How can I programmatically render a node's field respecting the view mode settings?

Question

I want to render a node's field inside a block. It works like this:

<?php

if ($node) {
  if (isset($node->field_body_secondary) && $field = $node->field_body_secondary->value) {
    $markup = render($field);
    $build = array(
      '#type' => 'markup',
      '#markup' => $markup,
    );
  }
}

return $build;

But this is not 100% as if I would just render the field normally, making it visible in the view mode settings.

Answer 1

I think the viewmode should be applied to the node, not to the field. So you need to get the viewbuilder and render the node. Afterwards you can pick the rendered array for the field from the node'r render array. Kind of like this:

$vb = [EntityTypeManager]->getViewBuilder('node'); // Drupal\node\NodeViewBuilder
$nodeview = $vb->view($node, $viewmode);
$fieldrenderarray = $nodeview[youfield-here];

P.S. You need to "[EntityTypeManager]" anyhow injected as @entity_type.manager service. Or get it in your Block-Plugin create() from $container->get('entity_type.manager').

Answer 2

To render a single field with the display setting of a view mode you can use the view() method of the field:

Example for rendering the image the way it's configured in the node's teaser view-mode:

$build['image'] = $node->field_image->view('teaser');

Or the body as it's configured in the node's full view-mode:

$build['body'] = $node->body->view('full');

Or if you want to have more fine-grained control, you can programmatically recreate how Drupal is doing view-modes:

$display_options = [
  'label' => 'hidden',
  'type' => 'entity_reference_entity_view',
  'settings' => [
    'view_mode' => 'some_media_image_view_mode',
  ],
];
$build['image'] = $node->field_image->view($display_options);

You can figure out the type/settings by inspecting the HTML on the view-modes form (e.g. /admin/structure/types/manage//display/full ) or export the configuration and inspect the YAML files.

Answer 3

This answer builds on https://drupal.stackexchange.com/a/208061/394

// Designate the field we want to render.
$field_name = 'body';
// Retrieve a render array for that field with the given view mode.
$render_array = $entity->$field_name->view('full');
// Render the result.
\Drupal::service('renderer')->renderRoot($render_array);

To completely programmatically render the field you finish by calling renderRoot(), which establishes a separate render context from what typical page responses would use -- a single render context for a request or sub-request. We could also use renderPlain(), but then it would escape all the things.

In the Drush repl but not in normal page execution, this threw a warning for me:

PHP warning:  DOMDocument::loadHTML(): Tag drupal-entity invalid in Entity, line: 1 in /drupal/core/lib/Drupal/Component/Utility/Html.php on line 286

Answer 4

Thanks to Rainer Feike's answer I came to the solution:

<?php

public function build() {
  $node = \Drupal::routeMatch()->getParameter('node');
  $build = array();
  $markup = array();

  $fieldsToRender = array(
    'field_node_ref', 'field_foo', 'field_bar',
  );

  $viewmode = 'default';
  $entityType = 'node';
  $display = entity_get_display($entityType, $node->getType(), $viewmode);
  $viewBuilder = \Drupal::entityTypeManager()->getViewBuilder($entityType);

  foreach ($fieldsToRender as $field_name) {
    if (isset($node->{$field_name}) && $field = $node->{$field_name}) {
      $fieldRenderable = $viewBuilder->viewField($field, $display->getComponent($field_name));
      if (count($fieldRenderable) &&! empty($fieldRenderable)) {
        $markup[] = \Drupal::service('renderer')->renderRoot($fieldRenderable);
      }
    }  
  }

  if (count($markup)) {
    $build = array(
      '#type' => 'markup',
      '#markup' => implode("", $markup),
    );
  }

  return $build;

}

Using $viewBuilder->viewField I can render any fields separately I need. I just need to find out how to add caching depending on the view mode settings, but this is another question :)

Answer 5

related to Alex's answer, here is how I modified it to use config_pages and build a global_footer block:

<?php

public function build() {
$config_name = 'global_footer';
$config = config_pages_config($config_name);
$build = array();
$markup = array();

$fieldsToRender = array(
  'field_body', 'field_foo', 'field_bar'
);

$viewmode = 'default';
$entityType = 'config_pages';
$display = entity_get_display($entityType, $config_name, $viewmode);
$viewBuilder = \Drupal::entityTypeManager()->getViewBuilder($entityType);

foreach ($fieldsToRender as $field_name) {
  if (isset($config->{$field_name}) && $field = $config->{$field_name}) {
    $fieldRenderable = $viewBuilder->viewField($field, $display->getComponent($field_name));
    if (count($fieldRenderable) &&! empty($fieldRenderable)) {
      $markup[] = \Drupal::service('renderer')->renderRoot($fieldRenderable);
    }
  }
}

if (count($markup)) {
  $build = array(
    '#type' => 'markup',
    '#markup' => implode("", $markup),
  );
}

return $build;

}

It's probably better to render arbitrary fields from a config_pages setup as opposed to pulling data from a node, but I guess it really depends on the specific use-case as to which method is best.