disable the auto upload

This my controller examples.php



function ebook()

{

    $crud = new grocery_CRUD();

    $crud->set_table('ebooks');

  $crud->set_field_upload('file_name','libs/pdf');

  //$crud->set_field_upload('image_captions','libs/image-captions');            //disabled for html upload

    $crud->edit_fields('document_title','image_captions','file_name');

    $crud->columns('document_title','image_captions','file_name');

$crud->callback_field('image_captions',array($this,'uploadimg'));  //change into html upload

  $crud->callback_before_insert(array($this, 'upload'));    //do upload

  $crud->callback_before_upload(array($this, 'cekpdf'));  

  $crud->callback_before_delete(array($this, 'delete'));  

  //$crud->callback_after_upload(array($this,'resize'));  

    $output = $crud->render();

 

    $this->_example_output($output);



}

this my callback



function uploadimg()

{

  return '<input id="field-image_captions" name="image_captions" type="file" value="" maxlength="100">';

}

function delete($primary_key)

{

  $image = $this->db->get_where('ebooks', array('ebook_id'=>$primary_key), 1)->row();

  if (unlink('libs/image_captions/'.$image->image_captions))

  return true;

  else

  return false;

}

function upload($post_array)

{

  if(!empty($post_array['image_captions']))  //if I remove the if, it can upload but no change to database, but when I put the if, always return false

  {

    $cover = 'image_captions';

    $this->load->library('upload');

    $cover_name="";   

    $conf_cover['upload_path'] = 'libs/image-captions/';

    $conf_cover['allowed_types'] = 'gif|jpg|png';

    $this->upload->initialize($conf_cover);

    if (!$this->upload->do_upload($cover))

    {

    return false;

    }

    else

    {

    $data = $this->upload->data();

    $cover_name = $data['file_name'];

	 $config = array(

	  'source_image' => $data['full_path'],

	  'width' => 95,

	  'height' => 130

	 );

	 $this->load->library('image_lib', $config);

	 $this->image_lib->resize();

    }	  

    $post_array['image_captions']=$cover_name;

    return $post_array;

  }else{return false;}

}

function cekpdf($files_to_upload,$field_info)

{

  foreach($files_to_upload as $value) {

   $ext = pathinfo($value['name'], PATHINFO_EXTENSION);

  }



  $allowed_formats = array("pdf");

  if(in_array($ext,$allowed_formats))

  {

   return true;

  }

  else

  {

   return 'Document file must be pdf format';   

  }

}

function resize($uploader_response,$field_info, $files_to_upload)

{

  $this->load->library('image_moo');

 

  //Is only one file uploaded so it ok to use it with $uploader_response[0].

  $file_uploaded = $field_info->upload_path.'/'.$uploader_response[0]->name;

 

  $this->image_moo->load($file_uploaded)->resize(95,130)->save($file_uploaded,true);

 

  return true;

}

I already can resize image and specify the file type but the setting parameter is global for any upload
My question is.. is it possible to validate upload file_name to pdf and upload image_captions to jpg,png,gif ?
if cannot, I have tried to use the html upload but the data did not insert to database even thought the upload successfully ?

vhanxer