json encode in magento 2

Question

I just wanted to know that what is the right way to print array data into json format. I Know we can use php function json_encode() but is this the right way to print array data? Because i saw one of magento's core file, there was something like this

        if (!$_isValidFormKey || !$_isValidSecretKey) {
        $this->_actionFlag->set('', self::FLAG_NO_DISPATCH, true);
        $this->_actionFlag->set('', self::FLAG_NO_POST_DISPATCH, true);
        if ($this->getRequest()->getQuery('isAjax', false) || $this->getRequest()->getQuery('ajax', false)) {
            $this->getResponse()->representJson(
                $this->_objectManager->get(
                    \Magento\Framework\Json\Helper\Data::class
                )->jsonEncode(
                    ['error' => true, 'message' => $_keyErrorMsg]
                )
            );
        } else {
            $this->_redirect($this->_backendUrl->getStartupPageUrl());
        }
        return false;
    }
    return true;
}

so if we look at this section

$this->getResponse()->representJson(
                $this->_objectManager->get(
                    \Magento\Framework\Json\Helper\Data::class
                )->jsonEncode(
                    ['error' => true, 'message' => $_keyErrorMsg]
                )
            );

we see magento is encoding data using \Magento\Framework\Json\Helper\Data class.

I am working on custom APIs where i need to send data in json format. So please correct me if i am not wrong that we can also print Array data using this \Magento\Framework\Json\Helper\Data class.

Thankyou.

Answer 1

Nowadays, the recommended dependency to inject would be the \Magento\Framework\Serialize\SerializerInterface.

Answer 2

You cannot use \Magento\Framework\Json\Helper\Data using object manager you can use like this

/**
 * @var \Magento\Framework\Json\Helper\Data
 */
protected $jsonHelper;

/**
 * Constructor.
 * 
 * @param \Magento\Framework\Json\Helper\Data $jsonHelper
 */
public function __construct(\Magento\Framework\Json\Helper\Data $jsonHelper)
{
    $this->jsonHelper = $jsonHelper;
}

/**
 * @param array $dataToEncode
 * @return string
 */
public function encodeSomething(array $dataToEncode)
{
    if (!$_isValidFormKey || !$_isValidSecretKey) {
    $this->_actionFlag->set('', self::FLAG_NO_DISPATCH, true);
    $this->_actionFlag->set('', self::FLAG_NO_POST_DISPATCH, true);
    if ($this->getRequest()->getQuery('isAjax', false) || $this->getRequest()->getQuery('ajax', false)) {
        $this->getResponse()->representJson(
            $this->jsonHelper->jsonEncode(
                ['error' => true, 'message' => $_keyErrorMsg]
        );
    } else {
        $this->_redirect($this->_backendUrl->getStartupPageUrl());
    }
    return false;
}
return true;

} }

You can see This Another Example

Answer 3

If you still need to use the old json helper \Magento\Framework\Json\Helper\Data, i.e. you are implementing \Magento\ImportExport\Model\Import\Entity\AbstractEntity that has:

protected $jsonHelper;

built with the old helper by constructor, you still can overwrite the constructor of the abstract class in yours, and use a custom class to override $jsonHelper, like this one:

<?php
namespace Vendor\Module\Model;

use InvalidArgumentException;
use Magento\Framework\Serialize\Serializer\Json;

class JsonSerializer extends Json
{
    /**
     * Serialize data into string
     *
     * @param mixed $data
     * @return string|bool
     * @throws InvalidArgumentException
     */
    public function jsonEncode($data)
    {
        return $this->serialize($data);
    }

    /**
     * Unserialize the given string
     *
     * @param string $string
     * @return mixed
     * @throws InvalidArgumentException
     */
    public function jsonDecode(string $string)
    {
        return $this->unserialize($string);
    }
}