PropertyWriteSubscriber.php

<?php

namespace App\EventSubscriber;

use ApiPlatform\Core\EventListener\EventPriorities;
use App\Entity\Property;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpKernel\Event\GetResponseForControllerResultEvent;
use Symfony\Component\HttpKernel\KernelEvents;

class PropertyWriteSubscriber implements EventSubscriberInterface
{

    public static function getSubscribedEvents()
    {
        return [
            KernelEvents::VIEW => ['propertyWritten', EventPriorities::PRE_WRITE],
        ];
    }

    public function propertyWritten(GetResponseForControllerResultEvent $event)
    {
        $property = $event->getControllerResult();
        $method = $event->getRequest()->getMethod();

        if (!$property instanceof Property ||
            !in_array($method, [Request::METHOD_POST, Request::METHOD_PUT])) {
            return;
        }

        $property->setPoint(
            sprintf(
                'POINT(%f %f)', 
                (string)$property->getLongitude(),
                (string)$property->getLatitude()
            )
        );
    }
}