升級 PHP Facebook SDK 到 4.0.x 版本

CodeIgniter

最近幫公司建立 Staging 環境,申請了新的 FB App 來,用原本 Facebook v3.2.3 SDK 發現已經不能 work 了,去翻了 Facebook Platform Changelog,看到今年 4 月 30 號以後申請的 App 會強制走 v2.0 Auth 機制,所以原本用 php sdk 3.2.3 版本的話,完全無法呼叫 Auth 2.0 API,導致整個網站爛掉,當然線上的網站是不會隨意換 App ID 及 secret,免得怎麼爆掉的都不知道。這次來教學在 CodeIgniter 轉換 PHP Facebook SDK,可以直接參考官方 4.0.0 的教學,原本 3.2.3 版本直接下載程式碼,放到 library 目錄,直接 include 就可以取得 Facebook 個人資料,4.0.0 版本以後,請先確認系統是否升級為 PHP 5.4 版本以上,並且支援 Composer 安裝,當然如果不用 Composer 也可以,只是要 include 很多檔案,真的比較麻煩。

先在根目錄建立 composer.json 內容填入

{
  "require" : {
    "facebook/php-sdk-v4" : "4.0.*"
  }
}

接著執行 composer install,系統會自動建立 vendor 目錄。在 application/libraries 建立 lib_login.php 檔案,並且寫入底下程式碼

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

/**
* Name: Facebook Login Library
*
* Author: appleboy
*
*/

require 'vendor/autoload.php';

use Facebook\FacebookSession;
use Facebook\FacebookRequest;
use Facebook\GraphUser;
use Facebook\FacebookRequestException;
use Facebook\FacebookRedirectLoginHelper;

class Lib_login
{
    /**
     * CodeIgniter global
     *
     * @var string
     **/
    protected $ci;

    /**
     * __construct
     *
     * @return void
     * @author Ben
     **/
    public function __construct()
    {
        $this->ci =& get_instance();
        $this->ci->load->library('session');
        $this->ci->config->load('facebook');

        if (! isset($_SESSION)) {
            session_start();
        }
    }

    public function facebook()
    {
        $facebook_default_scope = explode(',', $this->ci->config->item("facebook_default_scope"));
        $facebook_app_id = $this->ci->config->item("facebook_app_id");
        $facebook_api_secret = $this->ci->config->item("facebook_api_secret");

        // init app with app id and secret
        FacebookSession::setDefaultApplication($facebook_app_id, $facebook_api_secret);

        // login helper with redirect_uri
        $helper = new FacebookRedirectLoginHelper(site_url('login/facebook'));
        // see if a existing session exists
        if (isset($_SESSION) && isset($_SESSION['fb_token'])) {
            // create new session from saved access_token
            $session = new FacebookSession($_SESSION['fb_token']);

            // validate the access_token to make sure it's still valid
            try {
                if (!$session->validate()) {
                    $session = null;
                }
            } catch (Exception $e) {
                // catch any exceptions
                $session = null;
            }
        }

        if (!isset($session) || $session === null) {
            // no session exists

            try {
                $session = $helper->getSessionFromRedirect();
            } catch(FacebookRequestException $ex) {
                // When Facebook returns an error
                // handle this better in production code
                print_r($ex);
            } catch(Exception $ex) {
                // When validation fails or other local issues
                // handle this better in production code
                print_r($ex);
            }
        }

        // see if we have a session
        if (isset($session)) {
            // save the session
            $_SESSION['fb_token'] = $session->getToken();
            // create a session using saved token or the new one we generated at login
            $session = new FacebookSession($session->getToken());

            // graph api request for user data
            $request = new FacebookRequest($session, 'GET', '/me');
            $response = $request->execute();
            // get response
            $graphObject = $response->getGraphObject()->asArray();
            $fb_data = array(
                'me' => $graphObject,
                'loginUrl' => $helper->getLoginUrl($facebook_default_scope)
           );
            $this->ci->session->set_userdata('fb_data', $fb_data);

        } else {
            $fb_data = array(
                'me' => null,
                'loginUrl' => $helper->getLoginUrl($facebook_default_scope)
           );
            $this->ci->session->set_userdata('fb_data', $fb_data);
        }

        return $fb_data;
    }
}

最後寫簡單 controller

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

class Login extends CI_Controller
{
    public function __construct()
    {
        parent::__construct();
        $this->load->library(array('session', 'lib_login'));
    }

    /**
     * facebook login
     *
     * @return void
     * @author appleboy
     **/
    public function facebook()
    {
        $fb_data = $this->lib_login->facebook();

        // check login data
        if (isset($fb_data['me'])) {
            var_dump($fb_data);
        } else {
            echo '<a href="' . $fb_data['loginUrl'] . '">Login</a>';
        }
    }
}

/* End of file login.php */
/* Location: ./application/controllers/login.php */

打開瀏覽器,直接執行 http://xxxx/login/facebook 就可以看到 Facebook 登入連結。所以程式碼都放在 Githubcodeigniter-facebook-php-sdk-v4,歡迎取用。