RdfParsingTrait.php

<?php

namespace Drupal\Tests\rdf\Traits;

use Drupal\Core\Url;
use EasyRdf\Graph;
use EasyRdf\Parser\Rdfa;

/**
 * Defines a trait for parsing RDF properties from HTML.
 */
trait RdfParsingTrait {
    
    /**
     * Checks if a html document contains a resource with a given property value.
     *
     * @param string $html
     *   The HTML to parse.
     * @param string $base_uri
     *   The base URI for the html being parsed.
     * @param string $resource
     *   The URI of the resource which should have the given property.
     * @param string $property
     *   The property being tested.
     * @param array $value
     *   The expected value. This should include the following keys:
     *   - type: one of literal, uri and bnode
     *   - value: the expected value
     *   - datatype: the expected datatype in URI format - e.g.
     *     - http://www.w3.org/2001/XMLSchema#integer
     *     - http://www.w3.org/2001/XMLSchema#dateTime
     *   - lang: language code of the property.
     *
     * @return bool
     *   TRUE if the property exists with the given value.
     *
     * @throws \EasyRdf\Exception
     */
    protected function hasRdfProperty($html, $base_uri, $resource, $property, array $value) {
        $parser = $this->getInstanceParser();
        $graph = $this->getInstanceGraph();
        $parser->parse($graph, $html, 'rdfa', $base_uri);
        return $graph->hasProperty($resource, $property, $value);
    }
    
    /**
     * Checks if a html document contains a resource with a given property value.
     *
     * @param string $html
     *   The HTML to parse.
     * @param string $base_uri
     *   The base URI for the html being parsed.
     * @param string $resource
     *   The URI of the resource which should have the given property.
     * @param string $parent_property
     *   The parent property being tested.
     * @param string $child_property
     *   The child property being tested.
     * @param array $value
     *   The expected value. This should include the following keys:
     *   - type: one of literal, uri and bnode
     *   - value: the expected value
     *   - datatype: the expected datatype in URI format - e.g.
     *     - http://www.w3.org/2001/XMLSchema#integer
     *     - http://www.w3.org/2001/XMLSchema#dateTime
     *   - lang: language code of the property.
     *
     * @return bool
     *   TRUE if the property exists with the given value.
     *
     * @throws \EasyRdf\Exception
     */
    protected function hasRdfChildProperty($html, $base_uri, $resource, $parent_property, string $child_property, array $value) {
        $parser = $this->getInstanceParser();
        $graph = $this->getInstanceGraph();
        $parser->parse($graph, $html, 'rdfa', $base_uri);
        $node = $graph->get($resource, $parent_property);
        return $graph->hasProperty($node, $child_property, $value);
    }
    
    /**
     * Counts the number of resources of the provided type.
     *
     * @param \Drupal\Core\Url $url
     *   URL of the document.
     * @param string $base_uri
     *   The base URI for the html being parsed.
     * @param string $type
     *   Type of resource to count.
     *
     * @return int
     *   The number of resources of the provided type.
     *
     * @throws \EasyRdf\Exception
     */
    protected function getElementByRdfTypeCount(Url $url, $base_uri, $type) {
        $parser = $this->getInstanceParser();
        $graph = $this->getInstanceGraph();
        $parser->parse($graph, $this->drupalGet($url), 'rdfa', $base_uri);
        return count($graph->allOfType($type));
    }
    
    /**
     * Gets type of RDF Element.
     *
     * @param \Drupal\Core\Url $url
     *   URL of the document.
     * @param string $base_uri
     *   The base URI for the html being parsed.
     * @param string $resource_uri
     *   The URI of the resource from where to get element.
     *
     * @return string|null
     *   The type of resource or NULL if the resource has no type.
     *
     * @throws \EasyRdf\Exception
     */
    protected function getElementRdfType(Url $url, $base_uri, $resource_uri) {
        $parser = $this->getInstanceParser();
        $graph = $this->getInstanceGraph();
        $parser->parse($graph, $this->drupalGet($url), 'rdfa', $base_uri);
        return $graph->type($resource_uri);
    }
    
    /**
     * Checks if RDF Node property is blank.
     *
     * @param string $html
     *   The HTML to parse.
     * @param string $base_uri
     *   The base URI for the html being parsed.
     * @param string $resource_uri
     *   The URI of the resource which should have the given property.
     * @param string $property
     *   The property being tested.
     *
     * @return bool
     *   TRUE if the given property is blank.
     *
     * @throws \EasyRdf\Exception
     */
    protected function rdfElementIsBlankNode($html, $base_uri, $resource_uri, $property) {
        $parser = $this->getInstanceParser();
        $graph = $this->getInstanceGraph();
        $parser->parse($graph, $html, 'rdfa', $base_uri);
        return $graph->get($resource_uri, $property)
            ->isBnode();
    }
    
    /**
     * Gets a new instance of EasyRdf\Parser\Rdfa or EasyRdf_Parser_Rdfa.
     *
     * @return \EasyRdf\Parser\Rdfa|\EasyRdf_Parser_Rdfa
     *   The instance.
     *
     * @todo Clean this up in drupal:10.0.0.
     * @see https://www.drupal.org/node/3176468
     */
    private function getInstanceParser() {
        if (class_exists('EasyRdf\\Parser\\Rdfa')) {
            return new Rdfa();
        }
        return new \EasyRdf_Parser_Rdfa();
    }
    
    /**
     * Gets a new instance of EasyRdf\Graph or EasyRdf_Graph.
     *
     * @return \EasyRdf\Graph|\EasyRdf_Graph
     *   The instance.
     *
     * @todo Clean this up in drupal:10.0.0.
     * @see https://www.drupal.org/node/3176468
     */
    private function getInstanceGraph() {
        if (class_exists('EasyRdf\\Graph')) {
            return new Graph();
        }
        return new \EasyRdf_Graph();
    }

}