I looked up how to create custom validators in Symfony1.4, practiced it, so here’s a memo.

First, before creating a custom validator, check if the validator you want to use doesn’t already exist among the existing ones.

・symfony Forms in Action | 付録 B - バリデータ | symfony | Web PHP Framework (symfony Forms in Action | Appendix B - Validators | symfony | Web PHP Framework)

If the validator you want doesn’t exist, create your own.

The articles that were helpful when creating custom validators for Symfony1.4 are as follows:

・The More with symfony book | カスタムウィジェットとバリデータ | symfony | Web PHP Framework (The More with symfony book | Custom Widgets and Validators | symfony | Web PHP Framework)

・symfonyでカスタムバリデータを使ってフィルタを実装する - spanstyle::monolog (Implementing Filters Using Custom Validators in symfony - spanstyle::monolog)

・symfonyのValidatorで全角/半角変換などを行う - ゆっくりゆっくり (Performing Full-width/Half-width Conversion etc. with symfony Validator - SlowlySlowly)

I actually created a validator to check the length and character composition of input values for ISBN, which is a number used to identify books.

By the way, ISBN-10 is 10 digits, with the first digit being 0-9 or X, and other digits being numbers. ISBN-13 is 13 digits, composed only of numbers.

・Reference: ISBN - Wikipedia

I referred to this for regular expression usage:

・正規表現 | PHP Labo (Regular Expressions | PHP Labo)

・正規表現 (Regular Expressions)

And here’s the source I actually created:

■ myValidatorIsbn.class.php

(Validator to check if it matches ISBN format)

 $value));
      }
    }
    
    // If input value length is 13 characters, return input value as is
    if (strlen($value) == 13){
      // ISBN-13 is composed only of numbers
      if (preg_match("/^[0-9]{13}?$/" ,$value))
      {
        return $value;
      } else {
        throw new sfValidatorError($this, 'ISBN-13は数字のみで入力して下さい', array('value' => $value));
      }
    }
    // Otherwise, error
    throw new sfValidatorError($this, 'ISBNは10文字、または13文字で入力して下さい', array('value' => $value));
  }
}

■ IsbnSearchForm.class.php

(Form file defining ISBN input form)

setWidgets(array(
      'isbn' => new sfWidgetFormInput(array(), array('size' => 20, 'maxlength' => 13, )),
    ));
    
    $this->setValidators(array(
      'isbn' => new myValidatorIsbn(array('required' => true, ),
                      array('required' => '未入力', )),
    ));
    
    $this->widgetSchema->setNameFormat('isbn_search[%s]');
    
    $this->widgetSchema->setLabels(array('isbn' => 'ISBN10/13', ));
  }
}

That’s all from the Gemba.