feat(ipc): add an endpoint for getting current track (#911)

backend/ipc/api.go

@@ -28,6 +28,7 @@ const (
 	ShowPath              = "/window/show"
 	ReloadThemePath       = "/window/reload-theme"
 	QuitPath              = "/window/quit"
+	CurrentTrackPath      = "/current_track"
 	RateCurrentTrackPath  = "/current_track/rate" // ?r=<rating 0-5>
 )
 

backend/ipc/client.go

@@ -118,6 +118,10 @@ func (c *Client) AdjustVolumePct(pct float64) error {
 	return err
 }
 
+func (c *Client) CurrentTrack() (string, error) {
+	return c.sendRequest(CurrentTrackPath)
+}
+
 func (c *Client) RateCurrentTrack(rating int) error {
 	_, err := c.sendRequest(BuildRateCurrentTrackPath(rating))
 	return err

backend/ipc/server.go

@@ -29,6 +29,7 @@ type PlaybackHandler interface {
 	PlayAlbum(string, int, bool) error
 	PlayPlaylist(string, int, bool) error
 	PlayTrack(string) error
+	NowPlaying() mediaprovider.MediaItem
 }
 
 type IPCServer interface {
@@ -41,16 +42,21 @@ type ServerManager interface {
 }
 
 type serverImpl struct {
-	server          *http.Server
-	pbHandler       PlaybackHandler
-	rateFn          func(int)
-	sm              ServerManager
-	showFn          func()
-	quitFn          func()
-	reloadThemeFn   func()
+	server        *http.Server
+	pbHandler     PlaybackHandler
+	rateFn        func(int)
+	sm            ServerManager
+	showFn        func()
+	quitFn        func()
+	reloadThemeFn func()
 }
 
-func NewServer(pbHandler PlaybackHandler, rateFn func(int), sm ServerManager, showFn, quitFn, reloadThemeFn func()) IPCServer {
+func NewServer(
+	pbHandler PlaybackHandler,
+	rateFn func(int),
+	sm ServerManager,
+	showFn, quitFn, reloadThemeFn func(),
+) IPCServer {
 	s := &serverImpl{pbHandler: pbHandler, rateFn: rateFn, sm: sm, showFn: showFn, quitFn: quitFn, reloadThemeFn: reloadThemeFn}
 	s.server = &http.Server{
 		Handler: s.createHandler(),
@@ -175,6 +181,13 @@ func (s *serverImpl) createHandler() http.Handler {
 
 		return tracks, nil
 	}))
+	m.HandleFunc(CurrentTrackPath, s.makeStatusEndpointHandler(func() (any, error) {
+		track := s.pbHandler.NowPlaying()
+		if track == nil {
+			return nil, errors.New("nothing is playing right now")
+		}
+		return track.Metadata(), nil
+	}))
 	m.HandleFunc(RateCurrentTrackPath, func(w http.ResponseWriter, r *http.Request) {
 		v := r.URL.Query().Get("r")
 		if rating, err := strconv.Atoi(v); err == nil {
@@ -231,6 +244,21 @@ func (s *serverImpl) makeTracklistEndpointHandler(f func(string, int, bool) erro
 	}
 }
 
+func (s *serverImpl) makeStatusEndpointHandler(f func() (any, error)) func(http.ResponseWriter, *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		data, err := f()
+		if err != nil {
+			s.writeErr(w, err)
+			return
+		}
+		bytes, err := json.Marshal(data)
+		if err != nil {
+			s.writeErr(w, err)
+		}
+		s.writeData(w, bytes)
+	}
+}
+
 func (s *serverImpl) makeSearchEndpointHandler(f func(string) (any, error)) func(http.ResponseWriter, *http.Request) {
 	return func(w http.ResponseWriter, r *http.Request) {
 		search := r.URL.Query().Get("s")