Fix double prepended forward slash in certain cases (#7091)

* test: add test with no base

* fix: don't always prepend a forward slash

* chore: changeset

* `'/' + base`   ------> `prependForwardSlash(base)`

.changeset/swift-moons-drop.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fix double prepended forward slash in SSR

packages/astro/src/core/app/index.ts

@@ -14,7 +14,7 @@ import { call as callEndpoint, createAPIContext } from '../endpoint/index.js';
 import { consoleLogDestination } from '../logger/console.js';
 import { error, type LogOptions } from '../logger/core.js';
 import { callMiddleware } from '../middleware/callMiddleware.js';
-import { removeTrailingForwardSlash } from '../path.js';
+import { prependForwardSlash, removeTrailingForwardSlash } from '../path.js';
 import {
 	createEnvironment,
 	createRenderContext,
@@ -101,7 +101,7 @@ export class App {
 		if (this.#manifest.assets.has(url.pathname)) {
 			return undefined;
 		}
-		let pathname = '/' + this.removeBase(url.pathname);
+		let pathname = prependForwardSlash(this.removeBase(url.pathname));
 		let routeData = matchRoute(pathname, this.#manifestData);
 
 		if (routeData) {
@@ -178,7 +178,7 @@ export class App {
 		status = 200
 	): Promise<Response> {
 		const url = new URL(request.url);
-		const pathname = '/' + this.removeBase(url.pathname);
+		const pathname = prependForwardSlash(this.removeBase(url.pathname));
 		const info = this.#routeDataToRouteInfo.get(routeData!)!;
 		// may be used in the future for handling rel=modulepreload, rel=icon, rel=manifest etc.
 		const links = new Set<never>();

packages/integrations/node/test/prerender.test.js

@@ -9,6 +9,12 @@ describe('Prerendering', () => {
 	let fixture;
 	let server;
 
+	async function load() {
+		const mod = await import('./fixtures/prerender/dist/server/entry.mjs');
+		return mod;
+	}
+
+	describe('With base', () => {
 		before(async () => {
 			process.env.ASTRO_NODE_AUTOSTART = 'disabled';
 			fixture = await loadFixture({
@@ -27,11 +33,6 @@ describe('Prerendering', () => {
 			await server.stop();
 		});
 
-	async function load() {
-		const mod = await import('./fixtures/prerender/dist/server/entry.mjs');
-		return mod;
-	}
-
 		it('Can render SSR route', async () => {
 			const res = await fetch(`http://${server.host}:${server.port}/some-base/one`);
 			const html = await res.text();
@@ -66,4 +67,50 @@ describe('Prerendering', () => {
 			expect(res.status).to.equal(301);
 			expect(res.headers.get('location')).to.equal('/some-base/two/');
 		});
+	});
+	describe('Without base', () => {
+		before(async () => {
+			process.env.ASTRO_NODE_AUTOSTART = 'disabled';
+			fixture = await loadFixture({
+				root: './fixtures/prerender/',
+				output: 'server',
+				adapter: nodejs({ mode: 'standalone' }),
+			});
+			await fixture.build();
+			const { startServer } = await await load();
+			let res = startServer();
+			server = res.server;
+		});
+
+		after(async () => {
+			await server.stop();
+		});
+
+		it('Can render SSR route', async () => {
+			const res = await fetch(`http://${server.host}:${server.port}/one`);
+			const html = await res.text();
+			const $ = cheerio.load(html);
+
+			expect(res.status).to.equal(200);
+			expect($('h1').text()).to.equal('One');
+		});
+
+		it('Can render prerendered route', async () => {
+			const res = await fetch(`http://${server.host}:${server.port}/two`);
+			const html = await res.text();
+			const $ = cheerio.load(html);
+
+			expect(res.status).to.equal(200);
+			expect($('h1').text()).to.equal('Two');
+		});
+
+		it('Can render prerendered route with query params', async () => {
+			const res = await fetch(`http://${server.host}:${server.port}/two/?foo=bar`);
+			const html = await res.text();
+			const $ = cheerio.load(html);
+
+			expect(res.status).to.equal(200);
+			expect($('h1').text()).to.equal('Two');
+		});
+	});
 });