title: Make sure user clicked my link through whatsapp
body: <p>I want to build a PHP page and ask people to share my link through WhatsApp. </p>
  
  <p>If user clicks my link through whatsapp, they will be able to see the page content.</p>
  
  <p>If user clicks my link through LINE or Facebook Messenger or something else, they won't be able to see the page content.</p>
  
  <p>Is it possible to do that?</p>