Facebook Graph API Implementation

fb.class.php

<?php
/*  Facebook Graph API Implementation
 *  @author Ozgur Arslan 
 *  github.com/blueorange589
 *  http://stackoverflow.com/users/7838027/Оzgur
 * 
 *  To use;
 *      1. set configuration values
 *      2. call public methods defined in this class
*/

class fb {
    // CONFIG
    private $appid = '';
    private $appsecret = '';
    private $graphver = '';
    private $callbackurl = '';
    
    // PARAMS
    private $app;
    private $accesstoken = '';
    private $helper;
    private $loginurl = '';
    private $permissions = ['email'];
    private $error = '';
    private $oauth2;
    private $response;
    private $user;
    private $object;
    
    function __construct() {
         require_once __DIR__ . '/Facebook/autoload.php';
          
         $this->app = new Facebook\Facebook([
  'app_id' => $this->appid,
  'app_secret' => $this->appsecret,
  'default_graph_version' => $this->graphver,
]);
         $this->helper = $this->app->getRedirectLoginHelper();

    }

    private function getloginurl() {
         return $this->helper->getLoginUrl($this->callbackurl, $this->permissions);
    }

    private function getaccesstoken() {
        if(isset($_SESSION['fb_access_token'])) {
               $this->accesstoken = $_SESSION['fb_access_token'];
               return $_SESSION['fb_access_token'];
        }

         try {
  $this->accesstoken = $this->helper->getAccessToken();
  if(!$this->accesstoken) {
         $this->debugaccesstoken();
         return false;
  }
  $this->setlonglived();
  $_SESSION['fb_access_token'] = $this->accesstoken;
  // var_dump($this->accesstoken);
} catch(Facebook\Exceptions\FacebookResponseException $e) {
  $this->error = $e->getMessage();
  exit;
} catch(Facebook\Exceptions\FacebookSDKException $e) {
  $this->error = $e->getMessage();
  exit;
}


    }

    private function debugaccesstoken() {
         if ($this->helper->getError()) {
    header('HTTP/1.0 401 Unauthorized');
    echo "Error: " . $this->helper->getError() . "\n";
    echo "Error Code: " . $this->helper->getErrorCode() . "\n";
    echo "Error Reason: " . $this->helper->getErrorReason() . "\n";
    echo "Error Description: " . $this->helper->getErrorDescription() . "\n";
  } else {
    header('HTTP/1.0 400 Bad Request');
    echo 'Bad request';
  }
    }

    private function accesstokenvalue() {
          return $this->accesstoken->getValue();
    }

    private function setoauth2() {
        if(!$this->oauth2) {
            $this->oauth2 = $this->app->getOAuth2Client();
        }
    }

    private function setlonglived() {
        $this->setoauth2();
        if (!$this->accesstoken->isLongLived()) {
           
  try {
    $this->accesstoken = $this->oauth2->getLongLivedAccessToken($this->accesstoken);
  } catch (Facebook\Exceptions\FacebookSDKException $e) {
    $this->error = $helper->getMessage();
    exit;
  }
        }
    }

    private function request($endpoint) {
    if(!$this->accesstoken) {
        $this->getaccesstoken();
        //$this->error = "empty access token";
        //return false;
    }
        try {
  // returns fb response object
    $this->response = $this->app->get($endpoint, $this->accesstoken);
} catch(Facebook\Exceptions\FacebookResponseException $e) {
  $this->error = $e->getMessage();
  exit;
} catch(Facebook\Exceptions\FacebookSDKException $e) {
  $this->error = $e->getMessage();
  exit;
}
    }

////------ PUBLIC --------////

    public function gettokenmetadata() {
        $this->setoauth2();
        $this->tokenMetadata = $this->oauth2->debugToken($this->accesstoken);
    return $this->tokenMetadata;
    }

    public function fetchuser($ep) {
          $this->request($ep);
          $this->user = $this->response->getGraphUser();
     return $this->user;
    }

    public function fetchobject($ep) {
          $this->request($ep);
          $this->object = $this->response->getGraphObject();
     return $this->object;
    }

    public function fetchuserpicurl() {
          if(!$this->user['picture']) {
               return false;
          }
          $pic = json_decode($this->user['picture']);
          return $pic->url;
    }
    

}

?>