Introduction

Polder Knowledge EntityService is a service layer to interact with any data storage you might want to use. By using this extra abstraction layer you will be able to create a loose binding with your data storage. In many situations an ORM is used to connect with a database for example. But what if your users are moved to a micro-service? Will you have to adapt your full application? This is where this library comes in.

It gives you the option to interact with any storage like it was a database. Extra functionality like sending an email when a user was created can be added by attaching a listener to the required service.

Usage

The example below shows a very basic setup of a service.

<?php
  // Container is your applications InteroperableContainer    
  $entityManager = $container->get(Doctrine\ORM\EntityManager::class);
  // Repository can be the provided ORMRepository or any other custom repository you want to use.
  $repository = new \PolderKnowledge\EntityService\Repository\Doctrine\ORMRepository($entityManager, MyEntity::class);

  // Setup the service
  $entityService = new \PolderKnowledge\EntityService\EntityService($repository);

  // Ready to fetch the required entity.
  $myObject = $entityService->find(1);

To attach a new event handler simply create your handler class like the example below. And attach it using the attach method of the EntityService

<?php

use Zend\EventManager\EventManagerInterface;

final class MyHandler extends \Zend\EventManager\AbstractListenerAggregate
{
    public function attach(EventManagerInterface $events, $priority = 1)
    {
        // Use positive priorities to attach your handler before execution.
        // Use negative priorities to attach your handler after execution.
        $this->listeners[] = $events->attach('persist', array($this, 'onPersist'), 10);
    }

    public function onPersist(\PolderKnowledge\EntityService\Event\EntityEvent $event)
    {
        // Do your magic

        // Fetch the current entity
        $entity = $event->getParam('entity');

        // Call stop propagation to abort
        // $event->stopPropagation();
    }
}

For more information about the available events look at the events page. When you are not familiar with zend-eventmanager take a look at their docs.

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