JSON LD ViewHelpers to create information for Google & Co. out of pages or other records. Files in this examples in EXT:in2template/Classes/ViewHelpers/JsonLdSchema/

AbstractJsonLdSchemaViewHelper.php

<?php
namespace In2code\In2template\ViewHelpers\JsonLdSchema;

use TYPO3\CMS\Fluid\Core\ViewHelper\AbstractViewHelper;

/**
 * Class AbstractJsonLdSchemaViewHelper
 */
abstract class AbstractJsonLdSchemaViewHelper extends AbstractViewHelper
{

    /**
     * @var bool
     */
    protected $escapeChildren = false;

    /**
     * @var bool
     */
    protected $escapeOutput = false;

    /**
     * @param array $arguments
     * @param string $propertyName
     * @return mixed|null
     */
    protected static function getProperty(array $arguments, string $propertyName)
    {
        $value = null;
        if (!empty($arguments[$propertyName])) {
            $value = $arguments[$propertyName];
        } elseif (!empty($arguments['properties'][$propertyName])) {
            $value = $arguments['properties'][$propertyName];
        }
        return $value;
    }
}

AddressViewHelper.php

<?php
namespace In2code\In2template\ViewHelpers\JsonLdSchema;

use TYPO3Fluid\Fluid\Core\Rendering\RenderingContextInterface;

/**
 * Schema.org ViewHelper for rendering an address (not person) in JSON-LD format
 * See http://schema.org/address (example 4, JSON-LD)
 *
 * Class AddressViewHelper
 */
class AddressViewHelper extends AbstractJsonLdSchemaViewHelper
{

    /**
     * Arguments can be submitted complete with the attribute "properties" or with single values
     * For argument properties, this keys are relevant:
     *  - name
     *  - description
     *  - city
     *  - zip
     *  - street (with number)
     *  - email
     *  - phone
     *  - url
     *
     * @return void
     */
    public function initializeArguments()
    {
        parent::initializeArguments();
        $this->registerArgument('properties', 'array', 'All properties');
        $this->registerArgument('name', 'string', 'Overrules name from properties');
        $this->registerArgument('description', 'string', 'Overrules description from properties');
        $this->registerArgument('city', 'string', 'Overrules city from properties');
        $this->registerArgument('zip', 'string', 'Overrules zip from properties');
        $this->registerArgument('street', 'string', 'Overrules street from properties');
        $this->registerArgument('email', 'string', 'Overrules email from properties');
        $this->registerArgument('image', 'string', 'Overrules image from properties');
        $this->registerArgument('phone', 'string', 'Overrules phone from properties');
        $this->registerArgument('url', 'string', 'Overrules url from properties');
    }

    /**
     * @return string
     */
    public function render(): string
    {
        return self::renderStatic(
            $this->arguments,
            $this->buildRenderChildrenClosure(),
            $this->renderingContext
        );
    }

    /**
     * @param array $arguments
     * @param \Closure $renderChildrenClosure
     * @param RenderingContextInterface $renderingContext
     * @return string
     */
    public static function renderStatic(
        array $arguments,
        \Closure $renderChildrenClosure,
        RenderingContextInterface $renderingContext
    ) {
        $properties = self::getProperties($arguments);
        $content = json_encode($properties, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);
        return '<script type="application/ld+json">' . $content . '</script>';
    }

    /**
     * @param array $arguments
     * @return array
     */
    protected static function getProperties(array $arguments): array
    {
        $properties = [
            '@context' => 'http://schema.org',
            '@type' => 'LocalBusiness',
            'address' => [
                '@type' => 'PostalAddress',
                'addressLocality' => self::getProperty($arguments, 'city'),
                'postalCode' => self::getProperty($arguments, 'zip'),
                'streetAddress' => self::getProperty($arguments, 'street')
            ],
            'name' => self::getProperty($arguments, 'name'),
            'description' => self::getProperty($arguments, 'description'),
            'telephone' => self::getProperty($arguments, 'phone'),
            'email' => self::getProperty($arguments, 'email'),
            'image' => self::getProperty($arguments, 'image'),
            'url' => self::getProperty($arguments, 'url'),
        ];
        return $properties;
    }
}

NewsArticleViewHelper.php

<?php
namespace In2code\In2template\ViewHelpers\JsonLdSchema;

use TYPO3Fluid\Fluid\Core\Rendering\RenderingContextInterface;

/**
 * Schema.org ViewHelper for rendering an address (not person) in JSON-LD format
 * See http://pending.schema.org/Article (example 2, JSON-LD)
 *
 * Class NewsArticleViewHelper
 */
class NewsArticleViewHelper extends AbstractJsonLdSchemaViewHelper
{

    /**
     * Arguments can be submitted complete with the attribute "properties" or with single values
     * For argument properties, this keys are relevant:
     *  - title
     *  - author
     *  - uid
     *  - date
     *
     * @return void
     */
    public function initializeArguments()
    {
        parent::initializeArguments();
        $this->registerArgument('properties', 'array', 'All properties');
        $this->registerArgument('title', 'string', 'Overrules title from properties');
        $this->registerArgument('author', 'string', 'Overrules author from properties');
        $this->registerArgument('uid', 'int', 'Overrules uid from properties');
        $this->registerArgument('date', \DateTime::class, 'Overrules date from properties');
    }

    /**
     * @return string
     */
    public function render(): string
    {
        return self::renderStatic(
            $this->arguments,
            $this->buildRenderChildrenClosure(),
            $this->renderingContext
        );
    }

    /**
     * @param array $arguments
     * @param \Closure $renderChildrenClosure
     * @param RenderingContextInterface $renderingContext
     * @return string
     */
    public static function renderStatic(
        array $arguments,
        \Closure $renderChildrenClosure,
        RenderingContextInterface $renderingContext
    ) {
        $properties = self::getProperties($arguments);
        $content = json_encode($properties, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);
        return '<script type="application/ld+json">' . $content . '</script>';
    }

    /**
     * @param array $arguments
     * @return array
     */
    protected static function getProperties(array $arguments): array
    {
        $properties = [
            '@context' => 'http://schema.org',
            '@type' => 'Periodical',
            'hasPart' => [
                '@id' => 'news' . self::getProperty($arguments, 'uid'),
                '@type' => 'PublicationVolume',
                'volumeNumber' => self::getProperty($arguments, 'uid'),
                'hasPart' => [
                    '@id' => 'newsarticle' . self::getProperty($arguments, 'uid') . '000000',
                    '@type' => 'PublicationIssue',
                    'datePublished' => self::getReadablePublishedDate($arguments),
                    'issueNumber' => self::getProperty($arguments, 'uid') . '000000'
                ]
            ],
            'name' => self::getProperty($arguments, 'title'),
            'publisher' => self::getProperty($arguments, 'author')
        ];
        return $properties;
    }

    /**
     * @param array $arguments
     * @return string like "2018-08-12"
     */
    protected static function getReadablePublishedDate(array $arguments): string
    {
        $date = self::getProperty($arguments, 'date');
        /** @var \DateTime $date */
        if (is_a($date, \DateTime::class)) {
            return $date->format('Y-m-d');
        }
        return '';
    }
}

PersonViewHelper.php

<?php
namespace In2code\In2template\ViewHelpers\JsonLdSchema;

use TYPO3Fluid\Fluid\Core\Rendering\RenderingContextInterface;

/**
 * Schema.org ViewHelper for rendering person in JSON-LD format
 * See http://schema.org/address (example 1, JSON-LD)
 *
 * Class PersonViewHelper
 */
class PersonViewHelper extends AbstractJsonLdSchemaViewHelper
{

    /**
     * Arguments can be submitted complete with the attribute "properties" or with single values
     * For argument properties, this keys are relevant:
     *  - name (first+lastname)
     *  - city
     *  - zip
     *  - street (with number)
     *  - email
     *  - image
     *  - jobTitle
     *  - phone
     *  - url
     *
     * @return void
     */
    public function initializeArguments()
    {
        parent::initializeArguments();
        $this->registerArgument('properties', 'array', 'All properties');
        $this->registerArgument('name', 'string', 'Overrules name from properties');
        $this->registerArgument('city', 'string', 'Overrules city from properties');
        $this->registerArgument('zip', 'string', 'Overrules zip from properties');
        $this->registerArgument('street', 'string', 'Overrules street from properties');
        $this->registerArgument('email', 'string', 'Overrules email from properties');
        $this->registerArgument('image', 'string', 'Overrules image from properties');
        $this->registerArgument('jobTitle', 'string', 'Overrules jobTitle from properties');
        $this->registerArgument('phone', 'string', 'Overrules phone from properties');
        $this->registerArgument('url', 'string', 'Overrules url from properties');
    }

    /**
     * @return string
     */
    public function render(): string
    {
        return self::renderStatic(
            $this->arguments,
            $this->buildRenderChildrenClosure(),
            $this->renderingContext
        );
    }

    /**
     * @param array $arguments
     * @param \Closure $renderChildrenClosure
     * @param RenderingContextInterface $renderingContext
     * @return string
     */
    public static function renderStatic(
        array $arguments,
        \Closure $renderChildrenClosure,
        RenderingContextInterface $renderingContext
    ) {
        $properties = self::getProperties($arguments);
        $content = json_encode($properties, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);
        return '<script type="application/ld+json">' . $content . '</script>';
    }

    /**
     * @param array $arguments
     * @return array
     */
    protected static function getProperties(array $arguments): array
    {
        $properties = [
            '@context' => 'http://schema.org',
            '@type' => 'person',
            'address' => [
                '@type' => 'PostalAddress',
                'addressLocality' => self::getProperty($arguments, 'city'),
                'postalCode' => self::getProperty($arguments, 'zip'),
                'streetAddress' => self::getProperty($arguments, 'street')
            ],
            'email' => self::getProperty($arguments, 'email'),
            'image' => self::getProperty($arguments, 'image'),
            'jobTitle' => self::getProperty($arguments, 'jobTitle'),
            'name' => self::getProperty($arguments, 'name'),
            'telephone' => self::getProperty($arguments, 'phone'),
            'url' => self::getProperty($arguments, 'url'),
        ];
        return $properties;
    }
}

ProductViewHelper.php

<?php
namespace In2code\In2template\ViewHelpers\JsonLdSchema;

use TYPO3Fluid\Fluid\Core\Rendering\RenderingContextInterface;

/**
 * Schema.org ViewHelper for rendering person in JSON-LD format
 * See http://schema.org/Product (example 2, JSON-LD)
 *
 * Class ProductViewHelper
 */
class ProductViewHelper extends AbstractJsonLdSchemaViewHelper
{

    /**
     * Arguments can be submitted complete with the attribute "properties" or with single values
     * For argument properties, this keys are relevant:
     *  - name
     *  - description
     *  - image
     *
     * @return void
     */
    public function initializeArguments()
    {
        parent::initializeArguments();
        $this->registerArgument('properties', 'array', 'All properties');
        $this->registerArgument('name', 'string', 'Overrules name from properties');
        $this->registerArgument('description', 'string', 'Overrules description from properties');
        $this->registerArgument('image', 'string', 'Overrules image string from properties');
    }

    /**
     * @return string
     */
    public function render(): string
    {
        return self::renderStatic(
            $this->arguments,
            $this->buildRenderChildrenClosure(),
            $this->renderingContext
        );
    }

    /**
     * @param array $arguments
     * @param \Closure $renderChildrenClosure
     * @param RenderingContextInterface $renderingContext
     * @return string
     */
    public static function renderStatic(
        array $arguments,
        \Closure $renderChildrenClosure,
        RenderingContextInterface $renderingContext
    ) {
        $properties = self::getProperties($arguments);
        $content = json_encode($properties, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);
        return '<script type="application/ld+json">' . $content . '</script>';
    }

    /**
     * @param array $arguments
     * @return array
     */
    protected static function getProperties(array $arguments): array
    {
        $properties = [
            '@context' => 'http://schema.org',
            '@type' => 'Product',
            'description' => self::getProperty($arguments, 'description'),
            'name' => self::getProperty($arguments, 'name'),
            'image' => self::getProperty($arguments, 'image')
        ];
        return $properties;
    }
}