Integrating Koko Analytics stats

It’s possible to integrate all kinds of external data to Relevanssi weights. Koko Analytics is a great analytics plugin. It collects stats about your visitors and stores them in the local database, which means those stats are available for Relevanssi.

For some sites, this makes a lot of sense. For example, I have Kirjavinkit, a book review site with an archive of about 10,000 book review posts. The popularity of the posts is primarily driven by external search traffic and seems like a good indicator of what users find interesting and valuable.

Integrating the Koko stats as a factor in the weight calculations is straightforward. The best tool to use is the relevanssi_results filter hook. It lets us modify the weights of the posts. For each post, we calculate a weight multiplier based on the visitor stats and then multiple the weight of the post with that.

I add some normalization here. I normalize all weights to the 1–1,000 range. I also set the minimum weight to 1 to avoid punishing the rarely-visited posts.

To avoid performance problems, I fetch all the stats once and store them in a global variable so that when the function processes all posts, it only needs to make one database request.

Here’s the code:

function rlv_koko_weight( int $post_id ) : float {
	global $relevanssi_koko_weights;

	if ( empty( $relevanssi_koko_weights ) ) {
		global $wpdb;
		$stats = $wpdb->get_results( "SELECT id, SUM(visitors) AS visits FROM {$wpdb->prefix}koko_analytics_post_stats GROUP BY id" );
		foreach ( $stats as $post_stats ) {
			$relevanssi_koko_weights[ $post_stats->id ] = $post_stats->visits;
		}
		$max_visits = max( $relevanssi_koko_weights );
		$factor     = $max_visits / 1000; // This controls the normalization.
		foreach ( $relevanssi_koko_weights as $post_id => $visits ) {
			$weight = $visits / $factor;
			if ( $weight < 1 ) {
				$weight = 1;
			}

			$relevanssi_koko_weights[ $post_id ] = $weight;
		}
	}
	return $relevanssi_koko_weights[ $post_id ] ?? 1;
}

add_filter( 'relevanssi_results', 'rlv_koko_weights' );

function rlv_koko_weights( $post_weights ) {
	foreach ( $post_weights as $post_id => $weight ) {
		$post_weights[ $post_id ] = rlv_koko_weight( intval( $post_id ) ) * $weight;
	}
	return $post_weights;
}