Node.php

<?php

namespace Drupal\node\Plugin\views\field;

use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Url;
use Drupal\views\ResultRow;
use Drupal\views\ViewExecutable;
use Drupal\views\Plugin\views\display\DisplayPluginBase;
use Drupal\views\Plugin\views\field\FieldPluginBase;

/**
 * Field handler to provide simple renderer that allows linking to a node.
 * Definition terms:
 * - link_to_node default: Should this field have the checkbox "link to node" enabled by default.
 *
 * @ingroup views_field_handlers
 *
 * @ViewsField("node")
 */
class Node extends FieldPluginBase {
    
    /**
     * {@inheritdoc}
     */
    public function init(ViewExecutable $view, DisplayPluginBase $display, array &$options = NULL) {
        parent::init($view, $display, $options);
        // Don't add the additional fields to groupby
        if (!empty($this->options['link_to_node'])) {
            $this->additional_fields['nid'] = [
                'table' => 'node_field_data',
                'field' => 'nid',
            ];
        }
    }
    
    /**
     * {@inheritdoc}
     */
    protected function defineOptions() {
        $options = parent::defineOptions();
        $options['link_to_node'] = [
            'default' => isset($this->definition['link_to_node default']) ? $this->definition['link_to_node default'] : FALSE,
        ];
        return $options;
    }
    
    /**
     * Provide link to node option
     */
    public function buildOptionsForm(&$form, FormStateInterface $form_state) {
        $form['link_to_node'] = [
            '#title' => $this->t('Link this field to the original piece of content'),
            '#description' => $this->t("Enable to override this field's links."),
            '#type' => 'checkbox',
            '#default_value' => !empty($this->options['link_to_node']),
        ];
        parent::buildOptionsForm($form, $form_state);
    }
    
    /**
     * Prepares link to the node.
     *
     * @param string $data
     *   The XSS safe string for the link text.
     * @param \Drupal\views\ResultRow $values
     *   The values retrieved from a single row of a view's query result.
     *
     * @return string
     *   Returns a string for the link text.
     */
    protected function renderLink($data, ResultRow $values) {
        if (!empty($this->options['link_to_node']) && !empty($this->additional_fields['nid'])) {
            if ($data !== NULL && $data !== '') {
                $this->options['alter']['make_link'] = TRUE;
                $this->options['alter']['url'] = Url::fromRoute('entity.node.canonical', [
                    'node' => $this->getValue($values, 'nid'),
                ]);
                if (isset($this->aliases['langcode'])) {
                    $languages = \Drupal::languageManager()->getLanguages();
                    $langcode = $this->getValue($values, 'langcode');
                    if (isset($languages[$langcode])) {
                        $this->options['alter']['language'] = $languages[$langcode];
                    }
                    else {
                        unset($this->options['alter']['language']);
                    }
                }
            }
            else {
                $this->options['alter']['make_link'] = FALSE;
            }
        }
        return $data;
    }
    
    /**
     * {@inheritdoc}
     */
    public function render(ResultRow $values) {
        $value = $this->getValue($values);
        return $this->renderLink($this->sanitizeValue($value), $values);
    }

}