title: How to Get Current User in Backend with Firebase in Node.js?
body: <p>I am so confused,
  all the Firebase authentication tutorial online are teaching how to login in frontend,</p>
  
  <p>of course you can get the token and send it to server for verification if its a post request,</p>
  
  <p>but what about normal get request like a page request? I have installed firebase-admin already but i didnt find any method for getting current user........ </p>
  
  <p>i am using node and express</p>
  
  <p>for example</p>
  
  <pre><code>app.get('/', function(req, res) {
      const idToken = (where can i get the token??)
      console.log(idToken);
      res.render('index.ejs');
  });
  </code></pre>