Question

I would like to filter some fields in my form with strtolower() function. Unfortunately I can’t find any example of doing that.

How can I write such filter, that will lowercase the input, check the database if element exists and then decide wheter to add the record or not?

Answer 1

1) new project custom validator (we will use it like value filter here):

/lib/validator/MyProjectStringLowerCase.class.php

<?php

class MyProjectStringLowerCase extends sfValidatorBase
{
  /**
  * @see sfValidatorBase
  */
  protected function doClean($value)
  {
     return strtolower($value);
  }
}

2) bound it to field:

$this->setWidget('my_field_name', new sfWidgetFormInputText());
$this->validatorSchema['my_field_name'] = new MyProjectStringLowerCase();

If you have some validator on that field already, you can merge them into combined validators this way:

$this->validatorSchema['my_field_name'] = new sfValidatorAnd(array(
    $this->validatorSchema['my_field_name'], // the original field validator
    new MyProjectStringLowerCase(),
));

The combined validators order influent how value will flow trough them, so if you want to have value filtrated in second validation, set MyProjectStringLowerCase as the first one.

There are 2 differences between this approach and using post processing (like doSave() for instance):

1. the value here will be filtered after each send (and will show
   filtered in displaying of form errors)
2. You can reuse it very cleanly and easily in other fields or forms in
   your project