feat: disable mailchimp-for-woocommerce plugin campaign tracking cook…

…ie (#618)

includes/class-newspack.php

@@ -131,6 +131,7 @@ private function includes() {
 		include_once NEWSPACK_ABSPATH . 'includes/plugins/class-gravityforms.php';
 		include_once NEWSPACK_ABSPATH . 'includes/plugins/google-site-kit/class-googlesitekit.php';
 		include_once NEWSPACK_ABSPATH . 'includes/plugins/class-newspack-newsletters.php';
+		include_once NEWSPACK_ABSPATH . 'includes/plugins/class-mailchimp-for-woocommerce.php';
 
 		include_once NEWSPACK_ABSPATH . 'includes/class-patches.php';
 

includes/plugins/class-mailchimp-for-woocommerce.php

@@ -0,0 +1,39 @@
+<?php
+/**
+ * Mailchimp for WooCommerce integration class.
+ *
+ * @package Newspack
+ */
+
+namespace Newspack;
+
+defined( 'ABSPATH' ) || exit;
+
+/**
+ * Main class.
+ */
+class Mailchimp_For_WooCommerce {
+	/**
+	 * Initialize hooks and filters.
+	 */
+	public static function init() {
+		// MC4WC fires it's hook at priority 10 so we need to move quicker.
+		add_action( 'init', [ __CLASS__, 'remove_campaign_tracking_cookie' ], 9 );
+	}
+
+	/**
+	 * Disable the cookie added by the Mailchimp for WooCommerce (MC4WC) plugin when on
+	 * a Newspack site because the cookie causes performance issues when logged out.
+	 */
+	public static function remove_campaign_tracking_cookie() {
+		// Don't do anything unless we know the MC4WC plugin is active.
+		if ( ! \class_exists( '\MailChimp_Service' ) ) {
+			return;
+		}
+
+		// Remove entirely the hook that sets the cookie.
+		$service = \MailChimp_Service::instance();
+		remove_action( 'init', [ $service, 'handleCampaignTracking' ] );
+	}
+}
+Mailchimp_For_WooCommerce::init();