Вы можете использовать Facebook SDK для PHP https://github.com/facebook/php-graph-sdk
Ниже моего решения
use Facebook\FacebookSession;
use Facebook\FacebookRequest;
use Facebook\GraphUser;
use Facebook\FacebookRequestException;
$pageUrl = 'some_url';
FacebookSession::setDefaultApplication('facebookAppId','facebookAppSecret');
//getting session
$Session = FacebookSession::newAppSession();
try
{
//validating if session is correct
$Session->validate();
//sending request
$Request = new FacebookRequest($Session, 'GET', '/',
array (
'id' => $pageUrl,
)
);
$Response = $Request->execute();
//getting UserGraph object
$UserObject = $Response->getGraphObject(GraphUser::className());
//return page id
return $UserObject->GetId();
}
catch (FacebookRequestException $ex)
{}
catch (Exception $ex)
{}