From 771b0a9a04ca4b4bcdd098b2062a5903cc988112 Mon Sep 17 00:00:00 2001
From: "Houston (Bot)" <108291165+astrobot-houston@users.noreply.github.com>
Date: Tue, 18 Aug 2026 14:15:53 -0700
Subject: [PATCH] fix(container): wire astroConfig.site through to the SSR
 manifest so Astro.site is available in container rendering (#17682) (#17703)

Co-authored-by: Matthew Phillips <matthew@matthewphillips.info>
---
 .changeset/social-paws-throw.md               |  5 +++
 packages/astro/src/container/index.ts         | 15 ++++----
 .../astro/test/units/render/container.test.ts | 34 +++++++++++++++++++
 3 files changed, 47 insertions(+), 7 deletions(-)
 create mode 100644 .changeset/social-paws-throw.md

diff --git a/.changeset/social-paws-throw.md b/.changeset/social-paws-throw.md
new file mode 100644
index 000000000000..a3ef0b5cc5d8
--- /dev/null
+++ b/.changeset/social-paws-throw.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes `Astro.site` always being `undefined` when rendering components via the Container API, even when `site` is set in `astroConfig`
diff --git a/packages/astro/src/container/index.ts b/packages/astro/src/container/index.ts
index 74d90a1ead15..f554bc8c50dd 100644
--- a/packages/astro/src/container/index.ts
+++ b/packages/astro/src/container/index.ts
@@ -134,6 +134,7 @@ function createManifest(
 	manifest?: AstroContainerManifest,
 	renderers?: SSRLoadedRenderer[],
 	middleware?: MiddlewareHandler,
+	site?: string,
 ): SSRManifest {
 	function middlewareInstance(): AstroMiddlewareInstance {
 		return {
@@ -174,6 +175,7 @@ function createManifest(
 		componentMetadata: manifest?.componentMetadata ?? new Map(),
 		inlinedScripts: manifest?.inlinedScripts ?? new Map(),
 		i18n: manifest?.i18n,
+		site: site ?? manifest?.site,
 		checkOrigin: false,
 		allowedDomains: manifest?.allowedDomains ?? [],
 		actionBodySizeLimit: 1024 * 1024,
@@ -281,6 +283,7 @@ type AstroContainerManifest = Pick<
 	| 'middlewareMode'
 	| 'assetsDir'
 	| 'image'
+	| 'site'
 >;
 
 type AstroContainerConstructor = {
@@ -288,6 +291,7 @@ type AstroContainerConstructor = {
 	renderers?: SSRLoadedRenderer[];
 	manifest?: AstroContainerManifest;
 	resolve?: SSRResult['resolve'];
+	site?: string;
 };
 
 export class experimental_AstroContainer {
@@ -315,8 +319,9 @@ export class experimental_AstroContainer {
 		manifest,
 		renderers,
 		resolve,
+		site,
 	}: AstroContainerConstructor) {
-		const ssrManifest = createManifest(manifest, renderers);
+		const ssrManifest = createManifest(manifest, renderers, undefined, site);
 		const containerRenderers = renderers ?? manifest?.renderers ?? [];
 		const containerResolve = async (specifier: string): Promise<string> => {
 			if (this.#withManifest) {
@@ -327,7 +332,6 @@ export class experimental_AstroContainer {
 			return specifier;
 		};
 		const interner = new WeakMap<RouteData, SinglePageBuiltModule>();
-		// Composition order: logger → environment → warm the route table.
 		setLogger(ssrManifest, createConsoleLogger({ level: 'error' }));
 		setEnvironment(
 			ssrManifest,
@@ -338,10 +342,6 @@ export class experimental_AstroContainer {
 				streaming,
 			}),
 		);
-		// Warm the derived route table. Deliberately left un-refreshed when
-		// routes are inserted later — route matching is irrelevant here
-		// because `renderToResponse` always assigns `state.routeData`
-		// explicitly.
 		getRouteTable(ssrManifest);
 		this.#manifest = ssrManifest;
 		this.#interner = interner;
@@ -363,12 +363,13 @@ export class experimental_AstroContainer {
 	public static async create(
 		containerOptions: AstroContainerOptions = {},
 	): Promise<experimental_AstroContainer> {
-		const { streaming = false, manifest, renderers = [], resolve } = containerOptions;
+		const { streaming = false, manifest, renderers = [], resolve, astroConfig } = containerOptions;
 		return new experimental_AstroContainer({
 			streaming,
 			manifest,
 			renderers,
 			resolve,
+			site: astroConfig?.site ?? manifest?.site,
 		});
 	}
 
diff --git a/packages/astro/test/units/render/container.test.ts b/packages/astro/test/units/render/container.test.ts
index e95a9460b0bf..1ef41f3f3594 100644
--- a/packages/astro/test/units/render/container.test.ts
+++ b/packages/astro/test/units/render/container.test.ts
@@ -276,4 +276,38 @@ describe('Container', () => {
 
 		assert.match(result, /Is open/);
 	});
+
+	it('Astro.site reflects astroConfig.site', async () => {
+		const $Astro = createAstro('https://example.com');
+		const SitePage = createComponent((result, props, slots) => {
+			const Astro = result.createAstro($Astro, props, slots);
+			const site = Astro.site;
+			return render`${maybeRenderHead()}<div>${site ? site.toString() : 'SITE_UNDEFINED'}</div>`;
+		});
+
+		const container = await experimental_AstroContainer.create({
+			astroConfig: {
+				site: 'https://example.com',
+			},
+		});
+
+		const response = await container.renderToString(SitePage);
+
+		assert.match(response, /https:\/\/example\.com/);
+		assert.doesNotMatch(response, /SITE_UNDEFINED/);
+	});
+
+	it('Astro.site is undefined when astroConfig.site is not set', async () => {
+		const $Astro = createAstro(undefined);
+		const SitePage = createComponent((result, props, slots) => {
+			const Astro = result.createAstro($Astro, props, slots);
+			const site = Astro.site;
+			return render`${maybeRenderHead()}<div>${site ? site.toString() : 'SITE_UNDEFINED'}</div>`;
+		});
+
+		const container = await experimental_AstroContainer.create();
+		const response = await container.renderToString(SitePage);
+
+		assert.match(response, /SITE_UNDEFINED/);
+	});
 });