From 7da4f03a5becd455bdc44c86bc2e03a6ccb12018 Mon Sep 17 00:00:00 2001
From: Sam James <sam@samdjames.uk>
Date: Wed, 15 Jul 2026 22:44:29 +0100
Subject: [PATCH] perf: skip pagebuilder preload regex scan for blocks with no
 preload image

view_block_abstract_to_html_after fires for every block on every page
(no block-type filter), so the 4-part chained-lazy-quantifier regex
here was running against the full HTML of every block on every
request, even though only a handful of PageBuilder image elements can
ever match. Add a cheap str_contains() guard for the literal
preload="Yes" marker before running the regex, ruling out the vast
majority of blocks with effectively no cost.
---
 Observer/View/BlockToHtmlAfter.php | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Observer/View/BlockToHtmlAfter.php b/Observer/View/BlockToHtmlAfter.php
index e8c7403..2bd8d8b 100644
--- a/Observer/View/BlockToHtmlAfter.php
+++ b/Observer/View/BlockToHtmlAfter.php
@@ -25,12 +25,17 @@ public function execute(Observer $observer)
 
         /** @var DataObject */
         $transport = $observer->getEvent()->getTransport();
+        $html = $transport->getHtml();
+
+        if (!str_contains($html, 'preload="Yes"')) {
+            return;
+        }
 
         $matches = [];
         // @TODO: Only preload images with the `preload` attribute set
         preg_match_all(
             '/<img.*?src="(.*?)".*?preload="Yes".*?data-element="(.*?)".*?>/',
-            $transport->getHtml(),
+            $html,
             $matches
         );