[Popular posts based on post view] #wp

popular-posts.php

// DIY Popular Posts @ https://digwp.com/2016/03/diy-popular-posts/
function shapeSpace_popular_posts($post_id) {
	$count_key = 'popular_posts';
	$count = get_post_meta($post_id, $count_key, true);
	if ($count == '') {
		$count = 0;
		delete_post_meta($post_id, $count_key);
		add_post_meta($post_id, $count_key, '0');
	} else {
		$count++;
		update_post_meta($post_id, $count_key, $count);
	}
}
function shapeSpace_track_posts($post_id) {
	if (!is_single()) return;
	if (empty($post_id)) {
		global $post;
		$post_id = $post->ID;
	}
	shapeSpace_popular_posts($post_id);
}
add_action('wp_head', 'shapeSpace_track_posts');

// shortcode: display diy popular posts: [diy_pop_posts num="10" cat="1,2,3"]
function shapeSpace_display_popular_posts($atts) {
	
	extract(shortcode_atts(array(
		'num' => 10,
		'cat' => '',
	), $atts)); 
	
	$temps = explode(',', $cat);
	$array = array();
	foreach ($temps as $temp) $array[] = trim($temp);
	
	$cats = !empty($cat) ? $array : '';
	
	?>
	
	<h3>Popular Posts</h3>
	<ul>
		<?php $popular = new WP_Query(array('posts_per_page' => $num, 'meta_key' => 'popular_posts', 'orderby' => 'meta_value_num', 'order' => 'DESC', 'category__in' => $cats));
		while ($popular->have_posts()) : $popular->the_post(); ?>
		<li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
		<?php endwhile; wp_reset_postdata(); ?>
	</ul>
	
<?php }
add_shortcode('diy_pop_posts', 'shapeSpace_display_popular_posts');