title: what is the role of handle request in symfony form
body: <p>I'm using FormBuilderInterface , to create my form, so i find that i can validate my form using the function  isvalid() , i have an issue with handleRequest($request) ,i did't understand what is the role of it.
  here is my code :</p>
  
  <pre><code>function ajout2Action()
  {
      $client= new \Esprit\PiBundle\Entity\Client();
      $formv= new \Esprit\PiBundle\Form\ClientType();
      $form=  $this-&gt;createForm($formv,$client);
       $request = $this-&gt;get('request');
    if($form-&gt;handleRequest($request)-&gt;isValid())
      {
           $em=$this-&gt;getDoctrine()-&gt;getManager();
           $em-&gt;persist($client);
           $em-&gt;flush();
  
  
  }
  </code></pre>
  
  <p>thank you for your help .</p>