问在代码触发器中集成facebook php sdk v4.0

EN

<?php 
if ( ! defined('BASEPATH')) exit('No direct script access allowed');

require_once( 'Facebook/HttpClients/FacebookHttpable.php' );
require_once( 'Facebook/HttpClients/FacebookCurl.php' );
require_once( 'Facebook/HttpClients/FacebookCurlHttpClient.php' );

require_once( 'Facebook/Entities/AccessToken.php' );
require_once( 'Facebook/Entities/SignedRequest.php' );

require_once( 'Facebook/FacebookSession.php' );
require_once( 'Facebook/FacebookRedirectLoginHelper.php' );
require_once( 'Facebook/FacebookSignedRequestFromInputHelper.php' );
require_once( 'Facebook/FacebookJavaScriptLoginHelper.php' );

require_once( 'Facebook/FacebookRequest.php' );
require_once( 'Facebook/FacebookResponse.php' );
require_once( 'Facebook/FacebookSDKException.php' );
require_once( 'Facebook/FacebookRequestException.php' );
require_once( 'Facebook/FacebookOtherException.php' );
require_once( 'Facebook/FacebookAuthorizationException.php' );
require_once( 'Facebook/GraphObject.php' );
require_once( 'Facebook/GraphSessionInfo.php' );

use Facebook\HttpClients\FacebookHttpable;
use Facebook\HttpClients\FacebookCurl;
use Facebook\HttpClients\FacebookCurlHttpClient;

use Facebook\Entities\AccessToken;
use Facebook\Entities\SignedRequest;

use Facebook\FacebookSession;
use Facebook\FacebookRedirectLoginHelper;
use Facebook\FacebookJavaScriptLoginHelper;
use Facebook\FacebookRequest;
use Facebook\FacebookResponse;
use Facebook\FacebookSDKException;
use Facebook\FacebookRequestException;
use Facebook\FacebookOtherException;
use Facebook\FacebookAuthorizationException;
use Facebook\GraphObject;
use Facebook\GraphSessionInfo;

class Facebook {
  var $ci;
  var $helper;
  var $session;
  var $permissions;

  public function __construct() {
    $this->ci =& get_instance();
    $this->permissions = $this->ci->config->item('permissions', 'facebook');
    if (!$this->permissions) {$this->permissions = array();}
    $this->ci->config->load('facebook');

    // Initialize the SDK
    FacebookSession::setDefaultApplication( $this->ci->config->item('api_id', 'facebook'), $this->ci->config->item('app_secret', 'facebook') );

    $this->helper = new FacebookRedirectLoginHelper( $this->ci->config->item('redirect_url', 'facebook') );

    if ( $this->ci->session->userdata('fb_token') ) {
      $this->session = new FacebookSession( $this->ci->session->userdata('fb_token') );

      // Validate the access_token to make sure it's still valid
      try {
        if ( ! $this->session->validate() ) {
          $this->session = null;
        }
      } catch ( Exception $e ) {
        // Catch any exceptions
        $this->session = null;
      }
    } else {
      // No session exists
      try {
        $this->session = $this->helper->getSessionFromRedirect();
      } catch( FacebookRequestException $ex ) {
        // When Facebook returns an error
      } catch( Exception $ex ) {
        // When validation fails or other local issues
      }
    }

    if ( $this->session ) {
      $this->ci->session->set_userdata( 'fb_token', $this->session->getToken() );

      $this->session = new FacebookSession( $this->session->getToken() );
    }
  }

  /**
   * Returns the login URL.
   */
  public function login_url() {
    return $this->helper->getLoginUrl( $this->permissions );
  }

  /**
   * Returns the current user's info as an array.
   */
  public function get_user() {
    if ( $this->session ) {
      /**
       * Retrieve User’s Profile Information
       */
      // Graph API to request user data
      $req = ( new FacebookRequest( $this->session, 'GET', '/me' ) );
      $request = $req->execute();

      // Get response as an array
      $user = $request->getGraphObject()->asArray();

      return $user;
    }
    return false;
  }
}