title: typo3 extbase: validate a form
body: <p>I created a simple "subscribe to newsletter" form: </p>
  
  <pre><code>&lt;f:form action="subscribe" method="post" name="newsletterform"&gt;
    &lt;f:form.textfield id="name" name="name" required="true" /&gt;
    &lt;f:form.textfield id="email" name="email" required="true"/&gt;
    &lt;button type="submit"&gt;Submit&lt;/button&gt;
  &lt;/f:form&gt;
  </code></pre>
  
  <p>as you can see, this is not a form that's based on an existing model, I have no interest in saving newslettersubscriptions to the database (they'll be stored somewhere else anyways). </p>
  
  <p>Now in my subscripeAction I want to do some form validating. I want to check if the email is really an email address, if its notEmpty etc. Is there a way to use the typo3 / extbase Validators? If so - how? </p>