client_hints-8.x-1.0-alpha3/src/Service/ClientHints.php

<?php

namespace Drupal\client_hints\Service;

use Drupal\Core\Cache\Cache;
use Drupal\Core\Cache\CacheBackendInterface;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\image\ImageStyleInterface;
use Drupal\image\Plugin\ImageEffect\ResizeImageEffect;
use Drupal\Core\Entity\EntityTypeManager;

/**
 * Client hints service.
 */
class ClientHints {

  /**
   * The cache backend.
   *
   * @var \Drupal\Core\Cache\CacheBackendInterface
   */
  protected $cacheBackend;

  /**
   * The entity type manager.
   *
   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
   */
  protected $entityTypeManager;

  /**
   * ClientHints constructor.
   *
   * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
   */
  public function __construct(CacheBackendInterface $cache_backend, EntityTypeManagerInterface $entity_type_manager) {
    $this->cacheBackend = $cache_backend;
    $this->entityTypeManager = $entity_type_manager;
  }

  /**
   * @param string $uri
   * @param int $dpr
   * @param int $width
   *
   * @return \Drupal\Core\GeneratedUrl|string
   *
   * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
   * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
   */
  public function getImageRedirectUrl($uri, $dpr, $width) {
    $image_style_id = $this->getAppropriateImageStyleId($width * $dpr);

    /* @var $image_style \Drupal\image\Entity\ImageStyle */
    $image_style = $this->entityTypeManager->getStorage('image_style')->load($image_style_id);
    return $image_style->buildUrl($uri);
  }

  /**
   * Gets the ID of the appropriate image style for a given width.
   *
   * @param int $target_width
   *
   * @return mixed
   *
   * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
   * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
   */
  protected function getAppropriateImageStyleId($target_width) {
    $image_styles = $this->getImageStylesByWidth();

    $wider_image_styles = array_filter($image_styles, function ($style_width) use ($target_width) {
      return $style_width > $target_width;
    }, ARRAY_FILTER_USE_KEY);

    // Return smallest appropriate image style's ID, if possible.
    if (!empty($wider_image_styles)) {
      return array_shift($wider_image_styles);
    }
    // Otherwise, return the biggest image style's ID.
    else {
      return array_pop($image_styles);
    }
  }
  /**
   * Gets a list of all image styles keyed by their respective width.
   *
   * @return string[]
   *
   * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
   * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
   */
  protected function getImageStylesByWidth() {
    if ($cached = $this->cacheBackend->get('client_hints.styles')) {
      // Return the cached options.
      return $cached->data;
    }

    // Get image styles.
    /* @var $image_styles \Drupal\image\Entity\ImageStyle[] */
    $image_styles = $this->entityTypeManager->getStorage('image_style')->loadMultiple();
    $entity_type = $this->entityTypeManager->getDefinition('image_style');
    $cache_tags = $entity_type->getListCacheTags();

    foreach ($image_styles as $image_style) {
      // Get image style's output width...
      $width = $this->getImageStyleWidth($image_style);
      // ...and use that to key the style id in a list of image styles.
      $image_styles_by_width[$width] = $image_style->id();
      Cache::mergeTags($cache_tags, $image_style->getCacheTags());
    }
    // Sort the image style list by ascending width.
    ksort($image_styles_by_width);

    $this->cacheBackend->set('client_hints.styles', $image_styles_by_width, Cache::PERMANENT, $cache_tags);

    return $image_styles_by_width;
  }

  /**
   * Gets the width of an image style.
   *
   * @param \Drupal\image\ImageStyleInterface $style
   *
   * @return int
   */
  protected function getImageStyleWidth(ImageStyleInterface $style) {
    $width = 0;

    $effects = $style->getEffects();
    foreach ($effects as $effect) {
      if ($effect instanceof ResizeImageEffect) {
        $width = $effect->getConfiguration()['data']['width'];
      }
    }

    return $width;
  }

}