title: validation on a input file in cakephp
body: <p>In cakephp I am trying to check if an file input field has a file attached, and if not output an error. I have done this with other fields but just can't seem to get this to work on that field.</p>
  
  <p>Here is the model</p>
  
   array('notempty'),
          'uploadeduploaded_file' => array('notempty')
      );
  ?>
  
  <p>and here is my ctp file</p>
  
  <pre><code>&lt;?php echo $form-&gt;input('Uploaded.uploaded_file', array('type' =&gt; 'file', 'label' =&gt; 'Upload file', "label" =&gt; false)); ?&gt;
  </code></pre>
  
  <p>I am guessing that it must be something to do with what I should call the field in the model, but I have tried all sorts of combinations and can't get it work.</p>
  
  <p>Any help would be grateful</p>