---
title: "Service Configuration"
description: "Form rendering services, isolated Twig and tagged contributions"
type: "docs"
category: "doc"
tags: []
authors: [Anonymous]
date: "2026-10-30"
last_update: "2026-10-30"
time_minutes: 3
draft: false
unlisted: false
url: "https://www.derafu.dev/docs/ui/form/services"
---

# Service Configuration

Import the production configurations and provide your application's translator.
The translator receives the catalogues contributed by the imported packages:

```yaml
imports:
    - { resource: '../vendor/derafu/data-processor/resources/config/data-processor-services.yaml' }
    - { resource: '../vendor/derafu/form/resources/config/form-services.yaml' }

services:
    Symfony\Contracts\Translation\TranslatorInterface:
        class: Symfony\Component\Translation\Translator
        factory: ['Derafu\Translation\TranslatorFactory', 'create']
        arguments:
            $defaultLocale: en
            $fallbackLocales: [en]
            $resourceProviders: !tagged_iterator derafu_translation.resource_provider
```

Inject `FormFactoryInterface`, `FormRendererInterface` and
`FormDataProcessorInterface` into your application services. The factory creates
forms from definitions; the renderer and processor share the configured types,
rule evaluator and optional CSRF/captcha integrations.

## Isolated Rendering

Form rendering owns qualified services such as
`Derafu\Twig\Contract\TwigServiceInterface $form` and
`Derafu\Renderer\Contract\RendererInterface $form`. Importing Form does not
replace the application's Twig or Renderer services. The internal
`FormTwigExtension` is loaded only in the form environment. Symfony bundles can
register a separate prefixed extension in the native page environment.

The package's template directory is contributed automatically. Scalar Twig
options belong to `derafu.form.twig.options`, for example `{ extra: false }`.
`derafu.form.twig.component_registrar.cache_key` identifies the form-specific
component configuration when a PSR cache pool is provided.

## Contributions

Each domain supplies only its own providers. The following tags belong to the
form environment:

| Tag | Provider contract | Contribution |
| --- | --- | --- |
| `derafu_form.element_renderer_provider` | `ElementRendererProviderInterface` | Element type to renderer map |
| `derafu_form.widget_renderer_provider` | `WidgetRendererProviderInterface` | Widget type to renderer map |
| `derafu_form.twig.template_path_provider` | `Derafu\Twig\Contract\TemplatePathProviderInterface` | Template directories |
| `derafu_form.twig.extension_provider` | `Derafu\Twig\Contract\ExtensionProviderInterface` | Twig extensions |
| `derafu_form.twig.component_provider` | `Derafu\Twig\Contract\ComponentProviderInterface` | Twig component classes |
| `derafu_form.formatter_handler_provider` | `Derafu\Renderer\Contract\FormatterHandlerProviderInterface` | Named formatter handlers |
| `derafu_form.renderer.engine` | `Derafu\Renderer\Contract\EngineInterface` | Rendering engines |

Individual component classes can also use `derafu_form.twig.component`.
Providers are processed by descending tag priority. The first contribution for
an element/widget type wins. Default element/widget providers and the package's
template-path provider have priority `-1000`, so ordinary consumer providers
can override their own entries without copying the defaults. Twig retains its
first extension of each class; template directories are searched in priority
order. Formatter providers use the first handler of each name.

```yaml
services:
    App\Form\TemplatePathProvider:
        tags: ['derafu_form.twig.template_path_provider']

    App\Form\WidgetRendererProvider:
        tags:
            - { name: derafu_form.widget_renderer_provider, priority: 100 }
```

Registries remain injectable through `ElementRendererRegistryInterface` and
`WidgetRendererRegistryInterface`. Rendering extensions are resolved when Twig
creates its environment, allowing the internal form functions to call the same
form renderer without eager construction cycles.



---
Last updated on 30/10/2026