JSON-LD for WordPress posts

functions.php

/**
* Remove hentry from post_class
* This is important to not get schema errors
*/
function visceral_remove_hentry_class( $classes ) {
    $classes = array_diff( $classes, array( 'hentry' ) );
    return $classes;
}
add_filter( 'post_class', 'visceral_remove_hentry_class' );

single.php

<?php
/**
 * Adding JSON-LD for structured data and SEO
 *
 * Official website: 		http://json-ld.org/
 * Examples: 			http://jsonld.com/
 * Generators: 			https://www.google.com/webmasters/markup-helper/u/0/
 * 				https://www.schemaapp.com/tools/jsonld-schema-generator/
 * Test: 			https://search.google.com/structured-data/testing-tool/u/0/
 * Google Docs: 		https://developers.google.com/search/docs/data-types/data-type-selector
 **/

$post_id = get_the_id(); // Store the ID

// JSON-LD amrkup For Articles
if ( 'post' == get_post_type() ) :
	$logo_url = get_site_icon_url(); // Feel free to customize. Otherwise will use WordPress site icon
	if ( $logo_url && has_post_thumbnail() ) :
		// Images are required. We only continue if we have them.
		$featured_img = wp_get_attachment_image_src( get_post_thumbnail_id(), 'full', true );

		// JSON-LD markup for Articles
		$json_ld = array(

			// Required
			"@context" => "http://schema.org",
			"@type" => "Article",
			"publisher" => array(	 
				"@type" => "Organization",
				"url" => get_site_url(),
				"name" => get_bloginfo('name'),
				"logo" => $logo_url
			),
			"headline" => get_the_title(),
			"author" => array(
				"@type" => "Person",
				"name" => get_the_author()
			),
			"datePublished" => get_the_date(),
			"image" => array(
				"@type" => "ImageObject",
				"url" => $featured_img[0],
				"width" => $featured_img[1],
				"height" => $featured_img[2]
			),

			// Recommended
			"dateModified" =>  get_the_modified_date(),
			"mainEntityOfPage" => get_permalink(),

			// Optional (Not sure if they affect SEO)
			// "url" => get_permalink(),
			// "description" => get_the_excerpt(),
			// "articleBody" => get_the_content(),
		);
		?>
		<script type='application/ld+json'>
			<?php echo json_encode( $json_ld ); ?>
		</script>
	<?php endif;
endif;


// JSON-LD markup for Persons
if ( 'person' == get_post_type() ) :
	$job_title = get_post_meta( $post_id, 'job_title', true); // Edit meta field name as needed
	$email = get_post_meta( $post_id, 'email', true); // Edit meta field name as needed

	$json_ld = array(
		"@context" => "http://schema.org",
		"@type" => "Person",
		"name" => get_the_title()
	);
	if ( has_post_thumbnail() ) {
		$featured_img = wp_get_attachment_image_src( get_post_thumbnail_id(), 'full', true );
		$json_ld['image'] = array(
			"@type" => "ImageObject",
			"url" => $featured_img[0],
			"width" => $featured_img[1],
			"height" => $featured_img[2]
		);
	}
	// These variables come from post meta above
	if ( $title ) {
		$json_ld['jobTitle'] = $title;
	}
	if ( $email ) {
		$json_ld['email'] = $email;
	}
	?>
	<script type='application/ld+json'>
		<?php echo json_encode( $json_ld ); ?>
	</script>
<?php endif;
?>