.. include:: /Includes.rst.txt .. _extending-vocabulary: ======================== Extending the vocabulary ======================== Target group: **Developers** .. contents:: Table of Contents :depth: 1 :local: Introduction ============ The TYPO3 schema extension ships :ref:`type models ` and :ref:`view helpers ` with their properties from the core section of the schema.org definitions. However, there are several extensions, like `Health and lifesciences`_ or `Autos`_. There are also `pending types and properties`_ available that enable schema.org to introduce terms on an experimental basis. The embedding of these vocabulary extensions goes beyond the scope of this TYPO3 extension, as it will considerably increase the number of terms – while most of them are not used by the majority of users. For your convenience there are separate extensions to :ref:`extend the vocabulary ` available with the terms of the different sections. But if you only want to add only a few terms you are encouraged to add them on your own, especially pending terms. Pending terms are experimental, after a certain time a term will be incorporated into the core section or dropped. This depends on the usage, adoption and discussions. To maintain backward-compatibility and to not break any pages, pending types are also not supplied by this extension. But the vocabulary delivered with this extension can be extended according to your needs. This chapter describes the necessary steps to register additional properties to existing types or to introduce new types on your website. .. _extending-register-additional-properties: Register additional properties ============================== .. versionchanged:: 3.10.0 The previous way to register additional properties was to :ref:`use a PSR-14 event `. This way will continue to work with schema v3, but will be removed with schema v4. Sometimes it may be necessary to use properties that are not standardised or `pending`_, or to add `property annotations`_. Therefore the schema extension provides a way to extend types. These additional properties are not only available in the :ref:`API ` but also as arguments in the :ref:`view helpers `. To add one or more properties to a type, create a new class, for example in :file:`EXT:my_extension/Classes/Schema/AdditionalProperties/` and implement the `\Brotkrueml\Schema\Core\AdditionalPropertiesInterface`. The interface requires two methods: .. confval:: getType(): string :name: additional-properties-interface-get-type Returns the type name. .. confval:: getAdditionalProperties(): array :name: additional-properties-interface-get-additional-properties Return a list of additional properties as string. Here is an example for such an implementation: .. literalinclude:: _ExtendingVocabulary/_Car.php :language: php :caption: EXT:my_extension/Classes/Schema/AdditionalProperties/Car.php For each type create a new PHP class. .. important:: Flush the cache after a change via the console or :guilabel:`Admin Tools > Maintenance`. .. note:: About 1-2 times a year a new version of the schema.org definition is `released`_. The extension adopts these changes in future releases. If you register a pending property for a type, this property can be included in the core section in a later version of this extension. However, it doesn't do any harm to register a property that already exists. .. _extending-adding-types: Adding types ============ .. versionchanged:: 3.0.0 You can add additional types for use in the :ref:`API ` or as a :ref:`WebPage type `. As an example, in March 2020, schema.org introduces a new `VirtualLocation`_ type related to the corona crisis, which was quickly adopted by Google. The type can be used as `location`_ in the `Event`_ type. So let's start with this example. .. rst-class:: bignums-xxl #. Create the type model class The model class for a type defines the available properties. The model class for the `VirtualLocation` type may look like the following: .. literalinclude:: _ExtendingVocabulary/_VirtualLocation.php :language: php :caption: EXT:my_extension/Classes/Schema/Type/VirtualLocation.php In the example, the class is stored in :file:`Classes/Schema/Type` of your extension, but you can choose any namespace. It has to extend from :php:`\Brotkrueml\Schema\Core\Model\AbstractType`. The class must have the :php:`\Brotkrueml\Schema\Attributes\Type` attribute assigned. It has one mandatory parameter: the type name. The protected static property :php:`$propertyNames` contains the available schema.org properties. Now you can use the `VirtualLocation` in your PHP code: .. literalinclude:: _ExtendingVocabulary/_MyController.php :language: php :caption: EXT:my_extension/Classes/Controller/MyController.php :emphasize-lines: 21-23 .. note:: With the :php:`\Brotkrueml\Schema\Attributes\Type` attribute the class is recognised as a type model class. All types are collected on :abbr:`DI (dependency injection)` compile time: When you add/change/remove a class, you have to flush the cache via :guilabel:`Admin Tools > Maintenance` or the :bash:`flush:cache` command on :ref:`CLI `. #. Create the view helper (optional) If you have the need for a view helper with that type, you can create one: .. literalinclude:: _ExtendingVocabulary/_VirtualLocationViewHelper.php :language: php :caption: EXT:my_extension/Classes/ViewHelpers/Schema/Type/VirtualLocationViewHelper.php .. versionchanged:: 3.0 The name of the type must be defined with the :php:`$type` property. To use the `schema` namespace in Fluid templates also with your custom view helpers add the following snippet to the :file:`ext_localconf.php` file of your extension: .. code-block:: php :caption: EXT:my_extension/ext_localconf.php $GLOBALS['TYPO3_CONF_VARS']['SYS']['fluid']['namespaces']['schema'][] = 'MyVendor\\MyExtension\\ViewHelpers\\Schema'; This way you don't have to think about which namespace to use. And if the pending type is moved to the core section you have no need to touch your Fluid templates. Of course, feel free to use another namespace. .. attention:: Add the schema extension as a dependency to your extension. This ensures that your class models take precedence over the delivered models from the schema extension. This may be necessary, if you define a pending type with pending properties (which you also use) to avoid breaks when the type is included into the core section but some properties aren't. .. tip:: Have a look into the `schema_virtuallocation`_ extension. It serves as a blueprint for adding own types and view helpers. Add a new WebPage type ====================== .. versionchanged:: 3.0.0 If you are responsible for a medical website, the chances are high that you need the `MedicalWebPage`_ web page type, which is part of the Health schema.org extension. Register this web page type so that it is available in the :ref:`web page type list ` in the page properties. Simply follow the steps in the :ref:`extending-adding-types` section. Mark your class as a WebPage type with the interface :php:`\Brotkrueml\Schema\Core\Model\WebPageTypeInterface`: .. literalinclude:: _ExtendingVocabulary/_MedicalWebPage.php :language: php :caption: EXT:my_extension/Classes/Schema/Type/MedicalWebPage.php The new web page type can now be selected in the page properties: .. figure:: /Images/Developer/MedicalWebPageTypeSelection.png :alt: MedicalWebPage in the list of available web page types *MedicalWebPage* in the list of available web page types .. _extending-adding-enumeration: Add a new enumeration ===================== .. versionadded:: 3.9.0 This feature is considered experimental and may change at any time until it is declared stable. However, feedback is welcome. schema.org provides the ability to use enumerations as values for certain properties. The TYPO3 schema extensions provide the :ref:`enumerations ` defined by schema.org. However, there are some enumerations where schema.org refers to other vocabularies. These enumerations are not provided by the TYPO3 schema extensions. An example is `BusinessEntityType`_, which suggests using the `GoodRelations`_ terms. If you want to use them, you can define and use your own enumeration to provide a defined set of of possible values satisfiying your needs (instead of plain strings): .. literalinclude:: _ExtendingVocabulary/_BusinessEntityType.php :language: php :caption: EXT:my_extension/Classes/Schema/Enumeration/BusinessEntityType.php All enumeration types must implement the interface :ref:`Brotkrueml\\Schema\\Core\\Model\\EnumerationInterface `, which requires a :php:`canonical()` method. Depending on the case, it returns the string to use in the JSON-LD output. Now you can make use of this enum in PHP, for example: .. code-block:: php // use MyVendor\MyExtension\Schema\Enumeration\BusinessEntityType; $demand = $this->typeFactory->create('Demand'); $demand->setProperty('eligibleCustomerType', BusinessEntityType::Enduser); or in :ref:`Fluid `: .. code-block:: html which results in: .. code-block:: json { "@type": "Demand", "eligibleCustomerType": "http://purl.org/goodrelations/v1#Enduser" } Another use case might be to create your own extended `GenderType` enum instead using the enum from this extension: .. literalinclude:: _ExtendingVocabulary/_GenderType.php :language: php :caption: EXT:my_extension/Classes/Schema/Enumeration/GenderType.php .. _Autos: https://schema.org/docs/automotive.html .. _BusinessEntityType: https://schema.org/BusinessEntityType .. _Event: https://schema.org/Event .. _GoodRelations: http://www.heppnetz.de/ontologies/goodrelations/v1 .. _Health and lifesciences: https://schema.org/docs/meddocs.html .. _location: https://schema.org/location .. _MedicalWebPage: https://schema.org/MedicalWebPage .. _pending: https://pending.schema.org/ .. _pending types and properties: https://pending.schema.org/docs/pending.home.html .. _property annotations: https://schema.org/docs/actions.html#part-4 .. _released: https://schema.org/docs/releases.html .. _schema_virtuallocation: https://github.com/brotkrueml/schema-virtuallocation .. _VirtualLocation: https://schema.org/VirtualLocation