Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\language;
Chris@0: 
Chris@0: use Drupal\Core\Session\AccountInterface;
Chris@0: 
Chris@0: /**
Chris@0:  * Common interface for language negotiation services.
Chris@0:  *
Chris@0:  * The language negotiation API is based on two major concepts:
Chris@0:  * - Language types: types of translatable data (the types of data that a user
Chris@0:  *   can view or request).
Chris@0:  * - Language negotiation methods: responsible for determining which language to
Chris@0:  *   use to present a particular piece of data to the user.
Chris@0:  * Both language types and language negotiation methods are customizable.
Chris@0:  *
Chris@0:  * Drupal defines three built-in language types:
Chris@0:  * - Interface language: The page's main language, used to present translated
Chris@0:  *   user interface elements such as titles, labels, help text, and messages.
Chris@0:  * - Content language: The language used to present content that is available
Chris@0:  *   in more than one language.
Chris@0:  * - URL language: The language associated with URLs. When generating a URL,
Chris@0:  *   this value will be used for URL's as a default if no explicit preference is
Chris@0:  *   provided.
Chris@0:  * Modules can define additional language types through
Chris@0:  * hook_language_types_info(), and alter existing language type definitions
Chris@0:  * through hook_language_types_info_alter().
Chris@0:  *
Chris@0:  * Language types may be configurable or fixed. The language negotiation
Chris@0:  * methods associated with a configurable language type can be explicitly
Chris@0:  * set through the user interface. A fixed language type has predetermined
Chris@0:  * (module-defined) language negotiation settings and, thus, does not appear in
Chris@0:  * the configuration page. Here is a code snippet that makes the content
Chris@0:  * language (which by default inherits the interface language's values)
Chris@0:  * configurable:
Chris@0:  * @code
Chris@0:  * function mymodule_language_types_info_alter(&$language_types) {
Chris@0:  *   unset($language_types[LanguageInterface::TYPE_CONTENT]['fixed']);
Chris@0:  * }
Chris@0:  * @endcode
Chris@0:  *
Chris@0:  * The locked configuration property prevents one language type from being
Chris@0:  * switched from customized to not customized, and vice versa.
Chris@0:  * @see \Drupal\language\LanguageNegotiator::updateConfiguration()
Chris@0:  *
Chris@0:  * Every language type can have a different set of language negotiation methods
Chris@0:  * assigned to it. Different language types often share the same language
Chris@0:  * negotiation settings, but they can have independent settings if needed. If
Chris@0:  * two language types are configured the same way, their language switcher
Chris@0:  * configuration will be functionally identical and the same settings will act
Chris@0:  * on both language types.
Chris@0:  *
Chris@0:  * Drupal defines the following built-in language negotiation methods:
Chris@0:  * - URL: Determine the language from the URL (path prefix or domain).
Chris@0:  * - Session: Determine the language from a request/session parameter.
Chris@0:  * - User: Follow the user's language preference.
Chris@0:  * - User admin language: Identify admin language from the user preferences.
Chris@0:  * - Browser: Determine the language from the browser's language settings.
Chris@0:  * - Selected language: Use the default site language.
Chris@0:  * Language negotiation methods are simple plugin classes that implement a
Chris@0:  * particular logic to return a language code. For instance, the URL method
Chris@0:  * searches for a valid path prefix or domain name in the current request URL.
Chris@0:  * If a language negotiation method does not return a valid language code, the
Chris@0:  * next method associated with the language type (based on method weight) is
Chris@0:  * invoked.
Chris@0:  *
Chris@0:  * Modules can define additional language negotiation methods by simply provide
Chris@0:  * the related plugins, and alter existing methods through
Chris@0:  * hook_language_negotiation_info_alter(). Here is an example snippet that lets
Chris@0:  * path prefixes be ignored for administrative paths:
Chris@0:  * @code
Chris@0:  * function mymodule_language_negotiation_info_alter(&$negotiation_info) {
Chris@0:  *   // Replace the original plugin with our own implementation.
Chris@0:  *   $method_id = \Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationUrl::METHOD_ID;
Chris@0:  *   $negotiation_info[$method_id]['class'] = 'Drupal\my_module\Plugin\LanguageNegotiation\MyLanguageNegotiationUrl';
Chris@0:  * }
Chris@0:  *
Chris@0:  * class MyLanguageNegotiationUrl extends LanguageNegotiationUrl {
Chris@0:  *   public function getCurrentLanguage(Request $request = NULL) {
Chris@0:  *     if ($request) {
Chris@0:  *       // Use the original URL language negotiation method to get a valid
Chris@0:  *       // language code.
Chris@0:  *       $langcode = parent::getCurrentLanguage($request);
Chris@0:  *
Chris@0:  *       // If we are on an administrative path, override with the default
Chris@0:  *       language.
Chris@0:  *       if ($request->query->has('q') && strtok($request->query->get('q'), '/') == 'admin') {
Chris@0:  *         return $this->languageManager->getDefaultLanguage()->getId();
Chris@0:  *       }
Chris@0:  *       return $langcode;
Chris@0:  *     }
Chris@0:  *   }
Chris@0:  * }
Chris@0:  * @endcode
Chris@0:  *
Chris@0:  * For more information, see
Chris@0:  * @link https://www.drupal.org/node/1497272 Language Negotiation API @endlink
Chris@0:  */
Chris@0: interface LanguageNegotiatorInterface {
Chris@0: 
Chris@0:   /**
Chris@0:    * The language negotiation method id for the language negotiator itself.
Chris@0:    */
Chris@0:   const METHOD_ID = 'language-default';
Chris@0: 
Chris@0:   /**
Chris@0:    * Resets the negotiated languages and the method instances.
Chris@0:    */
Chris@0:   public function reset();
Chris@0: 
Chris@0:   /**
Chris@0:    * Sets the current active user and resets all language types.
Chris@0:    *
Chris@0:    * @param \Drupal\Core\Session\AccountInterface $current_user
Chris@0:    *   The current active user.
Chris@0:    */
Chris@0:   public function setCurrentUser(AccountInterface $current_user);
Chris@0: 
Chris@0:   /**
Chris@0:    * Initializes the specified language type.
Chris@0:    *
Chris@0:    * @param string $type
Chris@0:    *   The language type to be initialized.
Chris@0:    *
Chris@0:    * @return \Drupal\Core\Language\LanguageInterface[]
Chris@0:    *   Returns an array containing a single language keyed by the language
Chris@0:    *   negotiation method ID used to determine the language of the specified
Chris@0:    *   type. If negotiation is not possible the default language is returned.
Chris@0:    */
Chris@0:   public function initializeType($type);
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns the language negotiation methods enabled for a language type.
Chris@0:    *
Chris@0:    * @param string $type
Chris@0:    *   (optional) The language type. If no type is specified all the method
Chris@0:    *   definitions are returned.
Chris@0:    *
Chris@0:    * @return array[]
Chris@0:    *   An array of language negotiation method definitions keyed by method id.
Chris@0:    */
Chris@0:   public function getNegotiationMethods($type = NULL);
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns an instance of the specified language negotiation method.
Chris@0:    *
Chris@0:    * @param string $method_id
Chris@0:    *   The method identifier.
Chris@0:    *
Chris@0:    * @return \Drupal\language\LanguageNegotiationMethodInterface
Chris@0:    */
Chris@0:   public function getNegotiationMethodInstance($method_id);
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns the ID of the language type's primary language negotiation method.
Chris@0:    *
Chris@0:    * @param string $type
Chris@0:    *   The language type.
Chris@0:    *
Chris@0:    * @return string
Chris@0:    *   The identifier of the primary language negotiation method for the given
Chris@0:    *   language type, or the default method if none exists.
Chris@0:    */
Chris@0:   public function getPrimaryNegotiationMethod($type);
Chris@0: 
Chris@0:   /**
Chris@0:    * Checks whether a language negotiation method is enabled for a language type.
Chris@0:    *
Chris@0:    * @param string $method_id
Chris@0:    *   The language negotiation method ID.
Chris@0:    * @param string $type
Chris@0:    *   (optional) The language type. If none is passed, all the configurable
Chris@0:    *   language types will be inspected.
Chris@0:    *
Chris@0:    * @return bool
Chris@0:    *   TRUE if the method is enabled for at least one of the given language
Chris@0:    *   types, or FALSE otherwise.
Chris@0:    */
Chris@0:   public function isNegotiationMethodEnabled($method_id, $type = NULL);
Chris@0: 
Chris@0:   /**
Chris@0:    * Saves a list of language negotiation methods for a language type.
Chris@0:    *
Chris@0:    * @param string $type
Chris@0:    *   The language type.
Chris@0:    * @param int[] $enabled_methods
Chris@0:    *   An array of language negotiation method weights keyed by method ID.
Chris@0:    */
Chris@0:   public function saveConfiguration($type, $enabled_methods);
Chris@0: 
Chris@0:   /**
Chris@0:    * Resave the configuration to purge missing negotiation methods.
Chris@0:    */
Chris@0:   public function purgeConfiguration();
Chris@0: 
Chris@0:   /**
Chris@0:    * Updates the configuration based on the given language types.
Chris@0:    *
Chris@0:    * Stores the list of the language types along with information about their
Chris@0:    * configurable state. Stores the default settings if the language type is
Chris@0:    * not configurable.
Chris@0:    *
Chris@0:    * @param string[] $types
Chris@0:    *   An array of configurable language types.
Chris@0:    */
Chris@0:   public function updateConfiguration(array $types);
Chris@0: 
Chris@0: }