Add a non-base field to a content entity form

Question

What is the proper way to add a non-base textarea field to the entity form of a custom content entity?

comment and user modules have non-base fields that display in their entity form (comment_body and picture), but it appears these fields are added to the form somewhere besides the main entity form method they use.

In my module, I've created a field and instance inside hook_install like this:

<?php
function mymodule_install() {
  $field = array(
    'name' => 'myfield',
    'entity_type' => 'myentitytype',
    'type' => 'text_long',
    'module' => 'text',
    'settings' => array(),
    'cardinality' => 1,
    'locked' => FALSE,
    'indexes' => array(),
  );
  entity_create('field_entity', $field)->save();

  $instance = array(
    'field_name' => 'myfield',
    'entity_type' => 'myentitytype',
    'bundle' => 'myentitytype',
    'label' => 'Field title',
    'description' => t('Field description.'),
    'required' => TRUE,
    'default_value' => array(),
    'settings' => array(
      'text_processing' => '0'
    ),
  );
  entity_create('field_instance', $instance)->save();
}

I think if I could be pointed to how comment_body gets added to the comment entity form, or picture to the user entity form, I'd be able to resolve this.

Answer 1

You can ship a locked Field with yml only, see core/modules/forum/config/field.*. Ie just make the fields in the ui and copy the yml files from your active store to a config folder inside your module.

This ships a locked boolean field for the container flag. You'll also need form and entity display entities, but you can create them in the ui and grab the yml for them too.

Answer 2

Parts of how to do this have chanaged or are deprecated. The arrays are mostly correct (name is now field_name) (look in the yml for example values if you don't know what to use) but the functions are now:

\Drupal::entityManager()->getStorage('field_storage_config')->create($field)->save();

\Drupal::entityManager()->getStorage('field_config')->create($instance)->save();

You can find out how this all works including setting the field on form displays and view displays in /core/modules/field_ui/src/Form/FieldStorageAddForm.php.

Answer 3

The solution is to add the following code after the field instance is created.

This is what the config files named entity.form_display* are based on.

entity_get_form_display('myentitytype', 'myentitytype', 'default')
->setComponent('myfield', array(
  'type' => 'text_long',
  'settings' => array(
    'text_processing' => '0'
  ),
  'weight' => 5,
))
->save();