Adds schema.org JSON-LD for MRP post ratings

mrp_jsonld_example.php

/**
 * Adds JSON-LD ratings for schema.org item types
 */
function mrp_jsonld_ratings() {

	if ( is_page() || is_single() ) {

    	$post_id = get_queried_object_id();
    	if ($post_id == null) {
    		return;
    	}

    	// in case you only want to add rich snippets on posts which have auto placement enabled...
    	if ( ! apply_filters( 'mrp_can_apply_auto_placement', true, 'the_title', null, $post_id ) ) {
			return;
		}

    	$post_type = get_post_type( $post_id );
    	$rating_form_id = MRP_Utils::get_rating_form( $post_id );

    	$rating_result = MRP_Multi_Rating_API::get_rating_result( array(
			'post_id' => $post_id,
			'rating_form_id' => $rating_form_id
		) );
		if ($rating_result == null 
			|| ($rating_result !== null && $rating_result['count_entries'] === 0)) {
			return;
		}

    	$item_type_map = [
    		"post" => 'Product',
    		"page" => 'Product'
    	];
    	$item_type = $item_type_map[$post_type];
    	$post_title = get_the_title( $post_id );
    	$post_thumbnail_url = get_the_post_thumbnail_url( $post_id );
    	$post_excerpt = get_the_excerpt( $post_id );

		?>
		<script type="application/ld+json">
		{
		    "@context": "https://schema.org/",
		    "@type": "<?php echo $item_type; ?>",
		    "name": "<?php echo $post_title; ?>",
		    <?php if ($post_thumbnail_url) { ?>
		    "image": [
		   	    "<?php echo $post_thumbnail_url; ?>"
		    ],
		    <?php } if ($post_excerpt) { ?>
			"description": "<?php echo esc_html($post_excerpt); ?>",
		    <?php } ?>
			"aggregateRating": {
		        "@type": "AggregateRating",
		        "ratingValue": "<?php echo $rating_result['adjusted_star_result']; ?>",
		        "reviewCount": "<?php echo $rating_result['count_entries']; ?>"
		    }
		}
		</script>
		<?php
	}
}
add_action( 'wp_head', 'mrp_jsonld_ratings' );