How to use YAML to configure validation

Simplicity is at the heart of Silex so there is no out of the box solution to use YAML files for validation. But this doesn’t mean that this is not possible. Let’s see how to do it.

First, you need to install the YAML Component. Declare it as a dependency in your composer.json file:

"require": {
    "symfony/yaml": "2.1.*"
}

Next, you need to tell the Validation Service that you are not using StaticMethodLoader to load your class metadata but a YAML file:

$app->register(new ValidatorServiceProvider());

$app['validator.mapping.class_metadata_factory'] = new Symfony\Component\Validator\Mapping\ClassMetadataFactory(
    new Symfony\Component\Validator\Mapping\Loader\YamlFileLoader(__DIR__.'/validation.yml')
);

Now, we can replace the usage of the static method and move all the validation rules to validation.yml:

# validation.yml
Post:
  properties:
    title:
      - NotNull: ~
      - NotBlank: ~
    body:
      - Min: 100