Prestashop file uploader usage

admincmscontroller.php

<?php

class AdminCmsController extends AdminCmsControllerCore
{
	public function renderForm()
    {
        if (!$this->loadObject(true)) {
            return;
        }

        if (Validate::isLoadedObject($this->object)) {
            $this->display = 'edit';
        } else {
            $this->display = 'add';
        }

        $this->initToolbar();
        $this->initPageHeaderToolbar();

        $categories = CMSCategory::getCategories($this->context->language->id, false);
        $html_categories = CMSCategory::recurseCMSCategory($categories, $categories[0][1], 1, $this->getFieldValue($this->object, 'id_cms_category'), 1);

        $this->fields_form = array(
            'tinymce' => true,
            'legend' => array(
                'title' => $this->l('CMS Page'),
                'icon' => 'icon-folder-close'
            ),
            'input' => array(
                // custom template
                array(
                    'type' => 'select_category',
                    'label' => $this->l('CMS Category'),
                    'name' => 'id_cms_category',
                    'options' => array(
                        'html' => $html_categories,
                    ),
                ),
                array(
                    'type' => 'text',
                    'label' => $this->l('Meta title'),
                    'name' => 'meta_title',
                    'id' => 'name', // for copyMeta2friendlyURL compatibility
                    'lang' => true,
                    'required' => true,
                    'class' => 'copyMeta2friendlyURL',
                    'hint' => $this->l('Invalid characters:').' &lt;&gt;;=#{}'
                ),
                array(
                    'type' => 'text',
                    'label' => $this->l('Meta description'),
                    'name' => 'meta_description',
                    'lang' => true,
                    'hint' => $this->l('Invalid characters:').' &lt;&gt;;=#{}'
                ),
                array(
                    'type' => 'tags',
                    'label' => $this->l('Meta keywords'),
                    'name' => 'meta_keywords',
                    'lang' => true,
                    'hint' => array(
                        $this->l('To add "tags" click in the field, write something, and then press "Enter."'),
                        $this->l('Invalid characters:').' &lt;&gt;;=#{}'
                    )
                ),
                array(
                    'type' => 'text',
                    'label' => $this->l('Friendly URL'),
                    'name' => 'link_rewrite',
                    'required' => true,
                    'lang' => true,
                    'hint' => $this->l('Only letters and the hyphen (-) character are allowed.')
                ),
                array(
                    'type' => 'textarea',
                    'label' => $this->l('Page content'),
                    'name' => 'content',
                    'autoload_rte' => true,
                    'lang' => true,
                    'rows' => 5,
                    'cols' => 40,
                    'hint' => $this->l('Invalid characters:').' <>;=#{}'
                ),
                array(
                    'type' => 'switch',
                    'label' => $this->l('Indexation by search engines'),
                    'name' => 'indexation',
                    'required' => false,
                    'class' => 't',
                    'is_bool' => true,
                    'values' => array(
                        array(
                            'id' => 'indexation_on',
                            'value' => 1,
                            'label' => $this->l('Enabled')
                        ),
                        array(
                            'id' => 'indexation_off',
                            'value' => 0,
                            'label' => $this->l('Disabled')
                        )
                    ),
                ),
                array(
                    'type' => 'switch',
                    'label' => $this->l('Displayed'),
                    'name' => 'active',
                    'required' => false,
                    'is_bool' => true,
                    'values' => array(
                        array(
                            'id' => 'active_on',
                            'value' => 1,
                            'label' => $this->l('Enabled')
                        ),
                        array(
                            'id' => 'active_off',
                            'value' => 0,
                            'label' => $this->l('Disabled')
                        )
                    ),
                ),
                array(
                	'type' => 'file',
                	'label' => $this->l('Attached files'),
                	'name' => 'attached_files',
                	'multiple' => true,
                	'required' => false,
                ),
            ),
            'submit' => array(
                'title' => $this->l('Save'),
            ),
            'buttons' => array(
                'save_and_preview' => array(
                    'name' => 'viewcms',
                    'type' => 'submit',
                    'title' => $this->l('Save and preview'),
                    'class' => 'btn btn-default pull-right',
                    'icon' => 'process-icon-preview'
                )
            )
        );

        if (Shop::isFeatureActive()) {
            $this->fields_form['input'][] = array(
                'type' => 'shop',
                'label' => $this->l('Shop association'),
                'name' => 'checkBoxShopAsso',
            );
        }

        if (Validate::isLoadedObject($this->object)) {
            $this->context->smarty->assign('url_prev', $this->getPreviewUrl($this->object));
        }

        $this->tpl_form_vars = array(
            'active' => $this->object->active,
            'PS_ALLOW_ACCENTED_CHARS_URL', (int)Configuration::get('PS_ALLOW_ACCENTED_CHARS_URL')
        );

        $smarty = Context::getContext()->smarty;
        $smarty->assign('list', 'list');

        return AdminController::renderForm();
    }

    public function initFormAttachments()
    {


        $helper = new HelperUploader();
        return $helper->render();
    }

    public function postProcess()
    {
    	if ($_FILES)
    		$this->processUploads();    	

    	parent::postProcess();
    }

    private function processUploads()
    {   


    	$files_being_uploaded = $_FILES["attached_files"];    	
        $savepath = _PS_ROOT_DIR_.DIRECTORY_SEPARATOR.'upload'.DIRECTORY_SEPARATOR.'cms_uploads/';

        $uploader = new Uploader("attached_files");
        $uploader->setCheckFileSize(false);        
        $uploader->setSavePath($savepath);
        $file = $uploader->process();               

    	return true;
    }

    private function processUploadsErrors($params=null)
    {

    }
}