Codeigniter RESTserver. Null response

I am using Codeigniter and Phil's REStful API.

I am making a call to the server and the problem is it return a NULL value. The value that should be return is a blob that is 65000 in length. I reckon its because of the length of the blob, but I don't know how to solve this issue.

Here's how i call the api:

$resp = call('upload_api/upload/format/json/', array('uploaded_files' => $_FILES['upload'], 'file_details' => 'test'));
echo '<pre>'; print_r($resp);

public static function call($resource, $params, $method='get')
{
    if (empty($params))
    {
        $params = array();
    }
    $headers = '';
    $url = self::API_URL . $resource;
    $curlObj = curl_init();
    curl_setopt_array($curlObj,
                    array(
                        CURLOPT_URL => $url,
                        CURLOPT_RETURNTRANSFER => true,
                        CURLOPT_TIMEOUT => 20
                    ));
    switch ($method)
    {
        case 'get':
            $query_str = http_build_query($params);
            $url = $url .= '?' . $query_str;
            curl_setopt($curlObj, CURLOPT_URL, $url);
            break;
        case 'put':
            $headers[] = 'Content-Type: application/json';
            curl_setopt($curlObj, CURLOPT_HTTPHEADER, $headers);
            curl_setopt($curlObj, CURLOPT_CUSTOMREQUEST, 'PUT');
            curl_setopt($curlObj, CURLOPT_POSTFIELDS, json_encode($params));
            break;
        case 'post':
            $headers[] = 'Content-Type: application/json';
            curl_setopt($curlObj, CURLOPT_HTTPHEADER, $headers);
            curl_setopt($curlObj, CURLOPT_POST, true);
            curl_setopt($curlObj, CURLOPT_POSTFIELDS, json_encode($params));
            break;
        default:
        // error message
    }

    $data = curl_exec($curlObj);

    $contentType = curl_getinfo($curlObj, CURLINFO_CONTENT_TYPE);
    switch ($contentType)
    {
        case 'application/json':
            $data = json_decode($data, true);
            break;
    }

    curl_close($curlObj);

    return $data;
}

Here's the method:

    require APPPATH.'/libraries/REST_Controller.php';
class Upload_api extends REST_Controller {

    public function upload_get()
    {

        $this->load->model('Upload_File');
        $upload_file = new Upload_File();
        $total_rows = $upload_file->count();
        $upload_file->get(1, 0)->all;

        // file_content is a blob
        $this->response(array('file' => $upload_file->file_content, 'total_rows' => $total_rows), 200); 

    }

}