From 907cd5f5f5f39e168f1a64845a1e337798b30cb2 Mon Sep 17 00:00:00 2001
From: Tim Kelty <tim@craftcms.com>
Date: Thu, 19 Dec 2024 10:24:20 -0500
Subject: [PATCH 1/2] Use CDN-Cache-Control

---
 src/HeaderEnum.php  |  2 ++
 src/StaticCache.php | 21 ++++++++++++++++++---
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/src/HeaderEnum.php b/src/HeaderEnum.php
index e67e18a..6aef573 100644
--- a/src/HeaderEnum.php
+++ b/src/HeaderEnum.php
@@ -8,6 +8,8 @@ enum HeaderEnum: string
     case CACHE_PURGE_TAG = 'Cache-Purge-Tag';
     case CACHE_PURGE_PREFIX = 'Cache-Purge-Prefix';
     case CACHE_CONTROL = 'Cache-Control';
+    case CDN_CACHE_CONTROL = 'CDN-Cache-Control';
+    case SURROGATE_CONTROL = 'Surrogate-Control';
     case AUTHORIZATION = 'Authorization';
     case DEV_MODE = 'Dev-Mode';
     case REQUEST_TYPE = 'Request-Type';
diff --git a/src/StaticCache.php b/src/StaticCache.php
index 5bff051..63db603 100644
--- a/src/StaticCache.php
+++ b/src/StaticCache.php
@@ -219,12 +219,27 @@ private function addCacheHeadersToWebResponse(): void
             'duration' => $this->cacheDuration,
         ]));
 
-        // Cache in proxy, not in browser
+        // Copy the cache-control header to the cdn-cache-control header
+        $cacheControl = Craft::$app->getResponse()->getHeaders()->get(
+            HeaderEnum::CACHE_CONTROL->value
+        );
+
+        // Enable ESI processing
+        // Note: The Surrogate-Control header will cause Cloudflare to ignore
+        // the Cache-Control header: https://developers.cloudflare.com/cache/concepts/cdn-cache-control/#header-precedence
         Craft::$app->getResponse()->getHeaders()->setDefault(
-            HeaderEnum::CACHE_CONTROL->value,
-            "public, s-maxage=$this->cacheDuration, max-age=0",
+            HeaderEnum::SURROGATE_CONTROL->value,
+            'content="ESI/1.0"',
         );
 
+        // Cache in CDN, not in browser
+        Craft::$app->getResponse()->getHeaders()->setDefault(
+            HeaderEnum::CDN_CACHE_CONTROL->value,
+            $cacheControl,
+        );
+
+
+
         // Capture, remove any existing headers so we can prepare them
         $existingTagsFromHeader = Collection::make($headers->get(HeaderEnum::CACHE_TAG->value, first: false) ?? []);
         $headers->remove(HeaderEnum::CACHE_TAG->value);

From 6b1b8627648c7e976c473807e668177f184b42ec Mon Sep 17 00:00:00 2001
From: Tim Kelty <tim@craftcms.com>
Date: Thu, 19 Dec 2024 14:23:06 -0500
Subject: [PATCH 2/2] Wrap conditional

---
 src/StaticCache.php | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/StaticCache.php b/src/StaticCache.php
index 63db603..ddcde8f 100644
--- a/src/StaticCache.php
+++ b/src/StaticCache.php
@@ -224,6 +224,14 @@ private function addCacheHeadersToWebResponse(): void
             HeaderEnum::CACHE_CONTROL->value
         );
 
+        // Cache in CDN, not in browser
+        if ($cacheControl) {
+            Craft::$app->getResponse()->getHeaders()->setDefault(
+                HeaderEnum::CDN_CACHE_CONTROL->value,
+                $cacheControl,
+            );
+        }
+
         // Enable ESI processing
         // Note: The Surrogate-Control header will cause Cloudflare to ignore
         // the Cache-Control header: https://developers.cloudflare.com/cache/concepts/cdn-cache-control/#header-precedence
@@ -232,14 +240,6 @@ private function addCacheHeadersToWebResponse(): void
             'content="ESI/1.0"',
         );
 
-        // Cache in CDN, not in browser
-        Craft::$app->getResponse()->getHeaders()->setDefault(
-            HeaderEnum::CDN_CACHE_CONTROL->value,
-            $cacheControl,
-        );
-
-
-
         // Capture, remove any existing headers so we can prepare them
         $existingTagsFromHeader = Collection::make($headers->get(HeaderEnum::CACHE_TAG->value, first: false) ?? []);
         $headers->remove(HeaderEnum::CACHE_TAG->value);