Extending Liform

If you need to transform custom Form Types and/or need extra data to be passed to your UI libraries you can easily extend the transformation with your own methods.

Transformer

A Transformer in Liform provides the JSON representation for a Form View. It must return a TransformResult that should include all information that is specific for the rendered Form Types.

use Pitch\Liform\Transformer\TransformerInterface;
use Pitch\Liform\TransformResult;
use Symfony\Component\Form\FormView;

class MyTransformer implements TransformerInterface
{
    public function transform(FormView $view): TransformResult
    {
        //...
    }
}

Resolver

Liform delegates the decision which Tranformer it should use to the Resolver.

The built-in Resolver traverses block_prefixes like a tranformation per Twig templates would.

You can write your own Transformers and bind them to a block prefix.

services:
    # ...
    App\MySpecialTransformer:
        tags:
            - { name: liform.transformer, block: my_block_prefix }
    App\MyTextFieldTransformer:
        tags:
            - { name: liform.transformer, block: text }

If you want to decide which Transformer another way you can replace the Resolver.

namespace App;

use Pitch\Liform\Transformer\TransformerInterface;
use Symfony\Component\Form\FormView;

class MyLiformResolver implements ResolverInterface
{
    public function resolve(FormView $view): TransformerInterface
    {
        /...
    }
}

services:
    # ...
    Pitch\Liform\ResolverInterface:
        class: App\MyLiformResolver

Extension

An Extension in Liform manipulates a TransformResult. It should add data structures that are shared across multiple Form Types.

use Pitch\Liform\Extension\ExtensionInterface;
use Pitch\Liform\TransformResult;
use Symfony\Component\Form\FormView;

class MyLiformExtension implements ExtensionInterface
{
    public function apply(TransformResult $transformResult, FormView $formView): void
    {
        // ...
    }
}

services:
    App\MyLiformExtension:
        tags:
            - { name: liform.extension }