Select entity based on session value - php

Question

I got two entities. One is a WebshopItem entity, the other one is a WebshopPrice entity.
Each time, you are creating a WebshopItem, you are also filling in 3 WebshopPrices. The WebshopPrices are 3 currencies (EUR, USD and GBP).
Based on the currency you selected (and is saved in your session) I want to display the currency you selected. So, if you picked EUR, I of course want to display the EUR price.
What's the general way of doing this in symfony? Should I use a twig extension which returns the price from the WebshopItem object, based on what's in your session? Should I already filter the WebshopPrices from the database?
Looking forward to your best solutions. Thanks!
Entity/WebshopItem.php
class WebshopItem
{
/**
* #var \Doctrine\Common\Collections\Collection
*/
private $prices;
etc....
}
Entity/WebshopItemPrice.php
class WebshopItemPrice
{
/**
* #var integer
*/
private $id;
/**
* #var string
*/
private $currency;
/**
* #var string
*/
private $price;
private $webshopItem;
}

Answer 1

UPDATE
You can use an entity listener too, but in that case you'll need to override the default resolver to get the session in your listener:
src/Your/GreatBundle/Resources/config/services.yml
doctrine.orm.default_entity_listener_resolver:
class: Your\GreatBundle\Listener\EntityListenerResolver
arguments: [#service_container]
src/Your/GreatBundle/Listener/EntityListenerResolver
namespace Your\GreatBundle\Listener;
use Doctrine\ORM\Mapping\EntityListenerResolver as EntityListenerResolverInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;
class EntityListenerResolver implements EntityListenerResolverInterface
{
private $instances = [];
private $container;
public function __construct(ContainerInterface $container)
{
$this->container = $container;
}
public function clear($className = null)
{
if ($className === null) {
$this->instances = [];
return;
}
if (isset($this->instances[$className = trim($className, '\\')])) {
unset($this->instances[$className]);
}
}
public function register($object)
{
if ( ! is_object($object)) {
throw new \InvalidArgumentException(sprintf('An object was expected, but got "%s".', gettype($object)));
}
$this->instances[get_class($object)] = $object;
}
public function resolve($className)
{
if (isset($this->instances[$className = trim($className, '\\')])) {
return $this->instances[$className];
}
// Here we are injecting the entire container to the listeners
return $this->instances[$className] = new $className($this->container);
}
}
You might listen to the Doctrine's postLoad event in a service injected with the user's session:
src/Your/GreatBundle/Resources/config/services.yml
services:
price.listener:
class: Your\GreatBundle\Listener\PriceListener
arguments: [#session]
tags:
- { name: doctrine.event_listener, event: postLoad }
src/Your/GreatBundle/Listener/PriceListener.php
namespace Your\GreatBundle\Listener\PriceListener;
use Symfony\Component\HttpFoundation\Session\SessionInterface;
use Doctrine\ORM\Event\LifecycleEventArgs;
use Your\GreatBundle\Entity\WebshopItem;
class PriceListener
{
private $session;
public function __construct(SessionInterface $session)
{
$this->session = $session;
}
public function postLoad(LifecycleEventArgs $event)
{
$entity = $event->getEntity();
if ($entity instanceof WebshopItem) {
$currency = $this->session->get('currency', 'EUR');
$entity->setCurrency(currency);
}
}
}
src/Your/GreatBundle/Entity/WebshopItem.php
namespace Your\GreatBundle\Entity;
class WebshopItem
{
...
// You don't need to persist this...
private $currency = 'EUR';
public function setCurrency($currency)
{
$this->currency = $currency;
}
public function getPrice()
{
foreach ($this->prices as $price) {
if ($price->getCurrency() === $this->currency) {
return ($price->getPrice();
}
}
return null;
}
}

Answer 2

You can query WebshopItem joined with WebshopItemPrice WHERE WebshopItemPrice.currency = $variableFromSesion. For example:
$queryBuilder
->select('WebshopItem, WebshopItemPrice')
->leftJoin('WebshopItemPrice.prices', 'WebshopItemPrice')
->where('WebshopItemPrice.currency = :currency')
->setParameter('currency', $variableFromSesion)
Where $variableFromSesion is a current user currency stored in session. After executing that query (by getResult() ) you can get price by calling $webshopItem->getPrices() - this should return only one result

Answer 3

The trick is not about how to retrieve the data but what to use to do it. Since this depends on the Request object you should go with something service-ish. If you're sure you'll never never use this elsewhere, then go with the twig extension. If your backend code would use it too then use a service, say MyPricePickerService (and get that in the twig extension). Note on twig extension that I cannot find anything that warrants that a new instance is created for every scope, so upon every call to this operation you should use the injected Container (so not a cached Request, or a previous instance of MyPricePickerService)!