single_post_rich_snippet.php

<?php

$featured_image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'img_post' ); 
// img_post is name of my thumbnail size ( I've added my own in functions.php ) 
$focuskw = get_post_meta(get_the_ID(), ‘_yoast_wpseo_focuskw’, true);
// It's focus keyword that you enter in Yoast Metabox in post edit page, it's really important
$primary_cat = get_post_meta(get_the_ID(), ‘_yoast_wpseo_primary_category’, true);
// Primary Category is important, for permalink format and meta keywords

if($primary_cat == NULL && $primary_cat == ''){
    $cats = wp_get_post_categories($post->ID);
          $primary_cat = $cats[0];
          // Wordpress posts always have at least one category.
}
$primary_cat = get_cat_name($primary_cat);
// I am building the template for description as the same as i built before in Yoast SEO Titles section, now i am sure that my Rich snippets are the same as my meta tags which is generated by Yoast. 
// My Fromat will be like this : 
// "Wordpress Development (Tutorial),Updated 1 April 2019. For Become professional in wordpress development ..."

$description = $focuskw . " (" .$primary_cat. "), Updated " .get_the_date(). ". " . get_the_excerpt();

// Post keywords
$tags = get_the_tags();
$tags_string = "";
$stripped_content = esc_attr(wp_strip_all_tags( get_the_content() ));                                                            
foreach ( $tags as $tag ) {
    $tags_string .= $tag->name . " ";
}

$post_date = mysql2date( 'c', $post->post_date, false );
$post_modified_date = mysql2date( 'c', $post->post_modified, false);     

?> 
                
<script type="application/ld+json">
{ 
"@context": "http://schema.org", 
 "@type": "Article",
 "mainEntityOfPage": {
    "@type": "WebPage",
    "@id": "https://google.com/article"
  },
 "headline": "<?php the_title(); ?>",
 "alternativeHeadline": "<?php echo $description; ?>",
 "image": "<?php echo $featured_image[0]; ?>",
 "author": {
    "@type": "Person",
    "name": "<?php the_author(); ?>"
  },
   "publisher": {
    "@type": "Organization",
    "name": "MyWebsite",
    "logo": {
      "@type": "ImageObject",
      "url": "https://cdn.myweb.com/logo.jpg"
    }
    },
 "genre": "<?php echo $primary_cat; ?>", 
 "keywords": "<?php echo $tags_string; ?>", 
 "wordcount": " <?php echo str_word_count($stripped_content); ?>",
 "url": "<?php the_permalink() ?>",
 "datePublished": "<?php echo $post_date; ?>",
 "dateCreated": "<?php echo $post_date; ?>",
 "dateModified": "<?php echo $post_modified_date; ?>",
 "description": "<?php echo $description ?>",
 "articleBody": "<?php echo $stripped_content; ?>",
 "aggregateRating": {
    "@type": "AggregateRating",
    "ratingValue": "<?php echo get_post_meta(get_the_ID(),'ratings_average', true); ?>",
    "bestRating": "5",
    "ratingCount": "<?php echo get_post_meta(get_the_ID(), 'ratings_users', true); ?>"
  }
 }
</script>