Create a Helper with Magento 2

Why create a Helper ?
Helper can be called everywhere you want if you inject it on the wanted class.
You can have “generic” method in order to avoid duplicate code.

Do you remember the last configuration we created ?
We added a constant string on the file app/code/Maxime/Jobs/Block/Department/View.php.
But, if you want to call the configuration on another class, you will have to instanciate this constant too.
So we will put it on a helper.

Helper creation

You can create the file :
app/code/Maxime/Jobs/Helper/Data.php

With :

<?php

namespace Maxime\Jobs\Helper;

class Data extends \Magento\Framework\App\Helper\AbstractHelper
{
    const LIST_JOBS_ENABLED = 'jobs/department/view_list';

    /**
     * Return if display list is enabled on department view
     * @return bool
     */
    public function getListJobEnabled() {
        return $this->scopeConfig->getValue(
            self::LIST_JOBS_ENABLED,
            \Magento\Store\Model\ScopeInterface::SCOPE_STORE
        );
    }
}

It’s a little class with the constant which contains the XML path of the configuration. And a method to retrive the value of the config. If the path changes, you will have to change it only on this file.

So we have to update our block class.

Call an Halper with Magento 2

Reopen the file :
app/code/Maxime/Jobs/Block/Department/View.php

And replace it with this content :

<?php
namespace Maxime\Jobs\Block\Department;
class View extends \Magento\Framework\View\Element\Template
{
    protected $_jobCollection = null;

    protected $_department;

    protected $_job;

    protected $_helper;

    /**
     * @param \Magento\Framework\View\Element\Template\Context $context
     * @param \Maxime\Jobs\Model\Department $department
     * @param \Maxime\Jobs\Model\Job $job
     * @param \Maxime\Jobs\Helper\Data $helper
     * @param array $data
     */
    public function __construct(
        \Magento\Framework\View\Element\Template\Context $context,
        \Maxime\Jobs\Model\Department $department,
        \Maxime\Jobs\Model\Job $job,
        \Maxime\Jobs\Helper\Data $helper,
        array $data = []
    ) {
        $this->_department = $department;

        $this->_job = $job;

        $this->_helper = $helper;

        parent::__construct(
            $context,
            $data
        );
    }

    /**
     * @return $this
     */
    protected function _prepareLayout()
    {
        parent::_prepareLayout();

        // Get department
        $department = $this->getLoadedDepartment();

        // Title is department's name
        $title = $department->getName();
        $description = __('Look at the jobs we have got for you');
        $keywords = __('job,hiring');

        $this->getLayout()->createBlock('Magento\Catalog\Block\Breadcrumbs');

        if ($breadcrumbsBlock = $this->getLayout()->getBlock('breadcrumbs')) {
            $breadcrumbsBlock->addCrumb(
                'jobs',
                [
                    'label' => __('We are hiring'),
                    'title' => __('We are hiring'),
                    'link' => $this->getListJobUrl() // No link for the last element
                ]
            );
            $breadcrumbsBlock->addCrumb(
                'job',
                [
                    'label' => $title,
                    'title' => $title,
                    'link' => false // No link for the last element
                ]
            );
        }

        $this->pageConfig->getTitle()->set($title);
        $this->pageConfig->setDescription($description);
        $this->pageConfig->setKeywords($keywords);


        $pageMainTitle = $this->getLayout()->getBlock('page.main.title');
        if ($pageMainTitle) {
            $pageMainTitle->setPageTitle($title);
        }

        return $this;
    }

    protected function _getDepartment()
    {
        if (!$this->_department->getId()) {
            // our model is already set in the construct
            // but I put this method to load in case the model is not loaded
            $entityId = $this->_request->getParam('id');
            $this->_department = $this->_department->load($entityId);
        }
        return $this->_department;
    }

    public function getLoadedDepartment()
    {
        return $this->_getDepartment();
    }

    public function getListJobUrl(){
        return $this->getUrl('jobs/job');
    }

    protected function _getJobsCollection(){
        if($this->_jobCollection === null && $this->_department->getId()){
            $jobCollection = $this->_job->getCollection()
                ->addFieldToFilter('department_id', $this->_department->getId())
                ->addStatusFilter($this->_job, $this->_department);
            $this->_jobCollection = $jobCollection;
        }
        return $this->_jobCollection;
    }

    public function getLoadedJobsCollection()
    {
        return $this->_getJobsCollection();
    }

    public function getJobUrl($job){
        if(!$job->getId()){
            return '#';
        }

        return $this->getUrl('jobs/job/view', ['id' => $job->getId()]);
    }

    public function getConfigListJobs() {
        return $this->_helper->getListJobEnabled();
    }
}

– The LIST_JOBS_ENABLED constant doesn’t exist anymore
– We inject our helper on __construct method
– The getConfigListJobs method call the helper

On the front office, no change. The list display will always depends on the configuration value.