add volume control

main.go

@@ -28,6 +28,11 @@ type PointerMessageData struct {
 	Click string `json:click`
 }
 
+type MessageResponse struct {
+	Type  string `json:"type"`
+	Value string `json:"value"`
+}
+
 func getSimpleMessageValue(msg string) string {
 	data := SimpleMessageData{}
 	json.Unmarshal([]byte(msg), &data)
@@ -35,6 +40,11 @@ func getSimpleMessageValue(msg string) string {
 	return data.Value
 }
 
+func sendMessageResponse(ws *websocket.Conn, r MessageResponse) {
+	value, _ := json.Marshal(r)
+	websocket.Message.Send(ws, string(value))
+}
+
 func ws(c echo.Context) error {
 	var actions = Actions{
 		Functions: make(map[string]func(ws *websocket.Conn, msg string) error),
@@ -123,7 +133,40 @@ func ws(c echo.Context) error {
 	})
 
 	actions.add("volume", func(ws *websocket.Conn, msg string) error {
-		return nil
+		value := getSimpleMessageValue(msg)
+
+		if value == "" {
+			return errors.New("Invalid value")
+		}
+
+		if value == "up" {
+			cmd := exec.Command("amixer", "set", "Master", "2%+")
+			sendMessageResponse(ws, MessageResponse{
+				Type:  "response",
+				Value: "Volume up",
+			})
+
+			return cmd.Run()
+		}
+
+		if value == "down" {
+			cmd := exec.Command("amixer", "set", "Master", "2%-")
+			sendMessageResponse(ws, MessageResponse{
+				Type:  "response",
+				Value: "Volume down",
+			})
+
+			return cmd.Run()
+		}
+
+		cmd := exec.Command("amixer", "set", "Master", fmt.Sprintf("%s%%", value))
+
+		sendMessageResponse(ws, MessageResponse{
+			Type:  "response",
+			Value: fmt.Sprintf("Volume set to %s%%", value),
+		})
+
+		return cmd.Run()
 	})
 
 	actions.add("media", func(ws *websocket.Conn, msg string) error {
@@ -236,6 +279,7 @@ func ws(c echo.Context) error {
 
 func main() {
 	e := echo.New()
+	e.HideBanner = true
 
 	e.Use(middleware.BasicAuth(func(username, password string, c echo.Context) (bool, error) {
 		if subtle.ConstantTimeCompare([]byte(username), []byte("admin")) == 1 &&