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Pattern: Confirmation Form (ConfirmFormBase)

When to Use

Use ConfirmFormBase for delete operations and irreversible actions. Use FormBase for forms with additional input fields.

Appropriate Use Cases:

  • Delete operations (content, entities, config)
  • Destructive actions (purge, reset, uninstall)
  • Critical confirmations (irreversible operations)
  • Yes/no decision points

When NOT to Use:

  • Multi-field forms → Use FormBase
  • Confirmations with additional inputs → Use FormBase with custom styling

Pattern: Implementation

Core Example:

  • File: /web/core/modules/dblog/src/Form/DblogClearLogConfirmForm.php
  • Pattern: Minimal form, clear question, cancel link, custom confirm text

Form Structure:

Automatically provides:
- Question text (from getQuestion())
- Confirm button (from getConfirmText())
- Cancel link (from getCancelUrl())
- Standard confirmation form styling

use Drupal\Core\Form\ConfirmFormBase;
use Drupal\Core\Url;

class MyDeleteForm extends ConfirmFormBase {

  public function getQuestion() {
    return $this->t('Are you sure you want to delete this item?');
  }

  public function getCancelUrl() {
    return new Url('mymodule.collection');
  }

  public function getConfirmText() {
    return $this->t('Delete');
  }

  public function getFormId() {
    return 'mymodule_delete_confirm';
  }
}

Reference: Required Methods

Method Returns Purpose
getQuestion() TranslatableMarkup Main confirmation question
getCancelUrl() Url object Destination if user cancels
getConfirmText() TranslatableMarkup Submit button text (default: "Confirm")
getDescription() String (optional) Additional warning/info text
getFormName() String (optional) Internal form name

URL Pattern:

Cancel URL: Usually entity/list page or referring page
Use Url::fromRoute('entity.type.collection')
Or $entity->toUrl('collection')

Pattern: Customization Options

Custom Confirm Text:

Different from "Confirm":
- "Delete" for delete operations
- "Remove" for remove operations
- "Reset" for reset operations

Additional Elements:

Can add elements in buildForm()
Common: Checkboxes for "don't ask again", deletion options
Must call parent::buildForm() to preserve structure

Common Mistakes

  • Forgetting to implement required methods (getQuestion, getCancelUrl)
    • WHY BAD: PHP fatal error on form build, ConfirmFormBase expects these methods, form won't render
  • Returning string instead of Url object from getCancelUrl()
    • WHY BAD: Type error in Drupal 9+, expects Url object for route access checking and language prefix handling
  • Adding complex form elements (defeats purpose of confirm form)
    • WHY BAD: Users expect simple yes/no, complex forms confuse purpose, accessibility issues with mixed UI patterns
  • Not using descriptive confirm text (users ignore generic "Confirm")
    • WHY BAD: Users click without reading "Confirm", destructive actions executed without understanding, poor UX

See Also