observer to fire on system admin config display

Question

In my plugin I'm trying to create an event observer that should fire when I display my plugin system configuration page.

At first I created a new db table f24_staging by \Vendor\MyApp\Setup\UpgradeSchema.php I launched php bin/magento setup:upgrade from the terminal and it's ok;

This is the complete path of system.xml: \Vendor\MyApp\etc\adminhtml\system.xml

I already have got events.xml in the parent folder, that is \Vendor\MyApp\etc\events.xml

for example, here I catch the customer registration process

<event name="customer_register_success">
        <observer name="sMSHandleCustomerSaveAfter" instance="Vendor\MyApp\Observer\CustomerRegisterObserver" />
    </event>

I tried to create a new event in the same events.xml file, like this:

<event name="admin_system_config_changed_section">
        <observer
            name="templates_list"
            instance="Vendor\MyApp\Observer\F24ApiOptionsObserver"
        /> 
    </event> 

then I created my F24ApiOptionsObserver under Vendor\MyApp\Observer, like this:

class F24ApiOptionsObserver implements \Magento\Framework\Event\ObserverInterface
{
 public function __construct(
        \Vendor\MyApp\Helper\Data $helper,
        \Psr\Log\LoggerInterface $logger
     )
     {
         $this->helper = $helper;
         $this->_logger = $logger;
     }
public function execute(\Magento\Framework\Event\Observer $observer)
{
    $event = $observer->getEvent();
    $this->_logger('event :', $event);
    $objectManager =   \Magento\Framework\App\ObjectManager::getInstance();
    $resource = $objectManager->get('Magento\Framework\App\ResourceConnection');
    $connection = $resource->getConnection('\Magento\Framework\App\ResourceConnection::DEFAULT_CONNECTION'); 
    $f24_staging = $resource->getTableName('f24_staging');
    $storeId = (int) $this->getRequest()->getParam('store', 0);
    $apiKey = $this->helper->getConfig('myapp/generali/api_key', $storeId);
    $templates_res = $this->helper->apiCall('https://www.app.myapp.com/api/v0.3/GetTemplate', $apiKey);
    $templates_xml = simplexml_load_string(utf8_encode($templates_res));
    $json_templates = json_encode($templates_xml);
    $this->helper->trace('elenco templates :', $json_templates);
    $insert = "insert into $f24_staging set id_api_call='1',f24_options_value='$json_templates'";
    $connection->query($insert);
}

}

The observer should add data to my custom db table when I display system admin config page, but the event is not firing. Anyone could help me?

Answer 1

At last I found a solution.

This is my events.xml file

<event name="layout_generate_blocks_before">
        <observer name="f24apioptions" instance="Vendor\MyApp\Observer\F24ApiOptions" />
    </event>  

Then my Observer, path => \Vendor\MyApp\Observer\F24ApiOptions

<?php

namespace Vendor\MyApp\Observer;

class F24ApiOptions implements \Magento\Framework\Event\ObserverInterface
{
    public function __construct(
        \Vendor\MyApp\Helper\Data $helper
    ) {
        $this->helper = $helper;
    }

    

    public function execute(\Magento\Framework\Event\Observer $observer)
    {
        $event = $observer->getEvent();
        if ($event['full_action_name'] == 'adminhtml_system_config_edit') {
           
            $this->helper->saveTemplateList();
            $this->helper->saveNumeratorList();
            $this->helper->savePdcList();
        }
        
    }
}