Feature/cache last changed time

elasticpress.php

@@ -88,6 +88,11 @@ function( $class ) {
 	define( 'EP_IS_NETWORK', true );
 }
 
+/**
+ * Set global cache groups.
+ */
+wp_cache_add_global_groups( 'elasticpress-network' );
+
 /**
  * Sets up the indexables and features.
  *

includes/classes/Elasticsearch.php

@@ -137,6 +137,8 @@ public function index_document( $index, $type, $document, $blocking = true ) {
 			$response_body = wp_remote_retrieve_body( $request );
 
 			$return = json_decode( $response_body );
+
+			Utils\wp_cache_set_ep_last_changed();
 		} else {
 			$return = false;
 		}
@@ -191,6 +193,8 @@ public function refresh_indices() {
 
 		if ( ! is_wp_error( $request ) ) {
 			if ( isset( $request['response']['code'] ) && 200 === $request['response']['code'] ) {
+				Utils\wp_cache_set_ep_last_changed();
+
 				return true;
 			}
 		}
@@ -560,6 +564,8 @@ public function delete_document( $index, $type, $document_id, $blocking = true )
 			$response = json_decode( $response_body, true );
 
 			if ( ! empty( $response['found'] ) ) {
+				Utils\wp_cache_set_ep_last_changed();
+
 				return true;
 			}
 		}
@@ -660,6 +666,8 @@ public function delete_network_alias( $alias ) {
 		if ( ! is_wp_error( $request ) && ( 200 >= wp_remote_retrieve_response_code( $request ) && 300 > wp_remote_retrieve_response_code( $request ) ) ) {
 			$response_body = wp_remote_retrieve_body( $request );
 
+			Utils\wp_cache_set_ep_last_changed();
+
 			return json_decode( $response_body );
 		}
 
@@ -767,6 +775,8 @@ public function create_network_alias( $indexes, $network_alias ) {
 		$request = $this->remote_request( $path, $request_args, [], 'create_network_alias' );
 
 		if ( ! is_wp_error( $request ) && ( 200 >= wp_remote_retrieve_response_code( $request ) && 300 > wp_remote_retrieve_response_code( $request ) ) ) {
+			Utils\wp_cache_set_ep_last_changed();
+
 			return true;
 		}
 
@@ -816,6 +826,8 @@ public function put_mapping( $index, $mapping ) {
 		if ( ! is_wp_error( $request ) && 200 === wp_remote_retrieve_response_code( $request ) ) {
 			$response_body = wp_remote_retrieve_body( $request );
 
+			Utils\wp_cache_set_ep_last_changed();
+
 			return true;
 		}
 
@@ -927,6 +939,8 @@ public function update_index_settings( $index, $settings, $close_first = false )
 			return ( $updated && $opened );
 		}
 
+		Utils\wp_cache_set_ep_last_changed();
+
 		return $updated;
 	}
 
@@ -951,6 +965,8 @@ public function delete_index( $index ) {
 		if ( ! is_wp_error( $request ) && ( 200 === wp_remote_retrieve_response_code( $request ) || 404 === wp_remote_retrieve_response_code( $request ) ) ) {
 			$response_body = wp_remote_retrieve_body( $request );
 
+			Utils\wp_cache_set_ep_last_changed();
+
 			return json_decode( $response_body );
 		}
 
@@ -1041,6 +1057,8 @@ public function bulk_index( $index, $type, $body ) {
 			return new WP_Error( $response, wp_remote_retrieve_response_message( $request ), $request );
 		}
 
+		Utils\wp_cache_set_ep_last_changed();
+
 		return json_decode( wp_remote_retrieve_body( $request ), true );
 	}
 

includes/utils.php

@@ -633,3 +633,22 @@ function is_integrated_request( $context, $types = [] ) {
 	 */
 	return apply_filters( 'ep_is_integrated_request', $is_integrated, $context, $types );
 }
+
+/**
+ * Sets the last changed times for ElasticPress and ElasticPress Network cache groups.
+ *
+ * @return void
+ *
+ * @since 3.7
+ */
+function wp_cache_set_ep_last_changed() {
+	/**
+	 * Set the `last_changed` for this specific blog / site.
+	 */
+	wp_cache_set( 'last_changed', microtime(), 'elasticpress' );
+
+	/**
+	 * Set the `last_changed` for this specific network (for all blogs / sites).
+	 */
+	wp_cache_set( 'last_changed', microtime(), 'elasticpress-network' );
+}