Ajax not working in Magento 2 admin

Question

I'm using ajax in Magento 2 admin. But it not working.

My controller:

class CustomAjax extends \Magento\Backend\App\Action{

protected $resultJsonFactory;

public function __construct(
    \Magento\Backend\App\Action\Context $context,
    \Magento\Framework\Controller\Result\JsonFactory $resultJsonFactory

)
{
    parent::__construct($context);
    $this->resultFactory = $resultJsonFactory;
}

public function execute()
{
    $resultJson = $this->resultJsonFactory->create();

    return $resultJson->setData([
        'messages' => 'Successfully. Params: ',
        'error' => false
    ]);
}
public function indexAction(){
    return $this->resultJsonFactory->create()->setData(['a' => 'b']);
}}

• If I use url of jQuery ajax without isAjax=true it say 302 found error in response.
• If I use isAjax=true for url ajax it say invalid form key....
• When I add form_key: "form key value" in data:{} of ajax it say 404 Forbidden.

Please help me, thank so much!

--- update

My url in this case is http://localhost/magento/admin/mymodule/customAjax/index/key/417a3857c3ee5d1ec2c2c474ce5ce0a217779619d313b12e0d668b950ac80d9d/?isAjax=true

and this is ajax:

jQuery.ajax({
    type:"POST",
    url: ajaxUrl,
    data:{
        form_key: formKey
    },
    beforeSend : function(data){

    },
    success : function(data){

    }
});

formKey in this case is u5XSzd7EmRKQM7kN

But it say 404 Forbidden error.

Answer 1

Seem that your Ajax is missing the form key param. We need to add the form key value to url. For example:

var form = jQuery('#edit_form');
var action = form.attr('action');

//Assume your form action form.attr('action'): http://{admin_url}/custom/ajax/key/f7f0ad18f378d5458e936d216981f1418702a8381da453a094b6273410f2eb0e/

var newActionUrl = action + '?' + encodeURIComponent(form.find('[name="form_key"]').val());

You can see an example: vendor/magento/module-import-export/view/adminhtml/templates/import/form/before.phtml