Symfony/Silex + Facebook SDK：會話開始衝突

Question

如何在不更改原始源代碼的情況下解決session_start衝突？ Symfony組件或Silex如何檢查會話是否已經存在？

Notice: A session had already been started - ignoring session_start() in 
myapp/vendor/symfony/http-foundation/Symfony/Component/HttpFoundation/Session/Storage/NativeSessionStorage.php on line 146 

編輯：這裏的index.php

require_once __DIR__.'/vendor/autoload.php'; 

/** 
* from Heroku's Facebook template 
*/ 
require_once('AppInfo.php'); 
require_once('utils.php'); 


use Symfony\Component\HttpFoundation\Request; 
use Symfony\Component\HttpFoundation\Response; 
use Symfony\Component\HttpKernel\HttpKernelInterface; 
use Symfony\Component\Yaml\Parser; 
use Silex\Provider\FormServiceProvider; 
use Symfony\Component\Validator\Constraints as Assert; 

/** 
* Currently using git submodule, will move to composer.json 
*/ 
require_once('sdk/src/facebook.php'); 

$facebook = new Facebook(array(
    'appId' => AppInfo::appID(), 
    'secret' => AppInfo::appSecret(), 
)); 

$app = new Silex\Application(); 
// ... 

Answer 1

的FB SDK啓動會話only if it's not started already的前幾行。在啓動silex會話的代碼之後移動sdk初始化。

This是Symfony2用來查看用戶是否有會話的功能。本質上它檢查會話cookie的存在。