Event in Magento-2?

Question

I'm using

<event name="controller_action_predispatch">

This event not working when I refresh category page second time .

If anyone knows please explain me.

public function saveVisitorData()
    {      
        $currentUrl = $this->_urlInterface->getCurrentUrl();       
        $s = $this->sValues();      
        $this->setUrl($currentUrl);     
        $this->setS1($s[1]);
        $this->setS2($s[2]);
         $this->save();
          }
 public function getCookieValue($val)
    {
        $value = $this->_cookieManager->getCookie($val);
        return $value;
    }  
    public function setCookie($cn, $v1)
    {
        $metadata = $this->cookieMetadataFactory->createPublicCookieMetadata()->setDuration(static::COOKIE_LIFETIME)->setPath($this->sessionManager->getCookiePath())->setDomain($this->sessionManager->getCookieDomain());        
        $this->_cookieManager->setPublicCookie($cn, $v1, $metadata);

    }

public function sValues()
    {
        $s = array();

        $s[1] = $this->_request->getParam('s1');
        $s[2] = $this->_request->getParam('s2');
        if ($s[1]) {
            $this->setCookie(self::COOKIE_s1, $s[1]);
        } else {
            $s[1] = $this->getCookieValue(self::COOKIE_s1);
        }
        if ($s[2]) {
            $this->setCookie(self::COOKIE_s2, $s[2]);
        } else {
            $s[2] = $this->getCookieValue(self::COOKIE_s2);
        }
        return $s;
    }

observer.php

public function execute(Observer $observer)
    {        
       $curModule = $observer->getEvent()->getControllerAction()->getRequest()->getFullActionName();
        if($curModule != 'customer_section_load'){
            echo 'In Observer';
            $this->_modelVisitor->saveVisitorData(); 
        }

    }

Answer 1

controller_action_predispatch event will not be called when FPC is turned ON. You have to use the event controller_front_send_response_before which will be called irrespective of the FPC running status.

Answer 2

in this case you can use following event

 <event name="controller_action_predispatch_customer_section_load" >

No need to check that condition