Google Sign-in callback functions

index.ejs

<script>
  // called by google client
  function onSignIn(googleUser) {
    var id_token = googleUser.getAuthResponse().id_token;
    // never log these out on a real app
    console.log('id_token: ', id_token);
    var profile = googleUser.getBasicProfile();
    console.log('ID: ' + profile.getId());
    console.log('Name: ' + profile.getName());
    console.log('Image URL: ' + profile.getImageUrl());
    console.log('Email: ' + profile.getEmail());
    // verification
    var xhr = new XMLHttpRequest();
    xhr.open('POST', '/tokensignin');
    xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    xhr.onload = function() {
      console.log('Server returned: ' + xhr.responseText);
    };
    xhr.send('idtoken=' + id_token);
  }
  // on sign out
  function signOut() {
    var auth2 = gapi.auth2.getAuthInstance();
    auth2.signOut().then(function() {
      console.log('User signed out.');
    });
  }
</script>