Get popular posts using Jetpack

jetpack-popular-posts.php

<?php
namespace Alley;

/**
 * Popular Posts
 */
class Popular_Posts {

	/**
	 * The number of days to query for post views.
	 *
	 * @var integer
	 */
	public static $jetpack_days = 7;

	/**
	 * The post types to which to restrict popular posts.
	 *
	 * @var array
	 */
	public static $post_types = [ 'post' ];

	/**
	 * Get a number of popular posts from Jetpack.
	 *
	 * The results are cached for an hour.
	 *
	 * @param  int $count The number of posts to return. We query 20 posts on
	 *                    top of this, because the Jetpack stats function can't
	 *                    restrict by post type.
	 * @return array WP_Post objects.
	 */
	public static function get_from_jetpack( $count ) {
		$cache_key = 'most-popular-jetpack-' . $count;
		if ( false === ( $return = get_transient( $cache_key ) ) ) {
			$return = [];
			do {
				if ( ! function_exists( 'stats_get_csv' ) ) {
					break;
				}

				// We add some buffer to the count for post types we don't want.
				$post_view_posts = stats_get_csv( 'postviews', [
					'days' => self::$jetpack_days,
					'limit' => $count + 20,
				] );
				if ( ! $post_view_posts ) {
					break;
				}

				$post_view_ids = array_filter( array_column( $post_view_posts, 'post_id' ) );
				if ( ! $post_view_ids ) {
					break;
				}

				$counter = 0;
				while ( ! empty( $post_view_ids ) && $counter < $count ) {
					$post_id = array_shift( $post_view_ids );
					$post = get_post( $post_id );
					if ( $post && in_array( $post->post_type, self::$post_types ) ) {
						$return[] = $post;
						$counter++;
					}
				}
			} while ( 0 );

			set_transient( $cache_key, $return, HOUR_IN_SECONDS );
		}

		return $return;
	}
}