feat(node)!: remove experimentalErrorPageHost (#15654)

Co-authored-by: Sarah Rainsberger <5098874+sarah11918@users.noreply.github.com>

Author: florian-lefebvre

.changeset/thirty-experts-tickle.md

@@ -0,0 +1,41 @@
+---
+'@astrojs/node': major
+---
+
+Removes the `experimentalErrorPageHost` option
+
+This option allowed fetching a prerendered error page from a different host than the server is currently running on.
+
+However, there can be security implications with prefetching from other hosts, and often more customization was required to do this safely. This has now been removed as a built-in option so that you can implement your own secure solution as needed and appropriate for your project via middleware.
+
+#### What should I do?
+
+If you were previously using this feature, you must remove the option from your adapter configuration as it no longer exists:
+
+```diff
+// astro.config.mjs
+import { defineConfig } from 'astro/config'
+import node from '@astrojs/node'
+
+export default defineConfig({
+  adapter: node({
+    mode: 'standalone',
+-    experimentalErrorPageHost: 'http://localhost:4321'
+  })
+})
+```
+
+You can replicate the previous behavior by checking the response status in a middleware and fetching the prerendered page yourself:
+
+```ts
+// src/middleware.ts
+import { defineMiddleware } from 'astro:middleware'
+
+export const onRequest = defineMiddleware(async (ctx, next) => {
+	const response = await next()
+	if (response.status === 404 || response.status === 500) {
+		return fetch(`http://localhost:4321/${response.status}.html`);
+	}
+	return response
+})
+```

packages/integrations/node/src/index.ts

@@ -29,22 +29,10 @@ export function getAdapter({ staticHeaders }: Pick<Options, 'staticHeaders'>): A
 	};
 }
 
-const protocols = ['http:', 'https:'];
-
 export default function createIntegration(userOptions: UserOptions): AstroIntegration {
 	if (!userOptions?.mode) {
 		throw new AstroError(`Setting the 'mode' option is required.`);
 	}
-	const { experimentalErrorPageHost } = userOptions;
-	if (
-		experimentalErrorPageHost &&
-		(!URL.canParse(experimentalErrorPageHost) ||
-			!protocols.includes(new URL(experimentalErrorPageHost).protocol))
-	) {
-		throw new AstroError(
-			`Invalid experimentalErrorPageHost: ${experimentalErrorPageHost}. It should be a valid URL.`,
-		);
-	}
 
 	let _config: AstroConfig | undefined = undefined;
 	let _routeToHeaders: RouteToHeaders | undefined = undefined;
@@ -90,7 +78,6 @@ export default function createIntegration(userOptions: UserOptions): AstroIntegr
 								host: _config.server.host,
 								port: _config.server.port,
 								staticHeaders: userOptions.staticHeaders ?? false,
-								experimentalErrorPageHost,
 							}),
 						],
 					},

packages/integrations/node/src/serve-app.ts

@@ -62,22 +62,15 @@ export function createAppHandler(app: BaseApp, options: Options): RequestHandler
 	// Read prerendered error pages directly from disk instead of fetching over HTTP.
 	// This avoids SSRF risks and is more efficient.
 	const prerenderedErrorPageFetch = async (url: string): Promise<Response> => {
-		if (url.includes('/404')) {
+		const { pathname } = new URL(url);
+		if (pathname.endsWith('/404.html') || pathname.endsWith('/404/index.html')) {
 			const response = await readErrorPageFromDisk(client, 404);
 			if (response) return response;
 		}
-		if (url.includes('/500')) {
+		if (pathname.endsWith('/500.html') || pathname.endsWith('/500/index.html')) {
 			const response = await readErrorPageFromDisk(client, 500);
 			if (response) return response;
 		}
-		// Fallback: if experimentalErrorPageHost is configured, fetch from there
-		if (options.experimentalErrorPageHost) {
-			const originUrl = new URL(options.experimentalErrorPageHost);
-			const errorPageUrl = new URL(url);
-			errorPageUrl.protocol = originUrl.protocol;
-			errorPageUrl.host = originUrl.host;
-			return fetch(errorPageUrl);
-		}
 		// No file found and no fallback configured - return empty response
 		return new Response(null, { status: 404 });
 	};

packages/integrations/node/src/types.ts

@@ -20,15 +20,6 @@ export interface UserOptions {
 	 * - The CSP header of the static pages is added when CSP support is enabled.
 	 */
 	staticHeaders?: boolean;
-
-	/**
-	 * The host that should be used if the server needs to fetch the prerendered error page.
-	 * If not provided, this will default to the host of the server. This should be set if the server
-	 * should fetch prerendered error pages from a different host than the public URL of the server.
-	 * This is useful for example if the server is behind a reverse proxy or a load balancer, or if
-	 * static files are hosted on a different domain. Do not include a path in the URL: it will be ignored.
-	 */
-	experimentalErrorPageHost?: string | URL;
 }
 
 export interface Options extends UserOptions {

packages/integrations/node/test/error-page-host.test.js

@@ -1,5 +1,5 @@
 {
-  "name": "@test/nodejs-prerender-error-page",
+  "name": "@test/nodejs-prerendered-error-page-fetch",
   "version": "0.0.0",
   "private": true,
   "dependencies": {

packages/integrations/node/test/fixtures/prerender-error-page/src/pages/404.astro

@@ -0,0 +1 @@
+<html><body><h1>Custom 404 Page</h1></body></html>