Form in custom module using Controller: The HTML tag form isn't present in Twig

Question

I'm trying to render limited user edit form on custom page using Drupal Controller. In the routing.yml I defined _controller, I do not want to use _form.

I want to display on the form e.g. only timezone field, but not the rest. And I'm not able to achieve it. I can render this field, other fields like form_build_id, form_id, form_token But form html tag is not rendered at all. It works only if I display the whole form with {{ form.form }}.

This is the content of the files I am using.

my_module.info.yml

name: 'My module'
type: module
description: 'my module'
core_version_requirement: ^8.8 || ^9

my_module.routing.yml

my_module.mymodule_controller_view::
  path: '/my-module'
  defaults:
    _controller: '\Drupal\my_module\Controller\MymoduleController::view'
    _title: 'My module'
  requirements:
    _permission: 'access content'

my_module.module

function my_module_theme($existing, $type, $theme, $path)
{
    $templates = array(
        'my_module_form' => [
            'render element' => 'form',
        ],
    );

    return $templates;
}

MymoduleController.php

namespace Drupal\my_module\Controller;

use Drupal\Core\Controller\ControllerBase;
use Drupal\user\Entity\User;

class MymoduleController extends ControllerBase
{

    public function view()
    {
        $data['header'] = [
            '#type' => 'markup',
            '#markup' => '<h1>HEADER</h1>',
        ];

        $user = User::load(\Drupal::currentUser()->id());
        $formObject = \Drupal::entityTypeManager()
            ->getFormObject('user', 'default')
            ->setEntity($user);

        $form = \Drupal::formBuilder()->getForm($formObject);

        $data['form'] = [
            '#theme' => 'my_module_form',
            'form' => $form,
        ];

        $data['footer'] = [
            '#type' => 'markup',
            '#markup' => '<h3>footer</h3>',
        ];

        return $data;
    }
}

my-module-form.html.twig

<div>TWIG TEMPLATE</div>

{{ form.form.timezone }}
{{ form.form.form_build_id }}
{{ form.form.form_token }}
{{ form.form.form_id }}
{{ form.form.actions }}

Answer 1

This is not working, you can't use a form template in a controller. You have to assign the template to $form['#theme'] when building the form or in a form alter hook. Then it gets used by formBuilder()->getForm() automatically.

See for example seven_form_node_form_alter():

$form['#theme'] = ['node_edit_form'];

and the corresponding twig file for a two column layout:

core/themes/seven/templates/node-edit-form.html.twig

{#
/**
 * @file
 * Theme override for a node edit form.
 *
 * Two column template for the node add/edit form.
 *
 * This template will be used when a node edit form specifies 'node_edit_form'
 * as its #theme callback.  Otherwise, by default, node add/edit forms will be
 * themed by form.html.twig.
 *
 * Available variables:
 * - form: The node add/edit form.
 *
 * @see seven_form_node_form_alter()
 */
#}
<div class="layout-node-form clearfix">
  <div class="layout-region layout-region-node-main">
    {{ form|without('advanced', 'footer', 'actions') }}
  </div>
  <div class="layout-region layout-region-node-secondary">
    {{ form.advanced }}
  </div>
  <div class="layout-region layout-region-node-footer">
    <div class="layout-region-node-footer__content">
      {{ form.footer }}
      {{ form.actions }}
    </div>
  </div>
</div>

---

Form modes

A different approach would be to configure a form mode in UI containing only the field you want and then use it in your controller:

    $formObject = \Drupal::entityTypeManager()
        ->getFormObject('user', 'custom_form_mode')
        ->setEntity($user);

See How do I load a form with a specific form display (form mode)?