The document discusses working with forms in Drupal 8. It covers creating a form by extending the FormBase class and implementing required methods. Forms can be rendered standalone or embedded in other pages. Validation checks form values and returns errors. Submitting stores values, outputs messages, and redirects. Existing forms can be reused and modified using form alterations.

1. Drupal 8: FormsDrupal 8: Forms
Working with forms in Drupal 8 modulesWorking with forms in Drupal 8 modules
Drupal Meetup StuttgartDrupal Meetup Stuttgart
05/07/2015

2. 1. Creating a form1. Creating a form

3. <?php
/**
* @file
* Contains DrupalconfigFormConfigExportForm.
*/
namespace DrupalconfigForm;
use DrupalCoreFormFormBase;
use DrupalCoreFormFormStateInterface;
class ConfigExportForm extends FormBase {
public function getFormId() {
return 'config_export_form';
}
public function buildForm(array $form, FormStateInterface $form_state) {
$form['description'] = array(
...
);
...
return $form;
}
public function submitForm(array &$form, FormStateInterface $form_state) {
...
}
}
Example: /modules/config/src/Form/ConfigExportForm.php

4. FormsForms
are classes
extending base forms
implementing parent methods / properties
using the Drupal Form API

5. Examples for base formsExamples for base forms
FormBase (generic)
ConfigFormBase (settings forms)
ConfirmFormBase (confirmation forms)
XYZFormBase (roll your own)

6. <?php
/**
* @file
* Contains DrupalconfigFormConfigExportForm.
*/
namespace DrupalconfigForm;
use DrupalCoreFormFormBase;
use DrupalCoreFormFormStateInterface;
class ConfigExportForm extends FormBase {
public function getFormId() {
return 'config_export_form';
}
public function buildForm(array $form, FormStateInterface $form_state) {
$form['description'] = array(
'#markup' => '<p>' . $this->t('Use the export button below to download your site configuration.') . '</p>',
);
$form['submit'] = array(
'#type' => 'submit',
'#value' => $this->t('Export'),
);
return $form;
}
public function submitForm(array &$form, FormStateInterface $form_state) {
$form_state->setRedirect('config.export_download');
}
}
Complete class: DrupalconfigFormConfigExportForm

7. 2. Rendering a form2. Rendering a form

8. ban.delete:
path: '/admin/config/people/ban/delete/{ban_id}'
defaults:
_form: 'DrupalbanFormBanDelete'
_title: 'Delete IP address'
requirements:
_permission: 'ban IP addresses'
ban.routing.yml
<?php
namespace DrupalbanForm;
use DrupalCoreFormConfirmFormBase;
...
class BanDelete extends ConfirmFormBase {
...
}
Rendering a standalone form on a page
BanDelete.php

9. ...
public function translatePage() {
return array(
'filter' => $this->formBuilder()->getForm('DrupallocaleFormTranslateFilterForm'),
'form' => $this->formBuilder()->getForm('DrupallocaleFormTranslateEditForm'),
);
}
...
DrupallocaleControllerlocaleContoller
<?php
namespace DrupallocaleForm;
use DrupalCoreFormFormStateInterface;
class TranslateFilterForm extends TranslateFormBase {
...
}
Embedding a form in other markup
DrupallocaleFormTranslateFilterForm

10. 3. Validating a form3. Validating a form

11. Validate =Validate =
Checking form values
Create error messages
Prepare for form submission
...

12. public function validateForm(array &$form, FormStateInterface $form_state) {
$this->file = file_save_upload('file', $form['file']['#upload_validators'], 'translations://', 0);
// Ensure we have the file uploaded.
if (!$this->file) {
$form_state->setErrorByName('file', $this->t('File to import not found.'))
}
}
Example: DrupallocaleFormImportForm

13. public function validateForm(array &$form, FormStateInterface $form_state) {
$name = trim($form_state->getValue('name'));
// Try to load by email.
$users = $this->userStorage->loadByProperties(array('mail' => $name, 'status' => '1'));
if (empty($users)) {
// No success, try to load by name.
$users = $this->userStorage->loadByProperties(array('name' => $name, 'status' => '1'));
}
$account = reset($users);
if ($account && $account->id()) {
$form_state->setValueForElement(array('#parents' => array('account')), $account);
}
else {
$form_state->setErrorByName('name', $this->t('Sorry, %name is not recognized as a
username or an email address.', array('%name' => $name)));
}
}
Example: DrupaluserFormUserPasswordForm

14. 4. Submitting a form4. Submitting a form

15. Submit =Submit =
Storing form values
Output messages
Write log information
Redirect to new URL
...

16. public function submitForm(array &$form, FormStateInterface $form_state) {
if ($form_state->getValue('confirm')) {
$this->commentStorage->delete($this->comments);
$count = count($form_state->getValue('comments'));
$this->logger('content')->notice('Deleted @count comments.', array('@count' => $count));
drupal_set_message($this->formatPlural($count, 'Deleted 1 comment.', 'Deleted @count comments.'));
}
$form_state->setRedirectUrl($this->getCancelUrl());
}
Example: DrupalcommentFormConfirmDeleteMultiple

17. public function submitForm(array &$form, FormStateInterface $form_state) {
$allowed_types = array_filter($form_state->getValue('book_allowed_types'));
// We need to save the allowed types in an array ordered by machine_name so
// that we can save them in the correct order if node type changes.
// @see book_node_type_update().
sort($allowed_types);
$this->config('book.settings')
// Remove unchecked types.
->set('allowed_types', $allowed_types)
->set('child_type', $form_state->getValue('book_child_type'))
->save();
parent::submitForm($form, $form_state);
}
Example: DrupalbookFormBookSettingsForm

18. 5. Reusing existing forms5. Reusing existing forms

19. Reuse =Reuse =
Create a new form based on an existing form

20. <?php
/**
* @file
* Contains DrupalblockFormBlockDeleteForm.
*/
namespace DrupalblockForm;
use DrupalCoreEntityEntityDeleteForm;
use DrupalCoreUrl;
/**
* Provides a deletion confirmation form for the block instance deletion form.
*/
class BlockDeleteForm extends EntityDeleteForm {
/**
* {@inheritdoc}
*/
public function getCancelUrl() {
return new Url('block.admin_display');
}
}
Example: DrupalblockFormBlockDeleteForm

21. 6. Modifying forms6. Modifying forms

22. Some old friends:Some old friends:
hook_form_alter()
hook_form_FORM_ID_alter()
hook_form_BASE_FORM_ID_alter()

23. ...
use DrupalCoreFormFormStateInterface;
...
function mymodule_form_node_form_alter(&$form, FormStateInterface $form_state, $form_id) {
// Add a checkbox to the node form about agreeing to terms of use.
$form['terms_of_use'] = array(
'#type' => 'checkbox',
'#title' => t("I agree with the website's terms and conditions."),
'#required' => TRUE,
);
}
Example: mymodule.module

24. Thank You!Thank You!
http://slides.com/drubb
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