class DefaultFetcher in Drupal 8

Defines a default fetcher implementation.

Uses the http_client service to download the feed.

Plugin annotation

@AggregatorFetcher(
  id = "aggregator",
  title = @Translation("Default fetcher"),
  description = @Translation("Downloads data from a URL using Drupal's HTTP request handler.")
)

Hierarchy

• class \Drupal\aggregator\Plugin\aggregator\fetcher\DefaultFetcher implements FetcherInterface, ContainerFactoryPluginInterface

1 file declares its use of DefaultFetcher

TestFetcher.php in core/modules/aggregator/tests/modules/aggregator_test/src/Plugin/aggregator/fetcher/TestFetcher.php

File

core/modules/aggregator/src/Plugin/aggregator/fetcher/DefaultFetcher.php, line 30

Namespace

Drupal\aggregator\Plugin\aggregator\fetcher

class DefaultFetcher implements FetcherInterface, ContainerFactoryPluginInterface {

  /**
   * The HTTP client to fetch the feed data with.
   *
   * @var \Drupal\Core\Http\ClientFactory
   */
  protected $httpClientFactory;

  /**
   * A logger instance.
   *
   * @var \Psr\Log\LoggerInterface
   */
  protected $logger;

  /**
   * The messenger.
   *
   * @var \Drupal\Core\Messenger\MessengerInterface
   */
  protected $messenger;

  /**
   * Constructs a DefaultFetcher object.
   *
   * @param \Drupal\Core\Http\ClientFactory $http_client_factory
   *   A Guzzle client object.
   * @param \Psr\Log\LoggerInterface $logger
   *   A logger instance.
   * @param \Drupal\Core\Messenger\MessengerInterface $messenger
   *   The messenger.
   */
  public function __construct(ClientFactory $http_client_factory, LoggerInterface $logger, MessengerInterface $messenger) {
    $this->httpClientFactory = $http_client_factory;
    $this->logger = $logger;
    $this->messenger = $messenger;
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    return new static($container
      ->get('http_client_factory'), $container
      ->get('logger.factory')
      ->get('aggregator'), $container
      ->get('messenger'));
  }

  /**
   * {@inheritdoc}
   */
  public function fetch(FeedInterface $feed) {
    $request = new Request('GET', $feed
      ->getUrl());
    $feed->source_string = FALSE;

    // Generate conditional GET headers.
    if ($feed
      ->getEtag()) {
      $request = $request
        ->withAddedHeader('If-None-Match', $feed
        ->getEtag());
    }
    if ($feed
      ->getLastModified()) {
      $request = $request
        ->withAddedHeader('If-Modified-Since', gmdate(DateTimePlus::RFC7231, $feed
        ->getLastModified()));
    }
    try {

      /** @var \Psr\Http\Message\UriInterface $actual_uri */
      $actual_uri = NULL;
      $response = $this->httpClientFactory
        ->fromOptions([
        'allow_redirects' => [
          'on_redirect' => function (RequestInterface $request, ResponseInterface $response, UriInterface $uri) use (&$actual_uri) {
            $actual_uri = (string) $uri;
          },
        ],
      ])
        ->send($request);

      // In case of a 304 Not Modified, there is no new content, so return
      // FALSE.
      if ($response
        ->getStatusCode() == 304) {
        return FALSE;
      }
      $feed->source_string = (string) $response
        ->getBody();
      if ($response
        ->hasHeader('ETag')) {
        $feed
          ->setEtag($response
          ->getHeaderLine('ETag'));
      }
      if ($response
        ->hasHeader('Last-Modified')) {
        $feed
          ->setLastModified(strtotime($response
          ->getHeaderLine('Last-Modified')));
      }
      $feed->http_headers = $response
        ->getHeaders();

      // Update the feed URL in case of a 301 redirect.
      if ($actual_uri && $actual_uri !== $feed
        ->getUrl()) {
        $feed
          ->setUrl($actual_uri);
      }
      return TRUE;
    } catch (RequestException $e) {
      $this->logger
        ->warning('The feed from %site seems to be broken because of error "%error".', [
        '%site' => $feed
          ->label(),
        '%error' => $e
          ->getMessage(),
      ]);
      $this->messenger
        ->addWarning(t('The feed from %site seems to be broken because of error "%error".', [
        '%site' => $feed
          ->label(),
        '%error' => $e
          ->getMessage(),
      ]));
      return FALSE;
    }
  }

}

Members

Name	Modifiers	Type	Description	Overrides
DefaultFetcher::$httpClientFactory	protected	property	The HTTP client to fetch the feed data with.
DefaultFetcher::$logger	protected	property	A logger instance.
DefaultFetcher::$messenger	protected	property	The messenger.
DefaultFetcher::create	public static	function	Creates an instance of the plugin. Overrides ContainerFactoryPluginInterface::create
DefaultFetcher::fetch	public	function	Downloads feed data. Overrides FetcherInterface::fetch	1
DefaultFetcher::__construct	public	function	Constructs a DefaultFetcher object.