title: What is the difference between $this->getRequest() and passing Request as a parameter in Symfony 2
body: <p>In a controller action we can get the request object in 2 ways:</p>
  
  <pre><code>$request = $this-&gt;getRequest();
  </code></pre>
  
  <p>or by passing it as a parameter to an action</p>
  
  <pre><code>public function testAction(Request $request)
  </code></pre>
  
  <p>What is the difference between them? Is a recommended way to get the request or specific situations when each is preferred?</p>