Trim whitespace from Float fields before validation

Question

I have a content type with a Float field. When my users accidentally enter (or copy/paste) a value with trailing whitespace (e.g. "11 "), drupal gives them the ugly error message:

Only numbers and the decimal separator (.) allowed in Weight.

But this should be a very easy thing to solve and is not something to bother the user with. However, I can't seem to figure out how to interject code from my module at the right place in order to trim() the value before drupal does its field validation.

Help?

Answer 1

Add the following to a custom module:

function MYMODULE_form_alter(&$form, &$form_state, $form_id) {
  //dpm($form_id);
  if ($form_id == 'BUNDLE_NAME_node_form'){
    $language_float = $form['MACHINE_NAME_FIELD']['#language'];
    $form['MACHINE_NAME_FIELD'][$language_float]['#after_build'][] = 'MYMODULE_field_float_rectify';
  }
}

function MYMODULE_field_float_rectify($element, &$form_state) {
  $children = element_children($element);
  foreach($children as $child){
    $element[$child]['value']['#value'] = trim($element[$child]['value']['#value']);
  }
  return $element;
}

I would think you can also add it to your admin theme's template.php file, but it seems to be more appropriate to add it to a module.