don't fail silently in createExportFile

h5p-default-storage.class.php

@@ -132,11 +132,18 @@ class H5PDefaultStorage implements \H5PFileStorage {
    *  Path on file system to temporary export file.
    * @param string $filename
    *  Name of export file.
+   * @throws Exception Unable to save the file
    */
   public function saveExport($source, $filename) {
     $this->deleteExport($filename);
-    self::dirReady("{$this->path}/exports");
-    copy($source, "{$this->path}/exports/{$filename}");
+
+    if (!self::dirReady("{$this->path}/exports")) {
+      throw new Exception("Unable to create directory for H5P export file.");
+    }
+
+    if (!copy($source, "{$this->path}/exports/{$filename}")) {
+      throw new Exception("Unable to save H5P export file.");
+    }
   }
 
   /**

h5p.classes.php

@@ -1595,6 +1595,7 @@ Class H5PExport {
     }
     catch (Exception $e) {
       $this->h5pF->setErrorMessage($this->h5pF->t($e->getMessage()));
+      return false;
     }
 
     unlink($tmpFile);