fix 404 error in web UI (#665)

Co-authored-by: crwxaj <crwxaj>

pkg/server/server.go

@@ -120,11 +120,7 @@ func StartServer(version, commit, branch, date string) {
 	restful.Add(restfulspec.NewOpenAPIService(restConfig))
 
 	// Static files
-	if !common.EnvConfig.Debug {
-		authHandle("/ui/", common.IsUIAuthEnabled(), common.GetUISecret, http.StripPrefix("/dist/", http.FileServer(http.FS(ui.Assets))))
-	} else {
-		authHandle("/ui/", common.IsUIAuthEnabled(), common.GetUISecret, http.FileServer(http.Dir("ui/dist")))
-	}
+	authHandle("/ui/", common.IsUIAuthEnabled(), common.GetUISecret, http.FileServer(ui.GetFileSystem(common.EnvConfig.Debug)))
 
 	// Imageproxy
 	r := mux.NewRouter()

ui/fs.go

@@ -1,6 +1,23 @@
 package ui
 
-import "embed"
+import (
+	"embed"
+	"io/fs"
+	"log"
+	"net/http"
+)
 
 //go:embed dist
 var Assets embed.FS
+
+func GetFileSystem(useOS bool) http.FileSystem {
+	if useOS {
+		return http.Dir("ui/dist")
+	}
+
+	fs, err := fs.Sub(Assets, "dist")
+	if err != nil {
+		log.Panic(err)
+	}
+	return http.FS(fs)
+}