WebClient: prevent uploads if no file is selected

Fixes #1980

Signed-off-by: Nicola Murino <nicola.murino@gmail.com>

static/locales/de/translation.json

@@ -284,6 +284,7 @@
         "download": "Herunterladen",
         "download_ready": "Download abgeschlossen",
         "upload_queue_not_ready": "Die Upload-Warteschlange wird noch geladen, bitte versuche es in ein paar Augenblicken erneut!",
+        "upload_no_files": "Keine Dateien ausgewählt. Bitte wählen oder ziehen Sie Dateien zum Hochladen",
         "move_copy": "Verschieben oder kopieren",
         "share": "Teilen",
         "home": "Startseite",

static/locales/en/translation.json

@@ -284,6 +284,7 @@
         "download": "Download",
         "download_ready": "Your download is ready",
         "upload_queue_not_ready": "The upload queue is still loading, please try again in a few moments",
+        "upload_no_files": "No files selected. Please choose or drag files to upload",
         "move_copy": "Move or copy",
         "share": "Share",
         "home": "Home",

static/locales/fr/translation.json

@@ -284,6 +284,7 @@
         "download": "Télécharger",
         "download_ready": "Votre téléchargement est prêt",
         "upload_queue_not_ready": "La file d'attente de téléchargement est en cours de chargement, veuillez réessayer dans quelques instants",
+        "upload_no_files": "Aucun fichier sélectionné. Veuillez choisir ou glisser des fichiers à téléverser",
         "move_copy": "Déplacer ou copier",
         "share": "Partager",
         "home": "Accueil",

static/locales/it/translation.json

@@ -284,6 +284,7 @@
         "download": "Scarica",
         "download_ready": "Il tuo download è pronto",
         "upload_queue_not_ready": "La coda di caricamento è in fase di elaborazione, riprova tra qualche istante",
+        "upload_no_files": "Nessun file selezionato. Scegli o trascina i file da caricare",
         "move_copy": "Sposta o copia",
         "share": "Condividi",
         "home": "Home",

templates/webclient/files.html

@@ -1981,6 +1981,17 @@ explicit grant from the SFTPGo Team (support@sftpgo.com).
     var playerKeepAlive;
 
     function uploadFiles(files) {
+        if (files.length == 0) {
+            ModalAlert.fire({
+                text: $.t('fs.upload_no_files'),
+                icon: "warning",
+                confirmButtonText: $.t('general.ok'),
+                customClass: {
+                    confirmButton: "btn btn-primary"
+                }
+            });
+            return;
+        }
         keepAlive();
         let keepAliveTimer = setInterval(keepAlive, keepAliveInterval);