Switch player to MPRIS interface

go.mod

@@ -2,4 +2,7 @@ module go.arsenm.dev/infinitime
 
 go 1.16
 
-require github.com/muka/go-bluetooth v0.0.0-20211122080231-b99792bbe62a
+require (
+	github.com/godbus/dbus/v5 v5.0.3
+	github.com/muka/go-bluetooth v0.0.0-20211122080231-b99792bbe62a
+)

internal/utils/dbus.go

@@ -0,0 +1,37 @@
+package utils
+
+import "github.com/godbus/dbus/v5"
+
+func NewSystemBusConn() (*dbus.Conn, error) {
+	// Connect to dbus session bus
+	conn, err := dbus.SystemBusPrivate()
+	if err != nil {
+		return nil, err
+	}
+	err = conn.Auth(nil)
+	if err != nil {
+		return nil, err
+	}
+	err = conn.Hello()
+	if err != nil {
+		return nil, err
+	}
+	return conn, nil
+}
+
+func NewSessionBusConn() (*dbus.Conn, error) {
+	// Connect to dbus session bus
+	conn, err := dbus.SessionBusPrivate()
+	if err != nil {
+		return nil, err
+	}
+	err = conn.Auth(nil)
+	if err != nil {
+		return nil, err
+	}
+	err = conn.Hello()
+	if err != nil {
+		return nil, err
+	}
+	return conn, nil
+}

pkg/player/player.go

@@ -0,0 +1,224 @@
+package player
+
+import (
+	"strings"
+
+	"github.com/godbus/dbus/v5"
+	"go.arsenm.dev/infinitime/internal/utils"
+)
+
+var (
+	method, monitor *dbus.Conn
+	monitorCh       chan *dbus.Message
+)
+
+// Init makes required connections to DBis and
+// initializes change monitoring channel
+func Init() error {
+	// Connect to session bus for monitoring
+	monitorConn, err := utils.NewSessionBusConn()
+	if err != nil {
+		return err
+	}
+	// Add match rule for PropertiesChanged on media player
+	monitorConn.AddMatchSignal(
+		dbus.WithMatchObjectPath("/org/mpris/MediaPlayer2"),
+		dbus.WithMatchInterface("org.freedesktop.DBus.Properties"),
+		dbus.WithMatchMember("PropertiesChanged"),
+	)
+	monitorCh = make(chan *dbus.Message)
+	monitorConn.Eavesdrop(monitorCh)
+
+	// Connect to session bus for method calls
+	methodConn, err := utils.NewSessionBusConn()
+	if err != nil {
+		return err
+	}
+	method, monitor = methodConn, monitorConn
+	return nil
+}
+
+// Exit closes all connections and channels
+func Exit() {
+	close(monitorCh)
+	method.Close()
+	monitor.Close()
+}
+
+// Play uses MPRIS to play media
+func Play() error {
+	player, err := getPlayerObj()
+	if err != nil {
+		return err
+	}
+	if player != nil {
+		call := player.Call("org.mpris.MediaPlayer2.Player.Play", 0)
+		if call.Err != nil {
+			return call.Err
+		}
+	}
+	return nil
+}
+
+// Pause uses MPRIS to pause media
+func Pause() error {
+	player, err := getPlayerObj()
+	if err != nil {
+		return err
+	}
+	if player != nil {
+		call := player.Call("org.mpris.MediaPlayer2.Player.Pause", 0)
+		if call.Err != nil {
+			return call.Err
+		}
+	}
+	return nil
+}
+
+// Next uses MPRIS to skip to next media
+func Next() error {
+	player, err := getPlayerObj()
+	if err != nil {
+		return err
+	}
+	if player != nil {
+		call := player.Call("org.mpris.MediaPlayer2.Player.Next", 0)
+		if call.Err != nil {
+			return call.Err
+		}
+	}
+	return nil
+}
+
+// Prev uses MPRIS to skip to previous media
+func Prev() error {
+	player, err := getPlayerObj()
+	if err != nil {
+		return err
+	}
+	if player != nil {
+		call := player.Call("org.mpris.MediaPlayer2.Player.Previous", 0)
+		if call.Err != nil {
+			return call.Err
+		}
+	}
+	return nil
+}
+
+type ChangeType int
+
+const (
+	ChangeTypeTitle ChangeType = iota
+	ChangeTypeArtist
+	ChangeTypeAlbum
+	ChangeTypeStatus
+)
+
+func (ct ChangeType) String() string {
+	switch ct {
+	case ChangeTypeTitle:
+		return "Title"
+	case ChangeTypeAlbum:
+		return "Album"
+	case ChangeTypeArtist:
+		return "Artist"
+	case ChangeTypeStatus:
+		return "Status"
+	}
+	return ""
+}
+
+// OnChange runs cb when a value changes
+func OnChange(cb func(ChangeType, string)) {
+	go func() {
+		// For every message on channel
+		for msg := range monitorCh {
+			// Parse PropertiesChanged
+			iface, changed, ok := parsePropertiesChanged(msg)
+			if !ok || iface != "org.mpris.MediaPlayer2.Player" {
+				continue
+			}
+
+			// For every property changed
+			for name, val := range changed {
+				// If metadata changed
+				if name == "Metadata" {
+					// Get fields
+					fields := val.Value().(map[string]dbus.Variant)
+					// For every field
+					for name, val := range fields {
+						// Handle each field appropriately
+						if strings.HasSuffix(name, "title") {
+							title := val.Value().(string)
+							if title == "" {
+								title = "Unknown " + ChangeTypeTitle.String()
+							}
+							cb(ChangeTypeTitle, title)
+						} else if strings.HasSuffix(name, "album") {
+							album := val.Value().(string)
+							if album == "" {
+								album = "Unknown " + ChangeTypeAlbum.String()
+							}
+							cb(ChangeTypeAlbum, album)
+						} else if strings.HasSuffix(name, "artist") {
+							artists := val.Value().([]string)
+							artistStr := strings.Join(artists, ", ")
+							if artistStr == "" {
+								artistStr = "Unknown " + ChangeTypeArtist.String()
+							}
+							cb(ChangeTypeArtist, artistStr)
+						}
+					}
+				} else if name == "PlaybackStatus" {
+					// Handle status change
+					cb(ChangeTypeStatus, val.Value().(string))
+				}
+			}
+		}
+	}()
+}
+
+// getPlayerNames gets all DBus MPRIS player bus names
+func getPlayerNames(conn *dbus.Conn) ([]string, error) {
+	var names []string
+	err := conn.BusObject().Call("org.freedesktop.DBus.ListNames", 0).Store(&names)
+	if err != nil {
+		return nil, err
+	}
+	var players []string
+	for _, name := range names {
+		if strings.HasPrefix(name, "org.mpris.MediaPlayer2") {
+			players = append(players, name)
+		}
+	}
+	return players, nil
+}
+
+// GetPlayerObj gets the object corresponding to the first
+// bus name found in DBus
+func getPlayerObj() (dbus.BusObject, error) {
+	players, err := getPlayerNames(method)
+	if err != nil {
+		return nil, err
+	}
+	if len(players) == 0 {
+		return nil, nil
+	}
+	return method.Object(players[0], "/org/mpris/MediaPlayer2"), nil
+}
+
+// parsePropertiesChanged parses a DBus PropertiesChanged signal
+func parsePropertiesChanged(msg *dbus.Message) (iface string, changed map[string]dbus.Variant, ok bool) {
+	if len(msg.Body) != 3 {
+		return "", nil, false
+	}
+	iface, ok = msg.Body[0].(string)
+	if !ok {
+		return
+	}
+	changed, ok = msg.Body[1].(map[string]dbus.Variant)
+	if !ok {
+		return
+	}
+	return
+}

pkg/player/playerctl.go

@@ -1,112 +0,0 @@
-package player
-
-import (
-	"bufio"
-	"io"
-	"os/exec"
-	"strings"
-)
-
-// Play uses playerctl to play media
-func Play() error {
-	return exec.Command("playerctl", "play").Run()
-}
-
-// Pause uses playerctl to pause media
-func Pause() error {
-	return exec.Command("playerctl", "pause").Run()
-}
-
-// Next uses playerctl to skip to next media
-func Next() error {
-	return exec.Command("playerctl", "next").Run()
-}
-
-// Prev uses playerctl to skip to previous media
-func Prev() error {
-	return exec.Command("playerctl", "previous").Run()
-}
-
-// Metadata uses playerctl to detect music metadata changes
-func Metadata(key string, onChange func(string)) error {
-	// Execute playerctl command with key and follow flag
-	cmd := exec.Command("playerctl", "metadata", key, "-F")
-	// Get stdout pipe
-	stdout, err := cmd.StdoutPipe()
-	if err != nil {
-		return err
-	}
-	go func() {
-		for {
-			// Read line from command stdout
-			line, _, err := bufio.NewReader(stdout).ReadLine()
-			if err == io.EOF {
-				continue
-			}
-			// Convert line to string
-			data := string(line)
-			// If key unknown, return suitable default
-			if data == "No player could handle this command" || data == "" {
-				data = "Unknown " + strings.Title(key)
-			}
-			// Run the onChange callback
-			onChange(data)
-		}
-	}()
-	// Start command asynchronously
-	err = cmd.Start()
-	if err != nil {
-		return err
-	}
-	return nil
-}
-
-func Status(onChange func(bool)) error {
-	// Execute playerctl status with follow flag
-	cmd := exec.Command("playerctl", "status", "-F")
-	// Get stdout pipe
-	stdout, err := cmd.StdoutPipe()
-	if err != nil {
-		return err
-	}
-	go func() {
-		for {
-			// Read line from command stdout
-			line, _, err := bufio.NewReader(stdout).ReadLine()
-			if err == io.EOF {
-				continue
-			}
-			// Convert line to string
-			data := string(line)
-			// Run the onChange callback
-			onChange(data == "Playing")
-		}
-	}()
-	// Start command asynchronously
-	err = cmd.Start()
-	if err != nil {
-		return err
-	}
-	return nil
-}
-
-func CurrentMetadata(key string) (string, error) {
-	out, err := exec.Command("playerctl", "metadata", key).Output()
-	if err != nil {
-		return "", err
-	}
-	data := string(out)
-	if data == "No player could handle this command" || data == "" {
-		data = "Unknown " + strings.Title(key)
-	}
-	return data, nil
-}
-
-func CurrentStatus() (bool, error) {
-	out, err := exec.Command("playerctl", "status").Output()
-	if err != nil {
-		return false, err
-	}
-	data := string(out)
-	return data == "Playing", nil
-}