Form Type Bundle

Form type bundle is an extension for the Contao CMS to provide a generic way to create forms for specific approaches with contao form generator. It is aimed at developers and contains no build-in form types.

Feature

• Generic way to create forms for specific approaches with contao form generator
• Options event for select, checkbox and radio form fields
• Form types can support a first time wizard to setup basic form fields

Installation

Install the bundle via composer and update your database afterwards:

composer require heimrichhannot/contao-form-type-bundle

Usage

Create a new form type

Create a new class that extends AbstractFormType. Register it as service with autoconfiguration enabled.

A label can be set within $GLOBALS['TL_LANG']['tl_form']['FORMTYPE']:

# contao/languages/de/tl_form.php
$GLOBALS['TL_LANG']['tl_form']['FORMTYPE']['huh_mediathek'] = 'Mediathek';

First time wizard

You can add a first time wizard to your form type by implementing getDefaultFields() method. It expects field definitions in array format as return values. These fields will be created when executing the wizard.

public function getDefaultFields(FormModel $formModel): array
{
    return [
        [
            'type' => 'text',
            'name' => 'title',
            'label' => $this->translator->trans('tl_example.title.0', [], 'contao_tl_example'),
            'mandatory' => '1',
        ],
        [
            'type' => 'textarea',
            'name' => 'text',
            'label' => $this->translator->trans('tl_example.text.0', [], 'contao_tl_example'),
        ],
    ];
}

Form events

You can register event listeners for events during form livecycle. These events are mappings of the corresponding contao form hooks but will only fire for the specific form type.

Following events are available:

Event	Name
CompileFormFieldsEvent	huh.form_type.[TYPE].compile_form_fields
LoadFormFieldEvent	huh.form_type.[TYPE].load_form_field
PrepareFormDataEvent	huh.form_type.[TYPE].prepare_form_data
ProcessFormDataEvent	huh.form_type.[TYPE].process_form_data
StoreFormDataEvent	huh.form_type.[TYPE].store_form_data
ValidateFormFieldEvent	huh.form_type.[TYPE].validate_form_field

Options event

If you want to provide options for a select, checkbox or radio form field, you can register an event listener. The event name is huh.form_type.<formtype>.<field>.options'.

// src/EventListener/OptionsEventListener.php
use HeimrichHannot\FormTypeBundle\Event\FieldOptionsEvent;

class OptionsEventListener implements EventSubscriberInterface
{
    public static function getSubscribedEvents()
    {
        return [
            'huh.form_type.huh_media_library.licence.options' => 'onLicenceOptions',
        ];
    }

    public function onLicenceOptions(FieldOptionsEvent $event): void
    {
        $event->addOption('free', 'Free');
        $event->addOption('adobe', 'Adobe');
        $event->addOption('istock', 'iStock');
    }
}

Unified Dispatcher for Field Options

Use FieldOptionsDispatcherTrait to dispatch FieldOptionsEvent huh.form_type.<formtype>.<field>.options and Contao fields.<field>.options callbacks alike.

Example:

use HeimrichHannot\MediaLibraryBundle\Trait\FieldOptionsDispatcherTrait;

class MyContainerOrFormType
{
    use FieldOptionsDispatcherTrait;

    #[AsCallback(table: 'tl_ml_product', target: 'fields.licence.options')]
    #[AsEventListener('huh.form_type.huh_media_library.licence.options')]
    public function getLicenceOptions(): array
    {
        return $this->dispatchFieldOptions([
            'free' => 'Released for use under indication of copyright',
            'locked' => 'Subject to licence'
        ]);
    }
}

Form Context

Implementing a form context evaluator on your from type allows you to change the form's behavior depending on the context it is used in. This can be used e.g. to load existing data into the form fields, perhaps to create an editing form.

Built-in Form Edit Context

A basic default form context evaluator providing editing functionality is built into the bundle. Just override DEFAULT_FORM_CONTEXT_TABLE in your form type to allow editing the respective database model:

protected const DEFAULT_FORM_CONTEXT_TABLE = 'tl_my_table';

• Create your form in Contao.
• Name your form fields like the database fields you want to edit, e.g. title for tl_my_table.title.
• Append the query parameter ?edit=<id> to the url of the page your form is included in to edit the existing row with a primary key of <id>.

If no DEFAULT_FORM_CONTEXT_TABLE is set, the form will be treated as a creation form by default.

Create your own Form Context

To implement your own form context evaluator, override evaluateFormContext() in your form type:

protected function evaluateFormContext(): FormContext
{
    $request = $this->container->get('request_stack')->getCurrentRequest();
    $editParameter = 'edit';
    $databaseTable = 'tl_my_table';

    if ($modelPk = $request->query->get($editParameter))
    {
        /** @var class-string<Model> $modelClass */
        $modelClass = Model::getClassFromTable($databaseTable);
        $modelInstance = $modelClass::findByPk($modelPk);
        if ($modelInstance === null) {
            return FormContext::invalid($databaseTable, 'Could not find object.');
        }
        return FormContext::update($databaseTable, $modelInstance->row());
    }

    return FormContext::create($databaseTable);
}

The example shows the implementation of a form context evaluator that allows editing a database model with a primary key given by the query parameter edit.

To retrieve the current form context, call the getter on your form type:

$formContext = $this->getFormContext();

We do not recommend to call $this->evaluateFormContext() directly, as it will skip future cache implementations if you do.

Form Context Actions

Most commonly used form context actions are already implemented.

use HeimrichHannot\FormTypeBundle\FormType\FormContextAction;

FormContextAction::CREATE;
FormContextAction::READ;
FormContextAction::UPDATE;
FormContextAction::DELETE;
FormContextAction::CLONE;
FormContextAction::INVALID;

FormContextAction::INVALID can be used to indicate that the form should not be processed.

To instantiate a FormContext object with a built-in action, use the static factory methods:

use HeimrichHannot\FormTypeBundle\FormType\FormContext;

$createContext  = FormContext::create('tl_my_table');
$readContext    = FormContext::read('tl_my_table', $data);
$updateContext  = FormContext::update('tl_my_table', $data);
$deleteContext  = FormContext::delete('tl_my_table', $data);

$cloneContext   = FormContext::clone('tl_my_table', $data);

$invalidContext = FormContext::invalid('tl_my_table', 'This is error detail.', $additionalData ?? []);

Alternatively, you may also use the FormContext constructor:

use HeimrichHannot\FormTypeBundle\FormType\FormContext;
use HeimrichHannot\FormTypeBundle\FormType\FormContextAction;

$formContext = new FormContext(FormContextAction::UPDATE, 'tl_my_table', $data);

However, you may also specify your own actions when constructing a FormContext object, or by overriding the action of an existing object.

use HeimrichHannot\FormTypeBundle\FormType\FormContext;
use HeimrichHannot\FormTypeBundle\FormType\FormContextAction;

$formContext = new FormContext('my_custom_action', 'tl_my_table', $data);
// or
$formContext->setAction('this_can_be_any_string_or_action');
// or
$formContext->setAction(FormContextAction::DELETE);

This way you are not bound to the built-in actions.