Frontend rendering

Basic code components

Basic code components

Basic code components

TYPO3\CMS\Form\Domain\Model\FormDefinition

The class TYPO3\CMS\Form\Domain\Model\FormDefinition encapsulates a complete form definition, with all of its

  • pages,
  • form elements,
  • applicable validation rules, and
  • finishers, which should be executed when the form is submitted.

The FormDefinition domain model is not modified when the form is executed.

The anatomy of a form

A FormDefinition domain model consists of multiple Page objects. When a form is displayed, only one Page is visible at any given time. Moreover, there is a navigation to go back and forth between those pages. A Page consists of multiple FormElements which represent the input fields, textareas, checkboxes, etc. shown on a page. The FormDefinition domain model, Page and FormElement objects have identifier properties which must be unique for each given <formElementTypeIdentifier>, i.e. the FormDefinition domain model and a FormElement object may have the same identifier but having the same identifier for two FormElement objects is disallowed.

Example

Basically, you can manually create a FormDefinition domain model just by calling the API methods on it, or you can use a FormFactory to build the form from a different representation format such as YAML:

$formDefinition = $this->objectManager->get(FormDefinition::class, 'myForm');

$page1 = $this->objectManager->get(Page::class, 'page1');
$formDefinition->addPage($page);

// second argument is the <formElementTypeIdentifier> of the form element
$element1 = $this->objectManager->get(GenericFormElement::class, 'title', 'Text');
$page1->addElement($element1);

Creating a form using abstract form element types

While you can use the TYPO3\CMS\Form\Domain\Model\FormDefinition::addPage() or TYPO3\CMS\Form\Domain\Model\FormElements\Page::addElement() methods and create the Page and FormElement objects manually, it is often better to use the corresponding create* methods (TYPO3\CMS\Form\Domain\Model\FormDefinition::createPage() and TYPO3\CMS\Form\Domain\Model\FormElements\Page::createElement()), as you pass them an abstract <formElementTypeIdentifier> such as Text or Page. EXT:form will automatically resolve the implementation class name and set default values.

The simple example shown above should be rewritten as follows:

// we will come back to this later on
$prototypeConfiguration = [];

$formDefinition = $this->objectManager->get(FormDefinition::class, 'myForm', $prototypeConfiguration);
$page1 = $formDefinition->createPage('page1');
$element1 = $page1->addElement('title', 'Text');

You might wonder how the system knows that the element Text is implemented by using a GenericFormElement. This is configured in the $prototypeConfiguration. To make the example from above actually work, we need to add some meaningful values to $prototypeConfiguration:

$prototypeConfiguration = [
    'formElementsDefinition' => [
        'Page' => [
            'implementationClassName' => 'TYPO3\CMS\Form\Domain\Model\FormElements\Page'
        ],
        'Text' => [
            'implementationClassName' => 'TYPO3\CMS\Form\Domain\Model\FormElements\GenericFormElement'
        ],
    ],
];

For each abstract <formElementTypeIdentifier> we have to add some configuration. In the snippet above, we only define the implementation class name. Apart form that, it is always possible to set default values for all configuration options of such elements, as the following example shows:

$prototypeConfiguration = [
    'formElementsDefinition' => [
        'Page' => [
            'implementationClassName' => 'TYPO3\CMS\Form\Domain\Model\FormElements\Page',
            'label' => 'This is the label of the page if nothing else is specified'
        ],
        'Text' => [
            'implementationClassName' => 'TYPO3\CMS\Form\Domain\Model\FormElements\GenericFormElement',
            'label' = >'Default Label',
            'defaultValue' => 'Default form element value',
            'properties' => [
                'placeholder' => 'Text that is shown if element is empty'
            ],
        ],
    ],
];

Using pre-configured $prototypeConfiguration

Often, it does not make sense to manually create the $prototypeConfiguration array. Bigger parts of this array are pre-configured in the extensions’s YAML settings. The TYPO3\CMS\Form\Domain\Configuration\ConfigurationService contains helper methods which return the ready-to-use $prototypeConfiguration.

Rendering a FormDefinition

To trigger the rendering of a FormDefinition domain model, the current TYPO3\CMS\Extbase\Mvc\Web\Request needs to be bound to the FormDefinition. This binding results in a TYPO3\CMS\Form\Domain\Runtime\FormRuntime object which contains the Runtime State of the form. Among other things, this object includes the currently inserted values:

// $currentRequest and $currentResponse need to be available
// inside a controller, you would use $this->request and $this->response;
$form = $formDefinition->bind($currentRequest, $currentResponse);
// now, you can use the $form object to get information about the currently entered values, etc.

TYPO3\CMS\Form\Domain\Runtime\FormRuntime

This class implements the runtime logic of a form, i.e. the class

  • decides which page is currently shown,
  • determines the current values of the form
  • triggers validation and property mappings.

You generally receive an instance of this class by calling TYPO3\CMS\Form\Domain\Model\FormDefinition::bind().

Rendering a form

Rendering a form is easy. Just call render() on the FormRuntime:

$form = $formDefinition->bind($request, $response);
$renderedForm = $form->render();

Accessing form values

In order to get the values the user has entered into the form, you can access the FormRuntime object like an array. If a form element with the identifier firstName exists, you can use $form['firstName'] to retrieve its current value. You can set values the same way.

Rendering internals

The FormRuntime inquires the FormDefinition domain model regarding the configured renderer (TYPO3\CMS\Form\Domain\Model\FormDefinition::getRendererClassName()) and then triggers render() on this Renderer.

This allows you to declaratively define how a form should be rendered.

TYPO3:
  CMS:
    Form:
      prototypes:
        standard:
          formElementsDefinition:
            Form:
              rendererClassName: 'TYPO3\CMS\Form\Domain\Renderer\FluidFormRenderer'

TYPO3\CMS\Form\Domain\Renderer\FluidFormRenderer

This class is a TYPO3\CMS\Form\Domain\Renderer\RendererInterface implementation which used to render a FormDefinition domain model. It is the default EXT:form renderer.

Learn more about the FluidFormRenderer Options.

Custom form element implementations

EXT:form ships a decent amount of hooks which are available at crucial points of the life cycle of a FormElement. Most of the time, own implementations are therefore unnecessary. An own form element can be defined by:

  • writing some configuration, and
  • utilizing the standard implementation of TYPO3\CMS\Form\Domain\Model\FormElements\GenericFormElement.
TYPO3:
  CMS:
    Form:
      prototypes:
        standard:
          formElementsDefinition:
            CustomFormElementIdentifier:
              implementationClassName: 'TYPO3\CMS\Form\Domain\Model\FormElements\GenericFormElement'

With the provided hooks, this FormElement can now be manipulated.

If you insist on your own implementation, the abstract class TYPO3\CMS\Form\Domain\Model\FormElements\AbstractFormElement offers a perfect entry point. In addition, we recommend checking-out TYPO3\CMS\Form\Domain\Model\Renderable\AbstractRenderable. All of your own form element implementations must be programmed to the interface TYPO3\CMS\Form\Domain\Model\Renderable\RenderableInterface. It is a good idea to derive your implementation from TYPO3\CMS\Form\Domain\Model\FormElements\AbstractFormElement.

“render” viewHelper

The RenderViewHelper is the actual starting point for form rendering and not the typical Extbase Controller as you may know it.

For more technical insights read more about the viewHelper’s arguments.

Render through FLUIDTEMPLATE (without controller)

tt_content.custom_content_element = COA_INT
tt_content.custom_content_element {
    10 = < lib.stdheader
    20 = FLUIDTEMPLATE
    20 {
        file = EXT:my_site_package/Resources/Private/Templates/CustomContentElement.html
        settings {
            persistenceIdentifier = EXT:my_site_package/Resources/Private/Forms/MyForm.yaml
        }
        extbase.pluginName = Formframework
        extbase.controllerExtensionName = Form
        extbase.controllerName = FormFrontend
        extbase.controllerActionName = perform
    }
}

my_site_package/Resources/Private/Templates/CustomContentElement.html:

<formvh:render persistenceIdentifier="{settings.persistenceIdentifier}" />

Render within your own Extbase extension

It is straight forward. Use the RenderViewHelper like this and you are done:

<formvh:render persistenceIdentifier="EXT:my_site_package/Resources/Private/Forms/MyForm.yaml"/>

Point the property controllerAction to the desired action name and provide values for the other parameters displayed below (you might need those).

type: Form
identifier: 'example-form'
label: 'TYPO3 is cool'
prototypeName: standard
renderingOptions:
  controllerAction: perform
  addQueryString: false
  argumentsToBeExcludedFromQueryString: []
  additionalParams: []

renderables:
  ...

Build forms programmatically

To learn more about this topic, head to the chapter ‘Build forms programmatically’ which is part of the API reference section.

Runtime manipulation

Hooks

EXT:form implements a decent amount of hooks that allow the manipulation of your forms during runtime. In this way, it is possible to, for example,

  • … prefill form elements with values from your database,
  • … skip a whole page based on the value of a certain form element,
  • … mark a form element as mandatory depending of the chosen value of another form element.

Please check out the ‘API reference section’ for more details.

TypoScript overrides

Each and every form definition can be overridden via TypoScript if the FormFrontendController of EXT:form is used to render the form. Normally, this is the case if the form has been added to the page using the form plugin or when rendering the form via FLUIDTEMPLATE.

The overriding of settings with TypoScript’s help takes place after the custom finisher settings of the form plugin have been loaded. In this way, you are able to manipulate the form definition for a single page. In doing so, the altered form definition is passed to the RenderViewHelper which then generates the form programmatically. At this point, you can still change the form elements using the above-mentioned concept of hooks.

plugin.tx_form {
    settings {
        formDefinitionOverrides {
            <formDefinitionIdentifier> {
                renderables {
                    0 {
                        renderables {
                            0 {
                                label = TEXT
                                label.value = Overridden label
                            }
                        }
                    }
                }
            }
        }
    }
}

Templates

The Fluid templates of the form framework are based on Twitter Bootstrap.

Custom templates

If you want to use custom Fluid templates for the frontend output of the form elements, you cannot register an additional template path using TypoScript. Instead, the registration of new template paths has to be done via YAML. The settings are part of the prototypes configuration.

TYPO3:
  CMS:
    Form:
      prototypes:
        standard:
          formElementsDefinition:
            Form:
              renderingOptions:
                templateRootPaths:
                  100: 'EXT:my_site_package/Resources/Private/Frontend/Templates/'
                partialRootPaths:
                  100: 'EXT:my_site_package/Resources/Private/Frontend/Partials/'
                layoutRootPaths:
                  100: 'EXT:my_site_package/Resources/Private/Frontend/Layouts/'

For each form definition - which references the prototype standard - the form framework will additionally look for Fluid templates within the path ‘EXT:my_site_package/Resources/Private/Frontend/[*]’ as set above. Apart from the ‘Form’ element, the process will search for templates within the partialRootPaths folder. The name of the partial is derived from the property formElementTypeIdentifier. For example, the template of the form element Text must be stored within the partialRootPaths folder named Text.html. In contrast, the template of the Form element must reside within the templateRootPaths folder. According to the introduced logic, the template name must be Form.html.

Translation

Translate form definition

The translation of form definitions works differently to the translation of the backend aspects. Currently, there is no graphical user interface supporting the translation process.

If the backend editor needed to translate the form definition properties in the same way the backend aspects are translated, he/ she would see long and unwieldy translation keys while editing a form within the form editor. In order to avoid this, rather the element properties are translated than their values. Thus, the form framework does not look for translation keys within the translation file. Instead, the system searches for translations of the form element properties independent of their property values. The property values are ignored if the process finds a proper entry within the translation file. As a result, the property values are overridden by the translated value.

This approach is a compromise between two scenarios: the exclusive usage of the form editor and/ or the manual creation of form definitions which can afterwards (theoretically) be edited with the form editor. In addition, the described compromise allows the editor to create forms in the default language whose form element property values are displayed as specified in the form editor. Based on this, an integrator could provide additional language files which automatically translate the specific form.

Additional translation files can be defined as follows:

TYPO3:
  CMS:
    Form:
      prototypes:
        standard:
          formElementsDefinition:
            Form:
              renderingOptions:
                translation:
                  translationFile:
                    # translation files for the frontend
                    10: 'EXT:form/Resources/Private/Language/locallang.xlf'
                    20: 'EXT:my_site_package/Resources/Private/Language/Form/locallang.xlf'

Due to compatibility issues, the setting translationFile is not defined as an array in the default configuration. To load your own translation files, you should define an array containing ‘EXT:form/Resources/Private/Language/Form/locallang.xlf’ as first entry (key 10) followed by your own file (key 20) as displayed in the example above. The array is processed from the highest key to the lowest, i.e. your translation file with the key 20 is processed first. If the look-up process does not find a key within all of the provided files, the property value will be displayed unmodified.

The following properties can be translated:

  • label
  • properties.[*]
  • properties.options.[*]
  • properties.fluidAdditionalAttributes.[*]
  • renderingOptions.[*]

The translation keys are put together based on a specific pattern. In addition, a fallback chain that depends on the form element identifiers exists. As a result, the following translation scenarios are possible:

  • translation of a form element property for a specific form and form element
  • translation of a form element property for a specific form element and various forms
  • translation of a form element property for an element type and various forms, e.g. the Page element

The look-up process searches for translation keys in all given translation files based on the following order:

  • <formDefinitionIdentifier>.element.<elementIdentifier>.properties.<propertyName>
  • element.<formElementIdentifier>.properties.<propertyName>
  • element.<elementType>.properties.<propertyName>

Form elements with option properties (properties.options), like the Select element, feature the following look-up process:

  • <formDefinitionIdentifier>.element.<elementIdentifier>.properties.options.<propertyValue>
  • element.<elementIdentifier>.properties.options.<propertyValue>

Example

identifier: ApplicationForm
type: Form
prototypeName: standard
label: 'Application form'

renderables:
  -
    identifier: GeneralInformation
    type: Page
    label: 'General information'

    renderables:
      -
        identifier: LastName
        type: Text
        label: 'Last name'
        properties:
          placeholder: 'Please enter your last name.'
        defaultValue: ''
      -
        identifier: Software
        type: MultiSelect
        label: 'Known software'
        properties:
          options:
            value1: TYPO3
            value2: Neos

For the form element LastName, the process will look for the following translation keys within the translation files:

  • ApplicationForm.element.LastName.properties.label
  • element.LastName.properties.label
  • element.Text.properties.label

If none of the above-mentioned keys exist, ‘Last name’ will be displayed.

For the form element Software, the process will look for the following translation keys within the translation files:

  • ApplicationForm.element.Software.properties.label
  • element.Software.properties.label
  • element.MultiSelect.properties.label

If none of the above-mentioned keys exist, ‘Known software’ will be displayed. The option properties are addressed as follows:

  • ApplicationForm.element.Software.properties.options.value1
  • element.Software.properties.options.value1
  • ApplicationForm.element.Software.properties.options.value2
  • element.Software.properties.options.value2

If none of the above-mentioned keys exist, ‘TYPO3’ will be displayed as label for the first option and ‘Neos’ as label for the second option.

Translation of validation messages

The translation of validation messages is similar to the translation of form definitions. The same translation files can be used. If the look-up process does not find a key within the provided files, the appropriate message of the Extbase framework will be displayed. EXT:form already translates all of those validators by default.

As mentioned above, the translation keys are put together based on a specific pattern. Furthermore, the fallback chain exists here as well. Thus, the following translation scenarios are possible:

  • translation of validation messages for a specific validator of a concrete form element and concrete form
  • translation of validation messages for a specific validator of various form elements within a concrete form
  • translation of validation messages for a specific validator of a concrete form element in various forms
  • translation of validation messages for a specific validator within various forms

In Extbase, the validation messages are identified with the help of numerical codes (UNIX timestamps). For the same validator, different codes are valid. Read more about concrete validator configurations.

The look-up process searches for translation keys in all given translation files based on the following order:

  • <formDefinitionIdentifier>.validation.error.<elementIdentifier>.<validationErrorCode>
  • <formDefinitionIdentifier>.validation.error.<validationErrorCode>
  • validation.error.<elementIdentifier>.<validationErrorCode>
  • validation.error.<validationErrorCode>

Example

identifier: ContactForm
type: Form
prototypeName: standard
label: 'Contact us'

renderables:
  -
    identifier: Page1
    type: Page
    label: 'Page 1'

    renderables:
      -
        identifier: LastName
        type: Text
        label: 'Last name'
        properties:
          fluidAdditionalAttributes:
            required: required
        validators:
          -
            identifier: NotEmpty

Amongst others, the NotEmpty validator sends 1221560910 as <validationErrorCode>. If a user submits this form without providing a value for the field “Last name”, the NotEmpty validator fails. Now, the look-up process searches for the following translation keys for the NotEmpty validator combined with the form element LastName:

  • ContactForm.validation.error.LastName.1221560910
  • ContactForm.validation.error.1221560910
  • validation.error.LastName.1221560910
  • validation.error.1221560910

As mentioned above, if there is no corresponding translation key available, the default message of the Extbase framework will be shown.

Translation of finisher options

The translation of finisher options is similar to the translation of form definitions. The same translation files can be used. If the look-up process does not find a key within all provided files, the property value will be displayed unmodified.

As mentioned above, the translation keys are put together based on a specific pattern. Furthermore, the fallback chain exists here as well. Thus, the following translation scenarios are possible:

  • translation of finisher options for a specific finisher of a concrete form
  • translation of finisher options for a specific finisher of various forms

The look-up process searches for translation keys in all given translation files based on the following order:

  • <formDefinitionIdentifier>.finisher.<finisherIdentifier>.<optionName>
  • finisher.<finisherIdentifier>.<optionName>

Example

identifier: ContactForm
type: Form
prototypeName: standard
label: 'Contact us'

finishers:
  -
    identifier: Confirmation
    options:
      message: 'Thank you for your inquiry.'

renderables:
  ...

The look-up process searches for the following translation keys for the <finisherIdentifier> ‘Confirmation’ and the option ‘message’:

  • ContactForm.finisher.Confirmation.message
  • finisher.Confirmation.message

If no translation key exists, the message ‘Thank you for your inquiry.’ will be shown.

Form element translation arguments are supported

Form element property translations and finisher option translations can use placeholders to output translation arguments. Translations can be enriched with variable values by passing arguments to form element properties. The feature was introduced with Issue #81363.

Form element properties

Pure YAML is sufficient to add simple, static values:

renderables:
  - identifier: field-with-translation-arguments
    type: Checkbox
    label: This is a %s feature
    renderingOptions:
      translation:
        translationFile: path/to/locallang.xlf
        arguments:
          label:
            - useful

This will produce the label: This is a useful feature.

Alternatively, translation arguments can be set via formDefinitionOverrides in TypoScript. A common usecase is a checkbox for user confirmation linking to details of the topic. Here it makes sense to use YAML hashes instead of YAML lists to give sections named keys. This simplifies references in TypoScript a lot since named keys are way more readable and also keep the setup working in case elements are reordered. With lists and numeric keys the TypoScript setup would also need to be updated in this case.

In the following example the list of renderables has been replaced with a hash of renderables and the field field-with-translation-arguments has received a named key fieldWithTranslationArguments. This key can be anything as long as it is unique on the same level, usually simply copying the identifier should be enough:

renderables:
  fieldWithTranslationArguments:
    identifier: field-with-translation-arguments
    type: Checkbox
    label: I agree to the <a href="%s">terms and conditions</a>
    renderingOptions:
      translation:
        translationFile: path/to/locallang.xlf

The following TypoScript setup uses the named key fieldWithTranslationArguments to refer to the field and adds a page URL as translation argument:

plugin.tx_form {
    settings {
        formDefinitionOverrides {
            <form-id> {
                renderables {
                    0 {
                        # Page
                        renderables {
                            fieldWithTranslationArguments {
                                renderingOptions {
                                    translation {
                                        arguments {
                                            label {
                                                0 = TEXT
                                                0.typolink {
                                                    # Terms and conditions page, could be
                                                    # set also via TypoScript constants
                                                    parameter = 42
                                                    returnLast = url
                                                 }
                                              }
                                           }
                                        }
                                     }
                                  }
                               }
                            }
                         }
                      }
                   }
                }
             }
         }
      }
   }
}

The Page element of the form definition was not registered with a named key so a numeric key 0 must be used which, as mentioned above, is prone to errors when more pages are added or pages are reordered.

Important

There must be at least one translation file with a translation for the configured form element property. Arguments are not inserted into default values defined in a form definition.

Finishers

The same mechanism (YAML, YAML + TypoScript) works for finisher options:

finishers:
  finisherWithTranslationArguments:
    identifier: EmailToReceiver
    options:
      subject: My %s subject
      recipientAddress: foo@example.org
      senderAddress: bar@example.org
      translation:
        translationFile: path/to/locallang.xlf
        arguments:
          subject:
            - awesome

This will produce My awesome subject.