ContextualLinks.php

<?php

namespace Drupal\contextual\Plugin\views\field;

use Drupal\Component\Serialization\Json;
use Drupal\Component\Utility\Html;
use Drupal\Component\Utility\UrlHelper;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Routing\RedirectDestinationTrait;
use Drupal\Core\Url;
use Drupal\views\Plugin\views\field\FieldPluginBase;
use Drupal\views\ResultRow;

/**
 * Provides a handler that adds contextual links.
 *
 * @ingroup views_field_handlers
 *
 * @ViewsField("contextual_links")
 */
class ContextualLinks extends FieldPluginBase {
    use RedirectDestinationTrait;
    
    /**
     * {@inheritdoc}
     */
    public function usesGroupBy() {
        return FALSE;
    }
    
    /**
     * {@inheritdoc}
     */
    protected function defineOptions() {
        $options = parent::defineOptions();
        $options['fields'] = [
            'default' => [],
        ];
        $options['destination'] = [
            'default' => 1,
        ];
        return $options;
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildOptionsForm(&$form, FormStateInterface $form_state) {
        $all_fields = $this->view->display_handler
            ->getFieldLabels();
        // Offer to include only those fields that follow this one.
        $field_options = array_slice($all_fields, 0, array_search($this->options['id'], array_keys($all_fields)));
        $form['fields'] = [
            '#type' => 'checkboxes',
            '#title' => $this->t('Fields'),
            '#description' => $this->t('Fields to be included as contextual links.'),
            '#options' => $field_options,
            '#default_value' => $this->options['fields'],
        ];
        $form['destination'] = [
            '#type' => 'select',
            '#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 contextual action.'),
            '#options' => [
                '0' => $this->t('No'),
                '1' => $this->t('Yes'),
            ],
            '#default_value' => $this->options['destination'],
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function preRender(&$values) {
        // Add a row plugin css class for the contextual link.
        $class = 'contextual-region';
        if (!empty($this->view->style_plugin->options['row_class'])) {
            $this->view->style_plugin->options['row_class'] .= " {$class}";
        }
        else {
            $this->view->style_plugin->options['row_class'] = $class;
        }
    }
    
    /**
     * Overrides \Drupal\views\Plugin\views\field\FieldPluginBase::render().
     *
     * Renders the contextual fields.
     *
     * @param \Drupal\views\ResultRow $values
     *   The values retrieved from a single row of a view's query result.
     *
     * @see contextual_preprocess()
     * @see contextual_contextual_links_view_alter()
     */
    public function render(ResultRow $values) {
        $links = [];
        foreach ($this->options['fields'] as $field) {
            $rendered_field = $this->view->style_plugin
                ->getField($values->index, $field);
            if (empty($rendered_field)) {
                continue;
            }
            $title = $this->view->field[$field]->last_render_text;
            $path = '';
            if (!empty($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 Url) {
                $path = $this->view->field[$field]->options['alter']['url']
                    ->toString();
            }
            if (!empty($title) && !empty($path)) {
                // Make sure that tokens are replaced for this paths as well.
                $tokens = $this->getRenderTokens([]);
                $path = strip_tags(Html::decodeEntities(strtr($path, $tokens)));
                $links[$field] = [
                    'href' => $path,
                    'title' => $title,
                ];
                if (!empty($this->options['destination'])) {
                    $links[$field]['query'] = $this->getDestinationArray();
                }
            }
        }
        // Renders a contextual links placeholder.
        if (!empty($links)) {
            $contextual_links = [
                'contextual' => [
                    '',
                    [],
                    [
                        'contextual-views-field-links' => UrlHelper::encodePath(Json::encode($links)),
                    ],
                ],
            ];
            $element = [
                '#type' => 'contextual_links_placeholder',
                '#id' => _contextual_links_to_id($contextual_links),
            ];
            return \Drupal::service('renderer')->render($element);
        }
        else {
            return '';
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function query() {
    }

}