Inject parameters to entity - symfony

Question

I encounter this issue a lot of times, but only until now do I want to learn the best way to do it.
Say I have an Image entity, it has a 'path' property, which stores the relative path to the image file. For example, an image has its 'path' as '20141129/123456789.jpg'.
In parameters.yml, I set the absolute path to the directory that stores image files. Like this:
image_dir: %user_static%/images/galery/
I want to add the method 'getFullPath()' to Image entity, inside which the 'image_dir' parameter will be concatenated with 'path' property. I don't want to do the concatenation in controllers because I will be using it a lot. Also I don't want to insert image dir into Image's 'path' property, because I may change the image dir path later (which means I'll have to update the 'path' of all images in database).
So how can I inject the parameter into Image entity, so that getFullPath() can use it? Since Image entities will be fetched by repository methods instead of creating a new instance of Image, passing variables to construction method won't work.
Or is there a more elegant approach? I just want Image entities to have getFullPath() method, and I will be fetching images via both repository methods (find, findBy...) and query builder.

Answer 1

You could listen to the doctrine postLoad event and set the image directory in that so that when you later call getFullPath() it can return the concatenated string of the image directory and the path.
postLoad listener
namespace Acme\ImageBundle\Doctrine\EventSubscriber;
use Acme\ImageBundle\Model\ImageInterface;
use Doctrine\Common\Persistence\Event\LifecycleEventArgs;
use Doctrine\ORM\Events;
class ImageDirectorySubscriber implements EventSubscriber
{
protected $imageDirectory;
public function __construct($imageDirectory)
{
$this->imageDirectory = $imageDirectory;
}
public function getSubscribedEvents()
{
return array(
Events::postLoad,
);
}
public function postLoad(LifecycleEventArgs $args)
{
$image = $args->getEntity();
if (!$image instanceof ImageInterface) {
return;
}
$image->setImageDirectory($this->imageDirectory);
}
}
services.yml
parameters:
acme_image.subscriber.doctrine.image_directory.class:
Acme\ImageBundle\Doctrine\EventSubscriber\ImageDirectorySubscriber
services:
acme_image.subscriber.doctrine.image_directory:
class: %acme_image.subscriber.doctrine.image_directory.class%
arguments:
- %acme_image.image_directory%
tags:
- { name: doctrine.event_subscriber }
Image Model
class Image implements ImageInterface
{
protected $path;
protected $imageDirectory;
.. getter and setter for path..
public function setImageDirectory($imageDirectory)
{
// Remove trailing slash if exists
$this->imageDirectory = rtrim($imageDirectory, '/');
return $this;
}
public function getFullPath()
{
return sprintf('%s/%s', $this->imageDirectory, $this->path);
}
}

Answer 2

An alternative to #Qoop's approach is to make an image manager service and do the path stuff in it. The code will be a bit simpler.
class ImageManager
{
public function __construct($imageDirectory)
{
$this->imageDirectory = $imageDirectory;
}
public function getFullPath($image)
{
return $this->imageDirectory . $image->getPath();
}
}
// Controller
$imageManager = $this->get('image_manager');
echo $imageManager->getFullPath($image);
It's a trade off. Explicitly managing images vs using "behind the scenes" events.