How to setup a Translate Controller Plugin in Zend Framework 3

Sometimes in our Zend Framework 3 multi-language application, we could need to access to Zend Translator component directly from Controllers. For example, when we have to translate a string to return in a JsonModel.

So, let’s see how to write a very simple Controller Plugin that will help us to save a lot of code (and time).

Following explanation will assume we just have at least a Skeleton ZF3 Application with working Zend Translator component.

First of all, we have to write our plugin that will take Zend Translator object in constructor and will wrap its translate() method. So let’s add following file module/Application/src/Controller/Plugin/TranslatePlugin.php:

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<?php
namespace Application\Controller\Plugin;

class TranslatorPlugin extends \Zend\Mvc\Controller\Plugin\AbstractPlugin
{
    /**
     * @var \Zend\I18n\Translator\Translator
     */
    protected $translator;

    function __construct(\Zend\I18n\Translator\Translator $translator)
    {
        $this->translator = $translator;
    }

    public function translate($string)
    {
        return $this->translator->translate($string);
    }
}

Now, we need a Factory class to initialize our plugin and inject in it the Zend Translator component. That class will be placed in module/Application/src/Controller/Plugin/Factory/TranslatorPluginFactory.php and will be something like:

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<?php
namespace Application\Controller\Plugin\Factory;

class TranslatorPluginFactory implements \Zend\ServiceManager\Factory\FactoryInterface
{
    public function __invoke(\Interop\Container\ContainerInterface $container, $requestedName, array $options = null)
    {
        if (!$container->has('translator')) {
            throw new \Exception("Zend I18n Translator not configured");
        }
  
        $translator = $container->get('translator');
        return new \Application\Controller\Plugin\TranslatorPlugin($translator);
    }
}

Finally, we have to configure ZF3 application to load plugin by adding following lines to module/Application/config/module.config.php file:

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<?php
return [
    'controller_plugins' => [
        'factories' => [
            'translator' => \Application\Controller\Plugin\Factory\TranslatorPluginFactory::class,
        ],
    ],
    ...
];

At this point, we can easily invoke our new plugin from each controller in application. For example we can do as following:

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<?php
namespace Application\Controller;
use Zend\Mvc\Controller\AbstractActionController;
use Zend\View\Model\ViewModel;

class IndexController extends AbstractActionController
{
    public function indexAction()
    {
        $translatedMessage = $this->translator()->translate('Message to be translated');
      
        return new JsonModel('message' => $translatedMessage);
    }
}