title: Symfony2 - how to extend a vendor bundle (e.g. of FOSFacebookBundle)
body: <p><strong>Scenario:</strong></p>
  
  <p>I'm using a bundle (FOSFacebookBundle) that allows me to set parameters for exactly one facebook app in my configuration. Everything works perfectly fine, but now I need to set not only one app, but multiple.</p>
  
  <p><strong>My approach:</strong></p>
  
  <p>I've created a AcmeFacebookBundle, which allows multiple apps to be defined (configuration defined in <em>Acme\FacebookBundle\DependencyInjection\Configuration</em>) in an array like so:</p>
  
  <pre><code>acme_facebook:
      apps:
          some_competition:
              server_url: %acme.facebook.some_competition.server_url%
              file:   %kernel.root_dir%/../vendor/facebook/php-sdk/src/base_facebook.php
              alias:  facebook
              app_id: %acme.facebook.some_competition.app_id%
              secret: % acme .facebook.some_competition.secret%
              cookie: true
              permissions: [email, user_birthday, user_location]
          some_other_competition:
              server_url: %acme.facebook. some_other_competition.server_url%
              file:   %kernel.root_dir%/../vendor/facebook/php-sdk/src/base_facebook.php
              alias:  facebook
              app_id: %acme.facebook. some_other_competition.app_id%
              secret: % acme .facebook. some_other_competition.secret%
              cookie: true
              permissions: [email, user_birthday, user_location]
  </code></pre>
  
  <p>In <em>Acme\FacebookBundle\DependencyInjection\AcmeFacebookExtension</em> I am then looping through all apps. The idea is to compare the server_url parameter against the current URL and override the fos_facebook configuration with mine. </p>
  
  <pre><code>class AcmeFacebookExtension extends Extension
  {
      ...
      /**
       * {@inheritDoc}
       */
      public function load(array $configs, ContainerBuilder $container)
      {
          $configuration = new Configuration();
          $config = $this-&gt;processConfiguration($configuration, $configs);
  
          foreach ($config['apps'] as $app)
          {
              // check for matching path here?
              foreach (array('file', 'app_id', 'secret', 'cookie', 'domain', 'logging', 'culture', 'permissions') as $attribute)
              {
                  $container-&gt;setParameter('fos_facebook.' . $attribute, $app[$attribute]);
              }
          }
      }
  </code></pre>
  
  <p><strong>Problem:</strong></p>
  
  <p>But this is exactly where I'm stuck. Obviously, I have no access to the Request object or the DiC from within AcmeFacebookExtension to do this comparison.
  Am I going completely wrong in my approach? Do you have any better idea on how to tackle this problem?</p>