title: Unable to decode json file in a controller
body: <p>I'm a new symfony user, and I'm actually trainning myself on it.
  Here is my problem:</p>
  
  <pre><code>echo $this-&gt;container-&gt;get('templating.helper.assets')-&gt;getUrl('bundles/tlfront/js/channels.json');
      $channels = json_decode($this-&gt;container-&gt;get('templating.helper.assets')-&gt;getUrl('bundles/tlfront/js/channels.json'));
      var_dump($channels);
  </code></pre>
  
  <p>I would like to decode a JSON file in my controller, but here is what the echo and vardump give me:</p>
  
  <pre><code>/Symfony/web/bundles/tlfront/js/channels.json ( the echo)
  null (the var_dump)
  </code></pre>
  
  <p>It seems that the path to the file is correct but json_decode doesn't work.</p>
  
  <p><code>json_last_error()</code> returns 4 which is <code>JSON_ERROR_SYNTAX</code></p>
  
  <p>But, when I run the json string in <a href="http://jsonlint.com/" rel="nofollow">http://jsonlint.com/</a> it returns Valid JSON</p>
  
  <p>Any ideas or advices ?</p>