Links.php

<?php

namespace Drupal\views\Plugin\views\field;

use Drupal\Component\Utility\Html;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Url as UrlObject;

/**
 * A abstract handler which provides a collection of links.
 *
 * @ingroup views_field_handlers
 */
abstract class Links extends FieldPluginBase {
    
    /**
     * {@inheritdoc}
     */
    public function usesGroupBy() {
        return FALSE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function defineOptions() {
        $options = parent::defineOptions();
        $options['fields'] = [
            'default' => [],
        ];
        $options['destination'] = [
            'default' => TRUE,
        ];
        return $options;
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildOptionsForm(&$form, FormStateInterface $form_state) {
        parent::buildOptionsForm($form, $form_state);
        // Only show fields that precede this one.
        $field_options = $this->getPreviousFieldLabels();
        $form['fields'] = [
            '#type' => 'checkboxes',
            '#title' => $this->t('Fields'),
            '#description' => $this->t('Fields to be included as links.'),
            '#options' => $field_options,
            '#default_value' => $this->options['fields'],
        ];
        $form['destination'] = [
            '#type' => 'checkbox',
            '#title' => $this->t('Include destination'),
            '#description' => $this->t('Include a "destination" parameter in the link to return the user to the original view upon completing the link action.'),
            '#default_value' => $this->options['destination'],
        ];
    }
    
    /**
     * Gets the list of links used by this field.
     *
     * @return array
     *   The links which are used by the render function.
     */
    protected function getLinks() {
        $links = [];
        foreach ($this->options['fields'] as $field) {
            if (empty($this->view->field[$field]->last_render_text)) {
                continue;
            }
            $title = $this->view->field[$field]->last_render_text;
            $path = '';
            $url = NULL;
            if (!empty($this->view->field[$field]->options['alter']['path'])) {
                $path = $this->view->field[$field]->options['alter']['path'];
            }
            elseif (!empty($this->view->field[$field]->options['alter']['url']) && $this->view->field[$field]->options['alter']['url'] instanceof UrlObject) {
                $url = $this->view->field[$field]->options['alter']['url'];
            }
            // Make sure that tokens are replaced for this paths as well.
            $tokens = $this->getRenderTokens([]);
            $path = strip_tags(Html::decodeEntities($this->viewsTokenReplace($path, $tokens)));
            $links[$field] = [
                'url' => $path ? UrlObject::fromUri('internal:/' . $path) : $url,
                'title' => $title,
            ];
            if (!empty($this->options['destination'])) {
                $links[$field]['query'] = \Drupal::destination()->getAsArray();
            }
        }
        return $links;
    }
    
    /**
     * {@inheritdoc}
     */
    public function query() {
    }

}