class LanguageNegotiationUrlFallback in Drupal 8

Class that determines the language to be assigned to URLs when none is detected.

The language negotiation process has a fallback chain that ends with the default language negotiation method. Each built-in language type has a separate initialization:

• Interface language, which is the only configurable one, always gets a valid value. If no request-specific language is detected, the default language will be used.
• Content language merely inherits the interface language by default.
• URL language is detected from the requested URL and will be used to rewrite URLs appearing in the page being rendered. If no language can be detected, there are two possibilities:
  • If the default language has no configured path prefix or domain, then the default language is used. This guarantees that (missing) URL prefixes are preserved when navigating through the site.
  • If the default language has a configured path prefix or domain, a requested URL having an empty prefix or domain is an anomaly that must be fixed. This is done by introducing a prefix or domain in the rendered page matching the detected interface language.

Plugin annotation

@LanguageNegotiation(
  id = Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationUrlFallback::METHOD_ID,
  types = {Drupal\Core\Language\LanguageInterface::TYPE_URL},
  weight = 8,
  name = @Translation("URL fallback"),
  description = @Translation("Use an already detected language for URLs if none is found.")
)

Hierarchy

• class \Drupal\language\LanguageNegotiationMethodBase implements LanguageNegotiationMethodInterface
  • class \Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationUrlFallback

1 file declares its use of LanguageNegotiationUrlFallback

language.module in core/modules/language/language.module

Add language handling functionality to Drupal.

File

core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationUrlFallback.php, line 38

Namespace

Drupal\language\Plugin\LanguageNegotiation

class LanguageNegotiationUrlFallback extends LanguageNegotiationMethodBase {

  /**
   * The language negotiation method id.
   */
  const METHOD_ID = 'language-url-fallback';

  /**
   * {@inheritdoc}
   */
  public function getLangcode(Request $request = NULL) {
    $langcode = NULL;
    if ($this->languageManager) {
      $default = $this->languageManager
        ->getDefaultLanguage();
      $config = $this->config
        ->get('language.negotiation')
        ->get('url');
      $prefix = $config['source'] == LanguageNegotiationUrl::CONFIG_PATH_PREFIX;

      // If the default language is not configured to convey language
      // information, a missing URL language information indicates that URL
      // language should be the default one, otherwise we fall back to an
      // already detected language.
      if ($prefix && empty($config['prefixes'][$default
        ->getId()]) || !$prefix && empty($config['domains'][$default
        ->getId()])) {
        $langcode = $default
          ->getId();
      }
      else {
        $langcode = $this->languageManager
          ->getCurrentLanguage()
          ->getId();
      }
    }
    return $langcode;
  }

}

Members

Name	Modifiers	Type	Description	Overrides
LanguageNegotiationMethodBase::$config	protected	property	The configuration factory.
LanguageNegotiationMethodBase::$currentUser	protected	property	The current active user.
LanguageNegotiationMethodBase::$languageManager	protected	property	The language manager.
LanguageNegotiationMethodBase::persist	public	function	Notifies the plugin that the language code it returned has been accepted. Overrides LanguageNegotiationMethodInterface::persist	1
LanguageNegotiationMethodBase::setConfig	public	function	Injects the configuration factory. Overrides LanguageNegotiationMethodInterface::setConfig
LanguageNegotiationMethodBase::setCurrentUser	public	function	Injects the current user. Overrides LanguageNegotiationMethodInterface::setCurrentUser
LanguageNegotiationMethodBase::setLanguageManager	public	function	Injects the language manager. Overrides LanguageNegotiationMethodInterface::setLanguageManager
LanguageNegotiationUrlFallback::getLangcode	public	function	Performs language negotiation. Overrides LanguageNegotiationMethodInterface::getLangcode
LanguageNegotiationUrlFallback::METHOD_ID		constant	The language negotiation method id.