title: What are the session variables which are to be validated in the whole application after successful Google OAuth Login
body: <p>I have implemented Google OAuth login on my website. A user signs in using his/her Google Account, reaches my welcome page &amp; now on my welcome page &amp; other subsequent pages/scripts what are the variables which I need to validate to authenticate &amp; check whether the user is logged in or not. Right now am just doing this : </p>
  
  <pre><code>checklogin.php (using it in require_once in all my subsequent php scripts)
  
  if(isset ( $_SESSION['access_token'] ))
  {
  
    //logged in 
  }
  else
  {
     //NOT LOGGED IN
  
      header('location:login.php');
  
  } 
  </code></pre>
  
  <p>Do I need to check the value also of the access token &amp; any other security variables to make my login inspection process more robust ? If yes, then how can it be checked ? Or is this check just sufficient enough ?</p>