how do I add contextual edit links in block template for a block entity?

Question

In Drupal 8, how do I add contextual edit links in a block template?

This is for block entities created at /block/add, not block plugins created by a class in a custom module.

I want an edit link to display on the front end. I want an edit link for the block, not for the block content type (bundle). For example, a link to /block/123.

I believe it's supposed to be output by

{{ title_prefix }}

But I don't see the links showing up and I'm not sure where to turn them on.

I was able to get them to render with this code, but then realized this only works for block plugins, not block entities:

function exampletheme_preprocess_block(&$variables) {

  if (!empty($variables['elements']['#contextual_links'])) {
    $variables['elements'] = ContextualLinks::preRenderLinks($variables['elements']);
    $variables['links'] = array(
      '#prefix' => '<div class="contextual-links-wrapper">',
      '#suffix' => '</div>',
      '#theme' => 'links__contextual',
      '#links' => $variables['elements']['#links'],
      '#attributes' => array('class' => array('contextual-links')),
      '#attached' => array(
        'library' => array(
          'contextual/drupal.contextual-links',
        ),
      ),
      '#weight' => -10,
    );
    $variables['attributes']['class'][] = 'contextual-links-region';
  }

}

This added some links to edit the content type (although I never got them to render).

Finally, I just rolled my own:

$entity_view = $render_controller->view($block);

$entity_wrapper = [
  '#type' => 'container',
  '#attributes' => [
    'id' => ['block-' . $block->id()],
    'class' => ['example-container-class'],
  ],
];

$entity_wrapper['content'] = [];

$edit_link = $block->toLink()->toRenderable();
$edit_link['#title'] = t('Edit');
$edit_link['#attributes'] = [
  'class' => ['edit-link'],
];
$entity_wrapper['content'][] = $edit_link;
$entity_wrapper['content'][] = $entity_view;

$build[] = $entity_wrapper;

After that, I dug around a little and found a way to render the built-in contextual links for block_content entities. You have to do a little legwork while building up your render array:

use Drupal\contextual\Element\ContextualLinks;

First load up your block_content entity:

In this case, I'm only expecting one of this bundle or type:

 $blocks = \Drupal::entityManager()->getStorage('block_content')->loadByProperties(['type' => 'footer_middle']);
    if (!empty($blocks)) {
      $block = array_shift($blocks);

}

Now we render the entity using the entity manager:

  $render_controller = \Drupal::entityManager()->getViewBuilder('block_content');
  $footer_middle = $render_controller->view($block);

The really tricky part is that block_content entities don't have a theme function or template, so you have to add the contextual links to a parent item, such as a container:

   $build['footer_middle'] = [
      '#type' => 'container',
      '#attributes' => [
        'id' => 'footer-middle',
        'class' => ['footer-container'],
      ],
    ];

      $build['footer_middle']['#contextual_links'] = $footer_middle['#contextual_links'];


Now we need to generate the links:

      $footer_middle = ContextualLinks::preRenderLinks($footer_middle);

Then set up the render array on the parent container, passing in the rendered links:

  $build['footer_middle']['links'] = array(
  '#prefix' => '<div class="contextual-links-wrapper">',
  '#suffix' => '</div>',
  '#theme' => 'links__contextual',
  '#links' => $footer_middle['#links'],
  '#attributes' => array('class' => array('contextual-links')),
  '#attached' => array(
    'library' => array(
      'contextual/drupal.contextual-links',
    ),
  ),
  '#weight' => -10,
);

And now add the rendered entity as a child of the container:

$build['footer_middle'][] = $footer_middle;

And now you have contextual links for your block_content entity!

Just make sure your container.html.twig is outputting

  {{ title_suffix }}

Since that's where the contextual drupal module puts it.

Answer 1

You probably want to have a look at contextual_preprocess.

If you add this to the render element or variables array before contextual_preprocess is called, it will handle the rest and add the stuff to title_prefix. Note I haven't tried this as an alter, only on entities I've created myself.

$render_element_or_variables['#contextual_links']['ENTITY_ID'] = [
  'route_parameters' => ['ENTITY' => $ID_OF_ENTITY],
];

If it's a render element, you should add it to the element key otherwise it should be the root of the array in the process/preprocess function you use.