使用Google登录检查登录的Google用户

Question

I'm working with the Google Sign-in library.

If I use Google's provided sign in button on my page, it quickly changes states to show that I am logged in before I've taken any action.

Is it possible to detect this signed in state without using Google's default button?

The main issue is that their button doesn't allow for checking for the hosted domain of the logged in account.

Answer 1

I was trying to use the GoogleAuth.currentUser.get() function to get the user, but as the documentation notes:

in a newly-initialized GoogleAuth instance, the current user has not been set. Use the currentUser.listen() method or the GoogleAuth.then() to get an initialized GoogleAuth instance.

Using GoogleAuth.then(onInit, onFailure) as mentioned above correctly retrieves the logged in state of the user.

/**
 * The Sign-In client object.
 */
var auth2;

/**
 * Initializes the Sign-In client.
 */
var initClient = function() {
  gapi.load('auth2', function(){
    /**
     * Retrieve the singleton for the GoogleAuth library and set up the
     * client.
     */
    auth2 = gapi.auth2.init({
        client_id: CLIENT_ID,
        scope: 'profile'
    });

    // Called once auth2 has finished initializing
    auth2.then(checkForLoggedInUser, onFailure);

  });
};

function checkForLoggedInUser() {
  var user = auth2.currentUser.get();
  var profile = user.getBasicProfile();
  console.log('Email: ' + profile.getEmail());
}

Answer 2

You can use the GoogleAuth.isSignedIn.get() method:

// 1. Make gapi.auth2 available (using gapi.load("auth2", ...))
// 2. Initialize the library (using gapi.init({ ... }))
const isSignedIn = gapi.auth2.getAuthInstance().isSignedIn.get();

isSignedIn is true if the user is signed to Google, otherwise false .