Facebook使用PHP登录然后使用get args重定向到URL

Question

I am trying to make a Facebook login in my website, I have faced a problems.

I have used this class to use Facebook login in PHP.

I have created a PHP file in my site called login.php which contain the following code

$facebook = new FacebookLogin(APP_ID, APP_SECRET);
$user = $facebook->doLogin();
// then initialize the SESSION variables here using $user info
header("Location: ' . $url);

The problem now, is that I want to pass get arguments to the login.php and from this argument I can know the $url which I will redirect to. But the FacebookLogin class is making a redirect call so the get argument in login.php is lost, so I have decided to add the login.php argument to $this->url in the FacebookLogin constructor with this line:

$this->my_url = 'http://' . $_SERVER['SERVER_NAME'] .  $_SERVER['PHP_SELF'] . '?' . $_SERVER['QUERY_STRING'];

The problem now is that this is not working too as in the verifyLogin() , this line is returning empty result as the URL is not correct:

$result = @file_get_contents(self::TOKEN_URL . '?' . http_build_query($data));

and it was supposed to return the access_token

So what do you think?

Simply I need a way that the user click a link to login by Facebook but before returning to the user, I want to pass by my code in PHP then redirect to a url that was specified by the user click in the get arguments.

I'm sorry, it may be silly but I've spent a lot of time trying to solve this problem and have a deadline after few hours.

Appreciate your help

Answer 1

What you try to achieve is simple with usage of PHP-SDK :

$facebook = new Facebook(array(
  'appId' => 'YOUR_APP_ID',
  'secret'=> 'YOUR_APP_SECRET'
));

$loginURL = $facebook->getLoginUrl(array(
  //'redirect_uri'=>'URL_WHERE_USER_WILL_BE_LANDED_AFTER_LOGIN' 
));

header("Location: {$loginURL}");

If you wish to pass some data to your application for later step than user came back authorized, pass that as parts of URL arguments for URL provided in redirect_uri parameter of getLoginUrl .

So if for example you will pass http://my.app.com/?link_to_visit=some_link as redirect_url you will be redirected to that URL instead of current URL (before authorization).

Later you can just:

$facebook = new Facebook(array(
  'appId' => 'YOUR_APP_ID',
  'secret'=> 'YOUR_APP_SECRET'
));

$userId = $facebook->getUser();
$accessToken = $facebook->getAccessToken();

$linkToVisit = $_REQUEST['link_to_visit'];

BTW , for the sake of humanity don't use some silly client written by someone with unknown reputation before couple of years in favor of Official Facebook PHP-SDK that do follow all changes (and they are huge) in platform...