Facebook integration with website - logout user from facebook if user doesn't grant permission to the app - facebook

I am working with integration of a website with facebook.
I have a specific requirement where-in the user should get logged-out from facebook if he/she doesn't grant permissions to my facebook-app (on first use).
Now, If user denies access for my facebook-app, I am redirected to the redirect_uri, but the problem is that on the page that handles the redirection, I cannot log the user out from facebook since my app won't have permission to perform logout.
Can anyone please tell me what is the workaround I could try?

I have a specific requirement where-in the user should get logged-out from facebook if he/she doesn't grant permissions to my facebook-app (on first use).
Is this in a very special environment (like a kiosk application or something) …?
Because otherwise, I’d hate it if random apps logged me out of FB while I’m browsing on my own computer, just because I don’t want to connect to them.
Now, If user denies access for my facebook-app, I am redirected to the redirect_uri, but the problem is that on the page that handles the redirection, I cannot log the user out from facebook since my app won't have permission to perform logout.
Can anyone please tell me what is the workaround I could try?
I don’t know any workaround – to perform a log out on behalf of the user, you need a valid access token – doesn’t matter, if you’re trying to do it client-side or server-side.
If that wasn’t the case, any website I’m visiting could log me out of Facebook, and that would be really annoying to users.

We have exactly the same problem. We've developed a kiosk application used to checkin and post HD photos.
If the user does not accept the permissions we need to reload the application because we can't logout the user in another way.
We've tried different ways but no one was successful

Related

How to logout from facebook or destroy an active session using php?

I have an application which asks for a registration through facebook but before a user can proceed to the registration, the system should first determine if there is an active session. If a user is logged in to facebook, it should then automatically logout for a fresh start.
But here is where I'm stuck. The SDKs only let the user log out from facebook if he is connected to your app. It uses the app's access token. But what if he is still not registered to your app? Their log out means to log out from your app, and not really from facebook.
My requirement :
1. How can i log out from facebook.
2. How can i clear the browser cookies?
Not on a specific app but the whole facebook session.
[from comments] But to use the getLogoutUrl() function, the user has to be connected to your app. What I need is to logout from the whole facebook and not just from the app
If the user is connected to your app, then the URL provided by the getLogoutUrl method does that – log the user out of your app (web-app) and out of facebook.com.
If the user is not connected to your app however, you don’t have an active user access token – and then logging out of Facebook is not possible. The obvious reason being that if it was, every website that I visit could log me out of Facebook in a “drive-by” manner – without me actively wanting that, so people would get annoyed quite quickly.
If a user is logged in to facebook, it should then automatically logout for a fresh start.
If this is a security consideration, then you are in fact looking for re-authentication, which can be done using the auth_type parameter, quote from docs:
In apps where security is very important, you may want to double-check someone's identity - perhaps before they make a purchase within the app, or use it to access some sensitive personal data.
To prevent situations where a user could leave a device logged in or man-in-the-middle hijacking of the user session, re-authentication forces a person to re-enter their Facebook password before they can continue to use your app.
Be aware to use the server-side Auth flow though – because in the client-side flow, using the JS SDK, there is a bug that allows the user to bypass re-entering his password by simply closing the popup, which is still open: https://developers.facebook.com/bugs/248632218597467 (Has been assigned Priority: High, but received still nothing more than a “we will follow up” response yet.)
Use the logout.php url.
https://developers.facebook.com/docs/reference/php/facebook-getLogoutUrl/
Basically,
http://facebook.com/logout.php?next=YOUR_NEXT_URL_FOR_LOGOUT&access_token=USER_TOKEN
1) logging out from facebook by using
facebook=>getLogoutUrl();
2) clearing the session by using :
$facebook->destroySession();
example:
Log Out
logout.php page codes as follow:
<?php
require 'facebook.php';
$facebook->destroySession();
header( "location:index.php" );
?>

How to logout users from Facebook without revoking website (app) permissions?

I am having some doubts about the proper facebook authorization/login flows and maybe some of you have more experience on the subject.
Basically I have a guest area on my website for non authenticated users and a button to connect through Facebook or the platform login/registration system.
As per the Facebook flow: once the guest clicks on the button, a popup dialog opens asking to login to fb (if needed) and to grant some permissions to the app. Once accepted, my website saves user data to the DB tables as if the user also registered to the website itself. This all works fine and once done, my users can navigate to the protected areas as expected.
Now... I don't totally get if it's mandatory to logout from Facebook AND to revoke permissions once the user chooses to logoff from my website or if it's allowed (and how) to simply log the user out of facebook (and so from the app) while the app still retains the user permissions.
I know this might sound like a silly question but last part of the flow is still foggy to me and i found the Facebook docs quite sparse. I hope I could explain it well enough!
Thanks.

Getting (and keeping) extended permissions in a facebook app

I'm using an fb login button on a site, and our app needs extended permissions: publish_stream. When the user logs in, we can get the permissions, get an access_token, and publish various items to their stream.
However, the site doesn't seem to know if the user's logged in to facebook or not, and I'm having to allow permissions on subsequent visits to the page. However, if I hit the website, I get the access_token - but I'm the admin of the facebook app.
Is there a way to get permissions and have them persist, or am I doing something wrong?
It sounds like you might need to request the "offline_access" extended permission (if you want to make API calls after a normal access token would have expired). I'm not sure this is what you need though - this is for making API calls as a user while the user is not logged in to Facebook anymore.
It sounds like your Application is not properly using the API to check if the user is logged in or not. Without seeing any code I can't tell what is happening, but if you are using the API correctly once a user has authorized your application, they should be able to make API calls via your App while they are logged in to Facebook. Unless you changed application's on them, they will not need to re-authorize the permissions.
Please edit your question to provide more details if this does not help, and good luck.

Preventing facebook user to automatically login my site

well i have used the facebook api couple of times. But last day i just came across a site which was really new to me. Heres the scenario
If a user is logged in at facebook and comes to my site, he will
automatically be logged in without asking him and also if user logs
out of my site he gets logged out of facebook. But the site i saw
yesterday, they had handled it perfectly, user dose not logs in their
site automatically and even if user logs out from their site, he does
not gets logged out of facebook.
So any help? what is this technique called? or any relevant help?
Best Regards
most site handled the login/authenication by using the login status of the user at facebook ends.
to do what u wants, simply add an additional layer of authentication / login status checking at your own site.
The site level login status is to be retained only for the current session. In other words, once the user went away from the site, the site level login status is gone. With this, when the user returns, you know that he needs to login again.
when the user logged out from your site, you only log him out of your site and do nothing about facebook login
Using the Facebook SDK it will likely tell you the user is logged out when not logged into Facebook, which in theory is the correct behaviour of the whole system, as Facebook want user's to always be connected to Facebook, I quote facebook:
As long as the user is signed into Facebook, they are automatically signed into your site as well.
So if they aren't connected to Facebook, you aren't connected to other sites. In a way it's a deterrant and increases Facebooks market.
But anyhow, it's likely the site you are describing are implementing their own authentican system rather than using Facebook's own SDK, or if they are using the SDK they are using it in moderation and understand about cookies/the above.
The flow to allow the user to be logged into Facebook but out of your site is as so:
When a user logs out of their site, it will unset session data for the site's own application, and also unset Facebook cookies, etc. That way the user is still logged into Facebook but out of your site.
When they try to log in again, Facebook will detect no cookies are available and hence will re-authenticate and pass you onto the url as passed during the authentication process. Your site will then login the user to the site's own application, setting any session variables, etc.
you need to check how you are handling the FB logins and sessions at your end..
my guess is you check the is login at your site and there are some access_tokens which are as per your app id in the cookies of your browser which are helping you to log in ..
and when logging out from your site you are explicitly logging out the user from FB as well
( thats what you are describing atleast )
you seem to be explicitly calling logout or clearing the cookies for fb app id ..

How can I avoid asking users to login (connect) to my facebook app again and again?

I am developing and testing a facebook app for which I have granted the permissions with my facebook account. Then the app is authorized to access my info, etc. nicely. The next time I close the browser, reopen it, login to facebook successfully then access the app, facebook wants me to login to that app again. I can access the current user id, but how can I automatically authorize the app (if the user has already authorized in the past) without needing the user to press that dread 'Login' button again and again upon each session's end?
UPDATE - offline_access has been deprecated. Read this post for more details: https://developers.facebook.com/roadmap/offline-access-removal/
You will need to request a token that has offline_access so that you can use their authentication token over and over again. Then you will need to set a cookie yourself that stores something indicating who the user is. Facebook does not support a "remember me" feature in their authentication so you have to build it yourself. Store the access token in your database and set the cookie to identify the user.
Unless you are building this for a very specific reason like an app that runs on work computers only, I would really encourage you to not implement this feature. The facebook connect authorization is well understood by users and is very easy to use. You are going to get a lot more security if you make your users press the button every time. Just make sure you make this optional. You never know if somebody is on a public computer.