Symfony Entity load calculated field but not always - symfony

Question

I have a symfony entity that has a not mapped calculated field
namespace AppBundle\Entity;
class Page
{
/**
* #var integer
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* Page count. Non-mapped
*
* #var integer
*/
protected $pageCount;
}
The $pageCount value is obtainable by consuming a remote service that will provide the value for use in the application.
I figured the best way is to use the postLoad event to handle this.
class PageListener
{
/**
* #ORM\PostLoad
*/
public function postLoad(LifecycleEventArgs $eventArgs)
{
// ...
}
}
I need to retrieve this value when loading values.
public function indexAction()
{
// I want to fetch the pageHits here
$pagesListing = $this->getDoctrine()
->getRepository('AppBundle:Pages')
->findAll();
// I don't want to fetch the pageHits here
$pagesListing2 = $this->getDoctrine()
->getRepository('AppBundle:Pages')
->findAll();
}
However, this will ALWAYS result in a call to a remote service.
There may be cases where I do not want the service to be invoked, so that it reduced a performance load on the application.
How can I fetch the remote values automatically, but only when I want to.

Answer 1

Your "problem" is pretty common and one of the reasons I never use Doctrine repositories directly.
Solution I would recommend
Always make custom repository services and inject Doctrine into them.
That way, if you want to merge some data from some other data source (eg. Redis, filesystem, some remote API), you have complete control over it and process is encapsulated.
Example:
class PageRepository
{
private $em;
private $api;
public function __construct(EntityManagerInterface $em, MyAwesomeApi $api)
{
$this->em = $em;
$this->api = $api;
}
public function find($id)
{
return $em->getRepository(Page::class)->find($id);
}
public function findAll()
{
return $em->getRepository(Page::class)->findAll();
}
public function findWithCount($id)
{
$page = $this->find($id);
$count = $this->myAwesomeApi->getPageCount($id);
return new PageWithCount($page, $count);
}
}
Solution I wouldn't recommend, but works :)
If you don't want to change your code structure and want to keep it as it is, you could make a really simple change that will make your pageCount be loaded only when it is necessary:
Move code from Page::postLoad method into Page::getPageCount()
Example:
public function getPageCount()
{
if (null === $this->pageCount) {
$this->pageCount = MyAwesomeApi::getPageCount($this->id);
}
return $this->pageCount;
}
This way, pageCount will only be loaded if something tries to access it.