WP Super Cache: add constants to modify preload timings (#36246)

* Add more constants to modify preload timing.

* changelog

Committed via a GitHub action: https://github.com/Automattic/jetpack/actions/runs/8198298813

CHANGELOG.md

@@ -11,6 +11,7 @@ This is an alpha version! The changes listed here are not final.
 
 ### Added
 - Setup: Detect Jetpack Boost cache and suggest troubleshooting steps
+- WP Super Cache: added WPSC_PRELOAD_POST_INTERVAL and WPSC_PRELOAD_LOOP_INTERVAL to modify preload timings
 
 ### Changed
 - Code Modernization: Replace usage of strpos() with str_contains()

wp-cache-phase2.php

@@ -5,8 +5,6 @@
  * It has all the code for caching and serving requests.
  */
 
-define( 'WPSC_PRELOAD_POST_COUNT', 10 );
-
 // phpcs:disable WordPress.WP.AlternativeFunctions.file_system_operations_is_writable -- TODO: Fix or determine for sure that these should not be fixed.
 // phpcs:disable WordPress.WP.AlternativeFunctions.file_system_operations_fwrite -- TODO: Fix or determine for sure that these should not be fixed.
 

wp-cache.php

@@ -45,6 +45,27 @@
 	unset( $wpsc_php_version );
 }
 
+/**
+ * Defines how many posts to preload per loop.
+ */
+if ( ! defined( 'WPSC_PRELOAD_POST_COUNT' ) ) {
+	define( 'WPSC_PRELOAD_POST_COUNT', 10 );
+}
+
+/**
+ * Defines the interval in seconds between preloading pages.
+ */
+if ( ! defined( 'WPSC_PRELOAD_POST_INTERVAL' ) ) {
+	define( 'WPSC_PRELOAD_POST_INTERVAL', 1 );
+}
+
+/**
+ * Defines the interval in seconds between preloading loops.
+ */
+if ( ! defined( 'WPSC_PRELOAD_LOOP_INTERVAL' ) ) {
+	define( 'WPSC_PRELOAD_LOOP_INTERVAL', 0 );
+}
+
 function wpsc_init() {
 	global $wp_cache_config_file, $wp_cache_config_file_sample, $wpsc_advanced_cache_dist_filename, $wp_cache_check_wp_config, $wpsc_advanced_cache_filename, $wpsc_promo_links;
 
@@ -3470,7 +3491,7 @@ function wp_cron_preload_cache() {
 						)
 					);
 					wp_cache_debug( "wp_cron_preload_cache: fetched $url" );
-					sleep( 1 );
+					sleep( WPSC_PRELOAD_POST_INTERVAL );
 
 					if ( ! wpsc_is_preload_active() ) {
 						wp_cache_debug( 'wp_cron_preload_cache: cancelling preload process.' );
@@ -3505,6 +3526,7 @@ function wp_cron_preload_cache() {
 
 		if ( $preload_more_taxonomies === true ) {
 			wpsc_schedule_next_preload();
+			sleep( WPSC_PRELOAD_LOOP_INTERVAL );
 			return true;
 		}
 	} elseif ( $c === 0 && $wp_cache_preload_email_me ) {
@@ -3594,7 +3616,7 @@ function wp_cron_preload_cache() {
 			wp_remote_get( $url, array('timeout' => 60, 'blocking' => true ) );
 			wp_cache_debug( "wp_cron_preload_cache: fetched $url", 5 );
 			++$count;
-			sleep( 1 );
+			sleep( WPSC_PRELOAD_POST_INTERVAL );
 		}
 
 		if ( $wp_cache_preload_email_me && ( $wp_cache_preload_email_volume === 'medium' || $wp_cache_preload_email_volume === 'many' ) ) {
@@ -3603,8 +3625,8 @@ function wp_cron_preload_cache() {
 		}
 
 		wpsc_schedule_next_preload();
-
 		wpsc_delete_files( get_supercache_dir() );
+		sleep( WPSC_PRELOAD_LOOP_INTERVAL );
 	} else {
 		$msg = '';
 		wpsc_reset_preload_counter();