d7:webform:filesave

d7:webform:filesave

Hook Webform Presave: http://drupalcontrib.org/api/drupal/contributions%21webform%21webform.api.php/function/hook_webform_submission_presave/7
Writing to a csv or excel file  : http://drupal.org/node/1177352


File Save with entity(Very short and simple code):
$entity = entity_load($id);
$data = file_get_contents($localpath);
$destination = file_create_filename(basename($localpath), file_default_scheme() . '://yourdir/' );
$file = file_save_data($data, $destination);
$entity->field_attachment[LANGUAGE_NONE][] = (array)$file;
$entity->save();