$_FILES in Magento2 ECG : system configuration

Question

How can I use $_FILES (Super global variable )in Magento2 system configuration as per ECG coding standard. I know I can use in simple form like below. where my_file_uploader is name of fieldId

$uploader = $this->_objectManager->create(
  'Magento\MediaStorage\Model\File\Uploader',
  ['fileId' => 'my_file_uploader']
);

But whats is the fieldId in system configuration ?

I have tried several way but couldn't succeed. I have tried

$uploader = $this->_objectManager->create(
      'Magento\MediaStorage\Model\File\Uploader',
      ['fileId' => '[groups][MY_GROUP][fields][import][value]'
    );

but it gives me error like

Undefined index: in /var/www/html/magento21/vendor/magento/framework/File/Uploader.php on line 542

any help will be appreciated

Thanks.

Answer 1

I have follow below steps :

1) Add system configuration

<field id="import" translate="label" type="Namespace\Module\Block\Adminhtml\Form\Field\Import" sortOrder="2" showInDefault="1" showInWebsite="1" showInStore="1">
    <label>Import</label>
    <backend_model>Namespace\Module\Model\Config\Backend\Import</backend_model>
</field>

2) Create Import.php block file and crete import element

<?php

namespace Namespace\Module\Block\Adminhtml\Form\Field;

class Import extends \Magento\Framework\Data\Form\Element\AbstractElement
{

    protected function _construct()
    {
        parent::_construct();
        $this->setType('file');
    }

    public function getElementHtml()
    {
        $html = '';

        $html .= '<input id="time_condition" type="hidden" name="'.$this->getName().'" value="'.time().'" />';

        $html .= '<input id="custom_sample_import" name="customimport" data-ui-id="file-groups-sample-fields-import-value" value="" class="" type="file" />';

        return $html;
    }
}

3) Use below code for uploader

$uploader = $this->_objectManager->create('Magento\MediaStorage\Model\File\Uploader', ['fileId' => 'customimport']);