✨ Added CDN base URL support for theme and public assets

no-issue                                                                                                                                                       
                                                                                                                                                                 
Static theme assets (/assets/*) and public assets (/public/*) were                                                                                             
always served from the origin, even when other content types like                                                                                              
images, media, and files already supported CDN base URLs. This meant                                                                                           
sites couldn't offload their heaviest cacheable resources to a                                                                                                 
cookie-free CDN domain, hurting page load performance and increasing                                                                                           
request overhead from unnecessary session cookies.                                                                                                             
                                                                                                                                                                 
Adding `urls:assets` completes the CDN story - sites can now serve all                                                                                           
static resources from a dedicated domain, matching the existing                                                                                                
pattern for `urls:image`, `urls:media`, and `urls:files`.

Author: muratcorlu

ghost/core/core/frontend/meta/asset-url.js

@@ -126,8 +126,12 @@ function getAssetUrl(assetPath, hasMinFile) {
     const isThemeAsset = !isPublicAsset && !assetPath.match(/^asset/);
 
     // CASE: Build the output URL
-    // Add subdirectory...
-    let output = urlUtils.urlJoin(urlUtils.getSubdir(), '/');
+    // If assetCdnUrl is configured, use it as the base (produces an absolute URL).
+    // Otherwise fall back to the subdirectory-relative path.
+    const cdnUrl = config.get('urls:assets');
+    let output = cdnUrl
+        ? cdnUrl.replace(/\/$/, '') + '/'
+        : urlUtils.urlJoin(urlUtils.getSubdir(), '/');
 
     // Optionally add /assets/
     if (isThemeAsset) {

ghost/core/test/unit/frontend/meta/asset-url.test.js

@@ -180,6 +180,61 @@ describe('getAssetUrl', function () {
         });
     });
 
+    describe('with asset CDN url configured', function () {
+        beforeEach(function () {
+            configUtils.set({assetHash: 'abc'});
+            configUtils.set({'urls:assets': 'https://assets.example.com/my-site'});
+        });
+
+        it('should return absolute CDN url for theme assets', function () {
+            const testUrl = getAssetUrl('css/screen.css');
+            assert.equal(testUrl, 'https://assets.example.com/my-site/assets/css/screen.css?v=abc');
+        });
+
+        it('should return absolute CDN url for public assets', function () {
+            const testUrl = getAssetUrl('public/cards.min.js');
+            assert.equal(testUrl, 'https://assets.example.com/my-site/public/cards.min.js?v=abc');
+        });
+
+        it('should handle trailing slash in assetCdnUrl', function () {
+            configUtils.set({'urls:assets': 'https://assets.example.com/my-site/'});
+            const testUrl = getAssetUrl('css/screen.css');
+            assert.equal(testUrl, 'https://assets.example.com/my-site/assets/css/screen.css?v=abc');
+        });
+
+        it('should not apply CDN url to favicon', function () {
+            const testUrl = getAssetUrl('favicon.ico');
+            assert.equal(testUrl, '/favicon.ico');
+        });
+
+        it('should still append hash to CDN url', function () {
+            configUtils.set({assetHash: 'xyz123'});
+            const testUrl = getAssetUrl('js/app.js');
+            assert.equal(testUrl, 'https://assets.example.com/my-site/assets/js/app.js?v=xyz123');
+        });
+
+        it('should still handle # anchor in CDN url', function () {
+            const testUrl = getAssetUrl('img/icons.svg#arrow-up');
+            assert.equal(testUrl, 'https://assets.example.com/my-site/assets/img/icons.svg?v=abc#arrow-up');
+        });
+
+        describe('with /blog subdirectory', function () {
+            beforeEach(function () {
+                configUtils.set({url: 'http://localhost:65535/blog'});
+            });
+
+            it('should use CDN url as-is and drop the subdirectory', function () {
+                const testUrl = getAssetUrl('css/screen.css');
+                assert.equal(testUrl, 'https://assets.example.com/my-site/assets/css/screen.css?v=abc');
+            });
+
+            it('should use CDN url as-is for public assets and drop the subdirectory', function () {
+                const testUrl = getAssetUrl('public/cards.min.js');
+                assert.equal(testUrl, 'https://assets.example.com/my-site/public/cards.min.js?v=abc');
+            });
+        });
+    });
+
     describe('file-based hash', function () {
         const fixturesPath = path.join(__dirname, '../../../utils/fixtures/themes/casper');