1 files changed, 41 insertions, 20 deletions

diff --git a/plugins/jetpack/modules/related-posts/jetpack-related-posts.php b/plugins/jetpack/modules/related-posts/jetpack-related-posts.php
index f8eaff22..5748e6a2 100644
--- a/plugins/jetpack/modules/related-posts/jetpack-related-posts.php
+++ b/plugins/jetpack/modules/related-posts/jetpack-related-posts.php
@@ -1014,17 +1014,27 @@ EOT;
 		if ( !empty( $filters ) )
 			$body['filter'] = array( 'and' => $filters );
 
-		// Load all cached values
-		$cache = get_post_meta( $post_id, $cache_meta_key, true );
-		if ( empty( $cache ) )
-			$cache = array();
-
 		// Build cache key
 		$cache_key = md5( serialize( $body ) );
 
-		// Cache is valid! Return cached value.
-		if ( isset( $cache[ $cache_key ] ) && is_array( $cache[ $cache_key ] ) && $cache[ $cache_key ][ 'expires' ] > $now_ts ) {
-			return $cache[ $cache_key ][ 'payload' ];
+		// Load all cached values
+		if ( wp_using_ext_object_cache() ) {
+			$transient_name = "{$cache_meta_key}_{$cache_key}_{$post_id}";
+			$cache = get_transient( $transient_name );
+			if ( false !== $cache ) {
+				return $cache;
+			}
+		} else {
+			$cache = get_post_meta( $post_id, $cache_meta_key, true );
+
+			if ( empty( $cache ) )
+				$cache = array();
+
+
+			// Cache is valid! Return cached value.
+			if ( isset( $cache[ $cache_key ] ) && is_array( $cache[ $cache_key ] ) && $cache[ $cache_key ][ 'expires' ] > $now_ts ) {
+				return $cache[ $cache_key ][ 'payload' ];
+			}
 		}
 
 		$response = wp_remote_post(
@@ -1055,25 +1065,36 @@ EOT;
 			}
 		}
 
-		// Copy all valid cache values
-		$new_cache = array();
-		foreach ( $cache as $k => $v ) {
-			if ( is_array( $v ) && $v[ 'expires' ] > $now_ts ) {
-				$new_cache[ $k ] = $v;
-			}
+		// An empty array might indicate no related posts or that posts
+		// are not yet synced to WordPress.com, so we cache for only 1
+		// minute in this case
+		if ( empty( $related_posts ) ) {
+			$cache_ttl = 60;
+		} else {
+			$cache_ttl = 12 * HOUR_IN_SECONDS;
 		}
 
-		// Set new cache value if valid
-		if ( ! empty( $related_posts ) ) {
+		// Update cache
+		if ( wp_using_ext_object_cache() ) {
+			set_transient( $transient_name, $related_posts, $cache_ttl );
+		} else {
+			// Copy all valid cache values
+			$new_cache = array();
+			foreach ( $cache as $k => $v ) {
+				if ( is_array( $v ) && $v[ 'expires' ] > $now_ts ) {
+					$new_cache[ $k ] = $v;
+				}
+			}
+
+			// Set new cache value
+			$cache_expires = $cache_ttl + $now_ts;
 			$new_cache[ $cache_key ] = array(
-				'expires' => 12 * HOUR_IN_SECONDS + $now_ts,
+				'expires' => $cache_expires,
 				'payload' => $related_posts,
 			);
+			update_post_meta( $post_id, $cache_meta_key, $new_cache );
 		}
 
-		// Update cache
-		update_post_meta( $post_id, $cache_meta_key, $new_cache );
-
 		return $related_posts;
 	}