Yii2 Application Development Cookbook - Third Edition

Writing your own validators

Yii provides a good set of built-in form validators that cover the most typical developer needs and are highly configurable. However, in some cases, a developer may need to create a custom validator.

This recipe is a good example of creating a standalone validator that checks the number of words.

Getting ready

Create a new application by using the Composer package manager, as described in the official guide at http://www.yiiframework.com/doc-2.0/guide-start-installation.html.

How to do it...

1. Create a standalone validator at @app/components/WordsValidator.php as follows:

   <?php namespace app\components; use yii\validators\Validator; class WordsValidator extends Validator { public $size = 50; public function validateValue($value){ ...