Issue #1848 EmitFileEvent.php: Call to undefined function getFileUri() (#838)

Explicitly check for function before it is called.

src/Plugin/Action/EmitFileEvent.php

@@ -105,11 +105,14 @@ class EmitFileEvent extends EmitEvent {
    * {@inheritdoc}
    */
   protected function generateData(EntityInterface $entity) {
+    $data = parent::generateData($entity);
+
+    // This function is called on Media and File entity types.
+    if (method_exists($entity, 'getFileUri')) {
       $uri = $entity->getFileUri();
       $scheme = StreamWrapperManager::getScheme($uri);
       $flysystem_config = Settings::get('flysystem');
 
-    $data = parent::generateData($entity);
       if (isset($flysystem_config[$scheme]) && $flysystem_config[$scheme]['driver'] == 'fedora') {
         // Fdora $uri for files may contain ':///' so we need to replace
         // the three / with two.
@@ -118,6 +121,7 @@ class EmitFileEvent extends EmitEvent {
         }
         $data['fedora_uri'] = str_replace("$scheme://", $flysystem_config[$scheme]['config']['root'], $uri);
       }
+    }
     return $data;
   }