Doctrine

webpush:
    doctrine_mapping: true

<?php

declare(strict_types=1);

namespace App\Entity;

use Doctrine\ORM\Mapping as ORM;
use WebPush\Subscription as WebPushSubscription;

#[ORM\Table(name: 'subscriptions')]
#[ORM\Entity]
class Subscription extends WebPushSubscription
{
    #[ORM\Id]
    #[ORM\Column(type: 'integer')]
    #[ORM\GeneratedValue(strategy: 'AUTO')]
    private ?int $id = null;

    #[ORM\ManyToOne(targetEntity: User::class, cascade: ['persist'], inversedBy: 'subscriptions')]
    #[ORM\JoinColumn(name: 'user_id', referencedColumnName: 'id', nullable: true)]
    
    private ?User $user;

    public function getId(): ?int
    {
        return $this->id;
    }

    public function getUser(): ?User
    {
        return $this->user;
    }

    public function setUser(?User $user): self
    {
        $this->user = $user;

        return $this;
    }

    // We need to override this method as it returns a WebPush\Subscription and we want an entity
    public static function createFromString(string $input): self
    {
        $base = BaseSubscription::createFromString($input);
        $object = new self($base->getEndpoint());
        $object->withContentEncodings($base->getSupportedContentEncodings());
        foreach ($base->getKeys()->all() as $k => $v) {
            $object->getKeys()->set($k, $v);
        }

        return $object;
    }
}

<?php

declare(strict_types=1);

namespace App\Entity;

use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;
use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Table(name="users")
 * @ORM\Entity
 */
#[ORM\Table(name: 'users')]
#[ORM\Entity]
class User //Usual interface here
{
    //Usual user stuff here

    #[ORM\OneToMany(targetEntity: Subscription::class, mappedBy: 'user')]
    private Collection $subscriptions;

    public function __construct()
    {
        $this->notifications = new ArrayCollection();
    }

    /**
     * @return Notification[]
     */
    public function getSubscriptions(): array
    {
        return $this->notifications->toArray();
    }

    public function addSubscription(Subscription $subscription): self
    {
        $subscription->setUser($this);
        $this->subscriptions->add($subscription);

        return $this;
    }

    public function removeSubscription(Subscription $subscription): self
    {
        $child->setUser(null);
        $this->subscriptions->removeElement($subscription);

        return $this;
    }
}

$subscriptions = $user->getSubscriptions();
foreach ($subscriptions as $subscription) {
    $report = $this->webPush->send($notification, $subscription);
    if ($report->isSubscriptionExpired()) {
        //...Remove this subscription
    }
}