(defaultImage, clientID, token, true)
+		return r.processImage(defaultImage, clientID, token, true)
 	}
 
 	if len(data) == 0 {
 		if isDefaultImage {
 			return "", fmt.Errorf("no data returned for default image")
 		}
-		return processImage(defaultImage, clientID, token, true)
+		return r.processImage(defaultImage, clientID, token, true)
 	}
 
 	image := data[0]["external_asset_path"]
@@ -130,7 +165,7 @@ func processImage(imageURL, clientID, token string, isDefaultImage bool) (string
 		if isDefaultImage {
 			return "", fmt.Errorf("empty external_asset_path for default image")
 		}
-		return processImage(defaultImage, clientID, token, true)
+		return r.processImage(defaultImage, clientID, token, true)
 	}
 
 	processedImage := fmt.Sprintf("mp:%s", image)
@@ -147,11 +182,15 @@ func processImage(imageURL, clientID, token string, isDefaultImage bool) (string
 	return processedImage, nil
 }
 
+// ============================================================================
+// Activity Management
+// ============================================================================
+
 // sendActivity sends an activity update to Discord.
-func sendActivity(clientID, username, token string, data activity) error {
+func (r *discordRPC) sendActivity(clientID, username, token string, data activity) error {
 	pdk.Log(pdk.LogInfo, fmt.Sprintf("Sending activity for user %s: %s - %s", username, data.Details, data.State))
 
-	processedImage, err := processImage(data.Assets.LargeImage, clientID, token, false)
+	processedImage, err := r.processImage(data.Assets.LargeImage, clientID, token, false)
 	if err != nil {
 		pdk.Log(pdk.LogWarn, fmt.Sprintf("Failed to process image for user %s, continuing without image: %v", username, err))
 		data.Assets.LargeImage = ""
@@ -164,17 +203,21 @@ func sendActivity(clientID, username, token string, data activity) error {
 		Status:     "dnd",
 		Afk:        false,
 	}
-	return sendMessage(username, presenceOpCode, presence)
+	return r.sendMessage(username, presenceOpCode, presence)
 }
 
 // clearActivity clears the Discord activity for a user.
-func clearActivity(username string) error {
+func (r *discordRPC) clearActivity(username string) error {
 	pdk.Log(pdk.LogInfo, fmt.Sprintf("Clearing activity for user %s", username))
-	return sendMessage(username, presenceOpCode, presencePayload{})
+	return r.sendMessage(username, presenceOpCode, presencePayload{})
 }
 
+// ============================================================================
+// Low-level Communication
+// ============================================================================
+
 // sendMessage sends a message over the WebSocket connection.
-func sendMessage(username string, opCode int, payload any) error {
+func (r *discordRPC) sendMessage(username string, opCode int, payload any) error {
 	message := map[string]any{
 		"op": opCode,
 		"d":  payload,
@@ -192,7 +235,7 @@ func sendMessage(username string, opCode int, payload any) error {
 }
 
 // getDiscordGateway retrieves the Discord gateway URL.
-func getDiscordGateway() (string, error) {
+func (r *discordRPC) getDiscordGateway() (string, error) {
 	req := pdk.NewHTTPRequest(pdk.MethodGet, "https://discord.com/api/gateway")
 	resp := req.Send()
 	if resp.Status() != 200 {
@@ -207,18 +250,18 @@ func getDiscordGateway() (string, error) {
 }
 
 // sendHeartbeat sends a heartbeat to Discord.
-func sendHeartbeat(username string) error {
+func (r *discordRPC) sendHeartbeat(username string) error {
 	seqNum, _, err := host.CacheGetInt(fmt.Sprintf("discord.seq.%s", username))
 	if err != nil {
 		return fmt.Errorf("failed to get sequence number: %w", err)
 	}
 
 	pdk.Log(pdk.LogDebug, fmt.Sprintf("Sending heartbeat for user %s: %d", username, seqNum))
-	return sendMessage(username, heartbeatOpCode, seqNum)
+	return r.sendMessage(username, heartbeatOpCode, seqNum)
 }
 
 // cleanupFailedConnection cleans up a failed Discord connection.
-func cleanupFailedConnection(username string) {
+func (r *discordRPC) cleanupFailedConnection(username string) {
 	pdk.Log(pdk.LogInfo, fmt.Sprintf("Cleaning up failed connection for user %s", username))
 
 	// Cancel the heartbeat schedule
@@ -238,8 +281,8 @@ func cleanupFailedConnection(username string) {
 }
 
 // isConnected checks if a user is connected to Discord by testing the heartbeat.
-func isConnected(username string) bool {
+func (r *discordRPC) isConnected(username string) bool {
-	err := sendHeartbeat(username)
+	err := r.sendHeartbeat(username)
 	if err != nil {
 		pdk.Log(pdk.LogDebug, fmt.Sprintf("Heartbeat test failed for user %s: %v", username, err))
 		return false
@@ -248,15 +291,15 @@ func isConnected(username string) bool {
 }
 
 // connect establishes a connection to Discord for a user.
-func connect(username, token string) error {
+func (r *discordRPC) connect(username, token string) error {
-	if isConnected(username) {
+	if r.isConnected(username) {
 		pdk.Log(pdk.LogInfo, fmt.Sprintf("Reusing existing connection for user %s", username))
 		return nil
 	}
 	pdk.Log(pdk.LogInfo, fmt.Sprintf("Creating new connection for user %s", username))
 
 	// Get Discord Gateway URL
-	gateway, err := getDiscordGateway()
+	gateway, err := r.getDiscordGateway()
 	if err != nil {
 		return fmt.Errorf("failed to get Discord gateway: %w", err)
 	}
@@ -278,7 +321,7 @@ func connect(username, token string) error {
 			Device:  "Discord Client",
 		},
 	}
-	if err := sendMessage(username, gateOpCode, payload); err != nil {
+	if err := r.sendMessage(username, gateOpCode, payload); err != nil {
 		return fmt.Errorf("failed to send identify payload: %w", err)
 	}
 
@@ -295,7 +338,7 @@ func connect(username, token string) error {
 }
 
 // disconnect closes the Discord connection for a user.
-func disconnect(username string) error {
+func (r *discordRPC) disconnect(username string) error {
 	if err := host.SchedulerCancelSchedule(username); err != nil {
 		return fmt.Errorf("failed to cancel schedule: %w", err)
 	}
@@ -307,7 +350,7 @@ func disconnect(username string) error {
 }
 
 // handleWebSocketMessage processes incoming WebSocket messages from Discord.
-func handleWebSocketMessage(connectionID, message string) error {
+func (r *discordRPC) handleWebSocketMessage(connectionID, message string) error {
 	if len(message) < 1024 {
 		pdk.Log(pdk.LogTrace, fmt.Sprintf("Received WebSocket message for connection '%s': %s", connectionID, message))
 	} else {
@@ -332,31 +375,26 @@ func handleWebSocketMessage(connectionID, message string) error {
 }
 
 // handleHeartbeatCallback processes heartbeat scheduler callbacks.
-func handleHeartbeatCallback(username string) error {
+func (r *discordRPC) handleHeartbeatCallback(username string) error {
-	if err := sendHeartbeat(username); err != nil {
+	if err := r.sendHeartbeat(username); err != nil {
 		// On first heartbeat failure, immediately clean up the connection
 		pdk.Log(pdk.LogWarn, fmt.Sprintf("Heartbeat failed for user %s, cleaning up connection: %v", username, err))
-		cleanupFailedConnection(username)
+		r.cleanupFailedConnection(username)
 		return fmt.Errorf("heartbeat failed, connection cleaned up: %w", err)
 	}
 	return nil
 }
 
 // handleClearActivityCallback processes clear activity scheduler callbacks.
-func handleClearActivityCallback(username string) error {
+func (r *discordRPC) handleClearActivityCallback(username string) error {
 	pdk.Log(pdk.LogInfo, fmt.Sprintf("Removing presence for user %s", username))
-	if err := clearActivity(username); err != nil {
+	if err := r.clearActivity(username); err != nil {
 		return fmt.Errorf("failed to clear activity: %w", err)
 	}
 
 	pdk.Log(pdk.LogInfo, fmt.Sprintf("Disconnecting user %s", username))
-	if err := disconnect(username); err != nil {
+	if err := r.disconnect(username); err != nil {
 		return fmt.Errorf("failed to disconnect from Discord: %w", err)
 	}
 	return nil
 }
-
-// nowPlaying returns the current timestamp in milliseconds.
-func nowMillis() int64 {
-	return time.Now().UnixMilli()
-}