mirror of
https://github.com/skidoodle/spotify-ws
synced 2025-10-09 05:22:43 +02:00
367 lines
8.0 KiB
Go
367 lines
8.0 KiB
Go
package main
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import (
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"context"
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"fmt"
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"net/http"
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"os"
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"os/signal"
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"strings"
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"sync"
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"syscall"
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"time"
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"github.com/gorilla/websocket"
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"github.com/joho/godotenv"
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"github.com/sirupsen/logrus"
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"github.com/zmb3/spotify"
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"golang.org/x/oauth2"
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)
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// Configuration holds application settings
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type Configuration struct {
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ServerPort string
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AllowedOrigins []string
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LogLevel logrus.Level
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Spotify struct {
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ClientID string
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ClientSecret string
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RefreshToken string
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}
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}
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var (
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config Configuration
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clients = make(map[*websocket.Conn]bool)
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clientsMutex sync.RWMutex
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broadcast = make(chan *spotify.CurrentlyPlaying)
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connectChan = make(chan *websocket.Conn)
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upgrader = websocket.Upgrader{
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HandshakeTimeout: 10 * time.Second,
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ReadBufferSize: 1024,
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WriteBufferSize: 1024,
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}
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spotifyClient spotify.Client
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tokenSource oauth2.TokenSource
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lastState struct {
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sync.RWMutex
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track *spotify.CurrentlyPlaying
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playing bool
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}
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)
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const (
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defaultPort = ":3000"
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tokenRefreshURL = "https://accounts.spotify.com/api/token"
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apiRetryDelay = 3 * time.Second
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heartbeatInterval = 3 * time.Second
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writeTimeout = 10 * time.Second
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)
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func main() {
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ctx, cancel := context.WithCancel(context.Background())
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defer cancel()
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initializeApplication()
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initializeSpotifyClient()
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router := http.NewServeMux()
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router.HandleFunc("/", connectionHandler)
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router.HandleFunc("/health", healthHandler)
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server := &http.Server{
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Addr: config.ServerPort,
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Handler: router,
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}
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go trackFetcher(ctx)
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go messageHandler(ctx)
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go connectionManager(ctx)
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startServer(server, ctx)
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handleShutdown(server, cancel)
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}
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func initializeApplication() {
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logrus.SetFormatter(&logrus.TextFormatter{
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FullTimestamp: true,
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TimestampFormat: time.RFC3339,
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ForceColors: true,
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})
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if err := loadConfiguration(); err != nil {
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logrus.Fatal(err)
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}
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upgrader.CheckOrigin = func(r *http.Request) bool {
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if len(config.AllowedOrigins) == 0 {
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return true
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}
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origin := r.Header.Get("Origin")
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for _, allowed := range config.AllowedOrigins {
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if origin == allowed {
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return true
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}
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}
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return false
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}
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}
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func loadConfiguration() error {
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_ = godotenv.Load()
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required := map[string]*string{
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"CLIENT_ID": &config.Spotify.ClientID,
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"CLIENT_SECRET": &config.Spotify.ClientSecret,
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"REFRESH_TOKEN": &config.Spotify.RefreshToken,
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}
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for key, ptr := range required {
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value := os.Getenv(key)
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if value == "" {
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return fmt.Errorf("missing required environment variable: %s", key)
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}
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*ptr = value
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}
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config.ServerPort = defaultPort
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if port := os.Getenv("SERVER_PORT"); port != "" {
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config.ServerPort = ":" + strings.TrimLeft(port, ":")
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}
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config.AllowedOrigins = strings.Split(os.Getenv("ALLOWED_ORIGINS"), ",")
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logLevel := strings.ToLower(os.Getenv("LOG_LEVEL"))
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switch logLevel {
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case "debug":
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config.LogLevel = logrus.DebugLevel
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case "warn":
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config.LogLevel = logrus.WarnLevel
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case "error":
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config.LogLevel = logrus.ErrorLevel
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default:
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config.LogLevel = logrus.InfoLevel
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}
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logrus.SetLevel(config.LogLevel)
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return nil
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}
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func initializeSpotifyClient() {
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token := &oauth2.Token{RefreshToken: config.Spotify.RefreshToken}
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oauthConfig := &oauth2.Config{
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ClientID: config.Spotify.ClientID,
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ClientSecret: config.Spotify.ClientSecret,
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Endpoint: oauth2.Endpoint{TokenURL: tokenRefreshURL},
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}
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tokenSource = oauthConfig.TokenSource(context.Background(), token)
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spotifyClient = spotify.NewClient(oauth2.NewClient(context.Background(), tokenSource))
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logrus.Info("Spotify client initialized successfully")
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}
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func startServer(server *http.Server, _ context.Context) {
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go func() {
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logrus.Infof("Server starting on %s", config.ServerPort)
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if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
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logrus.Fatalf("Server failed to start: %v", err)
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}
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}()
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}
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func handleShutdown(server *http.Server, cancel context.CancelFunc) {
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sigChan := make(chan os.Signal, 1)
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signal.Notify(sigChan, os.Interrupt, syscall.SIGTERM)
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<-sigChan
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logrus.Info("Initiating graceful shutdown...")
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cancel()
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ctx, cancelTimeout := context.WithTimeout(context.Background(), 5*time.Second)
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defer cancelTimeout()
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clientsMutex.Lock()
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for client := range clients {
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client.Close()
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}
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clientsMutex.Unlock()
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if err := server.Shutdown(ctx); err != nil {
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logrus.Errorf("Server shutdown error: %v", err)
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}
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logrus.Info("Server shutdown complete")
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}
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func connectionHandler(w http.ResponseWriter, r *http.Request) {
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w.Header().Set("X-Source", "github.com/skidoodle/spotify-ws")
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ws, err := upgrader.Upgrade(w, r, nil)
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if err != nil {
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logrus.Errorf("WebSocket upgrade failed: %v", err)
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return
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}
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// Add client to the pool
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clientsMutex.Lock()
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clients[ws] = true
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clientsMutex.Unlock()
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logrus.Debugf("New client connected: %s", ws.RemoteAddr())
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// Send initial state if available
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sendInitialState(ws)
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// Start monitoring the connection
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go monitorConnection(ws)
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}
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func connectionManager(ctx context.Context) {
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for {
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select {
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case <-ctx.Done():
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return
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case client := <-connectChan:
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// Add client to the pool
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clientsMutex.Lock()
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clients[client] = true
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clientsMutex.Unlock()
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logrus.Debugf("New client connected: %s", client.RemoteAddr())
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// Send initial state if available
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sendInitialState(client)
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// Start monitoring the connection
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go monitorConnection(client)
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}
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}
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}
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func monitorConnection(ws *websocket.Conn) {
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defer func() {
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// Clean up the connection
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clientsMutex.Lock()
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delete(clients, ws)
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clientsMutex.Unlock()
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// Close the WebSocket connection
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ws.Close()
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logrus.Debugf("Client disconnected: %s", ws.RemoteAddr())
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}()
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for {
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// Set a read deadline to detect dead connections
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ws.SetReadDeadline(time.Now().Add(30 * time.Second))
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// Attempt to read a message (even though we don't expect any)
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_, _, err := ws.NextReader()
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if err != nil {
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// Check if the error is a normal closure
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if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseNormalClosure) {
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logrus.Debugf("Client disconnected unexpectedly: %v", err)
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}
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break
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}
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}
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}
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func sendInitialState(client *websocket.Conn) {
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lastState.RLock()
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defer lastState.RUnlock()
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if lastState.track == nil {
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logrus.Debug("No initial state available to send")
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return
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}
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if err := client.WriteJSON(lastState.track); err != nil {
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logrus.Errorf("Failed to send initial state: %v", err)
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client.Close()
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}
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}
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func messageHandler(ctx context.Context) {
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for {
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select {
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case <-ctx.Done():
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return
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case msg := <-broadcast:
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broadcastToClients(msg)
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}
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}
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}
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func broadcastToClients(msg *spotify.CurrentlyPlaying) {
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clientsMutex.RLock()
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defer clientsMutex.RUnlock()
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for client := range clients {
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client.SetWriteDeadline(time.Now().Add(writeTimeout))
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if err := client.WriteJSON(msg); err != nil {
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logrus.Debugf("Broadcast failed: %v", err)
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client.Close()
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}
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}
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}
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func trackFetcher(ctx context.Context) {
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ticker := time.NewTicker(heartbeatInterval)
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defer ticker.Stop()
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for {
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select {
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case <-ctx.Done():
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return
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case <-ticker.C:
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fetchAndBroadcastState()
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}
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}
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}
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func fetchAndBroadcastState() {
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current, err := spotifyClient.PlayerCurrentlyPlaying()
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if err != nil {
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logrus.Errorf("Failed to fetch playback state: %v", err)
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time.Sleep(apiRetryDelay)
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return
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}
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logrus.Debugf("Fetched playback state: %+v", current)
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updateState(current)
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}
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func updateState(current *spotify.CurrentlyPlaying) {
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lastState.Lock()
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defer lastState.Unlock()
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if current == nil {
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logrus.Warn("Received nil playback state from Spotify")
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return
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}
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if lastState.track == nil {
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lastState.track = &spotify.CurrentlyPlaying{}
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}
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stateChanged := lastState.track.Item == nil ||
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current.Item == nil ||
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lastState.track.Item.ID != current.Item.ID ||
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lastState.playing != current.Playing
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lastState.track = current
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lastState.playing = current.Playing
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if stateChanged || current.Playing {
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broadcast <- current
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}
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}
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func healthHandler(w http.ResponseWriter, r *http.Request) {
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w.Header().Set("Content-Type", "text/plain")
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w.WriteHeader(http.StatusOK)
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w.Write([]byte("OK"))
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}
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