How to Logout of an Application Where I Used OAuth2 To Login With Google?

Question

In my application, I implemented Google signout using jsapi.

I used the url https://www.googleapis.com/oauth2/v1/tokeninfo?access_token=xxxxxx to connect to Google and then https://www.googleapis.com/plus/v1/people/xxxxxx to get user data from google profile.

Now I need to signout the user from Google while clicking a button from my application. How can I implement this in JavaScript, or at least it must ask the Google login page every time the user signs in.

I have tried approval_prompt=force, but seems not to be working.

Answer 1

Overview of OAuth: Is the User Who He/She Says He/She is?:

I'm not sure if you used OAuth to login to Stack Overflow, like the "Login with Google" option, but when you use this feature, Stack Overflow is simply asking Google if it knows who you are:

"Yo Google, this Vinesh fella claims that vinesh.e@gmail.com is him, is that true?"

If you're logged in already, Google will say YES. If not, Google will say:

"Hang on a sec Stack Overflow, I'll authenticate this fella and if he can enter the right password for his Google account, then it's him".

When you enter your Google password, Google then tells Stack Overflow you are who you say you are, and Stack Overflow logs you in.

When you logout of your app, you're logging out of your app:

Here's where developers new to OAuth sometimes get a little confused... Google and Stack Overflow, Assembla, Vinesh's-very-cool-slick-webapp, are all different entities, and Google knows nothing about your account on Vinesh's cool webapp, and vice versa, aside from what's exposed via the API you're using to access profile information.

When your user logs out, he or she isn't logging out of Google, he/she is logging out of your app, or Stack Overflow, or Assembla, or whatever web application used Google OAuth to authenticate the user.

In fact, I can log out of all of my Google accounts and still be logged into Stack Overflow. Once your app knows who the user is, that person can log out of Google. Google is no longer needed.

With that said, what you're asking to do is log the user out of a service that really doesn't belong to you. Think about it like this: As a user, how annoyed do you think I would be if I logged into 5 different services with my Google account, then the first time I logged out of one of them, I have to login to my Gmail account again because that app developer decided that, when I log out of his application, I should also be logged out of Google? That's going to get old really fast. In short, you really don't want to do this...

Yeh yeh, whatever, I still want to log the user out Of Google, just tell me how do I do this?

With that said, if you still do want to log a user out of Google, and realize that you may very well be disrupting their workflow, you could dynamically build the logout url from one of their Google services logout button, and then invoke that using an img element or a script tag:

<script type="text/javascript" 
    src="https://mail.google.com/mail/u/0/?logout&hl=en" />

OR

<img src="https://mail.google.com/mail/u/0/?logout&hl=en" />

OR

window.location = "https://mail.google.com/mail/u/0/?logout&hl=en";

If you redirect your user to the logout page, or invoke it from an element that isn't cross-domain restricted, the user will be logged out of Google.

Note that this does not necessarily mean the user will be logged out of your application, only Google. :)

Summary:

What's important for you to keep in mind is that, when you logout of your app, you don't need to make the user re-enter a password. That's the whole point! It authenticates against Google so the user doesn't have to enter his or her password over and over and over again in each web application he or she uses. It takes some getting used to, but know that, as long as the user is logged into Google, your app doesn't need to worry about whether or not the user is who he/she says he/she is.

I have the same implementation in a project as you do, using the Google Profile information with OAuth. I tried the very same thing you're looking to try, and it really started making people angry when they had to login to Google over and over again, so we stopped logging them out of Google. :)

Answer 2

You can log out and redirect to your site:

var logout = function() {
    document.location.href = "https://www.google.com/accounts/Logout?continue=https://appengine.google.com/_ah/logout?continue=http://www.example.com";
}

Answer 3

For me, it works (java - android)

void RevokeAcess()
{
    try{
    HttpClient client = new DefaultHttpClient();
    HttpPost post = new HttpPost("https://accounts.google.com/o/oauth2/revoke?token="+ACCESS_TOKEN);
    org.apache.http.HttpResponse response = client.execute(post);
    }
    catch(IOException e)
    {
    }
    CookieManager.getInstance().removeAllCookie(); // this is clear the cookies which tends to same user in android web view
}

You have to call this function in AsyncTask in android

Answer 4

To logout from the app only but not the Gmail:

window.gapi.load('auth2', () => {
      window.gapi.auth2
        .init({
          client_id:
            '<Your client id configired on google console>'
        })
        .then(() => {
          window.gapi.auth2
            .getAuthInstance()
            .signOut()
            .then(function() {
              console.log('User signed out.');
            });
        });
    });

I'm using above in my ReactJs code.

Answer 5

This works to sign the user out of the application, but not Google.

var auth2 = gapi.auth2.getAuthInstance();
auth2.signOut().then(function () {
  console.log('User signed out.');
});

Source: https://developers.google.com/identity/sign-in/web/sign-in

Answer 6

You can simply Create a logout button and add this link to it and it will utimately log you out from the app and will redirect to your desired site:

https://appengine.google.com/_ah/logout?continue=http://www.YOURSITE.com

just toggle YOURSITE with your website

Answer 7

Ouath just makes the Google instance null, hence it you out of Google. Now that's how the architecture is made. Logging out of Google, if you Logout of your app is a dirty work, but can't help if the requirement stipulates the same. Hence add the following to your signOut() function. My project was an Angular 6 app:

document.location.href = "https://www.google.com/accounts/Logout?continue=https://appengine.google.com/_ah/logout?continue=http://localhost:4200";

Here localhost:4200 is the URL of my app. If your login page is xyz.com then input that.

Answer 8

this code will work to sign out

    <script>
      function signOut() 
      {
        var auth2 = gapi.auth2.getAuthInstance();
        auth2.signOut().then(function () {   
        console.log('User signed out.');   
        auth2.disconnect();   
      }); 
        auth2.disconnect();
      } 
    </script>

Answer 9

I hope we can achieve this by storing the token in session while logging in and access the token when he clicked on logout.

    String _accessToken=(String)session.getAttribute("ACCESS_TOKEN");
    if(_accessToken!=null)
    {
        StringBuffer path=httpRequest.getRequestURL();
        reDirectPage="https://www.google.com/accounts/Logout?
        continue=https://appengine.google.com/_ah/logout?
        continue="+path;
    }
    response.sendRedirect(reDirectPage);

Answer 10

It looks like Google recently broke something with their revoke stuff (it's started returning 400 errors for us). You now have to call

auth2.disconnect();

In our case we then have to wait a couple of seconds for the disconnect call to complete otherwise the sign-in code will re-authorise before it's done. It'd be good if google returned a promise from the disconnect method.

Answer 11

If any one want it in Java, Here is my Answer, For this you have to call Another Thread.

Answer 12

1. Try this code, if you are using onSignIn() function
2.
        <script src="https://apis.google.com/js/platform.js?onload=onLoad" async defer></script>
       <script>
       function signOut() {
       onLoad();
       var auth2 = gapi.auth2.getAuthInstance();
       auth2.signOut().then(function () {
       console.log('User signed out.');
       if(auth2.isSignedIn)
       {
          auth2.isSignedIn.set(false);
       }
       });
       }
       function onLoad() {
          gapi.load('auth2', function() {
            gapi.auth2.init();
          });
        }
        </script>