Fix download task object validation

lib/api-functions.ts

@@ -226,11 +226,14 @@ function sanitizeTask(task): void {
       break;
 
     case "download":
+      // genieacs-gui sends file ID instead of fileName and fileType
+      if (!task.file) {
         if (typeof task.fileType !== "string" || !task.fileType.length)
           throw new Error("Missing 'fileType' property");
 
         if (typeof task.fileName !== "string" || !task.fileName.length)
           throw new Error("Missing 'fileName' property");
+      }
 
       if (
         task.targetFileName != null &&

lib/cwmp.ts

@@ -670,7 +670,7 @@ async function nextRpc(sessionContext: SessionContext): Promise<void> {
       break;
     case "download":
       session.addProvisions(sessionContext, `task_${task._id}`, [
-        ["download", task.fileType, task.fileName, task.targetFileName]
+        ["download", task.fileType, task.fileName, task.targetFileName || ""]
       ]);
       break;
     case "addObject":