Zend Framework 2: Database connection in view helper - php

Question

I found a few other posts relevant to this issue, however i wasn't able to achieve what i wanted so i decided to delete everything and start over with some help...
This is my work so far, which does the job but the data are provided hard coded in an array and i need to create a database connection to fetch those data.
In my module class i have:
public function getViewHelperConfig()
{
return array(
'factories' => array(
'liveStreaming' => function() {
return new LiveStreaming();
},
),
);
}
This is the code i have in my view helper:
namespace Application\View\Helper;
use Zend\View\Helper\AbstractHelper;
class LiveStreaming extends AbstractHelper
{
protected $liveStreamingTable;
public function __invoke()
{
$events = array(
'1' => array('name' => 'Event name',
'sport' => 'Soccer',
'time' => '11:30'),
'2' => array('name' => 'Event name',
'sport' => 'Soccer',
'time' => '17:00'),
);
return $events;
//this is what should be used (or something like that) to get the data from the db...
//return array('events' => $this->getLiveStreamingTable()->fetchAll() );
}
public function getLiveStreamingTable()
{
if (!$this->liveStreamingTable) {
$sm = $this->getServiceLocator();
$this->liveStreamingTable = $sm->get('LiveStreaming\Model\LiveStreamingTable');
}
return $this->liveStreamingTable;
}
}
So, i want to get the $events array from the database. I've created Application\Model\LiveStreaming and Application\Model\LiveStreamingTable (following the instructions of the ZF2 official tutorial) and i need some help proceeding to the next step, which should probably have to do with the service locator.

Answer 1

You seem to be almost there. The only thing missing is the ability to call $this->getServiceLocator(); from within the view helper (as the AbstractHelper doesn't provide this method).
There are two options
Inject the LiveStreamingTable into the view helper directly
inject the ServiceManager itself and create the LiveStreamingTable within the helper
Option 1 Make LiveStreamingTable a dependency of the view helper (type hint in constructor)
namespace Application\View\Helper;
use Zend\View\Helper\AbstractHelper;
use LiveStreaming\Model\LiveStreamingTable;
class LiveStreaming extends AbstractHelper
{
protected $liveStreamingTable;
public function __construct(LiveStreamingTable $liveStreamingTable)
{
$this->liveStreamingTable = $liveStreamingTable;
}
public function getLiveStreamingTable()
{
return $this->liveStreamingTable;
}
}
And the factory becomes:
public function getViewHelperConfig()
{
return array(
'factories' => array(
'liveStreaming' => function($sl) {
// Get the shared service manager instance
$sm = $sl->getServiceLocator();
$liveStreamingTable = $sm->get('LiveStreaming\Model\LiveStreamingTable');
// Now inject it into the view helper constructor
return new LiveStreaming($liveStreamingTable);
},
),
);
}
Option 2 - Implement the ServiceLocatorAwareInterface (making it again a dependency of the view helper)
namespace Application\View\Helper;
use Zend\View\Helper\AbstractHelper;
use Zend\ServiceManager\ServiceLocatorAwareInterface;
use Zend\ServiceManager\ServiceLocatorInterface;
class LiveStreaming extends AbstractHelper implements ServiceLocatorAwareInterface
{
protected $serviceLocator;
protected $liveStreamingTable;
public function __construct(ServiceLocatorInterface $serviceLocator)
{
$this->serviceLocator = $serviceLocator;
}
public function setServiceLocator(ServiceLocatorInterface $serviceLocator);
public function getServiceLocator();
public function getLiveStreamingTable()
{
if (null == $this->liveStreamingTable) {
$this->liveStreamingTable = $this->getServiceLocator()->get('LiveStreaming\Model\LiveStreamingTable');
}
return $this->liveStreamingTable;
}
}
Your factory will then look like:
public function getViewHelperConfig()
{
return array(
'factories' => array(
'liveStreaming' => function($sl) {
// Get the shared service manager instance
$sm = $sl->getServiceLocator();
// Now inject it into the view helper constructor
return new LiveStreaming($sm);
},
),
);
}
Personally, I feel that Option 1 makes more sense from a Dependency Injection (DI) point of view - It's clear that the LiveStreamingTable is what is needed to create the view helper.
Edit
Make sure you have the LiveStreaming\Model\LiveStreamingTable service also registered with the service manager (as we request it in the above code when we did $sm->get('LiveStreaming\Model\LiveStreamingTable');)
// Module.php
public function getServiceConfig()
{
return array(
'factories' => array(
'LiveStreaming\Model\LiveStreamingTable' => function($sm) {
// If you have any dependencies for the this instance
// Such as the database adapter etc either create them here
// or request it from the service manager
// for example:
$foo = $sm->get('Some/Other/Registered/Service');
$bar = new /Directly/Created/Instance/Bar();
return new \LiveStreaming\Model\LiveStreamingTable($foo, $bar);
},
),
);
}