Proper way to check if many-to-many relation exists - Symfony2/Doctrine - symfony

Question

Let's suppose I have two entities User and Product related by a Many-to-Many relationship with Doctrine.
I would like to know the best way to handle a $user->hasProduct($product) method for my User entity that returns true is relation exists or false if not.
I'm currently doing this :
public function hasProduct($id)
{
foreach($this->getProducts() as $product) {
if($product->getId() == $id) {
return true;
}
}
return false;
}
But i'm not sure it's the best way, especially if there is many relations in the loop.
If someone has something better, let me know :)

Answer 1

Your function getProducts gives you an ArrayCollection.
Just do
if($user->getProducts()->contains($product)) //the real product object not the id
//your stuff
Edit :
For twig template :
{% if product in user.products %}
//your stuff
{% endif %}

Answer 2

I was struggling with the same problem, and came across this blog entry which solved this problem by making use of Doctrine Filters.
If I understand your problem correctly and you have three tables (user, user_product and product) you should be able to rewrite your hasProduct($id) function like this:
use Doctrine\Common\Collections\Criteria;
public function hasProduct(int $productId): bool {
$criteria = Criteria::create();
$criteria->where(Criteria::expr()->eq('id', $productId));
if(count($this->products->matching($criteria)) > 0) {
return true;
}
return false;
}
When running this code, Doctrine does not load all the Products linked to the User. It in fact only queries the cross reference table (user_product).