How to add a custom view helper in zend framework2? - model-view-controller

Question

I used the skeleton zf2 application from github

Answer 1

here is an excerpt from the ZF2 reference that should get you started:
14.4.2. Registering Helpers Zend\View\Renderer\PhpRenderer composes a plugin broker for managing helpers, specifically an instance of
Zend\View\HelperBroker, which extends the base plugin broker in order
to ensure we have valid helpers available. The HelperBroker by default
uses Zend\View\HelperLoader as its helper locator. The HelperLoader is
a map-based loader, which means that you will simply map the
helper/plugin name by which you wish to refer to it to the actual
class name of the helper/plugin.
Programmatically, this is done as follows:
// $view is an instance of PhpRenderer
$broker = $view->getBroker();
$loader = $broker->getClassLoader();
// Register singly:
$loader->registerPlugin('lowercase', 'My\Helper\LowerCase');
// Register several:
$loader->registerPlugins(array(
'lowercase' => 'My\Helper\LowerCase',
'uppercase' => 'My\Helper\UpperCase',
));
Within an MVC application, you will typically simply pass a map of
plugins to the class via your configuration.
// From within a configuration file
return array(
'di' => array('instance' => array(
'Zend\View\HelperLoader' => array('parameters' => array(
'map' => array(
'lowercase' => 'My\Helper\LowerCase',
'uppercase' => 'My\Helper\UpperCase',
),
)),
)),
);
The above can be done in each module that needs to register helpers
with the PhpRenderer; however, be aware that another module can
register helpers with the same name, so order of modules can impact
which helper class will actually be registered!
14.4.3. Writing Custom Helpers Writing custom helpers is easy. We recommend extending Zend\View\Helper\AbstractHelper, but at the
minimum, you need only implement the Zend\View\Helper interface:
namespace Zend\View;
interface Helper
{
/**
* Set the View object
*
* #param Renderer $view
* #return Helper
*/
public function setView(Renderer $view);
/**
* Get the View object
*
* #return Renderer
*/
public function getView();
}
If you want your helper to be capable of being invoked as if it were a
method call of the PhpRenderer, you should also implement an
__invoke() method within your helper.
As previously noted, we recommend extending
Zend\View\Helper\AbstractHelper, as it implements the methods defined
in Helper, giving you a headstart in your development.
Once you have defined your helper class, make sure you can autoload
it, and then register it with the plugin broker.
Here is an example helper, which we're titling "SpecialPurpose"
namespace My\View\Helper;
use Zend\View\Helper\AbstractHelper;
class SpecialPurpose extends AbstractHelper
{
protected $count = 0;
public function __invoke()
{
$this->count++;
$output = sprintf("I have seen 'The Jerk' %d time(s).", $this->count);
return htmlspecialchars($output, ENT_QUOTES, 'UTF-8');
}
}
Then assume that when we register it with the plugin broker, we map it
to the string "specialpurpose".
Within a view script, you can call the SpecialPurpose helper as many
times as you like; it will be instantiated once, and then it persists
for the life of that PhpRenderer instance.
// remember, in a view script, $this refers to the Zend_View instance.
echo $this->specialPurpose();
echo $this->specialPurpose();
echo $this->specialPurpose();
The output would look something like this:
I have seen 'The Jerk' 1 time(s). I have seen 'The Jerk' 2 time(s). I
have seen 'The Jerk' 3 time(s).