Preventing automatic sign-in when using Google+ Sign-In

Question

I am in the process of integrating Google+ sign in with my site, which also lets users sign in with Twitter and Facebook. The sign in page of the site therefore has 3 button

Answer 1

I solved this by adding a click handler to my Google sign-in button. The click handler sets a global Javascript variable google_sign_in to true. When the onSuccess() handler fires (whether automatically on page load, or manually when the user clicks the sign-in button), it first checks whether google_sign_in == true and only then does it continue signing the user in:

<div id="google-signin2" onclick="return do_click_google_signin();"></div>

<script>
    var google_sign_in = false; // assume

    function do_click_google_signin() {
        google_sign_in = true;
    }

    function onSuccess( googleUser ) {
        if ( google_sign_in ) {
            // Process sign-in
        }
    }

    // Other redundant login stuff not shown...
</script>

Answer 2

I am using https://developers.google.com/identity/sign-in/web/build-button to build the sign in button for my web app which gives the user a choice to log in through either Facebook or Google. This code is pretty easy for obtaining the Id_token. However it also came with automatic signing in of the user if the user is already signed in.

Thus, adding the following snippet in the beginning of the script helped me control the signup procedure.

    window.onbeforeunload = function(e){
      gapi.auth2.getAuthInstance().signOut();
    };

Thanks!

Answer 3

I had this issue and used auth2.disconnect()

function onSignIn(googleUser) {
    var profile = googleUser.getBasicProfile();
    var auth2 = gapi.auth2.getAuthInstance();
    auth2.disconnect();

    //do other stuff
}

Edit: you need to store the token before you disconnect because in some cases id_token will become null after disconnect:

function onSignIn(googleUser) {
    var profile = googleUser.getBasicProfile();
    var idToken=profile.id_token;
    googleUser.disconnect()

    //use idToken for server side verification
}

If i'm correct you have your own sign in mechanism for your site and just need google sign in to sign up a user on verified email. in this case you can easily disconnect after you get the profile info. Next time you load the page you will see "sign in" button instead of "signed in " button.

Answer 4

I too has same issue this how i fixed it.I may not sure this is a stander way to do it but still it works fine with me...

add this Google JS from google developer

<script src="https://apis.google.com/js/platform.js" async defer></script>
<script>

function onSuccessG(googleUser) {
        var profile = googleUser.getBasicProfile();
        console.log('ID: ' + profile.getId()); // Do not send to your backend! Use an ID token instead.
        console.log('Name: ' + profile.getName());
        console.log('Image URL: ' + profile.getImageUrl());
        console.log('Email: ' + profile.getEmail());
}
function onFailureG(error) {
    console.log(error);
}
function renderGmail() {

  gapi.signin2.render('my-signin2', {
    'scope': 'https://www.googleapis.com/auth/plus.login',
    'width': 0,
    'height': 0,
    'longtitle': true,
    'theme': 'dark',
    'onsuccess': onSuccessG,
    'onfailure': onFailureG
  });
}

Now add html link and onClick call this renderGmail() function.

<a href="javascript:void(0)" onclick="renderGmail();"> SignUp with Gmail</a>

I hope this works...