add cmdline flags and some fixes to the IPC layer

backend/app.go

@@ -81,17 +81,6 @@ func StartupApp(appName, displayAppName, appVersionTag, latestReleaseURL string)
 	configdir.MakePath(confDir)
 	configdir.MakePath(cacheDir)
 
-	cli, err := ipc.Connect()
-	if err == nil {
-		log.Println("Another instance is running. Reactivating it...")
-		cli.Show()
-		return nil, ErrAnotherInstance
-	}
-
-	log.Printf("Starting %s...", appName)
-	log.Printf("Using config dir: %s", confDir)
-	log.Printf("Using cache dir: %s", cacheDir)
-
 	a := &App{
 		appName:       appName,
 		appVersionTag: appVersionTag,
@@ -101,7 +90,20 @@ func StartupApp(appName, displayAppName, appVersionTag, latestReleaseURL string)
 	}
 	a.bgrndCtx, a.cancel = context.WithCancel(context.Background())
 	a.readConfig()
-	a.startConfigWriter(a.bgrndCtx)
+
+	if HaveCommandLineOptions() || !a.Config.Application.AllowMultiInstance {
+		connected, err := a.checkCLIFlagsAndSendIPCMsg()
+		if err != nil {
+			log.Printf("error sending IPC message: %s", err.Error())
+		}
+		if connected /* we reached the other instance at all */ {
+			return nil, ErrAnotherInstance
+		}
+	}
+
+	log.Printf("Starting %s...", appName)
+	log.Printf("Using config dir: %s", confDir)
+	log.Printf("Using cache dir: %s", cacheDir)
 
 	a.UpdateChecker = NewUpdateChecker(appVersionTag, latestReleaseURL, &a.Config.Application.LastCheckedVersion)
 	a.UpdateChecker.Start(a.bgrndCtx, 24*time.Hour)
@@ -137,6 +139,8 @@ func StartupApp(appName, displayAppName, appVersionTag, latestReleaseURL string)
 		return a.ImageManager.GetCoverArtUrl(id)
 	})
 
+	a.startConfigWriter(a.bgrndCtx)
+
 	return a, nil
 }
 
@@ -367,6 +371,34 @@ func (a *App) SaveConfigFile() {
 	a.lastWrittenCfg = *a.Config
 }
 
+func (a *App) checkCLIFlagsAndSendIPCMsg() (connected bool, err error) {
+	cli, err := ipc.Connect()
+	if err != nil {
+		return false, err
+	}
+
+	switch {
+	case *FlagPlay:
+		err = cli.Play()
+	case *FlagPause:
+		err = cli.Pause()
+	case *FlagPlayPause:
+		err = cli.PlayPause()
+	case *FlagPrevious:
+		err = cli.SeekBackOrPrevious()
+	case *FlagNext:
+		err = cli.SeekNext()
+	case VolumeCLIArg >= 0:
+		err = cli.SetVolume(VolumeCLIArg)
+	case SeekToCLIArg >= 0:
+		err = cli.SeekSeconds(SeekToCLIArg)
+	default:
+		log.Println("Another instance is running. Reactivating it...")
+		err = cli.Show()
+	}
+	return true, err
+}
+
 func (a *App) configFilePath() string {
 	return path.Join(a.configDir, configFile)
 }

backend/cmdlineoptions.go

@@ -0,0 +1,41 @@
+package backend
+
+import (
+	"flag"
+	"strconv"
+)
+
+var (
+	VolumeCLIArg int     = -1
+	SeekToCLIArg float64 = -1
+
+	FlagPlay      = flag.Bool("play", false, "unpause or begin playback")
+	FlagPause     = flag.Bool("pause", false, "pause playback")
+	FlagPlayPause = flag.Bool("play-pause", false, "toggle play/pause state")
+	FlagPrevious  = flag.Bool("previous", false, "seek to previous track or beginning of current")
+	FlagNext      = flag.Bool("next", false, "seek to next track")
+	FlagVersion   = flag.Bool("version", false, "print app version and exit")
+	FlagHelp      = flag.Bool("help", false, "print command line options and exit")
+)
+
+func init() {
+	flag.Func("volume", "sets the playback volume (0-100)", func(s string) error {
+		v, err := strconv.Atoi(s)
+		VolumeCLIArg = v
+		return err
+	})
+
+	flag.Func("seek-to", "seeks to the given position in seconds in the current file (0.0 - <trackDur>)", func(s string) error {
+		v, err := strconv.ParseFloat(s, 64)
+		SeekToCLIArg = v
+		return err
+	})
+}
+
+func HaveCommandLineOptions() bool {
+	visitedAny := false
+	flag.Visit(func(*flag.Flag) {
+		visitedAny = true
+	})
+	return visitedAny
+}

backend/ipc/api.go

@@ -1,43 +1,29 @@
 package ipc
 
+import "fmt"
+
 const (
-	// GET
 	PingPath      = "/ping"
-
-	// POST
 	PlayPath      = "/transport/play"
-	// POST
 	PlayPausePath = "/transport/playpause"
-	// POST
 	PausePath     = "/transport/pause"
-	// POST
 	StopPath      = "/transport/stop"
-	// POST
 	PreviousPath  = "/transport/previous"
-	// POST
 	NextPath      = "/transport/next"
-	// POST(TimePos)
+	TimePosPath   = "/transport/timepos" // ?s=<seconds>
-	TimePosPath = "/transport/timepos"
+	VolumePath    = "/volume"            // ?v=<vol>
-	// POST to seek
-	PlayTrackPath = "/queue/playtrack"
-	// GET -> Volume
-	// POST(Volume)
-	VolumePath = "/volume"
-
-	// POST
 	ShowPath      = "/window/show"
-	// POST
 	QuitPath      = "/window/quit"
 )
 
-type TimePos struct {
-	Seconds float64 `json:"seconds"`
-}
-
-type Volume struct {
-	Volume int `json:"volume"`
-}
-
 type Response struct {
 	Error string `json:"error"`
 }
+
+func SetVolumePath(vol int) string {
+	return fmt.Sprintf("%s?v=%d", VolumePath, vol)
+}
+
+func SeekToSecondsPath(secs float64) string {
+	return fmt.Sprintf("%s?s=%0.2f", TimePosPath, secs)
+}

backend/ipc/client.go

@@ -25,56 +25,56 @@ func Connect() (*Client, error) {
 		},
 	}}
 	if err := client.Ping(); err != nil {
-		log.Println("ping error")
 		return nil, err
 	}
 	return client, nil
 }
 
 func (c *Client) Ping() error {
-	if c.makeSimpleRequest(http.MethodGet, PingPath) != nil {
+	if c.sendRequest(PingPath) != nil {
 		return ErrPingFail
 	}
 	return nil
 }
 
 func (c *Client) Play() error {
-	return c.makeSimpleRequest(http.MethodPost, PlayPath)
+	return c.sendRequest(PlayPath)
 }
 
 func (c *Client) Pause() error {
-	return c.makeSimpleRequest(http.MethodPost, PausePath)
+	return c.sendRequest(PausePath)
 }
 
 func (c *Client) PlayPause() error {
-	return c.makeSimpleRequest(http.MethodPost, PlayPausePath)
+	return c.sendRequest(PlayPausePath)
 }
 
 func (c *Client) SeekNext() error {
-	return c.makeSimpleRequest(http.MethodPost, NextPath)
+	return c.sendRequest(NextPath)
 }
 
 func (c *Client) SeekBackOrPrevious() error {
-	return c.makeSimpleRequest(http.MethodPost, NextPath)
+	return c.sendRequest(PreviousPath)
+}
+
+func (c *Client) SeekSeconds(secs float64) error {
+	return c.sendRequest(SeekToSecondsPath(secs))
+}
+
+func (c *Client) SetVolume(vol int) error {
+	return c.sendRequest(SetVolumePath(vol))
 }
 
 func (c *Client) Show() error {
-	return c.makeSimpleRequest(http.MethodPost, ShowPath)
+	return c.sendRequest(ShowPath)
 }
 
 func (c *Client) Quit() error {
-	return c.makeSimpleRequest(http.MethodPost, QuitPath)
+	return c.sendRequest(QuitPath)
 }
 
-func (c *Client) makeSimpleRequest(method string, path string) error {
+func (c *Client) sendRequest(path string) error {
-	var resp *http.Response
+	resp, err := c.httpC.Get("http://supersonic/" + path)
-	var err error
-	switch method {
-	case http.MethodGet:
-		resp, err = c.httpC.Get("http://supersonic/" + path)
-	case http.MethodPost:
-		resp, err = c.httpC.Post("http://supersonic/"+path, "application/json", nil)
-	}
 
 	if err != nil {
 		log.Printf("http err: %v\n", err)

backend/ipc/conn_other.go

@@ -3,19 +3,41 @@
 package ipc
 
 import (
+	"fmt"
 	"net"
 	"os"
+	"os/user"
+	"path"
+	"runtime"
 )
 
+var socketPath = "/tmp/supersonic.sock"
+
+func init() {
+	if runtime.GOOS == "darwin" {
+		if home, err := os.UserHomeDir(); err == nil {
+			socketPath = path.Join(home, "Library", "Caches", "supersonic", "supersonic.sock")
+		} else if user, err := user.Current(); err == nil {
+			socketPath = fmt.Sprintf("/tmp/supersonic-%s.sock", user.Name)
+		}
+	} else {
+		if runtime := os.Getenv("XDG_RUNTIME_DIR"); runtime != "" {
+			socketPath = path.Join(runtime, "supersonic.sock")
+		} else if user, err := user.Current(); err == nil {
+			socketPath = fmt.Sprintf("/tmp/supersonic-%s.sock", user.Name)
+		}
+	}
+}
+
 func Dial() (net.Conn, error) {
 	// TODO - use XDG runtime dir, also handle portable mode
-	return net.Dial("unix", "/tmp/supersonic.sock")
+	return net.Dial("unix", socketPath)
 }
 
 func Listen() (net.Listener, error) {
-	return net.Listen("unix", "/tmp/supersonic.sock")
+	return net.Listen("unix", socketPath)
 }
 
 func DestroyConn() error {
-	return os.Remove("/tmp/supersonic.sock")
+	return os.Remove(socketPath)
 }

backend/ipc/server.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"net"
 	"net/http"
+	"strconv"
 )
 
 type PlaybackHandler interface {
@@ -71,25 +72,20 @@ func (s *serverImpl) createHandler() http.Handler {
 	m.HandleFunc(PreviousPath, s.makeSimpleEndpointHandler(s.pbHandler.SeekBackOrPrevious))
 	m.HandleFunc(NextPath, s.makeSimpleEndpointHandler(s.pbHandler.SeekNext))
 	m.HandleFunc(TimePosPath, func(w http.ResponseWriter, r *http.Request) {
-		var t TimePos
+		_s := r.URL.Query().Get("s")
-		if err := json.NewDecoder(r.Response.Body).Decode(&t); err != nil {
+		if secs, err := strconv.ParseFloat(_s, 64); err == nil {
+			s.writeSimpleResponse(w, s.pbHandler.SeekSeconds(secs))
+		} else {
 			s.writeErr(w, err)
-			return
 		}
-		s.writeSimpleResponse(w, s.pbHandler.SeekSeconds(t.Seconds))
 	})
 	m.HandleFunc(VolumePath, func(w http.ResponseWriter, r *http.Request) {
-		if r.Method == http.MethodGet {
+		v := r.URL.Query().Get("v")
-			msg, _ := json.Marshal(Volume{Volume: s.pbHandler.Volume()})
+		if vol, err := strconv.Atoi(v); err == nil {
-			w.Write(msg)
+			s.writeSimpleResponse(w, s.pbHandler.SetVolume(vol))
-			return
+		} else {
-		}
-		var v Volume
-		if err := json.NewDecoder(r.Response.Body).Decode(&v); err != nil {
 			s.writeErr(w, err)
-			return
 		}
-		s.writeSimpleResponse(w, s.pbHandler.SetVolume(v.Volume))
 	})
 	return m
 }

main.go

@@ -1,6 +1,8 @@
 package main
 
 import (
+	"flag"
+	"fmt"
 	"log"
 	"os"
 	"runtime"
@@ -10,15 +12,29 @@ import (
 	"github.com/dweymouth/supersonic/res"
 	"github.com/dweymouth/supersonic/ui"
 
-	"fyne.io/fyne/v2"
 	"fyne.io/fyne/v2/app"
 )
 
 func main() {
+	// parse cmd line flags - see backend/cmdlineoptions.go
+	flag.Parse()
+	if *backend.FlagVersion {
+		fmt.Println(res.AppVersion)
+		return
+	}
+	if *backend.FlagHelp {
+		flag.Usage()
+		return
+	}
+	// rest of flag actions are handled in backend.StartupApp
+
 	myApp, err := backend.StartupApp(res.AppName, res.DisplayName, res.AppVersionTag, res.LatestReleaseURL)
 	if err != nil {
+		if err != backend.ErrAnotherInstance {
 			log.Fatalf("fatal startup error: %v", err.Error())
 		}
+		return
+	}
 
 	if myApp.Config.Application.UIScaleSize == "Smaller" {
 		os.Setenv("FYNE_SCALE", "0.85")
@@ -29,15 +45,7 @@ func main() {
 	fyneApp := app.New()
 	fyneApp.SetIcon(res.ResAppicon256Png)
 
-	w := float32(myApp.Config.Application.WindowWidth)
+	mainWindow := ui.NewMainWindow(fyneApp, res.AppName, res.DisplayName, res.AppVersion, myApp)
-	if w <= 1 {
-		w = 1000
-	}
-	h := float32(myApp.Config.Application.WindowHeight)
-	if h <= 1 {
-		h = 800
-	}
-	mainWindow := ui.NewMainWindow(fyneApp, res.AppName, res.DisplayName, res.AppVersion, myApp, fyne.NewSize(w, h))
 	myApp.OnReactivate = mainWindow.Show
 	myApp.OnExit = mainWindow.Quit
 

ui/mainwindow.go

@@ -60,7 +60,7 @@ type MainWindow struct {
 	radioBtn *widget.Button
 }
 
-func NewMainWindow(fyneApp fyne.App, appName, displayAppName, appVersion string, app *backend.App, size fyne.Size) MainWindow {
+func NewMainWindow(fyneApp fyne.App, appName, displayAppName, appVersion string, app *backend.App) MainWindow {
 	m := MainWindow{
 		App:    app,
 		Window: fyneApp.NewWindow(displayAppName),
@@ -89,7 +89,16 @@ func NewMainWindow(fyneApp fyne.App, appName, displayAppName, appVersion string,
 	m.BottomPanel = NewBottomPanel(app.PlaybackManager, app.ImageManager, m.Controller)
 	m.container = container.NewBorder(nil, m.BottomPanel, nil, nil, m.BrowsingPane)
 	m.Window.SetContent(m.container)
-	m.Window.Resize(size)
+
+	w := float32(app.Config.Application.WindowWidth)
+	if w <= 1 {
+		w = 1000
+	}
+	h := float32(app.Config.Application.WindowHeight)
+	if h <= 1 {
+		h = 800
+	}
+	m.Window.Resize(fyne.NewSize(w, h))
 	app.PlaybackManager.OnSongChange(func(item mediaprovider.MediaItem, _ *mediaprovider.Track) {
 		if item == nil {
 			m.Window.SetTitle(displayAppName)