Facebook SDK：PHP和Javascript之间的共享登录

Question

I'm building a small Facebook application where i ended up needing to use methods from the Facebook SDK both on the client (JS) and server (PHP). On the client, i'm mostly using FB.ui methods, and on the server i'm working a lot with the Graph API.

But, is there a way of doing that without having to force the user to login twice? How can i make the user login once, and use that login for the both client and server? Is this possible?

Answer 1

The best way to use Facebook SDK in JS and PHP with only one login (or not) is to use the token . The " server-side " process is the same in JS and PHP.

This process is useful for the first user login or to have a new token when it expired.

1. From your page, the user is redirected to Facebook to authorize your application.
2. After user accepts, Facebook redirects user on your page with the token , facebook ID , first name, last name, email, etc.
3. Save user information in a Database

Now, your application can have a connection with Facebook (in JS, PHP or other) without the user login. The elements required are your appId , your secret , the user ID and the user token .

Hope to help you

Answer 2

Infact this will not work, as tokens expire pretty fast. The offline_access was also removed so the user has to explicit use the facebook app when you want to maintain the connection with him (you simply wont be able to do anything when the token is expired).

You can still save the current token for login purposes but you should update the user table every time a user logs in via FB again.

Also, you can not login via token but you can get the token in JS OR PHP pretty easy.

    FB.getLoginStatus(function(response) {
    if (response.status === 'connected') {
        //user is logged in and has accepted you apps stuff.

        var uid = response.authResponse.userID;
        var accessToken = response.authResponse.accessToken;
        // do some fancy ajax function to send the token to the server here. 
    } 
    else if (response.status === 'not_authorized') {
        // the user is logged in to Facebook, 
        // but has not authenticated your app
        FB.login(function(response) {
           if (response.authResponse) {
             console.log('Welcome!  Fetching your information.... ');
             FB.api('/me', function(response) {
               console.log('Good to see you, ' + response.name + '.');
             });
           } else {
             console.log('User cancelled login or did not fully authorize.');
           }
         }), {scope: 'email,user_likes'}); //specify all the scopes you need for your app here. 
    } 
    else 
    {
        //user is not logged in to facebook. 
    }
 });

that would be the JS part to get the token and if you want to get it with PHP, it is even easier.

    <?php
require_once("/FBAPI/src/facebook.php");
$config = array();
$config['appId'] = 'your_app_id';
$config['secret'] = 'your_app_secret';
$facebook = new Facebook($config);

$user = $facebook->getUser();
if(!$user){
    $loginUrl = $facebook->getLoginUrl(array('scope'=>'publish_stream', 'redirect_uri'=>'http://www.example.com'));
}
if($user){
    try{
        $user_profile = $facebook->api('/me');
        $access_token = $facebook->getAccessToken();
    }
    catch(FacebookApiException $e){
        error_log($e);
        $user = NULL;
    }
}
else{
    echo '<a href="'.$loginUrl.'"><img src="img/login.png"/></a>';
}
?>

EDIT: infact, you can just do it like this:

Display landing page for the login and let the user login via JS. As soon as the Login Process is done, you can check if the user is logged in via the $facebook->getUser(); function of the PHP SDK

Answer 3

There is one neat trick I learn't when I used Heroku for deploying my tutorial Facebook application. On the sample template that Heroku provided they had Facebook Login button and subscribed to auth.authResponseChange like following:-

FB.Event.subscribe('auth.authResponseChange', function(response) {
    window.location = window.location;
});

This causes the page to refresh and the cookie set by JavaScript SDK after Facebook's authentication will be available to PHP SDK. You can also login user through PHP SDK and after user logs in the JavaScript SDK will be able to work without requiring to login again from JavaScript SDK