How can I resolve dependencies to a controller that is testable?
How it works: A URI is routed to a Controller, a Controller may have dependencies to perform a certain task.
<?php
require 'vendor/autoload.php';
/*
* Registry
* Singleton
* Tight coupling
* Testable?
*/
$request = new Example\Http\Request();
Example\Dependency\Registry::getInstance()->set('request', $request);
$controller = new Example\Controller\RegistryController();
$controller->indexAction();
/*
* Service Locator
*
* Testable? Hard!
*
*/
$request = new Example\Http\Request();
$serviceLocator = new Example\Dependency\ServiceLocator();
$serviceLocator->set('request', $request);
$controller = new Example\Controller\ServiceLocatorController($serviceLocator);
$controller->indexAction();
/*
* Poor Man
*
* Testable? Yes!
* Pain in the ass to create with many dependencies, and how do we know specifically what dependencies a controller needs
* during creation?
* A solution is the Factory, but you would still need to manually add every dependencies a specific controller needs
* etc.
*
*/
$request = new Example\Http\Request();
$controller = new Example\Controller\PoorManController($request);
$controller->indexAction();
This is my interpretation of the design pattern examples
Registry:
- Singleton
- Tight coupling
- Testable? No
Service Locator
- Testable? Hard/No (?)
Poor Man Di
- Testable
- Hard to maintain with many dependencies
Registry
<?php
namespace Example\Dependency;
class Registry
{
protected $items;
public static function getInstance()
{
static $instance = null;
if (null === $instance) {
$instance = new static();
}
return $instance;
}
public function set($name, $item)
{
$this->items[$name] = $item;
}
public function get($name)
{
return $this->items[$name];
}
}
Service Locator
<?php
namespace Example\Dependency;
class ServiceLocator
{
protected $items;
public function set($name, $item)
{
$this->items[$name] = $item;
}
public function get($name)
{
return $this->items[$name];
}
}
How can I resolve dependencies to a controller that is testable?