Add two tips about converting to File instance after fetching

Author: wouterj

cookbook/controller/upload_file.rst

@@ -203,6 +203,21 @@ You can use the following code to link to the PDF brochure of an product:
  View brochure (PDF)
  </a>
 
+.. tip::
+
+ When creating a form to edit an already persisted item, the file form type
+ still expects a :class:`Symfony\\Component\\HttpFoundation\\File\\File`
+ instance. As the persisted entity now contains only the relative file path,
+ you first have to concatenate the configured upload path with the stored
+ filename and create a new ``File`` class::
+
+ use Symfony\Component\HttpFoundation\File\File;
+ // ...
+
+ $product->setBrochure(
+ new File($this->getParameter('brochures_directory').'/'.$product->getBrochure())
+ );
+
 Creating an Uploader Service
 ----------------------------
 
@@ -411,4 +426,30 @@ This listeners is now automatically executed when persisting a new Product
 entity. This way, you can remove everything related to uploading from the
 controller.
 
+.. tip::
+
+ This listener can also create the ``File`` instance based on the path when
+ fetching entities from the database::
+
+ // ...
+ use Symfony\Component\HttpFoundation\File\File;
+
+ // ...
+ class BrochureUploadListener
+ {
+ // ...
+
+ public function postLoad(LifecycleEventArgs $args)
+ {
+ $entity = $args->getEntity();
+
+ $fileName = $entity->getBrochure();
+
+ $entity->setBrochure(new File($this->targetPath.'/'.$fileName));
+ }
+ }
+
+ After adding these lines, configure the listener to also listen for the
+ ``postLoad`` event.
+
 .. _`VichUploaderBundle`: https://github.com/dustin10/VichUploaderBundle