Block Editor: Move caching to endpoint for unique responses.

Now that the pattern API request includes the locale and version, the cache key needs to contain a hash of the query args.

Props ocean90, dd32, timothyblynjacobs
Fixes #53435

Built from https://develop.svn.wordpress.org/trunk@51208


git-svn-id: http://core.svn.wordpress.org/trunk@50817 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/block-patterns.php

@@ -45,7 +45,11 @@ function _register_core_block_patterns_and_categories() {
 }
 
 /**
- * Import patterns from wordpress.org/patterns.
+ * Register Core's official patterns from wordpress.org/patterns.
+ *
+ * @since 5.8.0
+ *
+ * @param WP_Screen $current_screen The screen that the current request was triggered from.
  */
 function _load_remote_block_patterns( $current_screen ) {
 	if ( ! $current_screen->is_block_editor ) {
@@ -64,8 +68,6 @@ function _load_remote_block_patterns( $current_screen ) {
 	$should_load_remote = apply_filters( 'should_load_remote_block_patterns', true );
 
 	if ( $supports_core_patterns && $should_load_remote ) {
-		$patterns = get_transient( 'wp_remote_block_patterns' );
-		if ( ! $patterns ) {
 		$request         = new WP_REST_Request( 'GET', '/wp/v2/pattern-directory/patterns' );
 		$core_keyword_id = 11; // 11 is the ID for "core".
 		$request->set_param( 'keyword', $core_keyword_id );
@@ -74,8 +76,6 @@ function _load_remote_block_patterns( $current_screen ) {
 			return;
 		}
 		$patterns = $response->get_data();
-			set_transient( 'wp_remote_block_patterns', $patterns, HOUR_IN_SECONDS );
-		}
 
 		foreach ( $patterns as $settings ) {
 			$pattern_name = 'core/' . sanitize_title( $settings['title'] );

wp-includes/rest-api/endpoints/class-wp-rest-pattern-directory-controller.php

@@ -111,6 +111,24 @@ class WP_REST_Pattern_Directory_Controller extends WP_REST_Controller {
 			$query_args['search'] = $search_term;
 		}
 
+		/*
+		 * Include a hash of the query args, so that different requests are stored in
+		 * separate caches.
+		 *
+		 * MD5 is chosen for its speed, low-collision rate, universal availability, and to stay
+		 * under the character limit for `_site_transient_timeout_{...}` keys.
+		 *
+		 * @link https://stackoverflow.com/questions/3665247/fastest-hash-for-non-cryptographic-uses
+		 */
+		$transient_key = 'wp_remote_block_patterns_' . md5( implode( '-', $query_args ) );
+
+		/*
+		 * Use network-wide transient to improve performance. The locale is the only site
+		 * configuration that affects the response, and it's included in the transient key.
+		 */
+		$raw_patterns = get_site_transient( $transient_key );
+
+		if ( ! $raw_patterns ) {
 			$api_url = add_query_arg(
 				array_map( 'rawurlencode', $query_args ),
 				'http://api.wordpress.org/patterns/1.0/'
@@ -120,18 +138,23 @@ class WP_REST_Pattern_Directory_Controller extends WP_REST_Controller {
 				$api_url = set_url_scheme( $api_url, 'https' );
 			}
 
+			/*
+			 * Default to a short TTL, to mitigate cache stampedes on high-traffic sites.
+			 * This assumes that most errors will be short-lived, e.g., packet loss that causes the
+			 * first request to fail, but a follow-up one will succeed. The value should be high
+			 * enough to avoid stampedes, but low enough to not interfere with users manually
+			 * re-trying a failed request.
+			 */
+			$cache_ttl      = 5;
 			$wporg_response = wp_remote_get( $api_url );
 			$raw_patterns   = json_decode( wp_remote_retrieve_body( $wporg_response ) );
 
 			if ( is_wp_error( $wporg_response ) ) {
-			$wporg_response->add_data( array( 'status' => 500 ) );
+				$raw_patterns = $wporg_response;
 
-			return $wporg_response;
+			} elseif ( ! is_array( $raw_patterns ) ) {
-		}
+				// HTTP request succeeded, but response data is invalid.
-
+				$raw_patterns = new WP_Error(
-		// Make sure w.org returned valid data.
-		if ( ! is_array( $raw_patterns ) ) {
-			return new WP_Error(
 					'pattern_api_failed',
 					sprintf(
 					/* translators: %s: Support forums URL. */
@@ -139,10 +162,22 @@ class WP_REST_Pattern_Directory_Controller extends WP_REST_Controller {
 						__( 'https://wordpress.org/support/forums/' )
 					),
 					array(
-					'status'   => 500,
 						'response' => wp_remote_retrieve_body( $wporg_response ),
 					)
 				);
+
+			} else {
+				// Response has valid data.
+				$cache_ttl = HOUR_IN_SECONDS;
+			}
+
+			set_site_transient( $transient_key, $raw_patterns, $cache_ttl );
+		}
+
+		if ( is_wp_error( $raw_patterns ) ) {
+			$raw_patterns->add_data( array( 'status' => 500 ) );
+
+			return $raw_patterns;
 		}
 
 		$response = array();

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.8-beta2-51207';
+$wp_version = '5.8-beta2-51208';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.