Working with forms in Drupal 8 modules, a presentation at Drupal Meetup Stuttgart, 05/07/2015

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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