class LanguageNegotiationUrlFallback in Drupal 10

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;
  }

}