add browser open function

main.go

@@ -7,6 +7,8 @@ import (
 	"os"
 	"slideshowApp/env"
 	"slideshowApp/handlers"
+	"slideshowApp/utils"
+	"time"
 
 	"github.com/gorilla/mux"
 )
@@ -23,11 +25,14 @@ func main() {
 
 	if _, err := os.Stat(uploadFolder); err != nil {
 		fmt.Println("upload folder for images not found: ", uploadFolder)
-		fmt.Println("use fallback")
+		fmt.Println("use fallback folder")
 		uploadFolder = "./images"
+		env.PhotoDir.SetValue(uploadFolder)
+
 	}
 
 	fmt.Println("upload folder for images: ", uploadFolder)
+
 	r.PathPrefix("/uploads/").Handler(http.StripPrefix("/uploads/", http.FileServer(http.Dir(uploadFolder))))
 	r.HandleFunc("/api/images", handlers.ListFilesHandler).Methods("GET")
 	r.HandleFunc("/ws", handlers.Websocket)
@@ -54,6 +59,12 @@ func main() {
 	host := env.Host.GetValue()
 	port := env.Port.GetValue()
 	url := fmt.Sprintf("%s:%s", host, port)
+	go func() {
+		time.Sleep(3 * time.Second)
+		if err := utils.OpenBrowser(fmt.Sprintf("%s:%s/slideshow", handlers.GetLocalIP(), port)); err != nil {
+			fmt.Println(err)
+		}
+	}()
 	fmt.Println("Server running at", url)
 	log.Fatal(http.ListenAndServe(url, r))
 }

utils/utils.go

@@ -0,0 +1,81 @@
+package utils
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"runtime"
+)
+
+func OpenBrowser(url string) error {
+	var commands [][]string
+
+	switch runtime.GOOS {
+	case "windows":
+		commands = [][]string{
+			// Chrome (most common)
+			{`C:\Program Files\Google\Chrome\Application\chrome.exe`, "--kiosk", url},
+			{`C:\Program Files (x86)\Google\Chrome\Application\chrome.exe`, "--kiosk", url},
+
+			// Edge (default on modern Windows)
+			{`C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe`, "--kiosk", url},
+			{`C:\Program Files\Microsoft\Edge\Application\msedge.exe`, "--kiosk", url},
+
+			// Firefox (no true kiosk, but fullscreen)
+			{`C:\Program Files\Mozilla Firefox\firefox.exe`, "--kiosk", url},
+			{`C:\Program Files (x86)\Mozilla Firefox\firefox.exe`, "--kiosk", url},
+
+			// System default browser (always works)
+			{"rundll32", "url.dll,FileProtocolHandler", url},
+		}
+
+	case "darwin":
+		commands = [][]string{
+			// Chrome
+			{"/Applications/Google Chrome.app/Contents/MacOS/Google Chrome", "--kiosk", url},
+
+			// Edge
+			{"/Applications/Microsoft Edge.app/Contents/MacOS/Microsoft Edge", "--kiosk", url},
+
+			// Firefox
+			{"/Applications/Firefox.app/Contents/MacOS/firefox", "--kiosk", url},
+
+			// Safari (no kiosk flag, opens normally)
+			{"open", "-a", "Safari", url},
+
+			// System default browser
+			{"open", url},
+		}
+
+	default: // Linux
+		if os.Getenv("DISPLAY") == "" &&
+			os.Getenv("WAYLAND_DISPLAY") == "" &&
+			os.Getenv("XDG_SESSION_TYPE") != "wayland" {
+			return fmt.Errorf("os is running in headless mode; do not start browser")
+		}
+
+		commands = [][]string{
+			// Chromium / Chrome
+			{"chromium-browser", "--kiosk", url},
+			{"chromium", "--kiosk", url},
+			{"google-chrome", "--kiosk", url},
+
+			// Firefox
+			{"firefox", "--kiosk", url},
+
+			// System default browser (best universal fallback)
+			{"xdg-open", url},
+		}
+	}
+
+	for _, cmd := range commands {
+		execCmd := exec.Command(cmd[0], cmd[1:]...)
+		if err := execCmd.Start(); err == nil {
+			return nil
+		} else {
+			return err
+		}
+	}
+
+	return fmt.Errorf("could not open browser")
+}