Using The API¶

Target group: Developers

Table of Contents

Introduction
Starting with an example
The model in-depth
- Available type model methods
Schema Manager
Other useful APIs
- Boolean data type
- List of types

Introduction ¶

With the extension’s API you can define the structured markup with PHP. For example, create a class which gets an Extbase model as input and defines the markup. Then instantiate the class in an action of your controller.

Each type model class in the PHP namespace Brotkrueml\Schema\Model\Type inherits from the abstract class Brotkrueml\Schema\Core\Model\AbstractType which defines methods to set and get the properties of a model.

There are currently over 600 models available.

Starting with an example ¶

Let’s start with a simple example. Imagine you describe a person on a plugin’s detail page that you want to enrich with structured markup. First you have to create the schema model:

$person = \Brotkrueml\Schema\Type\TypeFactory::createType('Person')

The schema type Person maps to the model Person. You can use every accepted type from the core vocabulary from schema.org. Also have a look into the ClassesModelType folder of this extension to get a general idea of the available types.

If the type is not available a \DomainException is thrown.

Every type implements the \Brotkrueml\Schema\Core\Model\TypeInterface. You will find a list of the available methods in the section <api-type-interface>.

Surely you will need to add some properties:

$person
   ->setId('http://example.org/#person-42')
   ->setProperty('givenName', 'John')
   ->setProperty('familyName', 'Smith')
   ->setProperty('gender', 'http://schema.org/Male');
;

That was easy … let’s go on and define an event the person attends:

$event = \Brotkrueml\Schema\Type\TypeFactory::createType('Event')
   ->setProperty('name', 'Fancy Event')
   ->setProperty('image', 'https:/example.org/event.png')
   ->setProperty('url', 'https://example.org/')
   ->setProperty('isAccessibleForFree', true)
   ->setProperty('sameAs', 'https://twitter.com/fancy-event')
   ->addProperty('sameAs', 'https://facebook.com/fancy-event')
;

Now we have to connect the two types together:

$person->setProperty('performerIn', $event);

The defined models are ready to embed on the web page. The schema manager does that for you:

$schemaManager = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(
   \Brotkrueml\Schema\Manager\SchemaManager::class
);
$schemaManager->addType($person);

That’s it … if you call the according page the structured markup is embedded automatically into the head section:

{
   "@context": "http://schema.org",
   "@type": "Person",
   "@id": "http://example.org/#person-42",
   "givenName": "John",
   "familyName": "Smith",
   "gender": "http://schema.org/Male",
   "performerIn": {
      "@type": "Event",
      "name": "Fancy Event",
      "image": "https://example.org/event.png",
      "url": "https://example.org",
      "isAccessibleForFree": "http://schema.org/True",
      "sameAs": ["https://twitter.com/fancy-event", "https://facebook.com/fancy-event"]
   }
}

The model in-depth ¶

Each type model, like Thing, Person or Event, must implement the interface Brotkrueml\Schema\Core\Model\TypeInterface. For convenience, a type model can also extend the abstract class Brotkrueml\Schema\Core\Model\AbstractType which implements every needed method.

Two other interfaces are available, they are used to “tag” a type model class as a “special type” and don’t require the implementation of additional methods:

Brotkrueml\Schema\Core\Model\WebPageTypeInterface for a web page type.
Brotkrueml\Schema\Core\Model\WebPageElementTypeInterface for a web page element type.

These interfaces can be useful when you want to extend the vocabulary.

Inheritance of the type models (namespaces are omitted for better readability)

Each type model delivered with this extension extends the AbstractType class.

Available type model methods ¶

The type models implement Brotkrueml\Schema\Core\Model\TypeInterface or extend Brotkrueml\Schema\Core\Model\AbstractType and expose the following methods:

setId(string $id)¶

The method sets the unique ID of the model. With the ID, you can cross-reference types on the same page or between different pages (and even between different web sites) without repeating all the properties.

It is common to use an IRI as ID like in the above example. Please keep in mind that the ID should be consistent between changes of the properties, e.g. if a person marries and the name is changed. The person is still the same, so the IRI should be.

The IRI is no URL, so it is acceptable to give a “404 Not Found” back if you call it in a browser.

Parameter: string $id: The unique id to set.
Return value: Reference to the model itself.

getId()¶

Gets the id of the type model.

Parameter: none
Return value: A previously set id or null (if not defined).

setProperty(string $propertyName, $propertyValue)¶

Call this method to set a property or overwrite a previously one.

Parameters

string $propertyName: The property name to set. If the property does not exist in the model, an exception is thrown.
string|array|bool|AbstractType|null $propertyValue: The value of the property to set. This can be a string, a boolean, another model or an array of strings, booleans or models. Also null is possible to clear the property value.

Return value

Reference to the model itself.

addProperty(string $propertyName, $propertyValue)¶

Call this method if you want to add a value to an existing one. In the example above, you can see that addProperty() is used to add a second value to the sameAs property.

Calling the addProperty() method on a property that has no value assigned has the same effect as calling setProperty(). So you can safely use it, e.g. in a loop, to set some values on a property.

Parameters

string $propertyName: The property name to set. If the property does not exist in the model, an exception is thrown.
string|array|bool|AbstractType|null $propertyValue: The value of the property to set. This can be a string, a boolean, another model or an array of strings, booleans or models. Also null is possible to clear the property value.

Return value

Reference to the model itself.

setProperties(array $properties)¶

Set multiple properties at once.

Parameter

array $properties: The properties to set. The key of the array is the property name, the value is the property value. Allowed as values are the same as with the method ->setProperty().

Return value

Reference to the model itself.

getProperty(string $propertyName)¶

Get the value of a property.

Parameter

string $propertyName: The property name to get the value from. If the property name does not exist in the model, an exception is thrown.

Return value

The value of the property (string, bool, model, array of strings, array of models, null).

hasProperty(string $propertyName)¶

Check whether the property name exists in a particular model.

Parameter

string $propertyName: The property name to check.

Return value

true, if the property exists and false, otherwise.

clearProperty(string $propertyName)¶

Resets the value of the property (set it to null).

Parameter

string $propertyName: The property name to set. If the property does not exist in the model, an exception is thrown.

Return value

Reference to the model itself.

getPropertyNames()¶

Get the names of all properties of the model.

Return value: Array of all property names of the model.

Schema Manager ¶

The Schema Manager (class Brotkrueml\Schema\Manager\SchemaManager) – well – manages the type models and prepares them for embedding into the web page.

The class exposes the following methods:

addType(TypeInterface $type)¶

Adds the given type model to the Schema Manager for inclusion on the web page.

Parameter

TypeInterface $type: The type model class with the set properties. This can be also “special” types, like a WebPage or a BreadcrumbList.

Return value

Reference to itself.

hasWebPage()¶

Checks, if a web page type is already available.

Parameter: none
Return value: true, if a web page type is available, otherwise false

addMainEntityOfWebPage(TypeInterface $mainEntity)¶

Adds a main entity to the web page.

Parameter

TypeInterface $mainEntity: The type model to be added.

Return value

Reference to itself.

Other useful APIs ¶

Boolean data type ¶

Boolean property values are mapped to the according schema terms http://schema.org/True or http://schema.org/False. You can also use the Brotkrueml\Schema\Model\DataType\Boolean class yourself. It exposes two public constants:

FALSE¶

Provides the value http://schema.org/False.

TRUE¶

Provides the value http://schema.org/True.

and one static method:

convertToTerm(bool $value): string¶

This method returns the according schema term.

List of types ¶

If you need a list of the available types or a subset of them, you can call methods on the Brotkrueml\Schema\Type\TypeRegistry class. As this is a singleton, instantiate the class with:

$typeRegistry = GeneralUtility::makeInstance(\Brotkrueml\Schema\Type\TypeRegistry::class);

or use dependency injection in TYPO3 v10+.

getTypes()¶

Get all available type names.

Parameter: none
Return value: Array, sorted alphabetically by type name.

getWebPageTypes()¶

Get the WebPage type and its descendants.

Parameter: none
Return value: Array, sorted alphabetically by type name.

getWebPageElementTypes()¶

Get the WebPageElement type and its descendants.

Parameter: none
Return value: Array, sorted alphabetically by type name.

getContentTypes()¶

The types useful for an editor are returned as an array, sorted alphabetically.

The following types are filtered out:

BreadcrumbList
WebPage and descendants
WebPageElement and descendants
WebSite

Parameter: none
Return value: Array, sorted alphabetically by type name.