Magento 2 - jQuery validation remote method

Question

I'm developing a custom form with a username that require validation at server side to check if the username exists. How can I apply the remote method of jquery validation plugin in Magento 2?

Answer 1

add remote property for 'data-validate' attribute. example:

<input name="email" id="email" title="<?php /* @escapeNotVerified */ echo __('Email') ?>" value="" class="input-text" type="email" data-validate="{required:true, 'validate-email':true, 'remote':'<?php /* @escapeNotVerified */ echo $block->getValidateEmailAction(); ?>'}"/>

Here $block->getValidateEmailAction(); should be return link. example:

public function getValidateEmailAction()
{
 return $this->getUrl('stackexchange/index/validate', ['_secure' => true]);
}

And validate controller should be

namespace Vendor\Module\Controller\Index;
use Magento\Framework\App\Action\Action;
class Validate extends Action
{
 /**
 * @var \Magento\Framework\Controller\Result\JsonFactory
 */
 protected $resultJsonFactory;
 /**
 * @param \Magento\Framework\App\Action\Context $context
 * @param \Magento\Framework\Controller\Result\JsonFactory $resultJsonFactory
 */
 public function __construct(
 \Magento\Framework\App\Action\Context $context,
 \Magento\Framework\Controller\Result\JsonFactory $resultJsonFactory
 ) {
 $this->resultJsonFactory = $resultJsonFactory;
 parent::__construct($context);
 }
 public function execute()
 {
 $resultJson = $this->resultJsonFactory->create();
 $data = $this->getRequest()->getParam('email');
 $resultJson->setData('true');
 /*
 if(true) {
 $resultJson->setData('true');
 } else {
 $resultJson->setData('That name is already taken, try peter123 instead');
 }
 */
 return $resultJson;
 }
}

• fotfs: I make a controller to handle the validation. public function execute() { return true; } It returns Invalid return type
• Sohel Rana: check updated answer
• Manish: Thanks @SohelRana for this post. Just I want to know when remote validation called on form submit or for texchange if I have text box with this validation. I want to call this validation on text change or focus out from input is there any way to do ??? thanks in advance.
• anujeet: Can I know when I get the response of this remote request I have to show loader till then? Is there a method for this event?
• Jona: Very good ! :) @anujeet if you want to show the loader, you can add 'showLoader: true' to the remote JSON options